Kenwood KR-9400 Idle Current (bias)

-60vdc on MJ21193
+40vcd on MJ21194
These are from the good side or the side where bias is adjustable. All on 100 watt DBT
 
Might have found it. There was no continuity between positive on the rectifier to pin 51 on the power supply board. When I removed the rectifier for testing I broke the trace when installing it back in. I jumpered a wire from positive of the rectifier to pin 51 with a slight spark. Could this be the issue? Haven’t powered up yet.
 
DBT in both amps good! Do I dare go full power? Bias set at 30mv or 50mv? Bulletin says 30 but Glenn says he disagrees. I’m gonna do 40mv and see what happens.
 
House power both amps are active! I’ll post later when I get stabilization. I’m gonna do 40mv. Bulletin says 30mv I’m gonna do 40mv. I trust Glenn more than the bulletin.
 
That's through the DBT, right? If so, set bias way low, then plug into the wall. Adjust, monitor and readjust for about an hour
 
All good. 40mv on both channels after an hour of house power. Thanks for the help Gort 69! It was the positive leg of the rectifier that had a broken trace. The power supply board cooks in this receiver and wires and traces are easily broken be careful when rebuilding this board. I broke 4 wires and had the rectifier break a trace.

Thanks again!
 
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Cool - good job. How's she sound? Those are really nice receivers

Sounds awesome, just re-foamed 4 Cerwin Vega DX-5 speakers sounds incredible, keeping the idle current at 40mV, heatsinks are cool to the touch. Thanks again!
 
If you have a 'scope and a wave generator, stick about 500 Hz to 2KHz into the TAPE input and check the waveform at the speaker outputs with either speakers or dummy loads connected. Look at the base of the waveform at various frequencies closely to see if there is any crossover lag or distortion. You can adjust this out/in with the bias settings until there is no lag. Of course, you'll want to have the unit up to operating temperature when the adjustments happen.
 
Good morning, this receiver sounds great on AUX, and PHONO, but when in FM mode the right channel is noticeably lower than the left channel. Any ideas?
 
Function switches, perhaps? I don't see a relay on the schematic. The signals head right out of the filter after the stereo demodulator and into the function / input selector switches. It seems that everything beyond there is O.K. or you might notice it with other sources.

If you have a signal tracer you might probe backward from the L & R outputs at LC1 for any loss of signal. There ARE a couple of 1µF electrolytic in front of LC1 isolating it from the output of the HA1156 demodulator. I'm not saying they are bad, but old caps are always a little suspicious, and there isn't much else in that circuit after the 1156. There could also be adjustment issues, but that's opening a different can of worms.
 
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