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Conmed 7550 ESU - Frank`s Hospital Workshop

1. 7 3 Display Panel 7 3 Activation 6StIng 7 5 Output Power 7 5 Argon teste 7 6 Remote Power Control Testing 7 6 Return Monitor A R M Aspen Return Monitor 7 7 Pulsed Qut Mode cea ei e Eee i ce t en dent 7 8 RF Leakage Wr 7 8 AL IDA 7 8 Mobile Storage Pedestal e 7 8 8 1 sem e ALLE IL iue 8 1 Eg ipment List sassaresi 8 1 Standard Equipment LISE 8 1 Optional Calibration Equipment Listes rr at he t reg d egre 8 1 Test Leads Gc Adaptors i cett tette rete e Fe eee 8 1 pas dtu 8 1 A R M Calibration HS A R M Assembly AIT 8 1 IO Ohm Calibration vere 8 1 150 Ohm ARM RA 8 2 High Voltage Calibration HV Flow Control Assembly 8 2 RAMP Calibration iere o B
2. eb cn EV 1 Troubleshooting Guide esee iie tt qtue Pet eser B 1 IntrodUctlOBs Ete ten ritiene B 1 Control Microcontroller Failure Codes and Troubleshooting Tips B 2 Monitoring Microcontroller Failure Codes and Troubleshooting Tips 3 Additional Troubleshooting Tips Non Error Code Related B 5 Error and CMG Val 7 Error Display Configuration 7 Example 07 8 Schematics amp 1 Bill of Material Chassis Cart 1 of Material HV Flow Control PCB Assembly oiii ters fto 2 Bill of Material Power Control PCB Assembly rettet C 4 Material Display DUB Asser 5 ot Material LV Power Supply PCB 10 of Material HV Output PCB cote rerit ien 11 of Material FB Amplifier PCB 12 Bill of Material SE Amplifier PCB Assembly eerte 13 Material RF Output PCB 14 of Materials ARM Handsense PCB Assembly 15 SYSTEM 7550 Figure T
3. o1 gt ow SVO ASSY 1084405 u3MOd HNI 34 0011 0001 Ld 0d Vd 6 1001 1100 Vd 2 00 sna viva DEMENS weed DIC MMC 03 ANAL S UMOYS AE 594271 21307 B 9 SYSTEM 7550 io UOHrAHOy 20 snas 0815 1 1 A6 1 9 AS SVOA L ova 1 1 v A6 NODA E ASSY 1 1 1 1 1 1 17009 SNE viva ULNOD MOTIAH x LAH LAT PU QD Od sin rody sna viva 1051409 480 0001 0000 L1 4 00 001 D LAOA 159 777 103 JANNI 52 UMOUS 80977 21807 B 10
4. 7 7 8 Activation Testing Caution Handcontrol accessory electrodes can cause RF burns if touched during activation even if the handcontrol accessory is not the one that is activated Place unused accessories into a suitable insulated cup or holster Set the power for all modes to 10W or less Load is not required for the following testing 1 Handcontrol 1 Monopolar handcontrol Activate Cut yellow button on handcontrol Verify an audible tone occurs and the yellow indicator in the cut section illuminates Activate Coag blue button on handcontrol Verify an audible tone occurs and the blue indicator in the coag section illuminates 2 Handcontrol 2 Beam Monopolar Handcontrol Activate Cut yellow button on handcontrol Verify an audible tone occurs and the yellow indicator in the cut section illuminates Activate Coag blue button on handcontrol Verify an audible tone occurs and the blue indicator in the coag section illuminates Activate ABC light blue button on handcontrol Verify an audible tone occurs and the blue indicator in the ABC section illuminates 3 Bipolar Handcontrol Bipolar handcontrol activation can be veri fied using forceps with handswitching capabilities or using a test lead between the right when facing the system Bipolar RF jack and the hand sensing jack located above and between the two bipo lar RF jacks Verify a tone occurs and the blue indicator in the
5. PWMEA failed to activate A4 failed ing POST HV out of range HVDC too high during POST HVDC control circuit HVDC monitor circuit HVMON 1 Triac Failure A7 332 not inhibited by HVINH failed to inhibit HVDC dur HVINH failed 1 A5 monitor ing POST Fuse on HV Power Supply open missing Additional Troubleshooting Tips Non Error Code Related Suggested Solutions No Activation or Tone Activation agreement error between Swap U16 amp U33 A5 An Err 307 or Controller and Monitor 303 occurs if U33 is bad Handsense Circuit failed Troubleshoot Request inputs on A5 Handcontrol Requests active low Footcontrol Requests active high A5 RF Jack worn out Test all handcontrols amp footcontrols to isolate down to a component or mode Half Power in Cut Blend phase of the Full Bridge Amp failed Troubleshoot for an open FET Pinpoint Bipolar Open power FET or no RF Drive to Test for RF Drive at the gate 12 ohm power FET resistor of each FET No power in Spray or ABC Open power FET or no RF Drive on Troubleshoot for an open FET SE Amp Test for RF Drive at the gate 12 ohm resistor of each FET SYSTEM 7550 Suggested Solutions Breaker trips when the system is Shorted power FET on amp Identify the amp with the problem FB activated CUT PINPOINT or SE SPRAY ABC Use a DVM to measure continuity of each FET Keyboard switches not work Front Panel Overlay
6. 8 8 3 Max Voltage Loading Verify that Position 1 of Switch 1 S1 on the back side of the display panel is ON up Remove the Patient Return Adaptor from the Patient Return Connector Press the Monitor Set Front Panel Switch Verify the second number in the Cut window is between 171 and 222 This is a stored value SYSTEM 7550 NON CONDUCTIVE TABLE P VY EARTH GROUND 1 METER Loo ence 25 METER 0 a RF AMMETER 2 PLACES A 5 200 OHMS Figure 3 2 Method RF Leakage Test Setup 8 9 RF Leakage Measurement Optional Due to the complex nature of the RF leakage environment in a typical operating suite the International Electrotechnical Commission IEC has adopted a repeatable test method to evaluate high frequency leakage currents alternate path leakage currents in electrosurgical generators in an unambiguous fashion The IEC test method positions the Active and Return Electrode cables a fixed distance from conductive surfaces By this method the cable capacitance is fixed or con stant and the resulting measurement is indicative of the unit under test s ability to minimize RF leakage RE leakage occurs because a conductive path provided by stray parasitic capacitance distrib uted along the length of the Active and Return Electrode cables to earth ground and other con ductive mediums return surgical current to the unit by means of an alt
7. H2CG M H2CT M HABC DR HBIP C M HCIR HC2R HV HV TRIGGER HV_MON HVMON HVR HVSN HVT_EN IMEA ISN KB DA LKCON LPS LPSW IV TRIGGER LVT EN OV TST PC EN PCON PERR PPR PSRQT PW MEA RCO RC3 RD RF INH RFEN RST or RST 50 53 5 SE DRV SE RST SP SPKR SPR VARM 2VARM VCON VGAS VPOT VSN WR XFMR A 2 Gas Enable opens the solenoid valve Handcontrol 1 Coag Activation Request Handcontrol 1 Coag Switch jack Handcontrol 1 Coag Activation Request Handcontrol 1 Cut Switch jack Handcontrol 1 RF active output jack Handcontrol 2 Coag Activation Request Handcontrol 2 Cut Activation Request Handcontrol ABC Drive 1K Hz square wave Handcontrol Bipolar Activation Request Handcontrol 1 Relay RF Active Output Handcontrol 2 Relay RF Active Output High Voltage HVDC negative terminal High Voltage Trigger Triac Drive High Voltage Monitor ratio of HVDC High Voltage Monitor ratio of HVDC for monitoring circuit High Voltage Reset when Set dumps charge from HVDC High Voltage Sense ratio of HVDC for control amp monitor circuit High Voltage Enable Set for Pinpoint Spray amp Current Limit reference current value for voltage limit Current Measured ratio of current delivered to patient Current Sense Current applied to patient x 7 Keyboard Data Available Set when a front panel sw
8. 1010 Hand Control 1 Coag and Foot Coag Example Error This example is for an error 301 The MONOPOLAR CUT BLEND POWER DISPLAY will toggle between Err and 301 The MONOPOLAR COAG POWER DISPLAY may toggle between 44 and 128 The Mode LED status 44 is displayed at the same time as Err To interpret the 44 convert from decimal to binary 00101100 From the Mode LED status list we can see that Single Pad Manual and Pin Point LED S were on at the time of the Err Convert 132 decimal to binary 10000100 From the Active status list we can see that the LOW GAS SUPPLY LED was on and ABC was activated at the time of the Err The table below is an illustration of this example SYSTEM 7550 CONTROL TRANSLATION PANEL MODE LED STATUS ACTIVE STATUS ENDO SPRAY PIN POINT AUTOMATIC MANUAL SINGLE PAD DUAL PAD REMOTE GO TO LIST ACTIVATION REQUEST LOW GAS SUPPLY LED RETURN FAULT LED LOW FAULT ALARM LED D7 D4 REMOTE POWER CONTROL MODE MONOPOLAR COAG POWER DISPLAY 2 22 aa 5 Z en PE Q aa lt 5 O Z 2 SYSTEM 7550 jsonbow ND o guoopueH 511035 29916 1 As 4 A6 4 465 AU
9. 2W 8 3 SYSTEM 7550 8 7 5 Bipolar Calibration Power Control Assembly A4 Connect 100 125 ohm load ESU analyzer between the two 2 Bipolar RF Output Jacks Set Bipolar for 50W Activate Bipolar and adjust BIP CAL for 50W 2W 8 7 6 ABC Calibration Power Control Assembly A4 Connect a 500 ohm load ESU analyzer between Patient Return and the ABC Output Connector It is necessary to use an ABC adaptor for ABC calibration Set the ABC Power for 15W Activate ABC and adjust RA2 for 15W 2W Set the ABC Power for 150W Activate ABC and adjust for 150W 2W 1 amp RA2 are interactive so adjusting one requires a check adjustment of the other until both output powers are correct 8 7 7 Over Voltage Calibration Power Control Assembly A4 Optional CAUTION High Voltage Potential on the RF Output can cause serious burns RF Leakage exceeds safe limits of 150mA during this cali bration do not hold the ABC adaptor while performing this procedure Connect 1000 1 oscilloscope probe differen tially to the ABC and Patient Return outputs To set the scope for differential measurement Press ADD invert channel 2 set amplitudes of both channels for maximum amplitude initially Connect a jumper to the bottom side of R67 of the Power Control Assembly and the other end of the jumper to ground TP3 GND Set ABC Power for 15W 20W initially A
10. ABC transformer The ABC transformer is mounted to the chassis and can be identified by the yellow color Relays K2 amp K4 are normally open and close anytime Spray mode is activated These relays switch the Spray mode to the RF Output Jacks On the outputs of K1 K4 is a transformer T4 called a Balun It has an additional winding called Balun sensing A balun transformer helps mini mize RF leakage during open circuit conditions During balanced conditions all the RF current leaving the RF amplifier exits and returns through the balun transformer Under this ideal condi tion the magnetic fields within the balun created by the RF currents are equal and opposite When the fields are equal and opposite the net magnetic field 1s zero resulting in zero impedance presented to the RF output current If alternate current paths exist some of the cur rent exiting through the balun is returned to the amplifier via an alternate path In this condition the fields of the balun are not equal presenting some degree of inductive impedance to the output current limiting available alternate path leakage current The impedance caused by the unbalanced current develops a magnetic field that is now greater than zero within the balun transformer allowing for a single turn winding that will sense the leakage The magnetic field caused by RF leakage currents can develop a voltage that is proportional to the amount of leakage currents
11. Pneumatic ii corii EE 6 13 M ss Flow Rate Relation next 6 14 Smart RE seas 6 15 Full Bridge Amplifier 6 15 SYSTEM 7550 Section 6 8 6 9 6 10 6 11 6 11 1 6 11 2 6 11 3 6 11 4 6 11 5 7 7 7 Title Page Sumele Ended Amplifier A9 6 16 RF Output Assembly Components 10 6 17 Low Voltage Power Supply 6 18 HS A R M Assembly ALL 6 18 TEandsense CABLE 6 18 Aspen CA 6 19 RE Leakage 6 20 Transformer Select eet 6 20 Arc Sense 6 20 Mamtenatice 4 7 1 EI 7 1 Cleaning 7 1 Generat r Mobile Storage Assam Oly 7 1 Access to Circuits Factory Settings 7 2 Det lt Settings Factory Settings 7 2 AC Mains Frequency amp Voltage 7 2 Jnitial Setup amp 7 3 COMMECHIONS
12. amp Bipolar Modes e Argon Flow Rate VGAs Each of these signals should be zero volts in the idle mode and increase as the power or flow increases The voltages listed below are the maxi mum limits at full power settings 757 7550 9V when HVDC is 200V 0V 9V 8 8V at full dial cut OV 8 8V 3 8V at full dial cut OV 3 8V VGAS 6 2V at 10 SLPM 15v to 6 2V 6 2 14 Keyboard Scanner U5 The 74C922 allows a 4X4 matrix keyboard to be connected When a Front Panel switch is pressed the location of the switch is latched into the device and the signal KB_DA keyboard data available is SET Only one switch press is stored and gets cleared after the device is read 6 2 15 5V Monitoring U29 U29 is a microcontroller supervisory device that automatically sets the RST when the 5V sup ply is less than 4 5V A short interruption of the mains power will cause a system reset to occur On the input of U29 pin 1 is a comparator U35 that will cause a reset to occur if the 5V exceeds 5 7V The pin RST is active high and RST is active low 6 2 16 Output PIA U21 Dedicated output PIA for the control microcontroller to latch control logic to system functions This device has three 3 output ports and each will be described briefly PORT A CON CON D7 Dedicated for mode identification to the Power Control Assembly When a mode activation occurs the cont
13. assembly generates the control signals required to regulate the high voltage output and performs other high voltage related tasks This section will be specific to the high voltage assembly and the control circuit for the high voltage will follow 6 4 1 Power Supply Topology The HVPS is a phase controlled type power sup ply With this topology output voltage is con trolled by varying the phase angle at which the AC mains sinusoidal waveform is permitted to conduct Typically a triac or SCR in series with the incoming AC line is off during the rise of the mains sinusoidal waveform Following the peak of the waveform a trigger is asserted at the gate allowing the triac or SCR to turn on and the line voltage present at the triggered phase angle 1s available to charge filter capacitors commonly used with these topologies The phase angle trig gering sequence occurs for each subsequent half cycle of the sinusoidal waveform 6 4 2 Phase Control Output Referring to the High Voltage Output schematic Figure C 12 the line isolated AC voltage enters the printed circuit assembly at J1 1 Hi J1 3 6 9 SYSTEM 7550 AC Lo and J1 4 Com We should note that these AC signals are isolated from AC Mains by means of an isolation transformer located in the generator assembly The AC signals are trans former taps with AC Lo rated for 125V and AC Hi rated for 185V with a nominal voltage input Referring once again to the
14. power Pcon at V10D The difference of the 6 6 two is called PERR Power Error a signal that can increase or decrease the HVDC for power control When the signal 1s positive the HVDC is reduced and when negative the HVDC is increased Digressing back to the outputs of the RMS to DC converters for a moment the DC value of the output voltage and current are both connected to the inverting input of the unity gain amplifiers As long as the load is within the defined limits for power regulation 300 ohms 1K ohms the measured value will exceed the reference level or the level on the non inverting inputs The output of the amplifier is then negative reverse biasing D3 amp D4 diodes and the output of the RMS DC converters is passed through the 2 7 ohm resis tors The signal called ILIM is actually a reference When the output current is less than this refer ence the ILIM value is used as the multiplier with the measured voltage ILIM is dependent on the dial setting however for each dial setting it is fixed and becomes a fictitious representation for the output current ILIM is multiplied against the measured voltage and the product is compared to the requested power With a fixed current being compared to a fixed power setting the result is a fixed voltage on the RF output For loads that are greater than the loads for power regulation R gt 1K ohms in cut the RF output voltage is fixed V P I On U2 3 VLIM is a ref
15. 3 Power Control Assembly A4 This assembly controls output power of all modes and has the driver logic for both RF Amplifiers It is important to remember that this system has two separate RF Amplifiers and each amplifier operates in a different manner The amplifier against the back wall 1s called Full Bridge FB and is used for Cut Pinpoint Blend and Bipolar Modes The other amplifier 1s against the side wall and is only activated for Spray and ABC modes This discussion will focus on each ampli fier independently 6 5 SYSTEM 7550 6 3 1 Power Control Full Bridge Amplifier Output power in the Full Bridge modes is con trolled by monitoring the output voltage and current multiplying the two together and the product of the operation is power The measured power is then compared to the requested power and if the power is greater than requested power the power control circuit reduces the HVDC If the power 1s less than the requested power then the power control circuit increases the HVDC The power control loop encompasses several assemblies however we will only focus on the cir cuits of the Power Control Assembly For this dis cussion it is important to refer to the schematic Figure C 6 The RF Output can be constant current power regulated or a fixed output voltage all depending on the RF load The inputs labeled VsN voltage sense ISN current sense are ratios of the RF output voltage and c
16. Fault indicator flashing Press Monitor Set Three 3 bargraph segments on Monitor Set indicator on Return Fault indicator off Resistance 130 ohms Eight 8 bargraph segments flashing Monitor Set indicator flashing Return Fault indicator flashing Press Monitor Set Eight 8 bargraph segments on Monitor Set indicator on Return Fault indicator off Resistance 160 ohms Ten 10 bargraph segments flashing Monitor Set indicator flashing Return Fault indicator flashing Press Monitor Set It will remain in the Alarm Mode Each time the Monitor Set is pressed an alarm tone will be gener ated SYSTEM 7550 7 8 Pulsed Cut Mode Pulsed Cut is a mode that delivers RF energy in pulsed durations for precise control of dissection The repetition rate of Pulsed Cut is approximately 640mS with RF ON time of approximately 75ms and RF OFF time of approximately 565115 for a duty cycle of 12 The activation tone consists of two different frequencies with the higher frequency being the tone that identi fies when RF is delivered and the lower frequency tone identifying when the RF is off The power delivered during the RF ON time of the Pulsed Cut is the power that is displayed in the Cut win dow so the rms power is approximately 12 of the displayed power To select the Pulsed Cut mode press the Down switch in the Program section on the Front Panel until P P for
