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CR-1020: After recap stuck in protection SOLVED

It seems like I have a mysterious 40V drop across the whole thing.

At C811+ I am getting around 8V, which is about 40V less than the spec'd 49.6. At C812- I am getting around -91V, which is also about 40V less than the spec'd -49.7V.

Could this be a result of something in C807 - C810 being faulty? Or is the seemingly even 40V drop merely an insignificant coincidence?

We're getting deeper into the fringe area of my knowledge of circuits, I went to school for mechanical engineering after all ... but I'm trying to take stock of everything we've learned, and form some hypotheses to test.
 
Well, the C806 voltage wasn't sitting well with me, so I swapped C806 and C805. The output voltages all changed - still not right, but they changed.

One or both must be bad. They're new Nichicon 1000uF / 50V KTs.

I swapped the originals back in, and now I'm getting -94V for the negative rail, and +14V for the positive rail. Still not right, does the same thing when re-assembled and turned on (stuck in protection, tuner dial stuck at -50).

I guess I'll order new ones and hope that's the answer.
 
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Check all of your black ground wires for good electrical connections.
 
Johnny_Law said:
(All of this work is being done, by the way, with the PS Board disconnected from the Electrolytic Cap Board. I believe that's OK. It still doesn't come out of protection if I connect them.)
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It will never come out of protection without those two boards connected. And may play a roll in the flaky voltages.
 
Johnny_Law said:
Well, the C806 voltage wasn't sitting well with me, so I swapped C806 and C805. The output voltages all changed - still not right, but they changed.

One or both must be bad. They're new Nichicon 1000uF / 50V KTs.
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Not so fast...
 
avionic said:
Check all of your black ground wires for good electrical connections.
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All continuous to chassis ground.

Both red AC are also continuous to ground (which makes sense because they're part of the same coil in the transformer, I think); and, on the PS board, E (which goes to E3 on the Elec board which is connected to CT), and SL are continuous to ground, and various others (I didn't have my note pad to write them down).

So CT must be connected to the chassis through the transformer? My pea brain is trying to make sense of each as I trace the paths in the circuit diagram to try to figure out what's actually supposed to be grounded to the chassis and what isn't.
 
All black wires should be connected to chassis ground.
 
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Pulled each 0.01uF ceramic cap, confirmed operation (all measure 13 nF +/- 0.5 nF), cleaned glue from each mounting position, re-installed. No change.
 
I had one spare 1N4004 on hand, so I installed it at D806. No change. Tried it at D804, still no change. Put the original 1S1886s back in.

avionic said:
On C817 while still in circuit measure the resistance across its two pins.
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The DMM shows OL when off, but when the unit was on was quickly jumping to 0 ohms and back to OL. Strange ... when off, it's at OL though.
 
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At a loss here. At this point everything on the E. Cap Board is either new or was pulled and tested (other than the big caps). I wonder if this points to the new components. I'll put the other original caps back in.

avionic said:
Never measure resistance with power applied !!! Good way to fry your multimeter.
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Makes sense - lesson learned! :whip: I think I got away with it, DMM seems OK. Never again!
 
Put in original C813, C817, no change. Put the new Nichicon FGs back in.

What's next?

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