Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: joesatch on December 19, 2021, 07:58:40 pm
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What is the general consensus to fix this? Heat gun? Carpet tape? JB Weld?
(https://i.ibb.co/TBpqNMh/20211219-205415.jpg)
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What's that in the bottom of the picture?
Can you "Waller out" a hole without it showing...
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It depends why it happened.
IF it's due to the holes being drilled incorrectly -- and that's very easy to do -- then enlarging the offending hole should do the trick.
If it's due to heat warping the plastic faceplate, then I'd make sure the heat problem is solved -- then somehow straighten the plate, along with some double sided tape - may or may not work pretty.
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Double sided adhesive tape...
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The 3M one seems to be the real deal. I'd make sure all the holes are finely adjusted before, though. A little filing shouldn't show behind washers.
Maybe you can heat it a very little bit before sticking it in place, if it holds the warpage?
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Folks, messing with the holes aint happening. The amp is all wired up and soldered and i aint removing switches either. I will try carpet tape and the head cab will at least keep the top part of the faceplate flush as it touches the face of the cab.
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It may be that you can solve this by simply loosening the potentiometer nuts,
pressing the faceplate and re-tightening the potentiometer nuts
while the faceplate is pressed
Franco
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Folks, messing with the holes aint happening. The amp is all wired up and soldered and i aint removing switches either. I will try carpet tape and the head cab will at least keep the top part of the faceplate flush as it touches the face of the cab.
Well, Joe most likely the number one cause is misaligned holes, easy fix. No big hassle, is it that hard to just take the pot nuts off, leave the switches for now, just see if the holes are off center. That faceplate looks flexible, may just be a hole or two off you can fix with the switches in..? But if you have to take the faceplate off, well do it, check the alignment, fix it and use double sided thin 3M tape or, just have a bulging face plate. Or maybe, wave a Magic Wand over the amp and pray, :icon_biggrin: . Of course I'm kidding but the solutions were all posted above.
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To clarify, no one is saying change the holes/locations on the chassis. That WOULD be a nightmare. But loosening nuts and removing the faceplate to adjust the faceplate holes is a pretty quick job. Likely only one or two holes that need expanding.
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Get a set of tapered reamers (https://www.amazon.com/Performance-Tool-W2967-Tapered-Reamer/dp/B073XVRG74/).
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Get a set of tapered reamers (https://www.amazon.com/Performance-Tool-W2967-Tapered-Reamer/dp/B073XVRG74/).
Or you can use a chainsaw file from home depot, get one slightly smaller then 3/8”, or smaller if you have 1/4” holes, they also make triangle small files if you have Sq. holes. One size fits all, probably can get a set of cheap reamers from Harbor Freight
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I would not risk messing up a purty face-plate with a heat gun, glue or tape. I agree with others that the control alignment does not seem to match the face plate hole alignment. Maybe it fit when it was new but it does not fit now. I would loosen all the pot nuts and see if the plate can be nudged a bit to lie flat. If not then probably removing the switch at the bottom of the picture and filing its' plate hole to allow the plate to expand slightly. Or maybe you see other ways to get it to fit?
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You need not use an heat gun, for sure. I'd rather use an hair dryer to soften it enough for it stays flat - if it has been warped enough for not staying flat on it own - while fixing it dead flat with double sided tape only after having carefully checked hole alignements.
As other said, a most probable cause for the warping is hole misalignment. Sometimes it doesn't show at the moment the plate is fixed, but as time goes by and the heat of the amp helps it relaxes its constraints, then this may happen. I experienced that with a plastic plate that I forced into place, at least.
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I had this happen on one of my amps. The holes were properly aligned, but when it got up to operating temp the backplate would bow slightly. I ended up using 3M 77 spray adhesive to secure it. A light spray on the chassis and a light spray on the back of the backplate did the trick. The adhesive didn't seem to harm the plastic backplate. The problem hasn't reoccurred (yet?).