Kenwood ts-430 AGC mod
Contents
1. Kenwood TS430 modifications repairs improvements 3 23 connector and works when the plug is inserted The fix was to insert and remove the plug in the jack several times Since I have done this my 430 has never shown this symptom again I wish I could claim to have deduced this myself but it was pointed out to me by a friend who read it in a snippet from someone in QST To whoever took the time to send in that suggestion I am eternally grateful Hope this solves your problem too Rob Stampfli rob colnet cmhnet org The neat thing about standards 614 864 9377 HAM RADIO kd8wk n8jyv oh There are so many to choose from To all Kenwood users The 430 has a corresponding problem to the older rigs specifically the 520 S 820 S 530S and 830S rigs Power drops while running if this occurs tighten the screws on the driver board and IF board Had this happen to me and friends a few times also watch out for the coax connector on the back they get loose too no lock washer on the back 73 Tom wb9rxj uiuc edu Diego I had a similar problem with a 430 Mine was intermittent Finally one cold day 0c it became permanent I traced my problem to an open via connection on one of the final transistor bases This resulted in that device not getting a dc return to gr2. Kenwood ts 430 AGC mod The type of speech processor circuit used in the ts 430 is an agc automatic gain control driven audio frequency amplifier By decreasing the time constant substantially the speech processing effect will be improved The modification is very simple Kenwood TS430 modifications repairs improvements 1 23 Replace capacitor c104 4 5 uf on the if board by a smaller value of o 47 uf To Modify This Capacitor 1 Remove the if board as indicated for the cw filter installation 2 Remove c104 from the board 3 Mount a 0 47 uf capacitor on the board 4 Mount the if board as indicated by cw filter installation 5 You are now fully operational again 6 Adjust the mic gain without the processor until normal alc deviation 7 Switch the processor on and adjust vr7 near c104 until normal ALC deviation do not alter the mic gain at this time 8 Enjoy the speech processor improvement Transmit enable for mars cap frq for the TS 430S For MARS and CAP transmit capability a minor change is required 1 Unplug the DC power cable 2 Remove the top and bottom covers of the set 3 Locate the RF unit connector 10 Diode D39 is near the connector labeled D39 on the circuit board Take a small pair of diagonal cutters and clip the lead at the top of the bend 4 Locate IC 2 on the Control Unit under the IF unit Resistor R148 is near IC 2 clip the resistor lead 5 This completes the modification Reassemble th
3. temperatura esterna e sopra i 20 gradi qui in Olanda Faccio notare che dentro casa la temperatura e circa la stessa Saluti I0WTD PA3FWP Stefano In this article Stefano I0WTD told that he had a similar problem on his IC745 and suggested to put a blower on the radio to solve it out His power fault happened only on summer mine in winter too ik3huk TS 430S Intermittent PLL Unlock in FM AM Author Trio Kenwood Communication inc Service Bulletin no 888 17 10 1984 Some owners of the TS 430S have reported intermittent loss of transmit and Receive when operating in the FM or AM modes along with a loss of the digital display The cause of this may be due to a loss of the FM AM Heterodyne Oscillator signal Replacing the components listed below will correct most instances of this failure Procedure ON the Control Unit X53 1290 XX change R131 to a 22 K ohm 1 4 watt carbon resistor and change C144 to a 3 pF 25v Disc ceramic capacitor Time required for this modification is 30 minutes No realignment is required Kenwood TS430 modifications repairs improvements 5 23 TS 430S PLL Unlock at High Temperatures Revision Author Trio Kenwood Communication inc Service Bulletin no 895 14 9 1985 This service bulletin supercedes bulletin 891 which concerned low input level to IC 16 as the radio warmed up This bulletin incorporates information contained in Bulletin 891 plus additional inf
