ekimezeerf
New Member
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 speaker protection relay click. After checking the relays with an power supply and verifying they work, I checked all other voltages I could and only found one thing out of place. Reading through the service manual on page 51 it states that if the center potential of the power transistors isn't at 0 volts, the diodes will detect the voltage and basically shut down the unit.
From what I can tell, the Diodes "read" this voltage from pins 6 & 7 which lead directly to the main Amp Board. These leads are reading ~4.5 volts on my unit, the diode array on the protection board is reading the same voltage.
Am I correct is thinking that there should be 0 volts coming from these pins? Is it this voltage that is turning on Qp3 and keeping the relays from operating?
If so, what's my next step in troubleshooting? Everything on the main amp board checks out fine. No shorted transistors, no blown resistors, all new caps...I checked the power resistors on the main output transistors, all seems fine. I am at a loss. Any help would be greatly appreciated.
When I power up the unit with a current limited variac, I get no speaker protection relay click. After checking the relays with an power supply and verifying they work, I checked all other voltages I could and only found one thing out of place. Reading through the service manual on page 51 it states that if the center potential of the power transistors isn't at 0 volts, the diodes will detect the voltage and basically shut down the unit.
From what I can tell, the Diodes "read" this voltage from pins 6 & 7 which lead directly to the main Amp Board. These leads are reading ~4.5 volts on my unit, the diode array on the protection board is reading the same voltage.
Am I correct is thinking that there should be 0 volts coming from these pins? Is it this voltage that is turning on Qp3 and keeping the relays from operating?
If so, what's my next step in troubleshooting? Everything on the main amp board checks out fine. No shorted transistors, no blown resistors, all new caps...I checked the power resistors on the main output transistors, all seems fine. I am at a loss. Any help would be greatly appreciated.