17. PCON Bipolar Power Control analog voltage for power control BPR Bipolar Relays 2 Bipolar Active amp Patient Return BRN OUT Brown out delayed discharge to signal temporary power loss CG Coag Power Control analog voltage for Pinpoint power control CON CON D7 Control Data bit 0 1 2 7 mode control CS 0 1 2 Chip Select active low value corresponds to decoder output CT Cut CT Cut Power Control analog voltage for power control DAM Data Available to the monitor monitor has mail DCM Data Cleared to the monitor monitor read mail F 2M Frequency 2M Hz F LN Frequency Line low voltage isolated line signal F MON Flow Monitor V that is proportional to Flow Rate DRV Full Bridge Drive RF Drive for FB amp FB EN Full Bridge Enable enables power control circuit FB MON Full Bridge Monitor DC average of FB Amp RF Drive FB RST Full Bridge Reset RF Drive reset pulse 200nS wide FBM Footcontrol ABC Activation Request FBP Footcontrol Bipolar Activation Request FCG Footcontrol Coag FCR Footcontrol Relay RF Active Output FCT Footcontrol Cut Activation Request FDEV Flow Deviance is set when hand piece is occluded FILR Filter Relays 2 Switches FB Amp to RF Output Relays FL Flow FMEA Flow Measured that is proportional to flow rate amp back pressure SYSTEM 7550 GAS HICG M HICGSW HICT C M HICTSW HIRF
18. Pulsed is displayed When select ing Pulsed Cut all power levels on the display panel will be set to zero therefore all power levels will have to be adjusted to desired settings When leaving the Pulsed Cut mode all powers will also be set to zero Because of the low repetition rate it is difficult to measure the rms power using stan dard electrosurgery analyzers therefore to test this mode use an oscilloscope and verify the output or RF drive on the Full Bridge 30 0134 assy are pulsed at a rate of approximately the values listed above To test the RF output with 1 1 or 10 1 scope probes simply lay the scope probe cable across a lead connected to the dispersive electrode Do not connect the scope probe directly to the lead as damage may occur to the probe Set Cut power to about 50W into a 500 ohm load and set the scope for 100mS Div Activate Pulse Cut and verify the output is pulsed 7 9 RF Leakage Test See Calibration Section for Test and Calibration of RF Leakage 7 10 Final Checks 1 Ensure the internal switch setting is set for Run Mode and ABC Argon Monitoring Mode This can be verified by turning on the Main Power If an Err 20 is displayed the default switch settings are not properly set Positions 1 and 6 should be down or off 2 Ensure the lid or cover is secured by the two screws on either side 7 8 3 Ensure the argon tank valve is off The pres sure within the argon lines will not bleed off
19. accessory is required to test the argon flow rate In the previous section for Display Panel testing three 3 tables listed flow limits as related to ABC power settings Refer back to the tables or keep in mind that when the argon setting does not increase or decrease beyond present settings the ABC power is forcing the limit Smart Sense can change the initial flow setting during an activation interval if the back pres sure caused by the accessory or any other type of partial occlusion exceeds internal limits When testing the flow rates the measured flow should match that of the displayed flow rate 1 Without an Argon Calibrated Mass Flow Meter Select Manual flow mode Set the flow to 4 slpm and power to 50W Activate ABC into a 500 ohm load The flow of the argon will typically be audible but a beam will only occur if the gas is flowing A typical beam length at these settings is close to Increase the flow in increments of 1 slpm and for each setting activate into a load Verify a beam occurs and has a length greater than 5mm To get more than 8 slpm of flow the power must be greater than 80W 7 6 2 With an Argon Calibrated Flow Meter Insure the nozzle of the ABC accessory is seated within the intake hose of the meter to minimize leaking A leak in the con nection will give false readings Flow should be checked at 2 4 amp 8 slpm as a minimum The flow is calibrated at the fa
20. and it is not necessary to bleed the lines 4 Ensure the Power Cord is secured by the strain relief that is connected to the argon tank strap support 7 11 Mobile Storage Pedestal Cart The System 7550 Mobile Storage Pedestal Cart houses the High Pressure pneumatics pressure relief valve tank pressure switch tank pressure gauge and wiring harness for the footswitch con nectors block diagram of the argon pneumat ics within the cart is shown in figure 6 3 on page 6 15 There are no requirements for annual main tenance on any components within the Cart The argon tank pressure input is rated for 3000 psi and is stepped down to 30 psi using a dual stage pressure regulator assembly The first stage of the dual stage pressure regulation reduces the tank pressure down to approximately 175 psi and the second stage reduces the 175 psi down to 30 psi The output of the second stage regulator connects to a fitting that carries the argon into the Generator Assembly and has a 50 psi pressure relief valve In the event a pressure regulator fails the pressure relief valve will open and vent the argon in the atmosphere so that argon tubes are not ruptured The low pressure switch and pressure gauge are both on the input side to the dual stage pressure regulator assembly The pressure gauge measures the pressure within a tank of argon that is con nected The low tank pressure switch is simply a set of contacts that are held o
21. bad Disconnect harness from J1 Use a ing indicators or modes do jumper to short pins 1 thru 4 to pins not change when switches are 5 thru 8 1 independently If front ressed anel indicators change the overla 8e y switches have failed Err 386 Have a Tone but get a Tone error any T MON signal failed A5 way No RF Output Open Relay A10 Test for RF from each active jack in both Cut and Spray No output from any Relay Driver failed Relay Driver failed A5 Relay Driver failed A5 mede bad relay driver No output ABC mode will not initiate Over voltage circuit active Recalibrate ABC over voltage U7 failed A4 If J4 23 spare is high then the pulse width or duty cycle has failed U4 A4 without a load U4 8 amp U4 9 should toggle high U4 16 should remain low Spray mode will not deliver Pulse width or duty cycle failure U7 failed A4 If J4 23 spare is high power then the pulse width or duty cycle has failed Blowing fuses or R19 on A7 8 shorted 7 08 drain should equal HV during gets too hot activation High Voltage gt 205VDC or 2 failed If only high for Cut or Spray check for failed triac Control Loop failed A control loop failure if high for all modes and for all dial settings when the unit is activated Flow rate is too high Shorted driver Q2 A1 Q2 emitter voltage should increase as Control loop failed A1 flow i
22. bipolar section illuminates 4 Footcontrol Testing Activate Cut footswitch and verify an audible tone occurs and the yellow indica tor in the cut section illuminates Activate Coag footswitch and verify an audible tone occurs and the blue indicator in the coag section illuminates Activate ABC footswitch and verify an audible tone occurs and the blue indicator in the ABC section illuminates Activate bipolar footswitch and verify an audible tone occurs and the blue indicator in the bipolar section illuminates 7 7 4 RF Output Power Checks Refer to Figure 7 2 for this section Power test ing for Cut Blend Pinpoint amp Spray can be per formed using handcontrol accessory However if a footcontrol adaptor is available connect a test lead from the Monopolar Footcontrol jack to the ESU analyzer If a footcontrol adaptor or the footcontrol switches are not available then mea sure output power from one of the handcontrol accessory electrodes To measure Bipolar power connect the ESU ana lyzer between the two bipolar RF jacks using test leads To measure power an ABC test adaptor is required Connect the ESU analyzer between the Argon Beam Coagulator connector and the Return Electrode Receptacle If measured power 1s out of the listed range refer to the calibration section for power calibration The power range is to allow for power differences in analyzers The specified power settings are only
23. data transfer A5 Reset system try again Mailbox failed A5 RAM Failure External RAM has failed U2 A5 Reset System Note error code if it reoc curs re lt 7550 Suggested Solutions 218 Bad EPROM CRC EPROM failed U1 A5 Reset System replace 01 if problem reoccurs 219 CPU RAM Failed Micro Internal RAM failed U15 A5 Reset System Replace 015 if problem reoccurs CPU Failed Microprocessor Failed U15 A5 Reset System Replace U15 if problem reoccurs Data transfer to Monitor Mailbox Failed A5 Reset System Note error code if it reoc failed Data Bus bad A5 Address Bus bad 5 E error ouem to Bad EEPROM 027 5 Reset System replace U27 or U37 if problem reoccurs E ERN error CRC error A5 Recalibrate See Calibration Section only the section for ABC at 11 amp 149 Bad data Bad data stored A5 Bad data stored A5 spray at 49 and A R M open circuit 386 Tone Fault Monitor did not detect a tone on signal Verify tone occurs T MON A5 Controller did not send a signal on Signals Tone A Tone B amp T Mon Tone A A5 should all have same frequency Interrupt External 0 interrupt A5 Reset System Note Error code if it reoccurs 392 Interrupt External 1 interrupt A5 Reset System Note Error code if it reoccurs 394 Interrupt A D interrupt A5 Reset System Note Error code if it reoccurs A D timer failed 5 A
24. four pulses are detected for one cycle the logic within U7 assumes a load 15 present and switches to the active mode Staying with the signal ASEN it is also connected to a comparator U16 This comparator is used for ABC over voltage detection Without going into significant detail if the output of 016 pulses 192 consecutive cycles the logic within U7 assumes the system has locked up in the active mode and the RF is inhibited Note that the inverting input of this comparator has a potenti ometer RA9 This potentiometer allows calibra tion of the over voltage limit and should fail to initiate it may be necessary to refer to the calibration section for this adjustment The target and booster pulses are a means of lim iting RF leakage by controlling both the output voltage and repetition rate when the output is not loaded Both modes are fixed outputs meaning the power setting has no influence on the output voltage The resistor ladder R24 RA4 R17 amp R19 sets the limits for both the target and booster modes Target has 1032 pulses with a peak voltage of approximately 1800V pk and then the booster is switched in The booster mode has 32 pulses with a peak voltage of 6000Vpk and these pulses are used to ionize the argon gas to assist with initiation When a load is not detected during the booster pulses then the target booster cycle is repeated until a load is sensed The volt age level of each mode is select
25. n diee ix rrt 6 3 36116 itte teer oo 6 3 A D Inputs Control 2 R 6 3 A D Inputs Monitor Microcontroller 6 4 EEPROM Driver U37 927 5 ioci etie eet n eoa tete AEE 6 4 D AcConventer ss easi 6 4 Keyboard Scanner iti torti o 6 5 SV Monitoring U29 rrt in te RE t Gentes 6 5 Output PIA U2L 6 5 T MONTU ee EVI MIN 6 5 Power Control Assembly AS Mx 6 5 Power Control Full Bridge Amplifier 6 6 Logic U7 on the Power Control Assembly sese 6 7 Power Control I O Signals ect toto ien n dra t eti e e e tein 6 8 III E 6 8 High Voltage Power Supply tto 6 9 Power Supply 6 9 Phase Control 6 9 HVPS Isolation Compohents 55 3 6 10 HVPS Low Voltage Components 6 11 HV Flow Control Assembly AL bes 6 11 Line Synchronization rep p rettet ip ieri dept 6 11 HV Regulation Control 6 12 Argon Flow Control DA 6 13
26. only be cleared with a system power down or reset To Power Up with the TEST MODE enabled hold down the STORE switch on the Front Panel until an Err 1 is displayed This allows the system to be powered on when error mes sages occur during system diagnostics 2 ABC TEST MODE When this switch is ON the ABC Mode can be tested without argon gas flow WARNING DO NOT PLACE UNIT IN SERVICE WITH ABC TEST MODE ON The ABC Test Mode can be enabled anytime when the Power is on If ABC TEST MODE is selected when the unit is Powered on an Err 20 is displayed An Err 20 can only be cleared with a system power down To Power Up with the ABC TEST MODE enabled hold down the STORE switch on the Front Panel until an Err 1 is displayed This allows the system to be powered on when error messages occur during system diagnos tics 7 6 The unit is shipped with the AC Mains Frequency properly set for the unit destination However if the label on back of the system has the frequency listed as 50 60 Hz then it may be necessary to verify the selected frequency is set correctly AC Mains Frequency amp Voltage 1 Mains Frequency Reference Figure C 1 for this section Remove the cover from the PCB card cage The card cage is located at the right rear of the the unit Two 2 PCB assem blies are within the card cage On the right side of PCB assembly is a switch The system is configured for 50 Hz when the switch i
27. suggested but it is recommended that at least two different power settings be tested in all modes Blend can be an exception l Select Pure Cut Blend Display reads 707 Set power to 50W Activate Cut and verify 50W 45W 55W Set power to 300W Activate Cut and verify 300W 270W 325W 2 Select Blend Blend Display reads 1 9 Set power to 50W Activate Cut and verify 50W 45W 55W 3 Select Pinpoint Coagulation Set power to 50W Activate Coag and verify 50W 45W 55W Set power to 120W Activate Coag and verify 120W 110W 130W 4 Select Spray Coagulation Set power to 25W Activate Coag and verify 25W 20W 30W Set power to 80W Activate Coag and verify 80W 72W 88W 7 5 SYSTEM 7550 5 Bipolar Coagulation Load 100 ohms Set the power to 20W Activate Bipolar and verify the power is 20W 15W 25 Set the power to 70 ohm Activate Bipolar and verify the power is 70W 62W 77W 6 Argon Beam Coagulation Load 500 ohms Set the power to 20W Activate and verify the power is 20W 16W 24W Set the power to 150W Activate ABC and verify the power is 150W 135W 165W 7 7 5 Argon Flow Testing mass flow meter calibrated for argon gas is required to measure and verify argon flow rates However if a flow meter is not available the flow can be tested and verified so as the flow setting is increased the flow rate increases An
28. the patient Write active low Transformer re SYSTEM 7550 ELECTROSURGICAL MODES Troubleshooting Guide Appendix B Introduction The following troubleshooting tips are a guide line to identify the source of a problem and in some cases the solution to correct the problem It will be necessary to refer to the Schematic Maintenance Calibration and or Circuit Description Sections This section will be done in three parts 1 Controller Error Codes 2 Monitor Error Codes 3 Additional Failures Error codes are displayed on the Front Panel with Err XX where the XX will be some numeric value in the Coag Display Window In the column marked Err are the numeric values for the system error codes Record or note all error codes as in some cases more than one error code will be displayed and the last error code displayed may be the effect and not the cause When requesting assistance from CONMED Technical Services be specific on which error codes if any are displayed Errors that occur when the unit is powered up are called POST Power On Self Test and in most cases are Fatal To bypass the POST or RUN TIME errors enable the TEST MODE see Maintenance Default Settings There are two kinds of Error Codes Fatal and Non Fatal A fatal error code cannot be cleared unless the system is reset A non fatal error code is cleared when the failure is corrected or activa tion is te
29. to open the tank valve Verify at least 200 psi of pressure registers on the pres sure gauge located on the back of the cart 8 4 A R M Calibration HS A R M Assembly A11 8 4 1 10 Ohm A R M Calibration Place 10 ohms across the two leads of a disper sive electrode cable 8 1 SYSTEM 7550 Connect a DVM from TP2 CAL 10 to 2VARM Adjust R2 ARMCAL 10 for OV 01V 8 4 2 150 Ohm A R M Calibration Place 150 ohms across the two leads of dis persive electrode cable Connect a DVM from CAL 150 to 2VARM e Adjust ARMCAL 150 for 01V 8 5 High Voltage Calibration HV Flow Control Assembly A1 8 5 1 HV RAMP Calibration Connect an oscilloscope probe to TP 6 RAMD Connect the oscilloscope ground to TP2 Gnd Set the oscilloscope for 5V Div and 1mS Div Trigger the oscilloscope for the bottom of the RAMP signal at the flat spot of the RAMP See Figure 8 1 1mS DIV FLAT SPOT Figure 3 1 RAMP Flat Spot With the System 7550 in idle mode adjust RA7 RAMD to set the flat spot at 400uS 8 5 2 High Voltage Adjust CAUTION burns can occur when skin comes in contact with exposed RF leads Ensure RF leads are properly connected to an analyzer or placed safely away from incidental contact e Connect a volt meter to the DC and DC terminals of the High Voltage Power Supply A7 Set the scale for
30. 200V Set ABC power for 20W to 50W 8 2 Activate ABC without a load connected to the output Adjust RA4 HV ADJ for 200V 2V HVDC 8 5 3 HV MON Adjust Connect a voltmeter to DC and DC HVDO on A7 Set Pure Cut power to 50W Activate Pure Cut and adjust the power setting of Pure Cut to get 50V at HVDC Connect the voltmeter to TP1 HVMON on the HV FLOW Control 1 assembly Adjust RA HVMON for 1V 30mV at with 50V 6V at HVDC 8 6 Argon Flow Calibration HV Flow Control Assembly A1 8 6 1 Calibration Differential Pressure Connect a DVM to TP3 dP and TP2 With the System 7550 in idle mode adjust RA2 dP ADJ for OV 8 6 2 PABS Calibration Absolute Pressure Connect DVM to PABS and TP2 Gnd With the System 7550 in idle mode adjust 5 PABS ADJ as listed in the table below for the altitude where the system is placed into service or proportional to the difference between two listed altitudes ELEVATION TABLE 8 6 3 Flow Rate Calibration Optional Connect an ABC accessory to the System 7550 SYSTEM 7550 Connect the nozzle of the ABC accessory to a Mass Flow Meter calibrated for argon gas Select the Manual Flow Mode Set the flow rate for 4 slpm Activate the ABC mode Adjust _ CAL for a flow rate of 4 slpm 3 slpm Set the flow rate for 8 slpm Activate the ABC mode verify the flo
31. A testing bipolar RF leakage is not necessary 8 6 ABC 30W The ABC mode has a fixed output voltage that is not dial dependent when a load is not connected directly between the active and return electrode outputs Use the ABC Test Adaptor when testing RF leak age from the active electrode SYSTEM 7550 ELECTROSURGICAL GENERATOR ABC MODES Mnemonic List Appendix A Note On the schematic a suffix _C indicates the signal is to the Controller Micro Signal On the schematic a suffix indicates the signal is to the Monitor Micro Signal MNEMONIC DESCRIPTION HV High Voltage HVDC plus terminal 01 Phase 1 RF Drive for FB amp 01 Not Phase 1 RF Drive reset pulse 200nS wide 02 Phase 2 RF Drive for FB amp 02 Not Phase 2 RF Drive reset pulse 200nS wide AT Active set or Target cleared ABC Mode only 80 ABC power greater than 80W Set when true ABCACT ABC Active output ABCR ABC Relay Dedicated Patient Plate Relay for ABC ABC Argon Beam Coagulator ADO AD1 AD7 Data bit 0 Data bit 1 Data bit 7 AR_EN Argon Enable Enables the flow control circuit ARM Aspen Return Monitor Patient Plate Monitor ASEN Arc Sense ratio of ABC transformer primary voltage BIPRF Bipolar RF jack BL Blend BM Beam another word for BM BST Beam Booster analog voltage for booster voltage BM TAR Beam Target analog voltage for target voltage BP or BIP Bipolar BP
32. B Schematic Sheet 2 0f 4 cose se testet mia C 7 Figure C 8c A5 Display PCB Schematic Sheet 3 ceca or pe barn ta C 8 Figure 84 A5 Display Schematic C 9 Fig re C 9 A6 LV Poser Supply POB Eti cob abere C 10 Figure C 10 LV Power Supply PCB Schematic tante arena C 10 Pipe ADV Output 11 Figure 712 A7 HV Output PCR Schemes 11 Figure Amplih r DOD 12 Here 14 A8 Amplifi r PCB Schematic 12 Figure C 15 AO SE Amplifier POB C 13 Figure 16 A9 SE PCD SC ie ate C 13 C 17 A10 Eds 14 Figure C 18 AIO RP Output PCB Schematic C 14 Figure C I9 15 Figure C 20 11 A R M Handsense PCB 15 SYSTEM 7550 ELECTROSURGICAL MODES Circuit Descriptions Section 6 0 6 1 Introduction The information on the System 7500 circuits identifies specific signals and I O ports that help identify t
33. D is within micro U15 Monitoring Microcontroller Failure Codes and Troubleshooting Tips Probable Problems Suggested Solutions 301 Flow Error Flow too high or low Recalibrate See flow in calibration sec pen S tion Flow Rate too high for accessory Correct the setting mode if accessory is the problem D A Failed VGas 5 Vaas range should be 5V 6V 302 IMEA Error Output Current Error too high A4 Recalibrate See Power Calibration sec tion Too much power into a heavy load Test if problem only occurs into a heavy load R 300 ohms Power Regulation Loop A4 Failed Test if problem in Cut Pinpoint and or Bipolar D A Failed PCON A5 PcoN range 0 9V A4 A5 Activation Error Controller amp Monitor Micro control Swap 016 amp 033 A different error code lers disagree on activation request or will occur if the problem is one of these the mode requested devices U16 or 033 failed SYSTEM 7550 Suggested Solutions 304 Output Power Power Control Circuit Failed A4 Recalibrate See Power Calibration sec tion D A Failed A5 PCON range 0 9 4 5 305 Activation Error Monitor Activation Request Error Swap 016 amp 033 A different error code U32 A5 failed will occur if the problem is one of these devices 306 PW MEA out of calibra U7 on Power Control Failed Recalibrate See Power Calibration sec tion Ramp transistors Q1 or Q2 fai
34. Display Assembly as a switch closure When the handswitch is released the LED goes dark causing the photo transistor to cease conduction and allow the signal line to be pulled high by a resistor network located on the display PCB Handcontrol 1 and Handcontrol 2 sense circuits operate in the same manner for Cut or Coag requests An exception however is ABC activation sensed as a result of both Cut and Coag photo transistors being in the ON state during SYSTEM 7550 a drive time that occurs on the diode of U6 A logic device on the Display Assembly drives this diode with a square wave and when this diode is conducting current and if ABC is requested then both U8 and U9 will be switched on and the collectors of both will go low 150 RESISTANCE OHMS N 30 10 2 4 6 8 RESISTANCE BARS Figure 6 4 Resistance vs Bargraph 6 11 2 Aspen Return Monitor A R M The A R M circuit converts the electrical resis tance appearing in the return electrode circuit into a digital value which can be processed by the microprocessor Software processes use this value in conjunction with the SINGLE PAD DUAL PAD and MONITOR SET buttons to determine when a RETURN FAULT condition exists The ASSIST resistance indicator is also driven by soft ware to indicate the value of the measured DUAL FOIL resistance in the 10 to 150 ohm range Figure 6 4 shows the approximate resistance vs number of illuminated bars in the r
35. ERE DR 8 2 PiN VON oo 8 2 8 2 Argon Flow Calibration HV Flow Control Assembly 8 2 dP Calibration Differential 8 2 PABS Calibration Absolute 2 8 2 Flow Rate Calibration Optional 24 ken 8 2 8 3 Power CalibtatiOn eite err trier 8 3 Filter Calibration Full Bridge Modes 8 3 Cut Power Calibration Power Control Assembly 4 8 3 07550 Section 8 7 3 8 7 4 8 7 5 8 7 6 8 7 7 8 8 8 8 1 8 8 2 8 8 3 8 9 Appx A Appx B Appx C Title Page Pinpoint Coag Calibration Power Control Assembly 4 8 3 Spray Coag Calibration Power Control Assembly 8 3 Bipolar Calibration Power Control Assembly 8 4 ABC Calibration Power Control Assembly A4 8 4 ABC Over Voltage Calibration Power Control Assembly 4 Optional 8 4 EEPROM 8 4 Spray Coag PW MBA Loading 8 4 MEA Loading tpe ees 8 4 ARM Voltage Loaditig eee Ri bp tidie rh an Rd Eran 8 4 Leakage Measurement 8 5
36. KHz for audible tone KB DA Keyboard Data Available SET when a front panel switch is pressed cleared when the device is read U31 Port C PCO PC6 Outputs from Control Microcontroller ABC gt 80 ABC Power is Greater than 80W SET when ABC power is set to greater than 80W CLEARED when power is 80W or less RFEN RF Enable SET to enable the RF drive for all activations FB EN Full Bridge Enable CLEARED when activation for Cut Blend Pinpoint amp Bipolar occurs OV TST Over Voltage Test Test pin that allows the control microcontroller to test and verify the ABC over voltage circuit is operational During Power On Sel Test POST this signal is clocked for a dura tion of about 7mS Alarm Tone for alarms 1KHZz signal tone for alarm volume cannot be adjusted Tone B Tone Mode Signal for all Tones except alarm tones Volume can be adjusted U32 Port B PBO PB7 Monitor Inputs This port has the switch for setting the system defaults The switch is located on the back side of the Display PCB for accessibility Default settings are with the switch in the OFF position off high on the input pin of U32 To change a default setting move the appropriate switch to the SYSTEM 7550 ON position To verify the selection turn the power off for at least 10 seconds and then restore power 1 TEST RUN Default RUN MODE TEST mode allows the system to be operated without err
37. Seana SYSTEM 7550 ELECTROSURGICAL GENERATOR ABC MODES LIMITED WARRANTY For a period of two years following the date of delivery CONMED Corporation warrants the CONMED Sys tem 7550 Electrosurgical Generator against any defects in material or workmanship and will repair or replace at CONMED s option the same without charge provided that routine maintenance as specified in this manual has been performed using replacement parts approved by CONMED This warranty is void if the product is used in a manner or for purposes other than intended 2006 CONMED Corporation 525 French Road Utica New York 13502 U S A U S Patent Numbers 4 437 464 4 569 345 4 617 927 4 727 874 4 848 335 4 961 739 5 152 762 5 626 575 and other patents pending For Technical Service or Return Authorization Phone 303 699 7600 1 800 552 0138 Extension 5274 Fax 303 699 1628 For Customer Service or to order parts phone 1 800 448 6506 315 797 8375 Fax 315 735 6235 or contact your CONMED Representative European Authorized Representative MDSS GmbH Burckhardtstr 1 D 30163 Hannover Germany The revision level of this manual 15 specified by the highest revision letter found on either the inside front cover or enclosed errata pages if any Manual Number 60 7552 ENG Rev D 10 06 Unit Serial Number 550 ELECTROSURGICAL 5 Table of Contents Lis
38. This voltage increases with flow A voltage that exceeds 3 3V in all flow modes will set a flow alarm by illuminating the red Flow Fault indica tor 6 2 11 A D Inputs Monitor Microcontroller Seven of the eight available inputs are used for monitoring system signals A failure with any one of the inputs will be displayed as an error code HV_MON High Voltage Power Supply Monitoring This A D input is 200mV 40mV when the system is in the idle mode The resolution is 20mV V 20mV for every volt on the DC amp DC terminals of the High Voltage power supply Calibrated for 1V with 50V on the High Voltage Power Supply IMEA Current Measure ratio of the output current that is applied to the patient when Cut Blend Pinpoint or Bipolar modes are used Used in conjunction with the HV MON to determine the output power F MON Flow Monitor The current through the flow control valve rep resents the flow rate A flow rate that exceeds requested flow by more than 2 SLPM will set an alarm and inhibit both RF Output and argon flow This signal is calibrated for 2V with a flow setting of 4 SLPM PW MEA Pulse Width Measure Spray and ABC modes only DC average of the RF Drive pulse width to the single ended amplifier In the voltage increases as the power increases if a load 15 connected to 6 4 the output In Spray the voltage is constant for all dial settings FB MON Full Bridge Monitor
39. With a balanced field within the balun the sense winding has zero volts and as the leakage increases the voltage on the sense winding increases allowing a circuit to be employed into the System 7500 that will reduce output voltage when RF leakage is sensed Each output of the system is discrete or has an output relay with the exception of ABC Active The active outputs are handcontrol 1 2 handcontrol 2 footcontrol and Bipolar In addition to the active outputs are the Patient Return which have three relays for isolation K9 is closed only when is activated to provide a return path back to output transformer K8 is closed when Cut Blend Pinpoint or Spray is activated and K11 is closed only when Bipolar is activated The table below identifies which relays are closed for each of the modes activated Mode Output Relays Selected Cut Blend Pinpoint HIRF K5 K8 Cut Blend Pinpoint H2RF K8 Cut Blend Pinpoint Bipolar K10 K11 K3 K1 Spray K5 K8 K2 K4 Spray H2RF K7 K8 K2 K4 Spray K6 K8 K2 K4 ABC K9 The A R M connector is also located on the RF Output Assembly however the A R M circuit is on the HS A R M Assembly and will be cov ered in that discussion A failure due to a relay will obviously appear as low or zero RF O
40. ad is not properly supported 5 Locate the wiring harness with the 15 pin connector within the Cart Connect the har ness to the connector on the bottom of the Head Assembly The connector is keyed so it can only be plugged in one way 6 Locate the nylon argon gas tube within the Cart Connect the argon gas tube to the con nector on the bottom of the head The fitting on the gas tube will snap into place when inserted into the mating connector on the bottom of the Head To DISCONNECT the argon gas tube press the release button on the side of the fitting When the button is pressed the argon gas tube can easily be pulled out of the mating connector Do not pull on the gas tube as it is easily damaged 7 Set the Head back down onto the Cart Add the two remaining wing nuts to the studs within the Cart to secure the Head to the Cart Insure all four 4 wing nuts are tight ened 7 1 SYSTEM 7550 8 Connect the Power cord to the power tacle located on the back side of the Head assembly Directly below the power receptacle is a strain relief Use the strain relief to secure the power cord to the Cart 7 4 Access to Circuits amp Factory Settings 1 Remove the two screws located on either side of the front portion of the top cover Lift the top cover and lock the cover support hinge Verify all internal assembly wiring harnesses and cables are securely connected This is best done by pres
41. calibration procedure provides an organized and comprehensive alignment method to ensure continued unit performance and safety Most unit alignments can be accomplished using com monly used test equipment however a few system alignments require equipment not ordinarily avail able All system alignment parameters have been calibrated at the factory and system calibration parameters that require specialized equipment are identified as Optional steps in the procedure CAUTION Do not attempt system calibration unless the proper test equipment is available Contact Conmed Corporation Technical Services Department with any questions regarding system calibration operation or safety issues The alignment procedure should be performed in the same order as listed in this service manual Refer to Figure C 1 for the location of the PCB assemblies 8 2 Equipment List 8 2 1 Standard Equipment List ESU Analyzer 500 ohm amp 100 or 125 ohm Voltmeter or Digital Volt Meter DVM Dual Channel Oscilloscope Current Meter 10A rating 8 2 2 Optional Calibration Equipment List 1000 1 Oscilloscope Probe s Mass Flow Meter calibrated for argon 8 2 3 Test Leads amp Adaptors Note See Figure 2 1 for drawings of Test Leads and Adaptors Dispersive Electrode Adaptor Made from a dispersive electrode cord that can be used on the System 75507 with a banana jack in place of the dispersive electrode Dispersive El
42. cated on the Mobile Storage Pedestal Cart 6 Connect a tank of argon gas Ensure the tank is securely fastened to the cart with the tank strap Once the tank connector is securely fastened to the tank turn the tank valve fully counter clockwise and verify the argon tank has at least 200 psi for test purposes 7 Insert a Footcontrol adaptor into the Footcontrol jack When testing output power using an ESU analyzer it is recommended to use a test lead from the Footcontrol jack to the ESU analyzer and use footswitches to activate the system 7 7 2 Display Panel Testing 1 Connect the power cord to a grounded AC outlet and press the main switch breaker to turn the system on 2 Verify during system initialization that Displays 788 on ones and tens digits Displays 3 on all hundreds digits mode indicators illuminate audible tone of variable frequency occurs An error code Err is not displayed in the cut window See Err in Troubleshooting if displayed 7 3 SYSTEM 7550 modes 10 19 Pure Cut Display above Blend knob dis plays 0 Pinpoint Indicator is illuminated 3 Verify the system defaults to the following ABC Power Range W Flow Range SLPM 5 illuminated The factory default settings can be changed by 7 4 Rotate each knob and verify all displays are working correctly Check for missing seg 10 0 ments or segments that are latched on Endo indi
43. cator is illuminated Dual Foil Return Electrode indicator is 35 39 0 0 Cut Range 0 300W Manual Flow 0 5 10 slpm Blend Range 0 200W 0 5 4 0 slpm 0 1 slpm increments Pinpoint Range 0 120W 4 0 6 0 slpm 0 2 slpm increments Spray Range 0 80W 6 0 10 slpm 0 5 slpm increments Bipolar Range 0 70W Range 0 150W Endo Mode 10 150W Auto amp Manual Modes Blend Modes 1 9 5 Argon Flow Control Modes Argon Flow Control has three independent modes Listed below are the flow rates and limits based upon the ABC power setting for each mode Endo Flow 0 1 4 slpm 0 1 6 Press the following dome switches and verify the indicator for each switch pressed is illumi nated Automatic in ABC section Manual in ABC section increments Flow rate is manually adjust Endo in ABC section ed with limits based upon the power set Single Return Electrode in Return ting Monitor Section Dual Return Electrode in Return Monitor Section Remote in Power Control Spray in Cong Seton Pinpoint in Section 7 Press Purge in the ABC section Verify that Automatic Flow 1 10 slpm 1 slpm Flow rate window has a 4 displayed increments Flow rate is automatically adjusted with the ABC power Argon flow occurs for approximately 4 seconds An audible tone occurs during the purge time SYSTEM 7550
44. cle 1 amp FB2 Full Bridge drive RF drive for the Full Bridge Amplifier The full bridge amplifier requires two drive signals that are 180 out of phase with each other The rate is 461KHz and the duty cycle of the signal varies with the mode requested These signals are active in Cut Blend Bipolar and Pinpoint amp 2 RST Full Bridge Drive Reset Reset signals for the amplifier drive transformers on the full bridge amplifier The 1 RST follows the FB1 DRV and has pulse duration TM 6 8 of about 200nS FB2 RST follows FB2 DRV and has a pulse duration of about 200nS SE Single Ended Drive RF drive for the single ended amplifier This signal is active when Spray and ABC modes are active FULL BRIDGE AMP PURE CUT BIPOLAR aeo 1 PINPOINT uui SINGLE ENDED AMP SPRAY ABC TARGET Figure 6 1 Drive Signals 6 3 3 Power Control I O Signals The following signals are in addition to those described for U7 PW_MEA Pulse Width Measured An average DC voltage of the Spray and ABC drive cycles The Monitor microcontroller verifies that the measured pulse width is cor rect for the power setting FB_MON Full Bridge Monitor An average DC voltage of the Full Bridge Amplifier drive to allow the monitor mi
45. crocontroller a means of verifying the duty cycle of the RF drive IMEA Current Measured The monitor microcontroller verifies that the output current is within limits 6 3 4 Arc Sense ABC has two modes Active and Target The active mode is enabled when a load is sensed and only in the active mode will the power control dial have any effect on the output voltage or power When a load is not present the target mode is enabled where the RF Output voltage is fixed and the repetition rate increased The Target mode also has two modes Target Pulses and Booster Pulses The ABC mode is quite similar to Spray in the sense that the output is a damped sinusoidal wave form The waveform is heavily damped when a heavy load is on the output and lightly damped lt 7550 with light load The degree of dampening is used to determine if a load is present or not Refer to Figure C 6 and locate the input labeled ASEN This signal is a ratio of the primary current on the ABC output transformer ASEN is compared to a reference voltage at U15 3 and each peak of the damped waveform that exceeds this reference level will cause the output of U15 to switch high at the same frequency as the output 570KHz If the output of U15 has four pulses for one cycle 1 cycle is 35uS active 60uS target the logic within U7 assumes a load is not pres ent and the system remains in the Target mode However if less than