4. with cathodes facing away from the plug side and the plug reconnected to the board The rig is now fully functional again It s incredible that the same LED s should fail in three different rigs Obviously just a bad batch of components used Maybe this mod can restore a dead TS 430 that someone has given up on Colin Robertson ZS2CR East London South Africa 25 January 2000 Packet ZS2CR ZS0ELD e Mail R Robertson ru ac za 23 03 2000 No signal on the meter Author Mike WP4COQ corsino attglobal net MODIFICATION NET I have a Kenwood TS430 that was transmiting and receiving fine except that the signal meter was not showing any signal on the AM CW LSB USB I open the radio and found that the VR3 pot that is on the X48 1370 00 board was defective i just replaced the pot with a new one and it start to receive the signals again 09 04 2000 TS 430S 500KHz Hetrodyne Author Trio Kenwood Communication inc Service Bulletin no 865 23 3 1983 Some users of the TS 430S have reported a hetrodyne signal at the 500KHz point on the band This tone may be reduced or eliminated by the following procedure Kenwood TS430 modifications repairs improvements 9 23 09 04 2000 S 430 Notch Control Author Trio Kenwood Communication inc Service Bulletin no 882 7 11 1983 Notch Squelch control VR5 may be replaced with part number R24 9403 15 to allow greater flexibility in adjustment As can be seen from
5. Problem Poor noise blanker NB performance on pulse noise This is caused by an over enthusiastic NB AGC which causes the NB to shut down prematurely Fix Change R81 on the RF unit from a 10K Ohm to a 24 30K Ohm R81 is near the front of the board between connectors 7 and 16 Problem Lack the transmit capability on non amateur frequencies Fix On the RF Unit remove connector 10 and remove pins 2 and 3 by pressing the release tabs on the side of the connector with a small jeweler s screwdriver and sliding the pins in the direction of their wires The loose pins should be covered with insulating tubing so they won t short out to the other circuits Problem 9 5db of treble roll off at 2800Hz in the receive audio This makes the audio sound muffled and hard to understand Fix On the IF Unit between L4 and connector 24 change C42 from a 033 F to a 003 F 0047 F non inductive capacitor A disc ceramic capacitor or a non inductive Mylar unit will do the job Note To prevent operator fatigue after this modification is made the RF Gain control should not be operated any higher than is necessary to just begin to hear the sky noise on the particular band being used In this way weak stations can still be heard but the background sky noise will not become annoying Problem Lack of crispness in transmit audio This can be due to the carrier oscillators periodically needing adjustment as the components in the radio age The adjustme
6. be caused by improper bias setting for the driver and the final in the 100W Final Unit The Service Manual describes a simple method of setting the two bias adjustments A much more common reason for causing splatter is excessive ALC Here s why The TS 430S has a sluggish ALC metering circuit and an ALC characteristic that needlessly delays the ALC attack throttle down time The ALC meter barely moves when there is already an abundance of ALC activity taking place So if the ALC meter indicates a mid scale normal amount of ALC the radio is being overdriven Under this condition due to the built in too lengthy ALC attack characteristic the radio will produce power output peaks of 140W at the beginning of loud syllables These peaks can be observed accurately on an oscilloscope Most power meters are not capable of observing the lt 2mS overshoot 140 watts of PEP output may sound good but it is beyond the linear output power capabilities of the final transistors The net result is rotten splatter To reduce splatter the microphone gain should be adjusted so that the ALC meter barely moves on loud voice peaks For those operators who like to see the meter jump whilst talking into the microphone operating the radio correctly is going to cause emotional stress This problem can be alleviated by increasing the sensitivity full clockwise of the ALC meter adjustment VR11 on the IF Unit This will make the ALC meter indication quite lively and some o
