Re: New developments in my amp dilemma..

Well I reheated the ugly solder joints (didn't add any) and brown crap oozed out of some.. flux? Either way, seems to play now.. Probably for another hour or two.. Problem is it's small (Whats the wattage on those things.. 40?) so it's going to have to be at full tilt all the time.. I give it 20 minutes.. :D Guess I should wipe all that brown crud away eh?

Mike Schway wrote: 
In article <fqcRe.7145$2F1.372783@xxxxxxxxxxxxxxxxxxxxx>,
 JohnnyK <johnkrikorian@xxxxxxx> wrote:


I never 'disconnected' anything.. i just placed a cord from preamp out to another amp to see if it would play distorted or clean.. But I mean, with my luck, it can't just be a dirty jack or pot.. So, if you knew nothing, like I Do, and NEEDED an amp next week for a new band project, which was your whole life goal, what would your next plan of action be? ;) Thanks guys!


I know you didn't disconnect anything, but I was just asking if for some unknown reason, inserting anything in the pre-out jack would interrupt the signal path to the power amp. Foolish, yeah, but I've seen some pretty bonehead designs. Of course the pre out jack probably isn't switched that way, but the power amp input usually is.

Sure, try cleaning the power amp input jack, and try the patch cable between the pre out and power in. In fact I'd do those first, but...

Despite what Ron said (and boy howdy, is he ever a wellspring of knowledge), my gut feeling is that the problem is caused by a solder joint shaking itself loose. I'd rate this at a 75% probability....dirty or weak power in jack is the other 25%.

If you need the amp ASAP, and know how to solder, remove the PCB and re-solder any connection bigger than a 1/4W resistor. Whole job takes, maybe an hour, (2 tops if you haven't done it before). The worst part on a recent SS Fender is removing the chassis from the cabinet!

Pay close attention to pots, big electrolytic caps (safely discharge those before proceding, of course), jacks, 5W and bigger resistors, and especially free-standing TO-220 devices (TO-220s are those 1/2" square transistors with a little metal tab on top...too heavy to reliably be mounted by solder alone, but that doesn't stop most manufacturers from doing it!)

If you have a scope, audio generator and dummy load, you can do mechanical testing one component at a time before fully removing the PCB.

Good luck.

--Mike

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Mike Schway | [Picture your favorite quote here] mschway@xxxxxxx |
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