Ugh,

After replacing those parts I have:

R61 -1.5
R64 41.3

d19 -.5
d21 -.5

R85 +19
R86 -19

The 680 mfd caps +16 on one side, -16 on the other.

R84 heats up and cant be touched.n I followed the traces on the board out and can visibly see an issue.

I am going to pick up replacement zeners. This is really confusing to me.

I replaced both of the 150ohm 1 watt resistors but they did test okay.
I also replaced R-84.
I dont have any zeners to use to replace the ones on the board, I will need to pick some up, however they do test good.
Probably a dumb question but how do I remove the load from the + and - 15 supply?

R84 is not open, it measures 500ohm, the schematic shows 10?
R85 has 19V on one side, 5.7V on the other
R86 has -19 one one side, -15V on the other
on the two caps, C52, C53 I have 19V on one side, and -19V on the other.

D19  5.7  on the line side, -.5v on  the other
D21  -.5v ob the line side, -15v on the other

Okay,

I do not have -15V, if I am checking in the right spot, on the end of D12 and R61? I have +1.7V.

At R64 I have 42V but it looks like it should be -15V on the schematic, am I seeing that incorrectly??

The reading was the same without the JFET.  .85 volts

oops, I didnt take a measurement without it...I will pull it again right now.

Okay,

Fed an IPOD thourgh the main in socket, it made a little blip on the scope, hooked up the speaker and no sound. Pulled the JFET and tried again, scope went nuts, decent sound out the speakers.
JFET out of circuit tested good. Reinstalled the JFET and tested the voltage on the gate. Only .85 volts.

It is in the correct orientation.

I think I need to hang my head in shame and embarassment.....

I had my meter set incorrectly last night and did not catch it, I usually use an old vaccuum tube volt meter and this one sits on the shelf

P5-5 +ve +36.3
P6-1 -ve  -37.3
P7-2 +12mv

The dim bulb tested is very dim with the 40 watt bulb.

T202 and T203 test good.

I really appreciate your assistance on this!  :dbtu:

I dont have my camera with me right now, I did scan the layout page and attach it though.

I was just confused by the terminology, I have a current limiting lamp, I have always known it as a dim bulb tester.

Okay,

I have made the measurments, speakers disconnected, current limited lamp with a 40w bulb in place.

+VE .01 vdc
-VE  .01 vdc
Half rail 0 vdc.

I am making an assumption that these are measured to the chassis?

Okay, deep breath.

I have recovered from yesterday. All of the transistors are okay, I replaced R77, R79 tested unharmed.

When you say current limiting bulb, is this just a bulb with a lead off of each contact to act as a dummy load? In my head it must be as the lamp tester for old radios is a different animal unless I am not seeing it correctly.

When you say output rail, is that the terminal strip that connects to the speaker fuse? Forgive me, I am not as familiar with the terminology.

Currently I am back to where I was before, it powers up, a very very slight hum through the speakers, nothing is apparently overheating or "freaking out" so to speak, but no output.

Ugh, maybe i need to throw the towel in on this one.

I havent touched it since the last post, made no changes whatsoever, but in turning it on today it popped R71, and the R77 bias pot. What the blank?? I think it has gremlins.

I am lousy with solid state.

Thank you for your replies.

Have replaced all the electrolytics, and non polarized foil type caps. Tested all the resistors and diodes.
Tested all the transistors, the power transistors were both bad, and replaced, the JFET was bad and replaced. I also went through all of the solder joints, a number of them were bad so I removed the solder and reset them with fresh solder. I am not sure where to put any test leads for testing this.


Now I get no hum, the channel switching is working, but I have no sound at all.

this is the schematic that I found, sorry I cant seem to get the PDF to have the correct orientation.

I picked this thing up for a song, very good physical condition, but not so hot in the function department. I wanted it for a project knowing it had issues. I have repaired tube amps and restore antique radios so I know some basics with point to point wiring, but not good at all with solid state beyond following instructions.

When I first got it it would just hum, an occasional blip of guitar would come through, but within a few minutes nothing.

It would switch channels when I first powered it up, but now the channel light is out, I am thinking it may be related.

Any ideas on what to look for?

I have already done the normal filter cap replacements since it quit working.