Fender Ultimate Chorus - bad hum

[ButchHutch]

OK Thanks Ronsonic ..... I did a Google search for Pic's of (Guitar amp main filter caps) and found a bunch.... Im trying to get this Fixed before this comming up weekend to use at our next gig..... waiting on a call from a amp repairman First, befor I start working on something I've never done...

Thanks, Butch

[ButchHutch]

Thank You Jazz P Bass ..... Im now itching to to This ! give me 48 hours to repost, I want to ease into it ;-)

[Mrcap]

Ultimate Chorus filter cap re-solder.

Thank you all for the posts. Had the same problem and just finished putting her back together and giving my Ultimate Chorus a test drive and it works great. I took a few pics that might be helpful. I'm a total rookie and pulled it off but it took me almost 3 hours.

[2tall4yall]

Hello, I have the same problem with my amp I bought second hand from some jerk with the hum. I have some soldering experience and have access to soldering equipment at my school. I want to try and fix it I just need to know what size socket I need to loosen the board from its housing.

[Enzo]

Hi, we'll try to help, but please start a new thread rather than tacking onto a thread started 11 years ago.


What size socket? You mean for the nuts on the controls and jacks? Whatever fits. Seems to me the jacks use something that fits my 9/16" wrench, though I assume it is metric. The controls? Well small controls like that I have a 9mm, 10mm, and 11mm wrench nearby. These nuts are probably 10mm, but could be other. And the screws through the chassis bottom into the heat sink I seem to recall had 1/4" hex heads?

That what you mean?

[2tall4yall]

Yes, thank you for your help. I'll make sure to start a new thread next time. take care! 👋

[glebert]

What size socket? You mean for the nuts on the controls and jacks? Whatever fits. Seems to me the jacks use something that fits my 9/16" wrench, though I assume it is metric.

I swear that some companies make up a custom size that saves them 0.0001 cents per nut or something but that no standard wrenches fit. I mostly just use pliers now, but using the tips of the jaws with the pliers on axis to the potentiometer shaft instead of perpendicular.

[Enzo]

The bog black plastic Fender jacks with the clear tops use that 9/16 nut, which fits the same socket as the common toggle switch. Whatever that size is really. The pots? well, the old ones on a million old Fender amps are 24mm size pots, the bushing is 3/8" thread, the nut is half inch. but these days the pots are almost always Asian, and will have metric nuts., in the sizes I mentioned.

If you don't have metric wrenches, get some, you will need them all the time. Don't expect imperial sizes to fit metrics.

I keep sets of SAE and Metric basic nut drivers by my bench. Example of both sets:
https://www.ebay.com/itm/Craftsman-1...5.c10#viTabs_0

[2tall4yall]

I fixed the amp it was in fact a cold solder on the filter caps she’s dead silent!!! but when I cut the power she makes a high pitched squeal? Did I do something wrong??

[glebert]

I fixed the amp it was in fact a cold solder on the filter caps she’s dead silent!!! but when I cut the power she makes a high pitched squeal? Did I do something wrong??

Do any lights flash on when it does that? I had an M-80 chorus head that did that after I did some repair work, and the chorus led would come on when it squealed even if chorus was off. On mine I think it was grounding issue around the pots, but I sold it off (with full disclosure) before I got around to fixing it.

[Enzo]

The control circuits have a normal or default condition. MANY amps will revert to default at power down. That default might be a gain channel, and if you turn the amp off in clean, as soon as power goes away, it reverts to gain, and if that is cranked you get noise for the second the caps discharge. No big.