46. ctivate ABC and adjust the ABC power con trol dial for an output voltage of 3500Vpk Adjust RA9 on the Power Control Assembly until the output signal disappears Return the ABC Power Control to a setting of less than 30W 8 4 Activate ABC and increase the power control and verify the signal disappears when the out put is 3500Vpk 200Vpk Remove the jumper 8 8 EEPROM Calibration This procedure loads MEA values into the EEPROM for Single Ended RF Drive monitor ing A load on the RF Output terminals is not required For each listed procedure the system will remain active for approximately 3 seconds to allow time for the microprocessor to read the ana log values and load into the EEPROM 8 8 1 Spray PW MEA Loading Verify that Position 1 of Switch 1 S1 on the back side of the display panel is ON up Set Spray power for 49W Activate Spray Coag for approximately 2 sec onds Verify that in the ABC Display Window the number displayed is between 80 and 115 This is a stored value 8 8 2 ABC PW MEA Loading Verify that Position 1 of Switch 1 S1 on the back side of the display panel is ON up Set ABC power for 11W Activate ABC Verify the number displayed in the Coag window is between 12 and 25 This is a stored value Set ABC power for 149W Activate ABC Verify the first number dis played in the Cut window is between 130 and 180 This is a stored value
47. ctory and is within specifications if the flow is 6 slpm If the flow rate 15 not correct go to the calibration section of this manual 7 7 6 Remote Power Control Testing A standard 2 button handcontrol is sufficient to test the Remote Power Control however it will only allow testing of Cut and Coag modes Remote Power Control can be tested with a Triple Option ABC accessory 1 Press the Remote front panel switch Ensure a handcontrol is connected to either Monopolar Handcontrol or Beam Monopolar Handcontrol jacks handswitchable accessories must be connected to the Beam Monopolar Handcontrol jacks Rapidly double press or double click the CUT yellow button on the handcontrol The Cut display will flash when the Remote Power mode is active and the tone will change If the displays do not flash it typi cally means the double press did not occur within a specified time of 400mS Try the function again To advance the power setting press the Cut button to reduce the power setting press the Coag button With the power 20W the power changes in 1W increments With the power gt 20W the power chang es in 5W increments brief tone occurs each time the power changes To exit the Remote Mode double press the Cut button or wait 5 seconds and the system will automatically exit the Remote Mode Rapidly double press or double click the COAG blue button o
48. discrete non logic circuitry sheet 3 is the control microcontroller logic and sheet 4 is the monitor microcontroller logic This assembly has several programmable logic devices to interface signals to the data bus for both the control and monitor microcontrollers During the discussion when two reference desig nators are listed together it means the logic func tions are the same and can be interchanged 6 2 2 Mailbox U19 A dual port logic device that allows data transfer between the two microcontrollers All system setups and messages are communicated through the mailbox between the two microcontrollers When data is loaded by either microcontroller a bit labeled DA data available is SET to inform the other microcontroller that it has mail Once the data is read from the mailbox another bit labeled DC data cleared is CLEARED to inform the sender that the mail has been retrieved Each microcontroller has independent access to the mailbox and the mailbox is the only component that connects the two data buses Each instruc tion sent through the mailbox requires two bytes of information with the first byte command byte identifying the instruction and the second byte data byte containing the data for the instruction 6 2 3 Power Adjustments U16 amp U33 C for controller M for monitor Power adjust ments on the System 7500 are made by rotat ing the power control encoders The mnemon ics for the power encoders ar
49. e CG COAG BIPOLAR BM Each encoder is a two bit counter 1 amp where the two counts are used to identify the direction of rotation The logic devices U16 amp U33 store the previous count and compare it to the new count in order to recognize if the count is increasing or decreasing which defines if the encoder is rotated clockwise or counter clockwise Each click of the encoder is a count and the number of counts are stored within 016 amp 033 until the microcontroller reads the port The microcontroller reads each encoder port independently and if an encoder has been rotated the count will be greater than zero The data the micro will see is a number 0 to 32 rep resenting the number of clicks the encoder has been rotated and a separate bit that signifies the direction of the count either up or down The microcontroller then takes this count and adds or SYSTEM 7550 subtracts it to the existing power value The control microcontroller reads and controls power change requests however the monitor microcontroller also looks at the encoders to verify the change is valid If the two microcontrollers disagree on the direction up or down number of counts or which encoder is rotating the power will not be changed i e the change request is ignored 6 2 4 Activation Requests U16 amp U33 Activation requests are looked at by both micro con
50. e components of the loop will be covered in the next few paragraphs To provide a simple description of this circuit we will start at the voltage divider with the switch 51 RA7 R66 R67 amp R68 The switch S1 is set for either 50Hz 60Hz operation To the right of 51 is a precision clamp U7B amp U7C with diodes on the outputs The outputs of the preci sion clamps if viewed with an oscilloscope are a square wave with a rate of Line Frequency x 2 or 120Hz when the line frequency 15 60 Hz precision clamp will control the anode of the output diode to the lowest voltage on the two inputs With on the inverting input the anode of the output diode will be 0V and when the inverting input switches high 5V then the anodes of the output diodes have the same voltage as SI C 60 Hz or 2 5V 50 Hz Following the precision clamp is a differential amplifier U7A with a gain of 9 on the non inverting input U7 3 and unity gain on the inverting input U7 2 The differential amplifier controls the direction of charge on the RAMP so that when the output of the differential amplifier is positive 3 2V the RAMP discharges or ramps 6 11 SYSTEM 7550 from 10 to 1 4 and when the output of the differential amplifier is negative 4V the RAMP charges from 1 4V to 10 The output of the comparator U5 1 provides the trigger for the gated Flip Flop U11A U11B U12A U12B As the RAMP char
51. e width of this signal is approximately luS The signal is ampli fied from 5V to 12V at U1 turning on the driver FET Q2 The driver Q2 drain is pulled to ground allowing current flow from the center tap of T1 The secondary of T1 enables the power devices Q8 and Q17 allowing current flow from the HV Power Supply HV input When Q17 switches on it allows current flow from the through 08 through and the primary of the output transformer connected to J2 1 amp J2 2 located on the RF Output Assembly and to HV This completes one half cycle of a drive waveform When 01 turns off 01 and 02 switch on The 01 on time is only 200nS long enough to switch on and pull the charge out of T1 The 02 however works the same as 01 only it switch es the power devices Q9 amp Q16 allowing current to flow from HV through Q9 and in the opposite direction of the output transformer reversing the polarity and then finally through 016 This completes one full phase of RF drive on this amplifier The switching action of alternately turning on 01 and 02 cause the primary of the output transform er to have a positive and negative polarity On the Output Assembly is the filter that converts the square wave generated by the amplifier to a sine wave that is delivered to the patient The drive frequency is 461K Hz and the repetition rate of each cycle is 5445 See Figure 6 1 6 8 Single Ended Amplifie
52. eading on the ammeter of approximately 3A Adjust the lug of L2 on the RF Output Assembly A10 for maximum current CAUTION if using a metallic adjuster an RF burn may occur if contact with the adjusting tool touches the skin Suggest using a non conductive adjuster Remove the short from the output Set the ammeter for 100mA to 500mA range Activate Pure Cut and adjust the power for a reading of approximately 100mA on the ammeter Adjust L1 on the RF Output Assembly 10 for a minimum current Disconnect the ammeter and reconnect the white red striped lead from the Full Bridge Amplifier to the High Voltage Power Supply 8 7 2 Cut Power Calibration Power Control Assembly A4 Connect a 500 ohm load ESU analyzer between Patient Return and the Footcontrol Jack Set Pure Cut for 100W Activate Pure Cut and adjust RA5 CUT CAL for 100W x 2W This potentiometer is at the bottom of the PCB assembly 8 7 8 Pinpoint Calibration Power Control Assembly A4 Connect a 500 ohm load ESU analyzer between Patient Return and the Footcontrol Jack Set Pinpoint Coag for 100W Activate Pinpoint Coag and adjust RA7 COAG CAL for 100W 2W 8 7 4 Spray Calibration Power Control Assembly A4 Connect a 500 ohm load ESU analyzer between Patient Return and the Footcontrol Jack Set Spray Coag for 70W Activate Spray Coag and adjust RA3 SPRAY ADJ for 70W
53. ectrode Cord Dispersive trode cord with the dispersive electrode cut off Strip the insulation approximately 25 off of both conductors Test Leads 2 ABC Adaptor Required to calibrate ABC power To make this adaptor use a dispos able ABC accessory Cut the nozzle off and in place of the nozzle connect a banana jack This adaptor should not be used with argon flow as it occludes the flow unless small exhaust ports are cut into the adaptor ABC Accessory measure argon flow rates an ABC accessory is required such as a Triple Option Handcontrol 8 3 Calibration Set Up Remove the two screws located on either side of the top cover Lift the cover and secure the hinge to hold the cover in the raised position Remove the cover from the card cage to allow access to the two PCB assemblies 1 and A4 within the card cage See Figure C 1 Attach a dispersive electrode cord to the dis persive electrode connector Calibration is easier to perform when using the footcontrol switches for activation If available connect the three 3 footcontrols to the receptacles located on the Cart f footcontrols are not available connect a Triple Option Handcontrol to the Monopolar Beam Handcontrol receptacle to allow activa tion in Cut Coag amp ABC Connect a tank of Argon gas Ensure the tank is securely fastened to the Cart with the supplied strap Turn the tank valve counter clockwise
54. ed This signal enables the power control circuit when cleared With FB_EN set an offset is placed on the non inverting input of the differ ential amplifier causing PERR to be greater than 0 volts which in the event of a failure would force the HVDC to be low PERR was covered earlier but as a reminder this signal is the difference between the measured output power and request ed power When PERR is positive the HVDC is decreased and when negative the HVDC is increased 6 3 2 RF Logic U7 on the Power Control Assembly U7 is an FPGA programmable logic device that is used to develop the RF amplifier drive signals for all modes This device will be described with respect to the I O only Listed below is a brief description of the I O on U7 CONDO COND Control Microcontroller Inputs The hex count on these inputs select which RF amplifier will be driven and sets the right drive signals for the mode The eight signals are latched into U7 when an activa tion request is made See display panel description for hex values as related to modes requested RF CLK Clock input 1MHz clock for RF drive timing Runs con tinuously RF INH inhibit input from monitor microcontroller When CLEARED low RF is inhibited CLEARED when no activation is requested or if a failure is detected FB EN Full Bridge Enable input from control microcontroller CLEARED when Cut Blend Pinpoint or Bipolar modes are re
55. ed by U4 with BM for target and BST for booster These two signals should toggle on and off when ABC is activated without a load on the output When a load is sensed PCON is set and now the power setting determines the pulse width and the logic reduces the repetition rate from 60uS to 35uS Output power is controlled by pulse width and the pulse width controller is 05 and Q2 For the start of each cycle of Q2 15 turned off and this allows C10 to charge linearly When the charge of C10 exceeds the PCON voltage on U5 3 the output of U5 switches high and terminates the pulse time Now is a good time to bring up Spray Spray Coagulation and ABC are quite similar only Spray is lower power and does not have the target modes The output power in spray is controlled by HVDC and the pulse width in spray is fixed at about 1 3uS Calibration of Spray is performed by adjusting which simply scales PCON down for a pulse width that will correct the out put power to match the dial setting 6 4 High Voltage Power Supply A7 The High Voltage Power Supply HVPS pro vides variable regulated DC voltage and current to the RF amplifiers which converts this energy into high frequency surgical current The HVPS is contained on two separate circuit board assem blies The High Voltage output assembly contains the power devices and capacitive filters which provide the high voltage output The HV Flow Control
56. ed ref erence The circuit monitoring for loaded or open circuit outputs will assume an open circuit if four peaks within each drive cycle exceeds the limits The output signal voltage and duty cycle is depen dent on whether the output is loaded or open The transformer is switched into the circuit by the relays and K2 and only for mode When Spray is activated the relays remove the Arc Sense Transformer from the circuit SYSTEM 7550 ELECTROSURGICAL MODES Maintenance Checkout Section 7 0 7 1 Introduction This section contains information on system main tenance and checkout procedures A new system should be tested to insure it is in proper working order before being placed into service Included in this section are Cleaning Generator amp Mobile Storage Assembly Factory Default Settings AC Mains Voltage amp Frequency Settings Accessory Connections System Testing Instrument repair or calibration should only be performed by personnel trained in electronic medical equipment service If the CONMED 7550 Electrosurgical Generator ABC is under warranty refer to the warranty information on the inside front cover of this manual Abbreviated terms used throughout this section ABC Argon Beam Coagulator ESU Electrosurgical Unit System 7550 A R M Aspen Return Monitor 7 2 Cleaning The interior of the unit may be vacuumed or blown ou
57. erence voltage that is really a fictitious value for the output voltage For heavy loads R 300 ohms in Cut the output voltage is less than this reference so the value is multiplied against the measured output current The product of the two is then compared to the requested power With a fixed voltage reference and a fixed power setting the output current is fixed I2 P V The resistance for power regula tion drops with power setting meaning at full power the load is 300 ohms but at 100 watts the load is 100 ohms Calibration of the Power Control circuit is set in Pure Cut initially by adjusting RA5 This poten tiometer calibrates the loop gain for accurate power monitoring and control Blend modes are a direct function of Pure Cut and do not need to be calibrated however Bipolar and Pinpoint do require calibration Bipolar is calibrated by adjust ing and Pinpoint is calibrated by adjusting 5757 7550 7 The signal labeled PCON power control is driven from the DAC on the Display PCB and is the control voltage for output power The range for PCON is 0V 9V IMEA is a ratio of the output current measured scaled from to 4V maximum IMEA allows the monitor microcontroller to monitor the output current Too much output current will cause RF to be inhibited and an error code displayed FB EN is cleared by the control microcontroller anytime that Cut Blend Bipolar or Pinpoint are activat
58. ernate path Internal unit capacitance and high frequency high voltage harmonic energy in the output voltage waveform also contribute to the magnitude of alternate leak age currents IEC has set a maximum limit for RF Leakage at 150mA when tested using the IEC setup Most of the modes available within the System 7550 are well under this limit however Spray and ABC are typically at 130mA to 145mA The IEC test set up is as follows Refer to Figure 8 2 1 Attach the handcontrol accessory to the Monopolar Handcontrol jack 2 Connect a full length return electrode cable to the Return Monitor receptacle on the System 7550 The Patient Plate adapter may be used for this test if the adapter is full length 3 Extend the Active and return electrode cables 5 meters from each other and 1 meter above the floor Note The RF leakage figure shown is the IEC method For consistency it uses a table to hold the cables at the proper distances However SYSTEM 7550 the cables be suspended to meet similar dis tances as shown in the figure The table or bench that the load and active accessories are placed on cannot be made of or have a conductive surface 4 RF leakage is tested with a 200 ohm resistor connected from the Active lead to ground and then connected from the return electrode lead to ground but not necessarily in that order Active cable Connect an RF milliammeter 250mA full scale in series wit
