# Lesson learned



## nonreverb (Sep 19, 2006)

So...I took on a repair this week. One I usually wouldn't take on as it's a cheapy Yamaha Thirty 112 amp from the '80's. Not worth much but since is it was a straightforward service, it came to the shop.
Pots were dirty and needed new AC cable. I got it apart and saw the pots were hidden under a sub-board they were mounted to. Took off the shaft screws and flipped the board to expose the small little square holes on the top them and proceeded to give each a small shot of DeOxit Gold (great pot cleaner).
As usual when you spray this stuff, especially in an opening that small, there's a bit of blow back. No problem I thought, it'll clean up just fine.
Because the front panel was facing away from me as that was the best way to get at the pots, I was totally unaware what was taking place on the panel.
Fast forward......I now have all the bolts back on the pots, the amps working great and I glance down at the control panel. To my horror, part of the stencil has disappeared. Perplexed, I can't understand at first how it happened then I realise it happened when I was mounting the bolts back on the amp. Some of the blow back came to rest on the panel. The stencil was not the robust powder coating or heat treated type, it reacted with the pot cleaner turning it into liquid instantly. Enter yours truly spreading the goodness around with my hand as I'm reattaching the bolts and you get the picture.
I will say that is is a very isolated incident as I've only ran into this problem once before many years ago....having said that, let this be a warning to all.


----------



## mhammer (Nov 30, 2007)

Wasn't that a Northern Pikes song? "She ain't sturdy, she just looks that way"

Thanks for the heads up.


----------



## WCGill (Mar 27, 2009)

And how are you liking your new (to you) Yamaha amp? ;-)


----------



## nonreverb (Sep 19, 2006)

Customer was OK with it...I suspect he got it cheap as it was covered in cobwebs. Anyhow, he got the service free of charge....I even repainted the border lines.



WCGill said:


> And how are you liking your new (to you) Yamaha amp? ;-)


----------



## loudtubeamps (Feb 2, 2012)

Back in the 80's I was doing a complete overhaul on a rental board at Kahlua Music,,,,,,,,,24 channels, a Studiomaster if I recall. They had those damn molex connectors everywhere so remove, clean replace, spray the pots on the strip and move on x 24. I got it all clean,nice and tight and back together and started doing a signal check on each strip. In out phase buttons....check..eq and aux. sends....check....100mm faders check.............input atten.switch pads...................all frozen .............the plastic housings had reacted with the "Safe for Plastics" spray that we had been using for quite some time, without any issues in the past. Guess what I was doing for the rest of the day and next!!


----------



## Guest (Mar 9, 2015)

Kahlua Music. Was that the Kingston Rd location?
I used to hang out there after school (mid/late 70's) , drooling, building up the nerve to ask for a part time job.
Finally did, but, they already had some kid (that they didn't seem to like). I should of pushed it.


----------



## Guitar101 (Jan 19, 2011)

nonreverb said:


> Took off the shaft screws and flipped the board to expose the small little square holes on the top them and proceeded to give each a small shot of *DeOxit Gold* (great pot cleaner).


This may be a good time to ask this question. Is this a good product to spray on the volume control shafts (well, all the control shafts for that matter) on my amps that I don't use very much or is there something else I should use? From lack of use, sometimes I hear a little crackling if I have to use the control knob. I usually just turn it a few times and it usually stops crackling. I'm thinking preventative maintenance here.


----------



## loudtubeamps (Feb 2, 2012)

Many good products out there, some to stay away from. I have been using this product for quite some time.......no issues.
http://www.circuitspecialists.com/404b-340g.html


----------

