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Synare 3 Service Manual

1. continued the strike force The capacitors each discharge at a rate determined by their bleed resistors Two envelopes have variable bleed resistors which are variable from panel controls labelled filter and amplifier decay Both variable envelopes are followed by emitter followers The third envelope has a fixed bleed resistor It bleeds through the voltage controlled amp lifiers together with one of the variable enve lopes The other variable envelope filter decay is used as a filter control voltage to produce sweep U TRICCER Filter Envelope Amplifier Envelopes Testing The envelopes are difficult to trouble shoot because of their common base connection A failure at one base looks like a failure at all The easiest thing to is to replace all three 04s Lt MODIFICATIONS Any modification to a Synare 3 not done by the factory or authorized by the factory voids the warranty The following group of potential modr ifications IS NOT authorization to do modifications External Power The Synare 3 requires 20 volts at 25 ma when being played Power can be applied through the 5 pin connector on the component side of the board or hardwired A description of the connector can be found in the section labelled TESTER Hardwiring consists of connecting sup ply plus to either end of the red twisted pair and supply minus to speaker minus the black wire The use of external power will add hum to the output unle
2. SYNARE 3 REPAIR MANUAL TAHR INSTRUMENTS INC BOX 71 STAFFORD SPRINGS CT 06076 USA INTRODUCTION synare 3 is a battery powered stick activated electronic drum that functions Tike a keyboard synthesizer The strike of a drum stick connects the batter ies to the voicing circuitry and activates the envelopes These two actions result in the production of a sound in accordance with the Settings of the front panel controls NOTE Before repairing a faulty unit it would be wise to do two things 1 go through the instruc tion manual using a good unit 2 go through the repair manual with a good unit COMMON PROBLEMS Description Most problems that occur in Synare 3 can be fixed without the use of schematics These problems result from two sources worn out batteries and careless use Worn out batteries Most Synare 3s returned for repair simply have worn out batteries Worn out batteries can manifest themselves in many sur prising ways by pitch drift frequency modu lation distortion no sound production etc Therefore always test a unit with fresh batter ies and request that units sent back for repair include the batteries Careless use No one plays harder than a drum mer This some times results in broken pot Shafts switch handles loose pot nuts broken battery snaps and broken wires A third less common class of problems is repre sented by those units that are intermittent or crackle when pl
3. ayed These result from cold solder joints which can be visually detected and faulty pots or switches Testing Begin by listening to the returned unit using fresh alkaline batteries If the unit does not respond check for broken wires or faulty battery snaps If the unit still does not respond or responds poorly visually check for cold solder joints If this fails to uncover anything gently pry the knobs off the pot shafts using a screw driver Remove the nine nuts holding the pots to the hood Inspect the back of each pot for broken pots All of the above problems can usually be solved without having to look at the schematics and rep resent the vast majority of Synare 3 problems SCHEMATICS i Eight circuits are used to produce the sound that results from the striking of the playing Surface 1 battery saver circuit 2 regulators 3 noise generator 4 oscillators 5 voltage controlled filter 6 filter control 7 voltage controlled amplifier 8 envelope generators BATTER SAVER CIRCUIT Description This circuit disconnects the bat teries from all remaining circuits 10 20 seconds after the last strike on the playing surface Its purpose is to extend battery life 2 BATTERY SAVER CIRCUIT Description continued A speaker is used as a transducer to detect strikes The voltage produced by the speaker coil s motion is applied to a transistor amp lifier The output of this amplifier goes to the envelope ge
4. ly ranges from 2 to 3 megs The filter s Osc 2 control adds frequency modu lation or vibrato to the filter The speed of modulation is determined by Osc 2 s tune control and selector switch The sweep control causes the filter pitch to instantly jump up on a pad strike and then to glide back down The time of the glide is set by the DE decay control Problems in this area are usually caused by faulty pots AMPLIFIERS Description The voltage controlled amplifier consists of a transconductance amplifier 3080 used as a two quadrant multiplier Its audio input comes from the filter and its control input is the combination of the outputs of two envelope generators The output of the 3080 drives the volume pot and the output jack AH 3080 x JACK R ver ENV cb IN T Voltage Controlled Amplifier Testing The output of the amplifier may be cone veniently tested at the volume pot or output jack There is rarely a problem with the 30805 In general suspect the envelope generators ENVELOPE GENERATORS Description There are three envelopes in Synare 3 The envelopes are initiated by a strike on the playing pad The output of the speaker amp lifier in the b s c is applied to three 04s each connected in an emitter follower configuration with large capacitors in their emitters The strike charges each capacitor to the base voltage The base voltage is proportional to ENVELOPE GENERATORS Description
5. nerators and a one shot used to switch the battery voltage to the regulators AIH i 4 zZ 1 1 REC At RE Speaker Amplifier One Shot Testing Install the batteries and put a phone plug into the unit The phone plug switches the battery voltage to the battery saver circuit With fresh batteries the voltage at point A should measure 16 20 volts us ng battery minus as ground The black wired speaker terminal is a convenient place to pickup battery minus If the battery voltage is not present check the battery snaps or the switching jack for function If the voltage is present tap the speaker coil with a screw driver to simulate the playing pad being struck Simultaneously check to see if the collectors of the 2n3906s have jumped to hattery voltage If so move on If not check the circuitry of the b s c for function Note that this voltage will disappear after 10 20 seconds 3 REGULATORS Description This cicuit provides regulated volt age to all the voicing circuits for 10 20 seconds beginning at the instant the playing pad is struck The one shot of the b s c is connected to a pair of PNP transistors wired in a darlington config uration This pair switches battery voltage to the regulators The two regulators produce 12 and 6 2 volts from the batteries 16 20 volts The 6 2 volt regulator is used as an imaginary ground Ground from all external equipment is connected to it Switch Regulato
