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  1. ekimezeerf

    Kenwood KR-8340 Protection No Click

    **SOLVED** On the protection board I installed Q2 (2SA1220) backwards. Re-installed in the correct orientation and now it works perfectly. Watch those pin-outs everyone! I feel so silly and so relieved at the same time.
  2. ekimezeerf

    Kenwood KR-8340 Protection No Click

    Both pins 9 and 30 on the main amp board have ~3.87 volts. Again, I assume this voltage should be 0 volts. I've tried tracing this voltage throughout the main amp board and all components test fine. No bad resistors, I've replaced all electrolytic caps, and tested all transistors for shorts...
  3. ekimezeerf

    Kenwood KR-8340 Protection No Click

    A-09 on the Protection Board? I have readings of the following: Pin 1 = 0.110 v Pin 2 = 0.052 v Pin 3 = -0.012v Pin 4 = 0.055 v Not exactly 0 volts, is there adjustment for this or does it indicate something elsewhere?
  4. ekimezeerf

    Kenwood KR-8340 Protection No Click

    Hello everyone! I looking for some help with a Kenwood KR-8340 Two Four Receiver. I've read through every post I could find about this family of receivers (KR-7340, 8340 & 9340) but haven't been able to narrow down my problem. When I power up the unit with a current limited variac, I get no...
  5. Kenwood KR-8340 Main Amp Close Up

    Kenwood KR-8340 Main Amp Close Up

  6. KR-8340 Protection Pin Voltage

    KR-8340 Protection Pin Voltage

  7. KR-8340 Protection Diode Voltage

    KR-8340 Protection Diode Voltage

  8. KR-8340 Protection Board

    KR-8340 Protection Board

    Protection Board from a Kenwood KR-8340
  9. KR8340 Protection

    KR8340 Protection

    Protection Relay Explanation
  10. Kenwood KR-8340

    Kenwood KR-8340

  11. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    I removed the incorrect 4.7k ohm resistors R626 & R627 and installed the correct 4.7 ohm resistors. It's working! Class B Mode bias was set at 50 mV Class A Mode bias at 850 mV It sounds amazing, really. I've had a chance to listen to a lot of cool vintage sets and amps but this CA-800 is...
  12. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    Just checked some photos of the rebuilt amp boards... R626 & R627 are supposed to be 4.7 ohm according to my schematic. Can I get a sanity check on that? From my photos I can clearly see that I installed 4.7k ohm resistors in both location on both boards :no: Time to go back and check all...
  13. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    Yeah...because both boards are affected/behaving the same way I'm really lost. I'll go back and check D603,4 and start a list of the voltages for the transistors. (may take me a few days to gather and post). As for the fuses, F602 on the Left Amp Board was blown when I first got the unit. I...
  14. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    I also wanted to note that on the Right Amp board, when the unit is powered up in Class B mode, There is definite ringing (oscillation?) noise coming from the bi-polar 47uF capacitor that sits between TR604 and TR601. If I touch it with an insulated screw driver, the bias drops 1-5 mv and the...
  15. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    I did note the pin-out difference and installed them accordingly. And TR605 was replaced with a KSC1815. It was turned 180 degrees from original transistor orientation, so the pin-out should be correct. It may be difficult to see in my photo (because of the heat shrink I used) but TR604 and...
  16. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    Here's the readings I got this weekend. I'll have to go back tonight and follow mbz's list of readings as they are more comprehensive: Mode------Pins------L-------R-------- Normal---BC----0.9ohms--0.9ohms SC----480ohms--484ohms AC----8.06K ohms---8.1K ohms Class A...
  17. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    For testing the Ohms verifying the switch is functional, in NORMAL mode I should have something like this: Normal: B-C <1 ohm S-C ~470 ohm A-C >5k ohm Class A: A-C <1 ohm S-C <1 ohm B-C >5 kohm Or do I have that reversed?
  18. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    Thanks avionic, I have 5k Bourns Multi-Turn trimmers installed. I'll double check the wiring from the amp board to the mode switch. Just to be clear, these are the wires you're talking about right?: Amp Board SCBA Wire by ekimezeerf posted Jun 9, 2018 at 1:29 PMOp Switch CSBA Wire by ekimezeerf...
  19. ekimezeerf

    CA-800 Bias Problems After DOA Rebuild

    Hey everyone, long time lurker, first time posting. A friend brought me a dead CA-800, would not power on and many signs of heat stress on main amp and power boards. Our thought was the PO has dumped a bottle of cologne on it due to it's aroma and the goop present everywhere inside. I've...
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