Nikko Alpha II speaker and meter audio output relay not clicking

EvanF

AK Member
I checked the voltage on the pins to the relay coil.It's 59+ VDC, the power supply rails voltage. What can be failing to cause this? The amp was working fine until the relay shut off. I changed the reservoir caps and 3 of the relay board caps. I see no damage on any part, it smells fine.
 
Stand by --I reread your post. Are you sure you were measuring the relay coil? If you were measuring the relay contacts and found rail voltage it would most likely be the outputs.
 
Need to measure the voltage from TP (output) of both of the amplifier circuits to ground.We are looking for near zero volts.
 
Stand by --I reread your post. Are you sure you were measuring the relay coil? If you were measuring the relay contacts and found rail voltage it would most likely be the outputs.
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Sorry, not the contacts. The input to the coil, each end of the coil was at 59 volts, the voltage measured on the reservoir caps and two pins on the amp boards, so the same voltage, the ps voltage, was on each end of the coil. No voltage between the ends of coil, which was why it wasn't clicking. I want to know why and how i can get a voltage on only one point instead of two.
 
Use TP pin 13 (out). On both of the main amplifier boards.
 
OK.. Looks like a problem in the protect circuit or its power supply.
 
I already figured the protect circuit was wonky, so I measured the protect trannies' forward voltage yesterday. All check out. I had replaced three e-caps on that board earlier, before this happened. I also check the two diodes. No dice. What should I check now? There are still two e-caps (the .47 uF) that I don't have a replacement for, so they might be the problem. Could they? Which pins are the power supply for the protect circuit?
 
Have a close look of C843 (220µf/16vdc) --suspect

If you have already replaced it disreguard..
 
Q805 (relay driver) may not be switching. Regardless what it tested.
 
Q805 (relay driver) may not be switching. Regardless what it tested.
This might be it. The cap was in spec, and the resistor measured within the DMM accuracy. The HFE was 141, not sure what that says about the switching. Looked good though.... What could be a replacement? And I'm still not sure if Q805 is the problem.
 
Even though transistors test good, they can and do , fail under circuit load.
 
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