Fender Ultimate Chorus help

[pecefrogg]

Hi there, new guy here.  I've got an amp question, and this seems like the place to ask.  Last night, I had the gain, presence, and secondary volume pretty cranked up, with the primary volume at about 3.  Long story short, I lost my balance and in trying to recover, I inadvertently jacked the primary volume waaaay the crap up. 

The amp immediately decided that it was not in favor of this new configuration, and seemingly a circuit breaker popped, and the amp went quiet.  It turns on, but it's as though the primary volume pot is disconnected.  I now have a very subdued amp.   :grr

So, did I screw the pooch, or is this an easy fix?  My local shop gets $80/hour in labor and I don't have that kinda coin, so any help would be greatly appreciated!
Thanks & be kind to the newbie.   

[phatt]

Hi pecefrogg,

I doubt the amp would blow a fuse or a component even if cranked full for a very short time.
It is possible that with a fair amount of force you may have cracked the solder joints on the pot in question or even broken the internal wiper.

Some pots are so cheap now with the internals of some made of plastic and they are very weak.

You may have to replace the pot.

Phil.

[pecefrogg]

Hey phatt!  Thanks for posting on this.  When it got cranked, I barely grazed the volume knob, trying to avoid jacking up any of the knobs.  There was no real force generated on it other than my sweatshirt sliding against it.  The force on it was so slight, that it could be characterized that I might as well have intentionally rotated the bugger too high.  The effect was immediate, though.  Just as if a fuse or circuit breaker had tapped out.  I'm pretty sure that the pot isn't the problem, but I'm open to any and all ideas. 

I've never messed with amps, but I've worked plenty with other electronics.  If this model is fused, or I blew a component, where would I look to see if that was the problem? 


Thanks in advance.

[J M Fahey]

Start by getting the schematic.

[pecefrogg]

Well, I found the schematic here.....http://support.fender.com/manuals/guitar_amplifiers/Ultimate_Chorus_manual.pdf

I just found one that's a whooole lot more comprehensive schematic, but so far only a pdf download file.  If I find a jpg format, I'll post it.  It's been a long time since school, and the schematics pretty much read like cuneiform at this point, but I'm willing to learn.  I really like this amp.

The one fuse that I've found is intact, and there are no obvious malfunctions, other than the very first pic detailing the connection of the speakers.  Both speakers are like this.  It's as though a plastic rivet held the connections in place, but maybe were broken when I gave it the super-volume oogie boogie. 
Here are some pics of the board, and the speaker connections.. Hopefully someone can point me in the right direction from these.  I read something earlier about flipping the board & looking for bad filter cap solders.  I've not flipped the board yet, but if someone suggests it, I'll take a look. 
http://profile.imageshack.us/user/pecefrogg/

I attached a link for the pdf schematic.  I thought I had it reconfigured, but it's still a download pdf.   

[Enzo]

pdf files are WAY better than JPEGs for schematics.

[pecefrogg]

I've got a sinking feeling about this.  No obvious thermal damage or otherwise on the top of the board.  I'll post a pic.  The underside is tweaking me out.  I'm going to post a pic of that, also.  It seems like there are scorch marks on the underside, which doesn't make me feel like a responsible amp owner.  Hopefully these pics will help you help me.  I really want to learn from this, and any help would be appreciated.   

Here's a link of the pics.. I think I'd posted like 6 before & now there's 12. 
http://profile.imageshack.us/user/pecefrogg/

Any help is welcome, & thanks in advance.

pecefrogg

[phatt]

Well I'd say the speakers need fixing before you venture into the circuitry.

Fairly obvious that someone has reefed on the speaker cable and broken the tabs. :grr

It is also possible that this has broken speaker braids where they meet the cone.

Depending *Where* they break can be the difference between a cheap fix or new speakers. 

So FIRST Check if the speakers have continuity.

Even if the Amp was dead shorted it's unlikely (though not impossible) to kill the electronics,, Most modern gear have protection systems.

Phil.

[J M Fahey]

Agree.
Probably one of your speakers is dead.
The terminal strip is torn, the braided wire attached to the white cable is , at least, tensioned and will break with a little playing, if it has not done so.
What phatt refers to, is that if the braided wire itself is broken, maybe you can re-solder it, but if the hair thin voice coil broke .... good luck: reconing or new speaker.

[pecefrogg]

Well, I have good news as far as the speakers go.  I also was worried about the hair thin voice coils, but I can feel that that they are attached, so I may have dodged a bullet on that.  I am a little bugged out by the filter cap solders.  They just look burned, or goopy, kind of like there was glue there that got exposed to too much heat.  Here's a pic that shows what I'm talking about. 

http://imageshack.us/f/690/sany0009x.jpg/  Click the pic to enlarge & they're just to the right of my hand.

I'm going to solder the speaker terminals back into place, and see what happens but if anyone can talk me off the ledge as far as the filter cap solders (Just tell me they look great & that's how they're supposed to be)  I'll feel a whole lot better about things.   :cheesy:

*edited for a "Thanks, guys!*

[joecool85]

I'm going to solder the speaker terminals back into place, and see what happens but if anyone can talk me off the ledge as far as the filter cap solders (Just tell me they look great & that's how they're supposed to be)  I'll feel a whole lot better about things.   :cheesy:

*edited for a "Thanks, guys!*

From the pic it looks like those solders are normal, I don't really see any burned/goopy type of stuff though...

[pecefrogg]

Well, I put the bugger back together & fixed the speaker connections, turned it on, and.......no improvement.  It still has no ooomph, it plays, but it's subdued as all get out.  This amp used to be able to drop a bird straight out of the sky with the right note, but now it wouldn't startle Tweak from South Park.  I'm bummed.   

I'm open to any and all suggestions.  It'll take me several months to save up enough to have it serviced by a pro. 

[Enzo]

No one has covered the loop jacks?

take a spare cord and plug it into the FX loop send jack, then plug the other end into the FX loop returnh jack.  ANy help?

And i forget if this amp has it, but if there is a pair of jacks marked preamp out and power amp in, try connecting them together.  ANy help?


If so, we know what to do.  If no help, then plug the guitar directly into the FX return jack.  Still weak or clear and reasonably strong?


Also, plug guitar into input jack as usual, then run a cord from FX send to the input of some other amp.  How does that sound through the other amp?

[pecefrogg]

No one has covered the loop jacks?

take a spare cord and plug it into the FX loop send jack, then plug the other end into the FX loop returnh jack.  ANy help? 


I plugged the guitar cord into the return & I did get a boost in volume.  Just to be clear, I also plugged the send jack.    Clean and clear.

And i forget if this amp has it, but if there is a pair of jacks marked preamp out and power amp in, try connecting them together.  ANy help?

Not on this one.  However, please continue.. :dbtu:


If so, we know what to do.  If no help, then plug the guitar directly into the FX return jack.  Still weak or clear and reasonably strong?

She's clear and strong.  Not full strength, but the same as earlier.


Also, plug guitar into input jack as usual, then run a cord from FX send to the input of some other amp.  How does that sound through the other amp?

Unfortunately, I don't have another amp to work with. I've got a good feeling about where this is headed!

[pecefrogg]

Hi kids!  Does anyone else have any other diagnostic ideas?  Or perhaps a link that could lead me to more diag information?  I think I'm out of my league here, but I really do want to learn. 
Thanks!     :tu: