Polytone 103 power troubles

[Mr_bibbles]

Hi all-

Got an (atrocious) Polytone 103 on the bench. I'm not super familiar with SS gear so I thought i'd ask for help in terms of where to start looking.

SYMPTOMS-

at first, it was low low power (but still signal) on channel one, nothing from channel two. To get inside was a huge battle, but eventually I had it open. I replaced one of the visually damaged 500uf caps on the preamp board, fired it up without realizing the mounting screws for the board were ALSO the chassis ground for parts of the circuit. Now I have a slight 'click' from the speaker that sounds like DC, and it happens rhythmically every half second or so when the amp is on. I have a limiter hooked up to it and have ordered 4 replacement 500uf caps, but what could this issue be??

Power amp:
http://el34world.com/charts/Schemati...0Schematic.pdf

Preamp:
??? I can't seem to identify which one it is. The faceplate has 2 channels with the following:

CH 1: Bass Treble Volume DARK/BRITE switch, two inputs Same for Channel 2, but with SPEED INT REVERB in between them. Could it be the V1B??

CH2:

[Jazz P Bass]

My two cents.

If there is not a major issue with the amp, ditch the limiter.

[Mr_bibbles]

Hey Jazz- If I remove the limiter, the amplifier will blow a fuse almost immediately.

[The Dude]

I would start by checking the power supply voltages. If it blows fuses, most likely something is shorted and it should show up as low/no supply somewhere. Be aware that all voltages will probably be slightly low because of the light bulb limiter. You are looking for an imbalance or something grossly low.

[Mr_bibbles]

Hey Dude- One more note before I do this, the current limiter (and therefor the voltages??) are pulsing at a steady rate, would I even be able to check the voltages at this point? Or should I just be trying to find our which parts are steady and which parts of the circuit are fluctuating?? Either way I'm gunna get in there and try and see what the meter says.

[The Dude]

Well, I'm not sure what you'll find, but it's a start and will give you information going forward.

[J M Fahey]

Start the amp with limiter without speaker or any load.
Then measure +/- rails and speaker out, DC voltage to ground.
Post results.

[Jazz P Bass]

Woah.

If the amp is eating fuses then you have a severe short somewhere.

Ten to one it's one or more of the output transistors.

Forget powering it up (well, after doing what Mr Fahey suggests, which will most probably verify a blown output section).

Critical shorts can be found easy enough with an ohmeter.

[52 Bill]

When you started the repair, was the amp blowing fuses? Was the low power symptom with the limiter on?

You need to first figure out if this is a preamp or power amp problem. If it was blowing fuses, then the power amp and high voltage power supply would be suspect. If the fuse blowing only happened after the replacement of the filter cap, then the low voltage power supply should be checked.

Dead channels in these amps tend to bad opamps.