7. called D39 and D40 3 Simply cut the two diodes D39 and D40 on the RF UNIT cutting the 2 diodes d39 d40 does not do anything removing the plug n 10 does the same nothing Kenwood TS430 modifications repairs improvements 22 23 do you have an other trick 73 marc fy5ls it is effective thanks TS430s low RX Author Beavan Gwilt gwilt telkomsa net MODIFICATION NET After 17 years service my TS430s also exhibited the problem of low RX over frequency ranges which coincided with the ranges of the LPF s on the filter unit Fix 1 Remove filter board and remove plastic covers of the relays by gently prizing with a small sharp edged screwdriver 2 Cut a narrow strip of photo copy paper insert it between the contacts and apply pressure to the contacts as you withdraw the paper Paper is relatively abrasive and this will clean the contacts 3 I found that that some of the contacts hardly made contact before the relay armature was fully home Fixed by bending the contact finger so that the contacts made before the armature was home this ensures adequate contact pressure Kenwood TS430 modifications repairs improvements 23 23
8. gt gt Approx every 3 4 hours of CW operation while working without any problem gt the power output drops down to a few watt tipically duringa pileup and when gt the dx sent ik3huk 599 During this power loss the ALC level is low gt regularly gt To have back the full power I have to do the following gt Turn CARRIER knob fully clockwise full power position ALC doesn t move gt Key down for several seconds very looooong time when in pileup gt gt I sent the radio to a laboratory for repair and friend of mine did the same gt but they re not able to reproduce the power fault when the radio is on their gt table They cleaned up all the relais but the RTX is still loosing power This sounds suspiciously like a problem I had with my 430 on voice It would behave quite similarly losing power and becoming distorted on an occasional basis There was a well reported problem with early 430 s where the finals were riveted but not soldered and the rivets could eventually develop a high electical resistance with ensuing power problems This was diagnosed and corrected by Kenwood early so I doubt it would be a problem in a unit manufactured as late as yours I bought mine in late 1984 and it already had a modified PA believe me I checked My problem turned out to be a marginal connection in the internal switch on the XVTR jack on the back of the rig This is the connector with 8 pins The switch is integral to the
9. in all modes The number of factory add on components found under the PC boards on the rig was a real surprise The Control and IF boards were first checked for dry joints and several were found but the fault persisted All switching circuits appeared to check out fine After searching the Web for assistance a mod described in a Kenwood Bulletin for a similar display problem was tried without success A change in our hot summer weather seemed to indicate the problem was temperature related as the rig worked normally for longer periods under colder conditions Freeze spray was then tried on all accessible components on the Control and IF Unit boards No joy A QSO with Roger ZS1J who used to run a ham radio outlet in Natal for several years had him recalling a similar problem he had encountered some years ago on two TS430 s brought in for repair The culprit in both cases turned out to be leaking LED s on the mode selector switch indicators He suggested this area be check out Removal of plug 13 from the Control Unit board X53 1290 00 proved Roger correct and brought the rig back to life There was a very low leakage on the LSB USB and CW indicator LED s Exact replacement LED s for D3 D7 were not obtainable locally so to get around this 1N4004 diodes were installed in series with the 5 leads on plug 13 The diodes Kenwood TS430 modifications repairs improvements 8 23 were soldered directly onto the pins in plug 13
10. e unit being careful not to pinch any leads Mods for the kenwood TS430S for amtor The mods are as follows On the I F board change C 164 from 0 22mfd to 10nfd 50v change C 60 from 10mfd to 4 7mfd 16v Parallel a 150kohm resistor across R 109 usuing a small switch or by whatever means you can design to switch this resistor in and out In for arq and out for all other modes some people use the send rec switch others have used the noise blanker switch I have used a small mini switch which i have mounted in place of Kenwood TS430 modifications repairs improvements 2 23 the left front rubber foot It will probaly help to cut diode d 50 on the i f board If you use a 500hz filter in the cwn or ssbn position then parallel a 10mfd capacitor across C 10 or C 8 add a 10mfd capacitor across C 161 actually i found that these last two were not necessary in my 430S You will find it best to take the audio from in front of the volume control but those people usuing audio from the speaker socket seem to get ok results Really you can get away with just the first two mods change C 60 and C 164 this originally came from VK2AGE 73s de larry in ravenshoe TS430 power fault ANSWERS Follows my original posting and answers gt As you read in the subject I have some sporadic but very annoying troubles gt with my 1988 Kenwood TS430s This is what happens to my gear and the same gt occours to the rig of a friend of mine