59. esistance indi cator If no bars are lit then the resistance is less than approximately 10 ohms and if 10 bars are lit the resistance is greater than approximately 150 ohms It is not possible for just 1 or 9 bars to be lit unless a segment has failed The Handsense A R M schematic Figure C 20 contains the A R M circuitry It is comprised of an oscillator section and an isolation section The isolation section employs a toroidal transformer T4 to couple the return electrode impedance to the A R M oscillator while isolating that circuit from the effects of applied RF electrosurgical cur rent and voltage C27 and C30 split the return current evenly between the two legs thus mini mizing the RF voltage appearing across T4 wind ings T4 also acts to step up the return imped ance by about 10 1 The A R M oscillator generates a low power sin ewave voltage of about 36 KHz This frequency is determined by the inductance of T2 in paral lel with C25 and that of C27 and C30 reflected through T4 Transistors Q2 and Q3 are cross coupled via R28 and R32 so that when one tran sistor is conducting the other is off due to lack of base drive The conducting transistor turns off at the next zero crossing of the sinusoidal voltage on the primary of T2 This allows its collector volt age to rise and thus provide base current to the other transistor to switch on The collector volt ages appear like half wave rectified AC with each co
60. ge is increased to enhance performance SYSTEM 7550 6 9 Output Assembly Components A10 The Output of the System 7500 is essen tially the secondary of three different output trans formers with only one of them actually located on the RF Output Assembly When troubleshooting this assembly caution must be taken on power set tings and test leads connected as voltage levels are rated in the thousands Refer to the schematic Figure C 18 and locate T3 primary The connections labeled P2 1 and P2 2 connect to the Full Bridge Amplifier at J2 1 and J2 3 The reactive components on the secondary C1 thru C7 L1 and L2 make up a bandpass filter that is calibrated for 461 KHz Following the filter are two transformers amp T2 is a current sense transformer with a 1 7 turns ratio T2 is a voltage sense transformer with a 100 1 turns ratio These transformers connect to the Power Control Assembly for output voltage and current monitoring VSN and ISN Relays and K3 are normally open and close any time Cut Blend Pinpoint or Bipolar modes are activat ed These relays switch the Full Bridge Amplifier Modes to the RF Output jacks Locate on the schematic the transformer labeled Spray Output This transformer is actually mounted to the chassis and can be identified by the color which is black The primary of this transformer is connected to the HS A R M Assembly A11 along with the primary of the
61. ges in the positive direction and exceeds the 10V on U5 2 the output U5 1 switches high which causes a trigger pulse for the Flip Flop U11 2 amp U12 The Flip Flop outputs U12 3 amp U12 4 toggle causing the RAMP to discharge and as the RAMP drops to less than 10V the output of the comparator U5 1 switches back low Using oscilloscope on U5 1 and the RAMP the output switches high for a short duration at the of each positive RAMP cycle providing a clock pulse for the flip flop circuit and each clock pulse causes the RAMP to switch between charging and discharging 6 5 2 HV Regulation Control Loop The High Voltage Power Supply HVDC and Control Circuits are part of the power control loop This discussion will not go into the power control loop but instead it will focus on how the power control loop works with this circuit Let us start the discussion at the inputs labeled HV_SNS high voltage sense J1 1 The HV_SNS connects to the high voltage power supply HVPS and is a ratio of the HVDC The HV_SNS comes into this circuit 1 1 amp 2 as a 40K Hz square wave that proportionally corresponds to the HVDC The HV_SNS signal is filtered and then converted to a DC voltage with a precision rectifier U4C U4D amp associated components To calibrate the HVDC requires only a single adjustment to the loop gain and this is done at RA4 labeled HV ADJ The amplifier U4B is a non inverting ampl
62. h a 200 ohm non inductive resistor to the Active cable as depicted in the RF Leakage figure Return Electrode Cable Connect an RF mil liammeter 250mA full scale in series with a 200 ohm non inductive resistor to the return electrode cable as depicted in the RF Leakage figure Connect the other side of the RF ammeter to earth ground A chassis ground stud located on the back side of the system under test is available for this connection 5 Test each mode and each RF Output jack at Full Dial Setting Pure Cut 300W Handcontrol 1 Handcontrol 2 amp Footcontrol Blend 9 200W Handcontrol 1 Handcontrol 2 amp Footcontrol Pinpoint Coag 120W Handcontrol 1 Handcontrol 2 amp Footcontrol Spray Coag 80W Handcontrol 1 Handcontrol 2 amp Footcontrol Spray typically has the greatest leakage of the modes tested thus far Should the Leakage of Spray or any other mode for that matter with the exception of exceed limits of 150mA a means of adjusting the leakage 15 available On the HS A R M Assembly A11 adjust LKADJ R15 until the RF Leakage is at about 140mA When adjusting R15 the Leakage is reduced by reducing the Note This adjustment affects the open circuit voltage so do not adjust unless it is necessary Bipolar Coag 70W Bipolar Output jacks Bipolar RF leakage is typically too low to measure if Cut Blend amp Pinpoint are well under 150m
63. he appropriate signal levels The text uses the word SET for high and CLEAR for low To locate the assemblies within the System 7500 refer to Figure C 1 Use the system inter connect Figure C 2 to identify wiring harness terminations and individual signals within a har ness 6 2 Display Panel Assembly A5 6 2 1 General Information The System 7500 has two 80C550 microcon trollers with one dedicated to system control and the other dedicated to system monitoring The control microcontroller 015 sets the system enables and control limits while the monitor microcontroller U22 monitors system perfor mance and sets inhibits when an error is detect ed Both of these devices have on board A D converters and each device independently moni tors separate analog signals The address data and control buses of both microcontrollers are isolated by a device called the mailbox U19 a dual port RAM that allows two way data transfer between the two microcontrollers On the schematic the signal labels will have either attached The is for the con troller logic U15 or control microcontroller and the is for the monitor logic U22 or moni tor microcontroller interface The schematic for the display panel Figure C 8 is on four separate sheets Sheet 1 is the schematic for the displays and drivers only sheet 2 shows all the connec tors that are on this assembly along with some
64. ifferent reason With a flow setting greater than 2 Ipm a par tial occlusion will reduce the flow rate down to 2 When the dial for flow is set for 2 or less then the flow will only be reduced by 5 lpm The purpose of the flow reductions is to allow a GI probe to be connected auto matically sensed and the flow rate adjusted to optimize arc initiation 6 7 Full Bridge Amplifier A8 Refer to Figure C 14 for this section The Full Bridge Amplifier assembly houses the power switching devices MOSFETS that amplify respective drive waveforms for Cut Blend Bipolar and Pinpoint modes of operation The power FETS are arranged in an H bridge con figuration where two separate drive signals are alternately switched on to develop a push pull action on the output transformer primary The drive signals are referred to as 01 and 02 phase 1 and phase 2 and each drive signal has a reset that is referred to as 01 and 02 not phase 1 and not phase 2 Phase 1 01 and Phase 2 02 drive signals are developed on the Power Control Assembly and they are 180 out of phase The 01 is turned on immediately after 01 is turned off and the same applies to 02 The 01 and 02 signals reset the magnetics of T1 amp T2 allowing a faster turn off of the power devices The drivers Ul amp U2 step up the drive voltage from 5V to 12V 6 15 SYSTEM 7550 Refer to the schematic Figure C 14 Each drive cycle starts with 01 and the puls
65. ifier U4 7 with an output that is proportional to the HVDC at 45mV V 1V 045V 22 HVDC This sig nal will be referred to as the measured HVDC A differential amplifier U4A is used for the dif ference between the measured voltage and request ed voltage VCON is referred to as requested HVDC When the output U4 1 is positive the measured voltage exceeds the requested voltage and causes the high voltage to be reduced When 04 1 is negative then the requested voltage is greater than the measured voltage and the HVDC is increased 6 12 VCON is driven by a DAC that is located on the Display Panel and has a range of OV to 9V In all modes except ABC VCON increases as the power setting is increased In VCON is fixed at 9V where 9V of VCON results in 200V on the high voltage power supply The input signal labeled PERR NOTE PERR orig inates on the Power Control Assembly product term of the output voltage and current is used to control the HVDC for power regulation and it will override VCON but only to reduce HVDC PERR cannot increase HVDC greater than the requested HVDC by PERR is active for Cut Blend Bipolar amp Pinpoint Coag only and it is part of the power regulation loop The analog switch U9B switches PERR into the circuit when ever one of the four listed modes is activated The output of U9 PERR ties into the voltage control loop using a precision clamp U3B which will pass o
66. ing Cut Blend Pinpoint and Bipolar modes only DC average of the full bridge RF Drive With Cut activated MON is approxi mately 2 85V and for each blend the voltage is about 225mV less than the previous blend or cut mode 10V Reference The 10V reference is monitored and must be 4 46V 2V 15V Supply The system 15V for control circuits is moni tored This voltage is used for op amps relays and flow control valves This voltage must 3 72V 5V 6 2 12 EEPROM amp Driver U37 U27 The EEPROM U37 is used to store user set tings and these settings are recalled when the unit is first powered on or if a 5 second brown out occurs On power up power settings will be the last settings for the default modes Included in the EEPROM are the calibration limits for ABC and SPRAY PW_MEA settings A failure detected with the EEPROM during system initialization will default all power settings to 0 A failure detected with the PW_MEA stored data will inhibit the system from being used until the prob lem is corrected U27 is a parallel to serial interface device The EEPROM is loaded serially however the PCF8584 allows the control microcontroller to load the serial data from the parallel data bus 6 2 13 D A Converter U12 The D A converter is used to control the follow ing High Voltage Output Power Maximum voltage at each dial setting ILIM for Cut Blend Pinpoint
67. is time As mentioned the System 7500 has two 2 6 14 microcontrollers on the display assembly Each of the microcontrollers have control and monitor ing responsibilities for argon flow The Control Microcontroller sets the flow rate with Vgas 5V 6 2 and enables the circuit with a SET AR_EN The Control Microcontroller can also monitor a predicted flow at FMEA The Monitor Microcontroller opens the solenoid valve with a SET on GASEN and verifies the flow rate by monitoring the current through the flow control valve The absolute pressure transducer X2 measures the atmospheric pressure plus the back pressure within the argon flow tubes when argon gas is flowing This signal is referred to as PABS TP4 and is calibrated for a specific voltage depending on the altitude where calibration occurs Once calibrated then PABS will automatically adjust to any change in altitude where the system may be placed into service At sea level PABS will be approximately 5 22V and at an altitude of one mile PABS will measure about 4 13V The differential pressure transducer X1 has two hoses or two input ports for argon hose connec SYSTEM 7550 tions This component has an output proportion al to the differential pressure across the calibrated restriction and the output is referred to as dP TP3 delta pressure With the unit in standby only dP is to be OV The PABS amp dP signals are processed by an analog mul
68. it are not com mon to the HV ground of this circuit The triacs are fired when the cathode of the triac drivers are pulled to signal ground The diode of these drivers is common with and controlled by the HV Control circuit A short pulse of current through the diode of the triac driver switches on the gate of the triac at a phase angle that is greater than 80 The triac will remain on until the AC signal is at approximately zero volts The optocoupler U5 is controlled by the HV Control Circuit and it switches on Q8 when the cathode of the diode is pulled low When 05 15 energized the emitter goes high which switches on Q9 switches off Q10 allowing approximately 14V to switch on the gate of 08 Pulling the cathode of U5 back high switches off U5 allow ing Q9 to be switched off and Q10 to pull the charge from the gate of Q8 and switch it off Following each activation system is unkeyed is switched on for approximately 100mS to allow R33 to dissipate the energy stored in the filter capacitors The two sense transformers T1 amp T2 transfer a proportional ratio of the HVDC across the isola tion barrier to the HV Control circuit pro vides what is called the HV sense for control and T2 provides the HV sense for monitoring Both circuits and transformers are the same and the ratio of voltage transferred 1s the same The pur pose for the monitoring circuit is a means of veri fying the controlling circuit is
69. itch pressed Leakage Control RF Leakage signal to decrease HVDC Low Pressure Switch signal to identify low tank pressure Low Pressure Switch Set when tank pressure lt 250 psi Low Voltage Trigger Triac Drive Low Voltage Triac Enable Set for Cut Blend amp Bipolar Over Voltage Test Tests ABC over voltage monitoring Power Control Enable integrates Power Control to HV control Power Control analog voltage for power control 0 to 9V Power Error HVDC control signal for Power Control Patient Plate Relay Proportioning Valve argon flow control valve Power Supply Request Enables HV Power Supply circuit Pulse Width Measured DC average of SE Amp drive Receive bit 0 bit 3 input from keyboard switches Read active low Inhibit inhibits RF drive RF Enable Enables amplifier RF drive Reset Reset signal set for RST cleared for RST Send bit 0 bit 3 output to keyboard switches Single Ended RF Drive for Single Ended Amp Single Ended Drive RF Drive for SE amp Single Ended Reset RF Drive reset pulse 200nS wide Spray Power Control analog voltage for power control Speaker Spray Relays 2 Switches SE Amp to RF Output Relays A R M Voltage Measured 2X A R M Voltage Measured Voltage Control Analog voltage for HVDC control 0 to 9V Voltage Gas Control analog voltage for flow control 5 to 6V Volume Pot volume control signal Voltage Sense 1 100th of the voltage applied to
70. itle Page Pure TRE Signals 6 8 Figure 6 2 Line p 6 11 Figure 6 3 Flow Diagrani M 6 14 Figure 6 4 Resistance egeta yt sieis 6 19 Figure 7 Test Adapters E E 7 9 Figure 7 2 Test Analyzer Connie cH Ont 7 10 Figure S l RAMP Pt ETNE 8 2 Figure 3 2 Method Leakage 8 5 Figure B 1 Signal Status for a Handcontrol 1 Cut Activation Request sess B 9 Figure B 2 Signal Status for Activation nettes B 10 Cala Assembly Location DUBIE C 1 1 Figure C 2 Interconnect 1 Figure 3 Control PCB sccsssissssssonsssatesosesosavedesesaponnesisenvitonstvstanenndeassenesensnonasvbnens C 2 Figure C 4a Al HV Flow Control PCB Schematic Sheet 1 02 see C 2 Figure 4 Al HV Flow Control PCB Schematic Sheet 2 54400 dan aen C 3 Figure 3 5 A4 Power Control C 4 Iure C 0 A4 Power Control PCB Schematic x bir C 4 Figure C 7 Display C 5 Figure C 8a 5 Display PCB Schematic Sheet 1 of 4 eese C 6 C 8b AS Display PC
71. larity 5V DIV 1mS DIV Figure 6 2 Line Sync RAM The HVPS that is controlled by this circuit has a variable DC voltage HVDC that is dependent on the dial setting and the load Power regulation of the System 7500 is accomplished by control ling the HVDC where each power setting results in a specific DC voltage at light loads RL gt 1K ohms and then the DC voltage will be reduced for heavier loads RL lt 1K ohms for power regu lation The HVPS amp HV Control circuit make up a control loop and a control circuit loop by nature feeds on itself such that one action in the loop results in another action which results in another action etc 6 5 1 Line Synchronization Circuit For this section refer to Figure C 4a The high voltage power supply HVPS is phase controlled and must be synchronized with the AC line volt age The synchronization is accomplished by the zero crossing detector U5 7 that is driven by F LN 73 13 a replica of the AC Line Voltage which comes from the low voltage line transform er secondary The sine wave of F LN is converted to a square wave at U5 7 and this results in a 505 pulse at U10 4 The lower trace of Figure 6 2 shows the 5045 trigger pulse that is synchronized with zero cross ing The upper trace represents a ramping wave form that is ultimately used to initiate the HVPS triac trigger The generation of the cyclic ramp waveform is accomplished with a circuit loop Th
72. led Recalibrate EEPROM See EEPROM Calibration Section U14B A4 Failed Test if the error occurs for both Spray and ABC 021 Port ConDO0 D7 4 amp ConDO0 D7 Spray 85h ABC C5h A5 wrong data D A Failed PCON A5 PCON range 0 9V A4 A5 307 FB Amp Drive Error U7 A4 Failed CONDO D7 CT 39H Pinpoint 6Fh U14A on A4 Failed FBMON A4 Ct 2 85V Pinpoint 35V U21 Port ConDO D7 on A4 amp A5 wrong data 308 HVDC too high HV Control Loop failed 1 Recalibrate See HV amp HVMON Calibration section HV Monitor Failed 1 HVMON Should be 1V when the HVDC is 50V HVDC should not exceed 200V 3V in Pinpoint or Spray at full power or ABC at any power D A Failed VCON A5 VCON range 9V FBMON idle limit too U14A A4 failed FBMON idle 155mV high 310 10V Ref Too high or low A5 U6 Failed 5 Too high or low A6 Filed 6 PW MEA idle PW MEA idle error A4 U14B Failed 4 313 IMEA idle IMEA idle error too high U14D Failed A4 U12 or 08 Failed A5 Stuck Activation Request U32 Failed A5 Swap with U31 to verify 315 Flow Idle Error Flow Control Loop Failed 1 Verify Q2 is off A1 Driver Q2 Failed Disconnect J2 e UI5B Failed 1 Verify FMON lt 150mV AI 316 HV Idle Test HVMON circuit failed A1 HVMON idle 2V 10 circuit on A7 Failed HVDC idle vo
