Fender Stage 100 Amp - How to get the PCB Out

[fieldcottage]

Hi all, just a quickie... how do you get the knobs off the pots on the Fender stage 100 ? They seem to be glued on ! I need to get the PCB out to resolder dry joints..

Many thanks

[daz]

Thats typical of that series and some other fender SS amps of that era. i've removed a ton of them and have also destroyed a few pots in the process. the best way i found is a big screwdriver and VERY slowly pry till it barely moves, the switch sides and repeat. Do that several times till it comes off a bit and once it's come off a little you can then pry it off quicker. It's a matter of going very slow of the shaft will pull out of the plastic part that holds the contacts. There have been some so tight there was no way then to just go and whichever pots get destroyed replace them ! most aren't THAT tight, but tight none the less. Use grease or such on reassembly. By the way, if you do ruin some pots they aren't hard to fix. The shafts can be put back into the plastic part by disassembling the pot and hammering the shaft back into the part. So if you do ruin some you can fix them.

[Chuckl]

Spoons work great too. A soup spoon seems to have a nice angle. A small tack pry bar works great as well.

[captntasty]

I use two screwdrivers (or spoons, that's an interesting technique!) on opposite sides to keep the pressure directly and evenly upward rather than at angles... I've trashed a couple pots that way... hope this helps.

[Alex R]

- or wrap a strip of cloth around under the knob and pull.

[Enzo]

I have a couple church keys in my drawer. Put one under each side and lever the thing off.



Of course regardless of the method used, if the force of the knob sticking to the shaft is greater than the force holding the innards to the base of the shaft, then the shaft will pull out of the works.

[Sweetfinger]

Inevitably you will come across an amp or more commonly, a guitar that has had those pesky knobs GLUED on. Usually after you've pulled out the shaft you can clearly see the glue!

[CharlieP]

I use a metal shoe horn. The bent end. Works great for me every time. I pry and pull straight up.

[R.G.]

There is actually a tool for that. It's like a flattened-bowl spoon with a slot in the middle to pass the shaft. Lets you put the pressure on diametrically opposed sides of the shaft so that the knob is not wobbled off-axis, which can reinforce the knob's grip.

I think every tech should have one - or a reasonable facsimile. Maybe TWO church keys, one on each side simultaneously.

Masking tape on the panel before using tools, of course. Or, if you have a custom tool, a layer of tape or plastic on the fulcrum point.

[dai h.]

- or wrap a strip of cloth around under the knob and pull.

I've done like that basically but just using a thin-ish rope(should help if it's just big enough to put under the knob on ea. side). Helps give more leverage when pulling a push-on knob off(plus rope shouldn't mar the plastic). Stew-Mac had some special tool for this IIRC (might be just the thing if you can't move it off at all and there is little space to stick something in betwixt the knob and surface).

[jrfrond]

I don't know if anyone else does this, but I have created several pairs of knob-pulling pliers for our shop. The biggest issue with many other systems is scarring either the chassis or the knob.

Take a pair of regular ol' "gas pliers". Even cheapies will do. Grind a curve (the long way) into each serrated jaw with a Dremel, leaving just a bit of the serrations. Then (figure out how to rig this yourself), keep the jaws separated by about a 1/2" or so, and dip them into Plasti-Grip (color of your choice). Let the first coat set, and dip again. Keep doing this until you build up about 3/16" of cushion on the jaws, and let it cure for a few days. Bingo! Knob-pulling pliers!!!

If you are just pulling a few knobs off of a guitar amp, then perhaps you do not need to do this, but the first time you need to pull all of the modules out of a Mackie mixer, you will appreciate having them, perhaps accompanied by ANOTHER tech with another pair pulling knobs at the same time. BTW- when the Plasti-Grip wears off, you just repeat the process. So far, I've only had to do that once since I made the first pair over ten years ago.

Incidentally, no matter how careful you are, there will be a time when you pull the shaft right out of a pot because the knob is bound to the shaft (anyone remember the old Tapco mixers?). Most times, you can repair this. Sometimes not. That's life folks.

[Enzo]

Oh God. A while back I had to replace all the ribbons in a big Mackie mixer AND its 24ch extender. I counted 896 knobs that had to come off. Praise the lord there was not a nut under each. There were already something like 250 nuts on the 1/4"jacks.

yes, your fingers can get a little raw pulling all that by hand.

[pecorporation]

Use a hair dryer to warm the knob first. Then it should slide right off and save the pot.