Peavey Classic 100 dead head.

[tbonuss]

Off the limiter-tube filaments are heating up--looks okay *to me*.

With the power amp tubes now pulled, I reconnected the fx send to the fx in of another known good amp.
If I fiddle with both the master volume AND the treble knob I can get a sufficient preamp out to drive the other main. All the other pots have no effect. To reiterate, if I get both the master volume and treble pots in just the right spot I get a strong preamp out.

[The Dude]

It could be the pots themselves or solder connections on the pots. Check the solder joints on the pots and clean and lube them all with Deoxit or similar.

[olddawg]

Off the limiter-tube filaments are heating up--looks okay *to me*.

With the power amp tubes now pulled, I reconnected the fx send to the fx in of another known good amp.
If I fiddle with both the master volume AND the treble knob I can get a sufficient preamp out to drive the other main. All the other pots have no effect. To reiterate, if I get both the master volume and treble pots in just the right spot I get a strong preamp out.

Could you explain this a little better? What are you using for a signal source? You need a constant signal source like the output from an iPod or receiver rec out (hopefully with a volume pot installed). What is the "right spot"? You should be able too dial an an undistorted signal level up and down with the channel volume. You may be swamping the preamp if you are cramming a line level signal into an instrument level input. I'm not sure if your effects out is before or after the master? Usually it's before and the master would have no effect on the effects out signal at all....

[tbonuss]

It could be the pots themselves or solder connections on the pots. Check the solder joints on the pots and clean and lube them all with Deoxit or similar.

I cleaned the heck out of them with de-oxit and a "pressurizer cap" and as far as I can tell, the preamp is fully functioning now. When I get the kids to bed tonight I'll put the power amp tubes back in and see if this was all it was. Seems unlikely, but maybe we'll get that lucky. My cynical nature leads me to believe that this was just an ancillary issue due to the fact that the dead amp set around for a very very long time.

I will keep you posted as soon as I find out.

[tbonuss]

Could you explain this a little better? What are you using for a signal source? You need a constant signal source like the output from an iPod or receiver rec out (hopefully with a volume pot installed). What is the "right spot"? You should be able too dial an an undistorted signal level up and down with the channel volume. You may be swamping the preamp if you are cramming a line level signal into an instrument level input. I'm not sure if your effects out is before or after the master? Usually it's before and the master would have no effect on the effects out signal at all....

Certainly.

Guitar->Classic 100 Input jack->Effect Send->Roland Amp Main In (aka: effects return)->Roland power amp->Roland Internal Speaker

After cleaning the pots this setup seems to be working fine. Classic 100 Preamp verified.

I agree that this amp is atypical (in my fairly narrow experience) in that the master volume is PRIOR to the effects send. I might have caught this little problem earlier if I had realized this.

[g1]

Not sure what you mean by "pressurizer cap"?
If it is something that allows you to clean pots from the front side (shaft), I would suggest you get the cleaner into the back of the pot.
If they are in as poor condition as described, the bushing method of cleaning may not be a reliable fix.

[tbonuss]

Yes, its a cap thingy (looks like a socket with a hole in the side to put the deoxit straw in) from StewMac. It works really well to flush from the front (shaft) and allows the particles to evacuate out the openings in the back of the pot. Seems legit???

I'll do both on all of the pots.

Thanks!

[tbonuss]

Please say the wattage of the bulb in your limiter. Anything less than 60w may not even get the heaters lit when you have all the tubes installed.

Ah, yes. It was only 53 watts.

[Justin Thomas]

Wait, is that a CFL? Do those things even work in an LBL?

Justin

[tbonuss]

So...I feel kind of foolish. I cleaned all the pots and its good to go. When I got the thing the guy said it smoked and smelled really bad then quit...

I can't tell you how much I appreciate the assistance around here. Not only did you help me SAFELY figure out what the problem was, but knowing that there was such a great resource here gave me the confidence to try repairing another amp. I got a great deal on this (and four other problem amps) so I really don't know how to say thank you enough.

I've gotten 4 of the 5 fixed now, so onto the last one, another broken Vox Valvetronix...

Can I say thanks again ?!? Thanks!

[tbonuss]

Wait, is that a CFL? Do those things even work in an LBL?

Justin

Its a halogen bulb with a tungsten filament.

[DrGonz78]

I too have a dead head amp!!

[g1]

The stew-mac type jig for cleaning pots via the bushing is something I prefer to use only if the rear of the pot is not accessible. It will flush the lube out of the bushing and change the feel of the pots. It can also leave grease or metal particles on the carbon track.
Not telling you not to use it, just to let you know the limitations.

[52 Bill]

When I got the thing the guy said it smoked and smelled really bad then quit...

It still might need some work, as you haven't really played it in yet.

Play it for a while and see if there are any problems, like red plating power tubes, etc.

[tbonuss]

It still might need some work, as you haven't really played it in yet.

Play it for a while and see if there are any problems, like red plating power tubes, etc.

Good point. I'll put it through its paces this weekend. Thank you Bill! Or is it 52?