73. lifiers 6 2 6 Display Drivers Seven Segment U14 U20 039 U40 U41 amp 017 Converts Hex to Seven Segment The hex value on bits 0 3 drive the ones digit the hex value on bits 4 7 drive the tens digit and the hex value on the address is used to drive the hundreds digit The displays are common anode therefore each segment is illuminated with an active low on the drivers The digits are mul tiplexed allowing only one digit to be on at any one time for each section 6 2 7 Indicator Driver U34 All indicators on the display panel with the excep tion of the numeric displays are driven with this logic device in a 4x7 matrix The outputs labeled 50 53 are multiplexed at 25 duty cycle and these outputs are converted to 15V at U38 amp U42 which provide drive current for all LED indicators U9 and UIO sink the current for the indicators The monitor microcontroller loads 4 eight bit registers with each bit dedicated to a specific display panel indicator The outputs 50 3 are send and the outputs labeled RO R7 are receive All the send and receive outputs are active high at a 25 duty cycle 6 2 8 Firmware U28 amp U1 The firmware or program for the control microcontroller is stored in U1 and the program for the monitor microcontroller is stored in U28 6 2 9 RAM 02 6116 U2 is the external RAM for the con trol microcontroller only and the monitor microcontroller only
74. ll system testing and calibration Figure 7 1 is a listing of test leads that are needed to test the System 7550 test the output power during the functional testing the test leads are necessary However if the output power is not tested then only the accessories are necessary 7 7 1 Accessory Connections 1 Connect a handcontrol accessory to the Monopolar Handcontrol Jack Handcontrol 1 2 To test the ABC mode with a handcontrol switched accessory it must be connected to the Beam Monopolar Handcontrol Jack Handcontrol 2 A Triple Option Handcontrol Accessory connected to Handcontrol 2 will allow activation of Cut Coag amp ABC modes Fasten the connector of the ABC accessory to the Argon Beam Coagulator connector 3 Connect a Patient Plate adapter from the Dispersive Electrode receptacle to an ESU analyzer 4 Set the electrosurgical analyzer load for 500 ohms to test all modes except bipolar Bipolar load should be 100 ohms Note To test bipolar output power use test leads Connect the test leads to the two bipolar RF out put jacks of the ESU and the other end to the 100 ohm load To activate bipolar use a footswitch if available and if not use a third test lead to short out the right RF output receptacle to the bipolar hand sensing receptacle located just above the RF output receptacles 5 Connect all three footswitches Monopolar ABC amp Bipolar to the footswitch recep tacles lo
75. llector 180 degrees out of phase The A R M oscillator is powered by a constant 0 5mA DC current driven from the VARM signal line This current feeds into the center tap of T2 primary The voltage on the center tap is the aver age of the two collector voltages so it appears as a full wave rectified sinewave Inductor L1 holds the current supplied to T2 constant regard less of these voltage variations while C18 serves as a bypass to limit the noise conducted from the VARM line to the amplifier UID Diode is 1 235V regulator whose output voltage appears across the 2 49K ohm resistor R20 thus driving a constant current of 0 5mA in the VARM line The voltage at is 2X VARM as UID is a 2X amplifier The ASSIST resistance indicator bargraph will be illuminated when the pad resistance is 10 to 150 ohms At just over 10 ohms the two left segments are illuminated As VARM increases additional segments illuminate in proportion to VARM progressing to the right until the resistance approaches 150 ohms where eight bars are illumi nated When the resistance exceeds 150 ohms all ten segments are illuminated In Dual Foil Mode the microprocessor declares a Return Fault if the resistance is less than 10 ohms or greater than 150 ohms If VARM is within acceptable limits 10 150 ohms the Return Fault Indicator will turn off when the Monitor Set switch 1s pressed A Return Fault is declared when the resistance increa
76. ltage 10V 2V J3 disconnected A7 J disconnect Failed Microcontroller U22 A5 Ince RAM fled U22 A5 Not in Run Mode A5 See Maintenance default setting SYSTEM 7550 Suggested Solutions FB Amp Drive Error U7 A4 Failed CONDO D7 CT 39H Pinpoint 6Fh U14A on A4 Failed FBMON A4 Ct 2 85V Pinpoint 35V U21 Port ConDO D7 on A4 amp A5 wrong data 324 FB Amp not inhibited RFINH Failed during POST A5 A4 During POST RFINH should go high two times A4 A5 325 Gas Flow not inhibited GASEN failed to turn off the solenoid During POST GASEN is low when valve during POST A1 A5 A6 EN is high 326 Gas Flow not inhibited Monitor Microcontroller detected FMON to be 150mV when GASEN is by Controller FMON gt 150mV during POST high proportioning valve may be on due to shorted driver 327 SE Amp not in range Drive for SE Amp failed PWMEA Recalibrate See Power Calibration sec not within limits during POST tion Recalibrate EEPROM See EEPROM Calibration Section ConD0 D7 Spray 85h ABC C5h PCON range 0 9V A4 A5 328 SE Amp not inhibited by RFINH failed to terminate RF Drive RFINH signal failed A4 A5 Monitor during POST 329 ABC Over Voltage Test ABC Over Voltage Circuit Failed dur U16 A4 failed to terminate RF Drive failed ing POST 330 ABC Over Voltage Test ABC Over Voltage Circuit Failed dur
77. ly inhibit the HVDC as a means of shutting down the RF output The high voltage triacs U1 amp U4 of this assem bly are only enabled when the system is activated for RF output otherwise the voltage at TP TP2 is an idle voltage of 10V Referring on the schematic to 33 ohm resistor and a fuse are shown in series with a MOSFET Q8 This tran sistor is switched on following each RF deactiva tion to dump the charge from the filter capacitors C13 amp C14 and bring the HVDC back to or near idle voltage The fuse would be the weak link of this power supply Each time an activation request is termi 6 10 nated the voltage on HVDC is dumped through this fuse If the fuse opens up then the only means of discharging the HVDC is through the bleed resistor R18 6 4 3 HVPS Isolation Components Digressing momentarily this assembly has three optically isolated triac drivers one opto coupler and two isolation sense transformers These components isolate the High Voltage Output cir cuit from the High Voltage Control circuit The System 7500 has two intermediate circuits that are both isolated from ground chassis ground and both are also isolated from each other When using a voltmeter or oscilloscope on these cir cuits it is imperative that the ground reference be connected to of this circuit or the signal ground of the control or low voltage circuit The signal grounds of the control circu
78. n Section ARMCAL 150 Calibration Tolerance Error too low Recalibrate See Calibration Section armcal 150 Calibration Tolerance Error too high Recalibrate See Calibration Section Watchdog Reset Timing Error in 015 A5 111 FMON out of tolerance FMON out of calibration Flow Control Valve Driver shorted R58 Al should be 0 Volts in idle Al Argon tubes to X1 A1 reversed If Al has been pulled from the card cage insure the tubes are connected correctly Recalibrate See Calibration Section Recalibrate See Calibration Section Flow Error FMON out of Calibration A1 Handpiece occluded Test at other flow rates Flow control circuit has failed Flow too high for accessory test in Manual Mode or lower flow rate level PIA with encoder logic failed A5 U16 or U33 may bad swap and 112 120 Controller and Monitor Bad data transfer A5 check for a different effect code A5 210 If only occurs once then may be a tim do not agree on power ing error 200 Interrupt Unused Interrupt tripped Reset System Note Error code if it reoccurs Monitor did not read message A5 If persistent 019 may have failed A5 Monitor did not respond A5 If persistent U19 may have failed A5 Bad Cal Data Calibration Data bad A5 Recalibrate see Calibration Section EEPROM failed A5 only the section for ABC at 11 amp 149 spray at 49 A R M open circuit 203 Mailbox error Bad
79. n the handcontrol The Coag display will flash when the Remote Power mode is active and the tone will change Ifthe displays do not flash it typi SYSTEM 7550 cally means the double press did not occur within a specified time of 400mS Try the function again To advance the power setting press the Cut button to reduce the power setting press the Coag button With the power lt 20W the power changes in 1W increments e With the power 220W the power changes in 5W increments brief tone occurs each time the power changes To exit the Remote Mode double press the Coag button or wait 5 seconds and the system will automatically exit the Remote Mode 4 Rapidly double press or double click the ABC light blue button on the handcontrol The ABC display will flash when the Remote Power mode is active and the tone will change If the displays do not flash it typically means the double press did not occur within a specified time of 400mS Try the function again To advance the power setting press the Cut button to reduce the power setting press the Coag button With the power 20W the power changes in 1W increments e With the power 220W the power changes in 5W increments brief tone occurs each time the power changes To exit the Remote Mode double press the ABC button or wait 5 seconds and the system will automatically exit the Remote Mode 7 7 7 Return Mo
80. n to the anode of the output diode D2 the highest voltage of the two inputs When the output power exceeds the requested power PERR is positive and will be passed through D2 which puts a positive voltage on the input to the integrator U3C The same applies when the measured HVDC is greater than requested HVDC at the Differential Amp U4A output A positive voltage on the input of an integrator will result in a negative integrator out put which reduces the HVDC The output of the integrator U3C is a positive voltage and is used as a reference on a compara tor U5D On the non inverting input U5 12 of the comparator is the RAMP that is synchronized to the AC Line Each time the RAMP on U5 12 exceeds the reference voltage on U5 13 it causes the output of the comparator to switch from low to high The purpose for the NAND function U12C insures the triac trigger cannot occur before the ramp transitions downward thereby limiting the triac triggering range to the values of 80 to 170 degrees U12 10 triggers U14 4 on the rising edge which results in a pulse of approximately 100uS on U14 6 U14 6 triggers the selected triac driver according to the mode activated The high voltage triac HVTR is selected for Pinpoint Spray and ABC while the low volt age LVTR is selected for Cut Blend amp Bipolar modes These two signals are active LOW SYSTEM 7550 To enable the correct triac the signals Pin
81. ncreases Argon hoses from the 5 way tee to the differential pressure transducer are reversed Intermittent activation using RF Output jacks worn out Replace Jacks handcontrol Dual Pad Monitor Set will not Resistance on PP receptacle 10 e Confirm resistance gt 12 ohms lock ohms Test to see if any other panel switches Monitor set switch on overlay failed have failed Recalibrate A R M re SYSTEM 7550 No Output No RE Drive on the Power FETs If true for both amps then HVDC lt 12V Check for 15 on amp T2 of the amplifiers PP relay not the problem if bipolar or ABC have no RF output If only one amp then Spray relays if only Spray K2 K4 FILR relay if Cut Blend Pinpoint and Bipolar K1 K3 PP relay if Cut Blend Pinpoint and Spray K8 ABC relay if only ABC K9 Bipolar relay s if only Bipolar K10 11 If only a handcontrol or footcontrol then the relay associated with that RF output Error Storage and Retrieval Press Store switch to display errors or to exit The last 16 activation errors are saved automati cally Power On Self Test idle and test mode First error to be displayed will be the newest errors are not stored Activation errors are saved BIPOLAR POWER DISPLAY will show 1 in a circular buffer that writes over the oldest Use PROGRAM SELECT SWITCHES to error and saves the new error If multiple error displa
82. nitor A R M Aspen Return Monitor The return monitor allows a Single Foil Dispersive Electrode or Dual Foil Dispersive Electrode to be connected to the System 7550 1 Select Single Pad The A R M tests for resistance at the pad site of 10 2 ohms To test the A R M parameters for a Single Pad connect a decade resistance box DRB or discrete resistors across the two conductors of a patient plate cord With resistance 8 ohms Return Fault indicator is With resistance gt 12 ohms Return Fault indicator is flashing Verify that when the Return Fault indica tor is flashing an audible alarm occurs if any mode but bipolar is activated 2 Select Dual Pad The A R M tests for resistance at the pad site of greater than 102 ohms and less than 150 5 ohms test A R M in Dual Pad it is recom mended a decade resistance box DRB be connected across the two conductors of a patient plate cord If a DRB is not available discrete resistors can be used Ensure Dual Pad is selected Resistance lt 5 ohms Bargraph off Return Fault indicator is flashing Resistance 12 ohms Two 2 bargraph segments flashing Monitor Set indicator flashing Return Fault indicator flashing Press Monitor Set Two 2 bargraph segments on Monitor Set indicator on Return Fault indicator off Resistance 20 ohms Three 3 bargraph segments flashing Monitor Set indicator flashing Return
83. ntative of maximum allow able alternate path leakage current at U1B If the leakage exceeds the limit value as set by R15 J1 5 slews positive The positive signal at J1 5 is supplied to the HV FLOW Control Assembly to limit the High Voltage Power Supply output HVDC Limiting or reducing the High Voltage Output results in reduced RF Leakage 6 11 4 Transformer Select Relays The ABC and Spray Coag transformers along with the associated tuning capacitors are coupled to the Single Ended Amplifier SE Amplifier by relays 1 and K2 on the HS A R M assembly These relays switch into the circuit the primary of the appropriate transformer depending on the mode requested The default or normally closed position of the relays selects the ABC transformer The relay driver is located on the Power Control Assembly When Spray Coag is activated J2 5 is pulled low allowing current to flow through the relay coils to energize them 6 20 6 11 5 Arc Sense Transformer The Arc Sense Transformer connected with the TANK terminal in mode sends a propor tional sample of tank ring down voltage to the Power Control assembly This sample signal 15 used to determine if the amplifier is loaded a heavily damped output signal or open circuit lightly damped output signal With a lightly damped output signal a peak detector on the Power Control assembly provides a switching sig nal for each peak that exceeds a predetermin
84. on tubing connections The sensing orifice is a calibrated 6 13 SYSTEM 7550 CONTROL MICRO Ito V gt DIFFERENTIAL PRES AMP FILTER SENSING ORIFICE TO ABC CONNECTOR AMPLIFIER ARGON FLOW DIFFERENTIAL AMPLIFIER FMON FMON SENSING RESISTOR MONITOR MICRO 50 psi PRES RELIEF GAUGE 3000 psi PNEUMATIC PRESSURE MANIFOLD REGULATOR Figure 6 3 Flow Diagram restriction that provides flow rate information back to the flow control circuit This orifice is the pneumatic equivalent of a current sense resistor The differential pressure across the orifice is pro portional to the flow rate or simply an increase in the flow rate increases the differential pressure as measured across the calibrated restriction Three hoses from the sensing orifice connect back to the flow circuitry Two of the hoses provide differential pressure information while the third hose provides atmospheric pressure information The atmospheric pressure information is used to compensate for usage at various altitudes Lastly the argon gas is filtered prior to delivery to the ABC handpiece accessory 6 6 2 Mass Flow Rate Regulation Referring to the HV Flow Control Schematic Figure C 4b is an analog voltage for the mass flow rate and has a range of 5V to 6 2V To enable the circuit AR_EN must be SET causing U13 7 to go low Signal control needs to be defined at th
85. operating properly SYSTEM 7550 6 4 4 HVPS Low Voltage Components The NPN transistor Q6 provides the supply voltage for the low voltage components on this assembly The voltage source for Q6 is the AC LO where R26 limits the current and the zener diode 12V sets the voltage on the cathode of D6 at about 10 This 10 is used to provide the supply voltage to U3 amp U2 of this assembly The monitoring circuit will test for this 10 and should a failure occur where this voltage is too high or too low the system activation will be ter minated The sense transformers are driven at about 40 KHz by U3 amp U2 with the outputs Q and Q out of phase by 180 The sense transformers are set up for a center tapped push pull drive signal When the top transistors 1 amp Q5 are they pull current from the center tap to ground which produces a signal on the secondary The top transistors then switch OFF and the lower transistors Q4 amp Q2 switch ON reversing the current through the primary and reversing the polarity on the output 6 5 HV Flow Control Assembly 1 The HV FLOW Control assembly provides two unrelated unit functions High Voltage Power Supply HVPS control and Argon Flow manage ment circuits are both on this assembly The sche matics Figures C 4a and C 4b for this assembly are on two pages with the high voltage control schematic and the argon flow control schematic on separate sheets for c
86. or detection and shut down This mode can be changed anytime while the sys tem is in standby Test mode can be selected before the unit is powered on however the store button must be held down until an Err 1 is displayed Test mode is to be used only for system level testing 2 SIN DUAL PAD Default DUAL PAD SIN is for single foil return electrodes 3 ZERO LAST Default LAST SETTING When ZERO is selected all power levels will default to zero when the system is powered on Last setting only applies to power levels of the default modes 4 SPRAY PPT Default PINPOINT COAG Spray Coagulation can be selected as a default mode 5 NON_SIM SIM Default SIMULTANEOUS When the switch is set for non simultaneous activation dual activation will not occur for coag modes 6 GAS TEST for testing purposes only Allows the ABC mode to be tested without argon gas connected Can only be set after the unit has been powered on and completed initialization U32 PORT C Outputs from Monitor This port has three 3 active outputs only and the outputs are used solely to inhibit internal circuits when a system fault is detected GAS En Gas Enable SET to enable argon gas flow CLEAR inhibits argon gas flow Drives the solenoid valve that is part of the argon flow control manifold HV_INH High Voltage Inhibit SET inhibits the HV to the amplifiers Drive Inhibit CLEAR inhibits the RF Drive to the amp
