Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Geo on June 22, 2012, 10:19:05 am
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Hey guys,
Long time no post. REALLY long time.
Okay. I have a gig tomorrow, so this is a bit urgent.
I'm replacing the power cord on my amp and I can't get the plastic clamp open that secures it in the chassis hole. Any tips on this?
Thank you!
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OK, if you mean the strain relief, then you can use your wire-strippers or needle nose pliers to depress the tab enough to clear the chassis. If you are having trouble opening it once it's out of the chassis, then you can use a flat head screwdriver to pry it open.
(http://store.marshamps.com/images/Strain%20relief.jpg)
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Just squeeze the two halves together with pump pliers. Heating with a heat gun (no open flames!) will help.
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Thanks guys! I got it off. Phew.
Now... how the hell do I get it back in there?!
The new cord is perhaps 1mm wider in diameter than the old. I can get it compressed properly with a C-clamp (working with a limited toolbox here), but I can't get it into the chassis fast enough after I take the clamp off. I.e., the outer insulation expands again and then the strain relief thing won't go into the hole.
Any ideas?
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You can use your pliers and keep it compressed tightly, then you will have to work the strain relief in one corner at a time. It's rubber and will comply with enough...persuasion. You will have to keep the jaws of the pliers as close to the tip of the strain relief as possible so its tip will compress. You can keep the pliers' jaws perpendicular to the strain relief and go in at a relatively flat angle and use the side of the pliers to give your other hand a place to add more down force. This will help minimize slipping, as opposed to going in with the tip of the pliers oriented towards the chassis, where nicking/scoring of the chassis may occur. Try using a little masking tape around the hole as protection.
Worst case scanario - I know I'll get a hand-slappin' from Sluckey..but! You can take your wire cutters and nip a hair off of the cord insulation beneath the strain relief or (better yet) use the hot barrel of your soldering iron to lightly mold the cord to give it a little reduction in diameter. I'm positive you can get it in using the first method and most here will consider the alamo methods I've just mentioned foolish, as it compromises the integrity of the insulation.
"Strain Relief"...what an oxymoron. It's the toughest part of building an amp haha.
Thanks guys! I got it off. Phew.
Now... how the hell do I get it back in there?!
The new cord is perhaps 1mm wider in diameter than the old. I can get it compressed properly with a C-clamp (working with a limited toolbox here), but I can't get it into the chassis fast enough after I take the clamp off. I.e., the outer insulation expands again and then the strain relief thing won't go into the hole.
Any ideas?
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Most of the time I use a round file to take some of the inner hump out. You just have to be careful, if you take too much out it will be too loose. So if squeezing it with pliers don't get you in, take a tiny bit out and try it again--again very carefully!