11. nt is made on the Control Unit Two small ceramic trimmer capacitors are located next to two crystals in the lower left hand corner of the board The designators are TC3 and TC4 The capacitor nearest the front of the radio adjusts LSB The other capacitor TC4 adjusts USB With the IF shift on 0 these adjustments can be set by ear while listening to a broadcast station tuned to zero beat The carrier oscillators can also be adjusted by transmitting into a wattmeter dummy load while feeding about a milli volt of audio into the microphone jack As the audio frequency varies the power output will fall off at the edges of the crystal filter passband or window Set the audio frequency to 1000Hz and adjust the microphone gain to produce 40 watts output Lower the frequency to about 300Hz Adjust the carrier oscillator to produce 10 watts The rest of the problem is caused by a 4 5db roll off at Kenwood TS430 modifications repairs improvements 19 23 2800Hz in the microphone amplifier Fix Change C96 on the IF Unit next to connector 10 from 015 F to a 001 F 1000pF 1nF disc ceramic capacitor Problem Noisy Transmit Receive Relay Cutting R28 2 2k Ohm 1 4 W on the X41 1470 Switch Unit behind the ATTN Switch will reduce the noise to less than 1 2 by stopping the ATTN Relay from activating on transmit In late serial number TS 430S it is easier to cut the only white wire that goes to the Switch Unit than to cut R28 Pr
12. oblem Intermittent ALC during transmit and or intermittent reduction or loss of power output The power output can sometimes be restored to normal by turning up the microphone gain or by dropping the radio a few inches Signal reports of intermittent transmit audio distortion are normal Note If the radio continues to be operated after displaying these symptoms the eventual result is often catastrophic failure of Q2 Q3 RF driver transistors and Q7 bias transistor on the 100W Final Unit Why This problem is caused by repeated thermal expansion and contraction of the cheap phenolic printed circuit board PCB which eventually breaks the two plated through the circuit board connections between the output of the 10W driver stage and the input base connections to the 100W RF final transistors Q4 and Q5 When the break occurs the RF from the drivers does not reach the input bases of the final transistors so there is no load on the driver output transformer T2 Without a load on its secondary the peak RF voltage across the primary of T2 runs wild and breaks down the collectors of the driver transistors When the driver transistors fail and short they destroy the bias transistor Q7 as well Changing these components is an unpleasant and uncheap job Worse than that the same components will most likely fail again unless the real problem on the PCB is taken care of Fix On the component side of the 100W Final Unit circuit board install a jum
13. ormation PROCEDURE On the Control Unit X53 1290 XX Check transistor Q8 If it is not a 2SC1815Y change it to this type Serial numbers 408XXXX 509XXXX For serial numbers before 408XXXX change R29 to 820 ohms and C41 to 100 pF Kenwood TS430 modifications repairs improvements 6 23 19 07 1998 TS 430 extended coverage Include 0 150 KHz Author Wim Beekman Date 25 Oct 1988 This modification is to include the receiving range from the TS430 from 0 150 kHz Connect a resistor from 1K from IC1 pin 14 to ground in the PLL Unit Pin 14 from IC1 goes to the base of a transistor The best way to do this is by soldering the resistor at the solder side of the PLL Unit PCB Kenwood TS430 modifications repairs improvements 7 23 19 07 1998 TS 430S Reset the microprocessor For those of you wanting to know how to reset the microprocessor in the TS 430S here s what it looks like in the service manual 1 FUNCTION SW A POWER SW OFF Set the POWER SW ON while depressing the A B key Then release the A B key Hope this helps someone 26 01 2000 Kenwood TS 430S no display no RX TX with certain modes Author Colin Robertson R Robertson ru ac za MODIFICATION NET I recently acquired a Kenwood TS 430 with an intermittent fault The rig would occasionally perform normally but the rest of the time the display and RX would be dead only in the LSB USB and CW modes The rig would also not transmit