6. on film Capacitors all values are Jisted in microfarads Transistors three different transistors are used and are referred to as 04 06 and Al4 An 04 is a 2N3904 an 06 is a 2N3906 These are general purpose NPN and PNP transistors The Al4 is an MPSA14 which is an NPN darlington Integrated Circuits Eight ICs are used Five are 3080 transconductance amplifiers available from National or RCA Two are TO 3 regulators One is a CMOS 4093BE only RCA 4093s will work Batteries Alkaline batteries are recommended Potentiometers Three different pots are used Their values are stamped on their faces The most common 5 is a 50K the balance 4 are 1 megs of two different tapers Jack The jack is multifunction It is used as an output and to switch battery voltage Speaker It is a standard 3 inch 8 ohm speaker Circuit Layout The circuits are seneral ly la cated near their front panel controls The sketch below showes their general location with respect to the ICs and pots This sketch does not exactly apply to early serial numbers ciel m Osc Voltage Controlled Filter Amp Battery Regulators saver Filter Control
7. put Stage 1 Stage 4 FILTER Testing It is easiest to test the filter with the resonance turned to zero non oscillating mode Input Osc 1 to the filter and turn up the filter tune The fourth stage of the filter should now be passing Osc 1 If not beginning with the first stage check the emitter of each darlington emitter follower for the presence of Osc 1 This should easily point out the faulty filter stage Testing of the filter as an oscillator will be covered in the next section FILTER CONTROL Description The filter control circuit tunes the filter s cutoff frequency by controlling the integrating current of all four filter sections The circuitry consists of a simple resistor mixer followed by a current generator 1 8 te JM oY Be a Pvt Mixer e Current Source Testing The easiest way to test this circuit is to have the filter in its oscillating mode 8 FILTER CONTROL Testing continued and to see if the filter responds properly to its control voltages To use the filter as an oscillator the selector Switches should be off and the resonance turned up full The filter has three panel controls that effect filter tuning filter tune filter Osc 2 appli cation of triangle wave and filter sweep filter envelope The filter tune control is capable of moving the filter from 30Hz to 4KHz The bottom end 30Hz is adjusted at the factory by selecting a resistor that normal
8. rs Testing Check to see if the regulators are pro ducing the proper output voltages For the re maining measurements it is useful to use the imaginary ground as a Scope reference This can be picked up at the terminal of the jack with a black wire on it NOISE GENERATOR Description The noise generator consists of a selected transistor whose base to emitter junction is used as a zener noise source The output of the noise source is amplified by a single trans istor amplifier NOISE GENERATOR KIA oe j ae z NOISE _ Source Amplifier Testing Noise can be checked at the output of this circuit Don t forget to tap the speaker to turn the power on Most noise problems con sist of insufficient amplitude or modulation on the noise They can be fixed by replacing the noise source OSCILLATORS Description The two oscillators are generated by a CMOS 4093 The 4093 contains four 2 input nand gates with Schmidt trigger inputs Two of the four sections are used to form oscillators Osc 1 is a single inverting schmidt trigger wired as a dual slope integrating oscillator A square wave is available at its output The frequency of this oscillator is variable from 40 to 1500Hz Osc 2 is identical to Osc 1 except for two abil ities 1 it is range switchable and 2 a tri angle output is available Range switching is achieved by increasing the J OSCILLATORS Description continued size of the intergra
9. ss the source is well filtered Reduced Oscillator Range The high end of the oscillators can be decreased in frequency by increasing the 22K resistor in series with each pot The low end can be increased by decreasing the 047 integrating capacitor This will also in crease the high end The high end can be brought back down by increasing the 22K resistor External Inputs Studios have used the output from their mixing board to trigger a Synare 3 This was accomplished by placing a switching jack in series with the red speaker wire When no external trigger is plugged in the normal 12 MODIFICATIONS External Inputs continued Synare 3 speaker a ts as an input When an ex ternal input is plugged in the speaker is dis connected and replaced by the external input Outputs from mixing boards and microphones have been used to trigger Synare 3s TESTER A 5 pin 0 100 inch centers connector is visible on the component side of the board This con nector is used during electrical checkout Two of the pins are used to apply the equivalent of battery voltage to the Synare 3 Two pins are used to electronically monitor the regulator outputs The fifth pin is used to simulate the striking of the playing surface Sketch shows component side Q o o Battery renee Speaker Input Battery Plus 12 Qutput 6 2 Output Connector GENERAL COMPONENT INFORMATION Resistors all resistors are watt 5 carb
10. ting capacitor The triangle is derived from the integrating capacitor at the input This point is buffered by a darlington emitter follower The triangle output is used as a filter control voltage The square wave outputs of the oscillators are used as audio inputs to the filter when their Selector switches are pushed to the right The center position of Osc 1 s switch inputs noise to the filter The center position of Osc 2 s switch reduces the frequency of Osc 2 by a factor of 20 Oscillator 2 6 OSCILLATORS Testing The output of the oscillators can be measured at the 4093 tuning pots or the input to the filter Common problems are broken switches pots and rarely a bad 4093 Note that only RCA 4093s work well in this circuit It is also normal for the triangle output to appear clipped until the filter s Osc 2 pot is turned up _ FILTER Description The four pole low pass voltage controlled filter is the dominant portion of the Synare 3 It can be used as a sine wave oscilla tor or as a timbre modifier of the oscillators and noise generator The filter is composed of four voltage controlled integrators Each integrator is a transconductance amplifier 3080 followed by a darlington emitter follower The fourth stage is fed back to the first through the resonance pot to permit adjust ment of the filter s Q Only two of the four stages are shown below Fc O ELD al Ex U Fe n

Synare 3 Service Manual

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