87. pen when the tank pressure is greater than 250 psi and close at lower pressures When the switch closes a yellow indicator on the display panel flashes to inform the user that the argon supply is low WARNING Input pressure lines can hold up to 3000 psi 200 bars of pressure Do not attempt service of pneumatic components within the cart before disconnecting the tank of argon Replacement of any pneumatic com ponents within the cart should have all fittings sealed with pipe sealant to prevent slow leaks Soapy water should be applied to all fittings to insure proper sealing against small leaks SYSTEM 7550 ABC TEST ii ADAPTOR Argon gas exhaust PATIENT PLATE r ADAPTOR PATIENT PLATE CORD TEST LEAD o oju FOOT CONTROL ADAPTOR Figure 7 1 Test Adapters SYSTEM 7550 HC FC BP ABC ESU PATIENT PLATE ADAPTOR T gt HC FC PP po ESU ANALYZER PATIENT PLATE ADAPTOR FOOT CONTROL ADAPTOR amp TEST LEAD HC oA ANALYZER ESU BIPOLAR TWO TEST LEADS Figure 7 2 Test Analyzer Connections 7 10 SYSTEM 7550 ELECTROSURGICAL MODES Calibration Section 8 0 8 1 Introduction This
88. point Spray amp ABC or LVT_EN Cut Blend amp Bipolar must be high These signals originate on the Display Board Assembly Referring to the schematic Figure C 4a a signal labeled LK_CON can also reduce the HVDC is the HVDC requested volt age however PERR power error can override and reduce the HVDC to a lower volt age if measured power is greater than requested power in Cut Blend Bipolar and Pinpoint modes only LK_CON can also reduce HVDC if the RF Leakage exceeds calibrated limits see calibration section RF Leakage is typically not a problem in any mode except Spray and then only when no load is on the output Should the RF Leakage exceed calibrated limits of 140mA 200 ohm load then this signal is positive with respect to ground which causes a reduction in the HVDC When Spray mode has a load then leakage is not an issue and the HVDC returns to the VCON set point To sum up PERR can override and reduce voltage in Cut Blend Bipolar and Pinpoint only LK_CON can reduce HVDC in all modes except Transistor 1 has a label High Voltage Reset attached and is enabled following each activation switches on a transistor of the HVPS that pulls the voltage down to idle in a time of about 100mS The last section of this circuit to be covered is the HV Monitoring Note on the schematic the inputs labeled HV_MON followed by a preci sion rectifier This circuit is an exact d
89. quested A CLEARED is required to enable output power control OV_TST Over voltage test input from control microcontroller A test pin used only to test the ABC Over Voltage circuit during system initialization by a series of pulses that simulate an ABC over voltage condition After the test is conducted the signal is latched low A T Active Target output to control microcontroller ABC mode only A high occurs when ABC is in the ACTIVE mode a low occurs when ABC is in the TARGET Mode For tone control only as the two modes have distinctive tones BM gt 80 Beam greater than 80W from control microcontroller SET when ABC power is greater than 80W An internal limit in U7 for switching from active to target mode Enable input from control microcontroller SET to enable RF Drive to the amplifiers RST Reset from system reset signal A SET causes internal latches to CLEAR CT_Pcon Cut Power Control voltage select SET when Cut or Blend modes are activated Switches Pcon for Cut CG_Pcon Coag Power Control voltage select SET when Pinpoint is activated Switches Pcon for Pinpoint BP_Pcon Bipolar Power Control voltage select SET when Bipolar is activated Switches Pcon for Bipolar SE_Pcon PCON for Spray amp ABC active select SET for Spray or ABC active only Switches in Pcon for Spray and ABC active BM_BST ABC Booster voltage control le
90. r A9 See Figure C 16 for this section The Single Ended Amplifier assembly houses the power switching devices MOSFETs that amplify the drive waveforms for Spray and ABC modes of operation The drive signals for this amplifier originate on the Power Control Assembly The signal labeled SE is the drive signal and the one labeled SE 15 only a reset pulse to reset the mag netics of T2 and it has a pulse duration of about 200nS The input signals are amplified by 01 from 5V to 12V When SE switches from low to high Q4 and Q2 are both switched on and then when SE switches back to low the SE signal switches high to switch Q3 and Q1 Each drive pulse SE enables all the power devices Q9 Q17 Q8 amp 16 at the same time 6 16 When the power devices switch on viewed as a closed switch the current flows from HV through the output transformer primary tank to tank and is passed to HV The current through the transformer primary is developing a charge that 1s stored in the primary of the trans former When the driver is turned off viewing the power devices as open switches now the charge stored in the primary is reversed and flows in the direction of It is during this time that the energy is delivered across the barrier to the secondary of the output transformer The components C6 and primary of the output trans former make up a tank circuit that can store a charge When a load is no
91. re 6 3 for this section Tank pressure indi cated on the pressure gauge located on the rear of the cart is indicative of the quantity of remain ing argon gas low pressure pneumatic electric switch connected to the high pressure tank line closes if the tank pressure falls below approxi mately 240 psi Closure of this switch is used to warn the user of minimal remaining gas supply in the tank indicated on the unit front panel by illuminating the yellow low tank indicator in the ABC section The high pressure of the argon tanks is reduced to approximately 30 psi by a pneumatic regula tor If for any reason pressure downstream of the pneumatic regulator should exceed 50 psi a safety relief valve opens to minimize the risk of excessive pressure in the low pressure lines Continuing downstream of the pneumatic circuit a solenoid valve opens during ABC activation periods This valve acts as a safety valve where it can be closed to shut argon flow off if necessary The proportioning valve is the controller for argon flow solenoid and proportioning valve are on a common manifold that increases and decreases gas flow as a result of the control signal developed by the control electronics Immediately following the pneumatic manifold is a dampener to reduce any oscillations of the gas flow that may occur The next element in the low pressure pneumatic circuit is the sensing orifice recognizable by the five 5 ports for arg
92. rminated In the table below all fatal error codes are shown in bold type The PCB assembly is identified by the assembly number Al A2 A3 etc See Figure C 1 for informa tion on assembly locations The Display PCB A5 has several devices that are programmable and in some instances more than one device has the same program By swap ping the location of like devices a failure may be identified by a change in the system behavior or a change in error codes When removing these devices from their sockets it is recommended to use an IC puller designed for PLCC type devices The following list is of devices with identical pro grams Display Drivers 014 U39 amp 041 Display Drivers 017 020 amp 040 Encoder Activation PIA 016 amp 033 Encoder I O PIA 031 amp 032 The system will not display an error code for all system faults which can make troubleshooting a real challenge This unit has two RF amplifiers multiple output relays and allows activation from either a handcontrol or footcontrol for all modes When attempting to isolate a problem or isolate a problem down to an specific assembly test all modes and test all RF outputs as the process of elimination may be the most reliable means of determining the failure Not all system failures will effect all modes or all RF outputs CAUTION Insure the unit is in the RUN MODE when placed back in service or a Fatal Error will occur Err 20 WARNING When
93. roller latches a Hex count into this register and the magnitude of the count identi fies to the RF Logic FPGA which mode is being requested Cut 39h Blend 1 37h Blend 2 35h Blend 3 33h Blend 4 31h Blend 5 29h Blend 6 27h Blend 7 25h Blend 8 23h Blend 9 21h Bipolar 6Fh PPT 43h Spray 82h C3h PORT OUTPUT RELAY SELECT These outputs connect to a relay driver U23 on this PCB Assembly Upon an activation hex counts are latched into this register for relay clo sure dependent on mode and method of RF acti vation PORT C CIRCUIT ENABLES The following signals are SET during activation as shown PSRQT Power Supply Request Enables the high voltage power supply circuit Enabled for all mode activations PC EN Power Control Enable Enables the Power Control Circuit to inter face with the HV Control Circuit for Power Control when Cut Blend Bipolar or Pinpoint modes are activated LVT EN Low Voltage Triac Enable Enables the low voltage triac 125 V when Cut Blend or Bipolar are activated HVT EN High Voltage Triac Enable Enables the high voltage triac 185 V when Pinpoint Spray or ABC are activated EN Argon Enable Enables the flow control circuit when ABC is activated 6 2 17 T MON U35 The monitor microcontroller verifies that for every activation of RF Output a tone is generated T MON is a signal with the same frequency as the tone generated 6
94. s to the left and 60 Hz when the switch is to the right 757 7550 Ensure the switch is in the correct position for the frequency for which the system will be placed in service Replace the card cage cover 2 Mains Voltage See Figure C 1 for this section To verify the correct Mains Voltage con figuration locate the terminal block that is above and behind the large line trans former In the center of the terminal block are shorting plugs and on the front of the terminal block are numbers to identify each position A system config ured for 120V or 100V will have five 5 shorting plugs A system configured for 210 240V system will have only three 3 shorting plugs The shorting plug loca tions are 120V amp 100V 1 2 2 3 4 5 6 7 7 8 210 240V Rated range 198V to 260V 1 2 5 6 7 8 NOTE The terminal block configuration is shown on the interconnect diagram Figure C 2 Close the cover and secure with the two screws located on both sides 7 7 Initial Setup amp Test Performing this procedure will verify functional operation of the CONMED 7550 Electrosurgical Generator ABC A system error detected on power up will be displayed as an error code See error codes in Troubleshooting Appendix B The testing of this section does not test or verify system calibration but only if the unit is func tioning from a user perspective The calibration section provides procedures for fu
95. schematic Q3 amp Q7 are triacs that are triggered by opto couplers U1 or U4 when the HVPS is enabled Q3 is selected when Spray Pinpoint or ABC modes are acti vated and Q7 is selected for Pure Cut Blend and Bipolar modes The resistor and capacitor that are connected from MT2 amp are snubbers for switching energy and the remaining discrete com ponents contribute to the generation of the trigger pulse The trigger pulse from the opto couplers U1 amp U4 occurs at phase angles of mately 80 to 170 of the AC waveform Following the triacs are two separate bridge recti fiers 1 amp B2 The rectified signal from the bridges is then filtered by C13 amp C14 which results in a DC voltage Resistor R18 is a bleed resistor that will dissipate the energy from the filter capacitors The schematic shows two test points 1 TP2 that are labeled and HV The voltage on these two test points is the regulated DC and is referred to as HVDC Connecting an oscilloscope to the HV and HV test points would show a voltage with 120 Hz ripple and the magnitude of the ripple depends on the load A heavy load on the output means a high ripple rate on the HVDC test points These test points have easy access and are a good place to connect a DVM when troubleshooting a system that does not have any RF Output A system failure detected by the monitor microcontroller and some hardware circuits will typical
96. sembly Each circuit will be covered separately The HS A R M assembly 1s located near the front of the system and is the top circuit board of the two that are stacked See Figure C 20 6 11 1 Handsense Circuit The Handsense circuit is comprised of three 1so lated Handcontrol circuits with each handcontrol circuit dedicated to Monopolar Handcontrol handcontrol 1 Beam Monopolar Handcontrol handcontrol 2 or Bipolar Handcontrol 1 allows activation of either Cut or Coag Handcontrol 2 allows activation of either Cut or ABC Bipolar allows activation of bipolar when using hand activation forceps The components that provide electrical isolation between the control circuits and the RF circuits are T3 continuity transformer and U4 U8 optoisolators On the control side of the bar U3 NE555 timer provides a 100K Hz drive signal at a 2096 duty cycle for T3 primary The secondary winding of T3 provides energy for the handcontrol sense electronics on the high volt age side of the isolation barrier The bipolar handswitch continuity detector will be used as an example since all sections are identical When the bipolar handswitch is closed DC cur rent flows through the LED of the opto isolator U7 The LED produces a beam of light which falls on the photo transistor in U7 causing it to switch on and draw current This current pulls the signal line HBP to a low voltage and this state 1s interpreted on the
97. ses about 2096 above the stored value or goes out of range When a Return Fault condition occurs and if the resis tance is within acceptable 2VARM limits the new 6 19 SYSTEM 7550 value can be locked into memory and the Return Fault condition will be cleared 6 11 3 RF Leakage Monitor The System 7500 actively monitors alternate path RF leakage currents caused by stray parasitic capacitance and limits the available open circuit voltage in response to prevailing leakage condi tions This circuit is primarily active in Spray Coag mode but is available in all modes of opera tion except ABC The balun transformer description was covered in the RF Output Assembly discussion where it was stated that the magnetic field is equal and oppos ing if the source and returning RF currents are equal If the source and returning currents are not equal alternate leakage paths exist and the balun transformer field becomes unbalanced resulting in restriction of the available output current due to the inductive impedance of the transformer The balun transformer has a single turn winding that has currents induced within it when a magnetic field of the balun is unequal due to RF leakage The RF Leakage sense winding connects to J16 on the HS A R M assembly The signal at J16 is an AC voltage that is converted to a DC volt age at U2 which is an RMS DC converter The true RMS voltage is compared with a reference DC voltage represe
98. sing on each connector to ensure they are seated Visually inspect the bottom of the inside of the Head assembly for any loose hardware 7 5 Each time the System 7550 is powered it will initialize to the default modes Four 4 of the default settings can be changed to best fit the user requirements To change the system default settings locate the micro switch on the back side of the Display PCB Viewing the switch with the cover raised down is OFF and up is ON The positions are numbered from left to right All default settings are OFF or down from the factory Pos 1 Default Run Mode ON Test Mode For system troubleshooting only Pos 2 Default Dual Pad ON Single Pad Pos 3 Default Last Power Setting ON Powers initialize to OW Pos 4 Default Pinpoint ON Spray Pos 5 Default Simultaneous Activation Default Settings Factory Settings ON Non Simultaneous Activation Pos 6 Default ABC Argon Monitor enabled ON ABC Test Mode Allows ABC testing without argon gas amp inhibits argon flow alarms 1 TEST MODE When this switch is ON the internal monitoring is shut off allowing system 7 2 testing without mode inhibits shutting the system down WARNING DO NOT PLACE UNIT IN SERVICE WITH TEST MODE ON The TEST MODE can be enabled anytime when the Power is on If TEST MODE is selected when the unit is powered on an Err 20 is displayed An Err 20 can
99. t as required The exterior of the unit may be cleaned by wiping it down with a damp not dripping cloth Use a mild detergent such as Windex or Formula 4099 7 3 Generator amp Mobile Storage Assembly The System 7550 consists of a Generator assembly Head Assembly and a Mobile Storage assembly Cart In most cases the two are shipped pre assembled disassemble the two follow the assembly steps below in reverse order Refer to page 2 3 of the Operator Manual CAUTION The Generator Head assembly is heavy and awkward Lifting of the Head on or off of the Cart should be done by two 2 people to reduce the risk of injury 1 Set the Head Assembly on the Cart the argon tanks are placed on the back of the cart 2 Insure the Head Assembly is fully seated on the Cart Notice that the Head has four 4 threaded studs that drop down into the Cart 3 Locate the two threaded studs that are inside the Cart but against the back wall Place a wing nut on each of the two back studs but thread the wing nuts on the studs by only two or three turns 4 With one person supporting the Head tilt the Head Assembly towards the back of the Cart This allows access to the footswitch connector and argon gas line CAUTION The Head Assembly is heavy and can topple off backwards if not supported the two wing nuts on the two back studs will help with the support but will not keep the head from tipping the cart backwards if the he