14. ound I re soldered the via to my success I found it by checking dc bias on each final transistor and found one being different in voltage reading Good luck regards George Hawkins Here is a solution I heard of for a problem like yours Perhaps it will be of use to you Luckily I have not had any problems with my TS430S I m very pleased with it Hope this is of use to you 73 es GL Mark KG7JL Kenwood TS430 modifications repairs improvements 4 23 KD7EV advises intermittent power output problems on his 430 was cured by installing a more conventional nut on the rear panel UHF style antenna connector Apparently a faulty ground connection at this point caused a change in the VSWR which affected the sensing circuit and thus reducing the RF output power Guarda che io ho lo stesso problema con un ICOM IC 745 Ogni tanto la c e una protezione che va in funzione e la potenza va giu Nel caso mio probabilmente c e un problema di corrente di fuga da compensare opportunamente ma per te potresti provare a vedere se con una semplice vantola puoi risolvere il caso Infine tanto per confermare che per me i diavoletti che muovono gli elettroni esistono il problema c e solo di estate quando la
15. per wire between the outer end of R12 that is nearest to the base of Q4 and the base lead of Q4 Install a jumper wire between the outer end of R13 that is nearest to the base of Q5 and the base lead of Q5 These two jumper wires make sure that the driver RF arrives at the final amplifier transistors whether or not the plated trough connections are are doing their job Another method of fixing the problem is to solder Z wires in the plated through holes a Z wire is a wire that is passed through the board and whose ends are bent in opposite directions so that it will stay in place during soldering Kenwood TS430 modifications repairs improvements 20 23 Problem AGC S Meter overshoot This affects the receive audio causing it to loose volume for about 2 seconds after switching from transmit to receive when a gt S9 signal is on frequency When this problem occurs the S meter will temporarily zoom up to 30db above the real signal level Turning the RF Gain control down is no help Fix Most of the trouble is caused by R32 on the IF Unit R32 is located behind the CW filter space on the circuit board R32 should be changed from a 390K Ohm to 2 2M Ohm 3 0M Ohm The lesser part of the problem is caused by R40 on the RF unit which is between connectors 4 and 15 R40 is changed from a 470K Ohm to a 20K Ohm 47K Ohm Problem Complaints of buckshot or splatter from other operators who are using adjacent frequencies This problem can
16. perators quite happy VR11 which is located on the right front of the board is very close to and easy to confuse with VR12 which should not be adjusted except per the directions in the Service Manual Kenwood TS430 modifications repairs improvements 21 23 Some repair hints for TS 430 Author Chris HB9BJL hb9bjl uska ch MODIFICATION NET 1 no display no TX RX with certain modes I read the article of Colin Robertson and I would like to tell you that my TS 430 S had exactly the same problem a few years ago soon after purchase The solution was to replace the excessively leaking Diodes D3 D7 but that meant to remove the front pane It took the Kenwood dealer quite a long time to repair it Meanwhile the exact replacement might not be available anymore Therefore it might be a good idea indeed to add the diodes in series as you have described 2 Low intermittent RX After a few years of usage I faced the Low intermittent RX problem The problem were the Fujitsu print relays on the LPF board I got around this by replacing all of them Lucky enough I was able to find them with a major electronics parts distributor who has Fujitsu relays in store 73s from Switzerland Chris HB9BJL hb9bjl uska ch MODIFICATION NET General coverage in transmission for the Kenwood TS 430S 1 On the the bottom board of the transceicer find the RF UNIT X44 1510 11 2 Near the two plugs numbered 9 and 10 you will see two diodes
