Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => The Newcomer's Forum => Topic started by: blugrassspecial on January 06, 2014, 07:08:31 PM

Title: Peavey studio Pro 112
Post by: blugrassspecial on January 06, 2014, 07:08:31 PM
The channel button, Lead or Clean, only works in the OUT position which is clean channel, when pushed in amp kinda goes dumb no sounds at all.
Title: Re: Peavey studio Pro 112
Post by: DrGonz78 on January 06, 2014, 07:41:17 PM
There is a relay K1C in the amp for switching channels. When toggling between ch1 and ch2 do you hear that relay make a clicking noise at all? Start with that first to make that observation. I have a schematic of that amp, but not sure it is the exact one, many model revisions.
Title: Re: Peavey studio Pro 112
Post by: blugrassspecial on January 07, 2014, 06:41:20 AM
Thanks for the reply !!! Button goes in and stays in so I know it works but I really do not hear a click ?? and as I mentioned the amp kinda goes dumb but only in that position. I will look for model numbers to try and get a clearer date of manufacture
Again Thanks
Title: Re: Peavey studio Pro 112
Post by: Enzo on January 07, 2014, 11:28:44 PM
All you know is that the button works mechanically.  What you don't know is whether the contacts inside the switch work.
Title: Re: Peavey studio Pro 112
Post by: Roly on January 09, 2014, 05:12:32 AM
Enzo, if the switch controls a relay, and operating the switch goes from one mode to nothing and back, it follows that the switch is operating the relay, but one of the relay signal contacts isn't making, n'est pas?.
Title: Re: Peavey studio Pro 112
Post by: blugrassspecial on January 09, 2014, 06:21:53 AM
Yes mechanically the button works well, it clicks into place very smoothly and without any resistence, again however it does not, I guess, connect to ALL the contacts inside and leaves the amp in limbo until returned to the out position. THE Question now is, one, is the AMP itself totally worth the cost of possibly reparing it? And two, has anyone done this repair and what was the cost ??
All in All it is a beautiful amp but only half of it works!!??
Title: Re: Peavey studio Pro 112
Post by: Enzo on January 09, 2014, 09:18:27 AM
Yes, in this case the switch only operates the relay, but until we consult schematics we could not make that assumption in general.

So you either have a bad relay - probably under $10 for the part - or something is wrong about that particular channel circuit.  In the channel you could have a bad transistor, a bad gain select switch, a bad control, a bad connection between any couple of things.  None of those parts are expensive either, leaving labor as your main repair expense.

The expensive parts of any repair would be the transformer and power transistors.  Yours work - the other channel proves that.

As to someone having seen this EXACT symptom AND having it be from the exact SAME cause, who knows.  As a professional tech, I am not going to waste the time to dig up sheets of possible repair scenarios when it is faster and more accurate to simply determine what is wrong and fix it.

In my shop I charge a one hour minimum for labor.  That is $60 here.   It is doubtful I would need more than an hour to fix this.  SO if you walked into my shop with $75, you would likely still have some left when you left with the repair.
Title: Re: Peavey studio Pro 112
Post by: blugrassspecial on January 10, 2014, 06:23:48 AM
Thanks for the info I'll start lookin for a repair shop and get some prices...
Title: Re: Peavey studio Pro 112
Post by: Roly on January 12, 2014, 08:08:42 AM
Quote from: blugrassspecial on January 10, 2014, 06:23:48 AM
Thanks for the info I'll start lookin for a repair shop and get some prices...

Caution: repairs are normally quoted on the worst case possibility, so be sure to mention that it's confined to one channel and is working fine on the other.