100. t connected to the system output then the current alternately flows from one side of C6 to the other until all the energy is dissipated The repetition rate for a drive cycle is 35S for Spray and the pulse width is fixed at about 1 348 typically See Figure 6 1 The output power for the Spray mode is controlled by varying the HVDC In ABC the power is controlled by varying the pulse width and the HVDC is fixed at 200V The pulse duration in ABC active is from 200 to approximately 34S ABC has three separate modes that will be discussed in this section The modes are Target Booster and Active The modes Target and Booster alternately are active whenever a load 15 not present at the tip of the ABC handpiece The Target mode is basically 1032 pulses at a 400nS pulse duration and then the next 32 pulses will have a pulse duration of 600nS which is called the Booster mode Following the Booster mode the cycle starts all over again until a load is sensed at the ABC handpiece and then the unit switches over to the Active mode The repetition rate is also different for the ABC modes Target and Booster have a drive pulse every 60S but in the active mode it occurs every 35uS The purpose for the Target and Booster mode is to reduce the RMS voltage when a load is not present and this results in lower RF Leakage Once a load is present which means the Beam is Active RF Leakage is no longer an issue and the RMS volta
101. t of Illustrations Section 1 0 2 0 3 0 4 0 5 0 6 0 6 1 6 2 6 2 1 6 2 2 6 2 3 6 2 4 6 2 5 6 2 6 6 2 7 6 2 8 6 2 9 6 2 10 6 2 11 6 2 12 6 2 13 6 2 14 6 2 15 6 2 16 6 2 17 6 3 6 3 1 6 3 2 6 3 3 6 3 4 6 4 6 4 1 6 4 2 6 4 3 6 4 4 6 5 6 5 1 6 5 2 6 6 6 6 1 6 6 2 6 6 3 6 7 Title Page General Information Refer to Operator s Manual P N 60 7551 System COmDpOHBCHES Refer to Operator s Manual OP CPA M Refer to Operator s Manual Operator au Refer to Operator s Manual Technical Information isei ccinsscxcavesoasexosseess Refer to Operator s Manual Circ it DesctiptiOnsS 6 1 6 1 Display Panes Assembly A5 i t Pare b 6 1 General Information er i 6 1 Malbos 6 1 Power Adjustments U16 amp 033 6 1 Activation Requests UIG 1039 ra 6 2 Mode Select Encoders U31 8210521 itte eren 6 2 Display Drivers Seven Segment U14 020 039 040 041 amp 017 6 3 Indicator Driver U34 6 3 Firmware U28 Gc
102. the TEST MODE is enabled the system is NOT SAFE for use in a procedure as most of the monitoring func tions are ignored or turned off Note Service at this level should only be per formed by qualified service technicians 1 SYSTEM 7550 Control Microcontroller Failure Codes and Troubleshooting Tips Probable Problems Suggested Solutions Stuck Front Panel Switch User pressing switch during power up Disconnect J1 on the Display Panel and Front Panel overlay failed power up again If Err 1 is displayed then U5 on A5 may be defective U5 A5 failed Stuck Hand or Foot User pressing switch during power Disconnect accessories one at a time to Activation Request up identify failed accessory start with the Failed Handcontrol or Footcontrol handcontrol if connected Failed component A5 or 11 Handcontrol signals Active low Footcontrol signals Active high 20 Default Switch Default switch position 1 or 6 is ON Position 1 and 6 should be OFF see Setting maintenance section for TEST Mode Stuck encoder bits Logic Failed Logic Device A5 Identify which encoder causes the device failed error Swap U16 amp 033 for power encoder Swap 031 amp U32 for Blend or Flow look for a difference when swapping 10 Calibration Tolerance Error too low Recalibrate See Calibration Section ARMCAL 10 Calibration Tolerance Error too high Recalibrate See Calibratio
103. tioning valve 6 6 3 Smart Sense The System 7500 utilizes Smart Sense to control the mass flow rate in different manners for each of the flow modes when a partial or total occlusion is detected This discussion will be lim ited to only Smart Sense response for each mode and what causes actions to occur Automatic Mode When a partial occlusion is detected in this mode the flow rate is reduced by 1 Ipm increments or until the maximum back pressure occurs which will set an alarm Flow reduction only occurs for flow settings greater than 4 lpm and for all dial settings that meet this criteria the flow rate may be reduced down to 4 slpm If the partial occlusion is removed the flow will return to the original setting Any change in the flow rate is displayed A partial occlusion may be caused when the tip of the handpiece is in contact with the tissue or by an accessory that has a small exit orifice or a reduced exit orifice with a long nozzle NOTE Some accessories cannot be used in the Automatic mode because the back pressure exceeds speci fied limits use manual mode instead Manual Mode Smart Sense only tests for total occlusions in Manual mode An occlusion alarm occurs with a back pressure greater than 7 psi within the argon flow tubes This mode will not override user settings Endo Mode This mode will reduce flow rates when partial occlusions are detected however at a different rate and for a d
104. tiplier U6 which results in a product term called Q measured flow at the cathode of D5 that is linearly propor tional to the mass flow rate With flow regulation the voltage at D5 cathode or Q will be approximately the same as VGAS differential amplifier compares the difference in VGas and Q at U8D Should Q be greater than VGas 08 14 will be positive and when is less than VGAs then 08 14 is negative The integra tor USB has an output of opposite polarity of the input 08 6 and as an integrator it controls the time at which the flow response can occur The output of the integrator U8 7 is always posi tive with a range of approximately 1V minimum flow to 12V maximum flow The transistor Q2 is the driver for the proportioning control valve The output signal labeled FMEA is monitored by the controlling microcontroller on the display assembly This signal 1s one half of the PABS volt age and is a means of allowing the system to mon itor the argon back pressure FMEA has a range of 2V to 3 5V The output signal labeled is watched by the monitoring microcontroller on the display assembly as a means of verifying the proportion ing valve current is within specified limits for each flow setting 15 calibrated at 4 lpm to be 2V A loop failure that can cause flow to deviate from the requested flow or a shorted driver will be detected by EMON and the flow is inhibited by shutting off the propor
105. trollers and if the two do not agree on an acti vation request an error code Err 303 or Err 307 will be displayed Footcontrol m Footcontrol ABC Active High Note HABC Handcontrol is activated at handcontrol 2 and is a result of H2CT H2CG DR which is an output of U16 6 2 5 Mode Select Encoders U31 amp U32 Blend Level BL and Argon Flow FL rate is adjusted by the same type of encoders as used for power adjustments The logic within U31 amp U32 for these two encoders is the same as for power adjustment and the discussion for power adjust ment applies here These logic devices have I O ports also and the following text provides a brief description of each port signal U31 Port PBO PB7 Inputs for Control Microcontroller LPSW Low Pressure Switch SET when the argon tank pressure is less than 240 psi Low Tank warning is illuminated Flow Deviance SET if an occlusion occurs to the argon flow A_T Active Mode or Target Mode ABC mode and used for tone selection only T SET tone 15 500 Hz and is active A T CLEARED tone is 250 Hz and ABC is in the Target mode BRN OUT Brown Out Holds high for at least 6 seconds when power fails and 15 used to identify a temporary power loss The user settings are returned following a temporary power loss Tone A Tone Signal Mode Activation and Alarms Square wave sig nal with frequency between 250 Hz to I
106. uplicate of the HV_SNS signal previously discussed on both this assembly and also on the HV power supply assembly A ratio of the HVDC is sampled at filtered and rectified for a DC voltage on the cathodes of the output diodes The resis tors 9 amp divide the monitored voltage down by one half so that it will not exceed 5V U1B is a non inverting amplifier that is calibrated for 1V when the HVDC is at 50V The resolution of this signal is 20mV V or for each 20mV measured on UI 7 the HVDC is 1V 6 6 Argon Flow Control A1 See Figure C 4b for this section The argon gas flow control circuitry provides control functions to produce a regulated argon gas mass flow rate at the ABC handpiece tip The requested mass flow rate VGAs signal originates on the unit front panel and is user controlled by the ABC power setting in the Automatic mode or by the user specified flow rates in the Manual and Endo Modes VGas has a range of 0 7V to 6 2V Argon Modes and Flow Rate Ranges liters per minute Manual Mode 0 5 10 Ipm Endo Mode 0 1 4 0 Ipm The Mass flow regulator is a closed loop system The requested mass flow rate is compared with the requested flow rate and the result is an error signal that adjusts a servo controller to either increase or decrease the argon flow under stand the circuit we will first identify the pneu matics which the circuit operates 6 6 1 Pneumatic Circuit See Figu
107. urrent that is delivered to the patient 171 amp U3 are RMS to DC converters that convert both signals to a DC level so they can be monitored and controlled The DC level is then connected to the input of a unity gain amplifier U2 U2 is used to control both voltage and current lim its outside of the load regulation range For the time we will focus on the simpler aspect of this circuit and cover the limits later in the discussion Power regulation can be seen on the load curves that are within this manual See Figure 5 1 10 Pure Load Curves Using Pure Cut as our mode for discussion the output power is regulated between 300 ohms to 1K ohms When the RF load is between 300 ohms and 1K ohms the outputs of the amplifiers connected to U1 amp U3 are negative or the diodes D4 amp D3 are reverse biased The DC value of the RMS to DC con verters 15 passed around the amplifier to the cath odes of D4 amp D3 where they are buffered by the unity gain amplifiers U2 U12 is a multiplier that multiplies the mea sured voltage VSN and measured current ISN together for a product term called POWER P VI On the output of 012 is an amplifier 010 with a potentiometer RA5 in the feed back This potentiometer is used to calibrate the gain of the loop and it is this potentiometer that is adjusted for Pure Cut calibration The output of the amplifier 010 is called measured power and the measured power is compared to the requested
108. uses internal RAM 6 2 10 A D Inputs Control Microcontroller Only four of the 8 internal A D inputs are uti lized and three of these inputs are for the A R M Aspen Return Monitor 2VARM A voltage that represents the resistance of the patient plate ARM 10 Calibration limit for 10 ohms See A R M cal ARM 150 Calibration limit for 150 ohms See A R M cal FMEA Back pressure monitoring for argon gas flow The control microcontroller monitors this signal as a means of detecting occlusions or special accessories with small orifice sizes When the monitor microcontroller senses an error at ARM 10 or ARM 150 it will display an error code to identify which input has the fault These are fatal errors that require the system to be reset 6 3 SYSTEM 7550 when they occur An error for 2VARM is return electrode fault and occurs when the resistance measured on the return electrode is not within specified limits for either a single or dual foil return electrode An error code is not displayed however the red indicator for a return electrode fault is illuminated In many cases intermittent or continuous alarms associated with these signals can be rectified by going through the calibration procedure for A R M FMEA has an idle voltage of one half of the value of PABs When testing or troubleshooting use the calibration procedure for PABs to determine the value of FMEA when no argon flow is occur ring
109. utput Power Finding the bad relay is not always obvi ous but when troubleshooting potential relay problems start with the driver The relay driver is 6 17 SYSTEM 7550 located on the Display Assembly and one should first verify that each relay according to the table above is receiving a drive signal Also spend time to test all modes and all outputs as the process of elimination may be the fastest and most effective way to identify a faulty relay 6 10 Low Voltage Power Supply A6 This assembly provides 5V 15V and 15V to the system circuits dedicated low voltage trans former connects into the assembly at J1 where it 1s tapped for 18Vrms and 8Vrms The regula tors of this assembly only require a rectified and filtered input that is at least two volts greater than the output voltage The regulators have current limit and thermal shutdown capabilities short ed component on a different assembly can cause excessive current draw from a regulator that will be limited however the current draw will allow the regulator temperature to heat up until the thermal shut down is activated There are two 2 15V regulators with Q1 dedi cated to the FB Amplifier and SE Amplifier Drives Q2 provides 15V for the system logic indicators and relays Regulator Q5 provides the 15 to the system to include the source for 10V and 5V that is used on the display panel The 5V supply uses a small switcher type de
110. vel SET to enable Boost Pcon BM ABC Target voltage control level SET to enable Target Pcon 6 7 SYSTEM 7550 5 Scaler to calibrate Spray power SET for Spray activation to rescale SE_Pcon for Spray calibration and control T RLY Tank Relay selects either the Spray or transformer primary set when Spray is acti vated XSLO Transformer Sense input must be low If the harness from the Handsense PCB to the Power Control PCB is not connected or bro ken this signal is pulled up and will inhibit single ended operation A SNS Arc Sense A pulsed signal that pulses high any time the ABC output exceeds a reference level Four or more pulses indicates an open circuit on ABC and less than four pulses indicates the output is loaded ABC OV ABC Over Voltage Pulses if the output exceeds 3500 Vpk and 192 consecutive pulses will cause ABC to be inhibited If a failure occurs that latches ABC in the Active Mode this signal will inhibit RF at power levels greater than approximately 45W SE EN Single Ended drive control When this signal goes low it allows C10 to start charging up and RF drive to the Single Ended Amplifier occurs SE PW Single Ended Pulse Width RF drive to the Single Ended Amplifier starts when SE EN goes low and stays on until this signal transitions high When this signal tran sitions high drive is terminated for one cy
111. vice because the 5V supply current can be close to 2A switcher operates more efficiently than a linear regulator such as Q1 Q2 amp Q5 not needing as much heat sink As set up the switcher oper ates quite similar to the other regulators where the input must be greater than the output for voltage regulation to occur The input to the switcher is 8Vrms and the output of the switcher is a square wave at 5V The LC L1 amp C10 components convert the switching signal to a DC signal Included on this assembly is the flow control pneumatic manifold This manifold assembly has the solenoid valve one nearest front and flow control proportioning valve assembled within it and if one should fail then both must be replaced The proportioning valve is current controlled so as the current is increased the internal opening is increased allowing more argon gas to flow The solenoid valve is also referred to as a digital valve meaning it is either on or off To test the valve coils place a DVM or oscillo scope on the driver for the device under test The coil resistance of both valves is 72 ohms The 6 18 proportioning valve voltage changes with the flow setting V IR The collector of the driver for the digital valve will switch from 15V to near ground when the valve is energized as the valve drops almost all of the voltage 611 HS A R M Assembly A11 There are four independent and unrelated cir cuits on this Board As
112. w rate is 8 slpm 5 slpm not then adjust for a flow rate as near 4 slpm and 8 slpm as possible 8 6 4 FMON Calibration Connect a standard ABC accessory to the System 75507 Select Manual Flow Mode at 4 slpm Activate ABC Mode adjust RA6 FMON for 2V 8 7 Power Calibration The power adjustments within this procedure will specify a load and power setting for calibration For each power mode the output power should be checked at low medium and high power set tings to verify the output power tracks the dis played power setting See Figure 2 2 for informa tion on connecting an analyzer to the RF outputs for power calibration 8 7 1 Filter Calibration Full Bridge Modes Optional This calibration is to calibrate the bandpass fil ter for the RF output modes of the Full Bridge Amplifier Disconnect the white red striped lead from the High Voltage Power Supply A7 to the Full Bridge Amplifier A11 e Connect the positive lead of an ammeter rated for and set for 10A to the DC terminal of the High Voltage Power Supply connector J2 Connect the negative lead of the ammeter to the white red striped lead that goes to the Full Bridge Amplifier Set all power controls to OW initially Adjust Pure Cut power for 2W Connect a lead from the Return Electrode con nector to the Footcontrol Connector Short the RF Output Activate Pure Cut Adjust the power of Pure Cut for a current r
113. y the other errors codes occur and are displayed during use of the Press Monitor Set switch to clear error unit they are stored in the sequence that they are memory displayed Unit must be in test mode to activate error display Error Display Configuration Toggle between Err and the error code Mode LED status is displayed when the MONOPOLAR CUT BLEND POWER DISPLAY shows Err Note the Active status and Mode LED status codes are in decimal and must be translated to binary The individual bit field description can be obtained from lists shown below DO is the least significant bit and D7 is the most the least significant bit Active status DO 1 when Return Fault LED on DI 1 when FLOW FAULT ALARM LED D2 1 when LOW GAS SUPPLY LED on D3 1 when Remote Power Control Mode active SYSTEM 7550 D7 D4 ACTIVATION REQUEST 1011 Hand Control 2 Coag and Foot Coag 0000 no request 1100 multiple keys not released 0001 Hand Control 1 Cut 1101 to 1111 are not used 0010 Hand Control 2 Cut Mode LED status 0011 Hand Control 1 Coag DO 1 when Remote on 0100 Hand Control 2 Coag DI 1 when Dual Pad on 0101 Hand Control 1 Coag and Hand D2 1 when Single Pad on Control 2 Coag D3 1 when Manual on 0110 Foot Cut D4 1 when Automatic on 0111 Foot D5 1 when Pin Point on 1000 ABC D6 1 when Spray on 1001 Bipolar D7 1 when Endo on

Conmed 7550 ESU - Frank`s Hospital Workshop

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