17. tep 12 12 Move the filter select jumper to the A pin as shown in figure 1 13 On control unit x53 1290 00 cut the lead of resistor R129 14 Solder a jumper wire to the metal lead of resistor R129 as shown in figure 5 Connect the other end to IF units connector 18 pin 2 from the foil side of the board as shown in figure 4 The wire may be conveniently routed between the circuit board and the chassis 15 Install insulating tape below the area of the modification to ensure that no components short out against the case 16 This completes the modification procedure The TS 430S will now select either AM Wide or Narrow Before reassemble go back through the procedure and check you work to ensure no Kenwood TS430 modifications repairs improvements 12 23 Kenwood TS430 modifications repairs improvements 13 23 Kenwood TS430 modifications repairs improvements 14 23 09 04 2000 Kenwood TS430 modifications repairs improvements 15 23 Kenwood TS430 modifications repairs improvements 16 23 Kenwood TS430 modifications repairs improvements 17 23 Kenwood TS430 modifications repairs improvements 18 23 As the diagram states use either one 10 Watt 28ohm resister or two 5W 56ohm resisters 24 07 2001 Circuit Improvements for the TS 430S Author Richard L Measures AG6K Note The component locater information is correct with the operator facing the front of the radio
18. the VOX controls and the speaker lead which may be unplugged 3 Loosen the two countersunk side screws and remove the 2 screws securing the IF unit bracket Swing the bracket up slightly to access and remove the two heat sink screws Swing the assembly down 4 Remove 7 screws from the IF unit Protect the top of the front panel from scratching 5 Desolder IB1 and discard use a 45 watt or less iron and solder wicking 6 Locate the white jumper wire that is plugged on to the S terminal of the IF unit Desolder the wire from its present location and reinstall as shown in figure 1 7 Install a short jumper wire as shown in figure 1 8 Cut the foil paths as shown in figure 2 There are five locations that must be cut CAUTION Ensure you cut only the traces as shown in the figure Spend a little extra time to ensure you have correctly identified the trace to cut 9 Install J401 J402 may all ready be installed J403 D403 D404 R403 R404 and R405 as shown in figure 2 use the shortest lead lengths possible Check to ensure there are no solder bridges or splashes on the board 10 Install Q401 Q402 R401 R402 D401 and D402 as shown on figure 2 again being careful to check for solder bridges short etc 11 Check to see if D82 is installed as shown in figure 1 If it is not install it 1S1555 D83 should also be installed on the foil side of the board as shown in figure 2 Note Some unit s have D82 and D83 installed if so go to s
19. the chart below the curve is smoother Kenwood TS430 modifications repairs improvements 10 23 on the high frequency side 1 KHz to 2 7 KHz making tuning easier VR5 is located on Switch unit X41 1470 00 09 04 2000 TS 430S AM Wide Narrow filter selection Author Trio Kenwood Communication inc Service Bulletin no 883A 8 12 1983 Service Bulletin no 883B 8 12 1983 Service Bulletin no 883C 8 12 1983 Service Bulletin no 883D 8 12 1983 Service Bulletin no 883E 8 12 1983 Service Bulletin no 883F 8 12 1983 This procedure will allow selection of the Wide or the Narrow filter for AM Kenwood TS430 modifications repairs improvements 11 23 Parts list Qty Description Circuit designation 2 2SA1115 E Transistor Q401 Q402 4 1S1555 Diode D401 D404 1 4 7 Kohm 1 8 Watt R405 2 22 Kohm 1 8 Watt R403 R404 2 47 Kohm 1 8 Watt R401 R402 Insulated hookup wire 28 goage or larger 1 Short jumper Modification procedure Caution This modification requires advance soldering and printed circuit board modification techniques and should only be performed by experienced kit builders and or technicians If you are at all unsure of your ability to install this modification after reading these instructions please have someone with more experience perform the modification for you 1 Remove the power connector from the radio 2 Using a 2 Philips screwdriver remove the top cover 8 screws Be careful of
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