Fishman Performer won't power up

[AlexRG46]

Hey everyone. There was a Fishman Performer that someone brought in and asked me to repair last week. It was a US model and he had plugged it right into a UK power outlet, blowing it. I took it apart, replaced the fuse, but I also noticed that you could solder a jumper on the power suppler board to convert it from 110V to UK 240V, so I jumper that wire aswell. I turned on the amp, it worked fine and gave it back to the guy.

He brought the amp back in the next day, saying that when he made to turn it on the power light flashed on for a second then almost immediately turned off and the amp hasnt worked since. I took it apart again, double checked everything I've done, tried a different power cable and replaced the fuse again (Wasn't blown). I drew out the power input schematic and it seemed to all be working correctly, which leads me to beleive theres something wrong with the power amp board. Theres still voltage on the transformers output, so apparently that hasnt been blown.

Im at my wits end, a visual inspection shows that nothing seems to be out of place and the components look alright. Is there any recommended troubleshooting steps that you guys can reccommend?

Thanks alot

[shortcircuit]

a visual inspection shows that nothing seems to be out of place and the components look alright.

Hello and welcome to the forum , an exact model # and a schematic you could post would help you get better results. Components can look great and still be crap, the only way to know for sure is to test them .

[nickb]

Hello and welcome to the forum , an exact model # and a schematic you could post would help you get better results. Components can look great and still be crap, the only way to know for sure is to test them .

..and a clear pic of the board will help too.
.

[g1]

I would think that the voltage conversion must involve something else aside from just soldering a jumper. I would think that it may now be wired for both 120 and 240V operation, which would not be good.
Maybe post what you drew up for the power transformer primary side.

[nevetslab]

Fishman Performer Schematics attached

I would think that the voltage conversion must involve something else aside from just soldering a jumper. I would think that it may now be wired for both 120 and 240V operation, which would not be good.
Maybe post what you drew up for the power transformer primary side.

I looked in our archives to see what was there on both Fishman and Fishman Performer. Take a look at this post: https://music-electronics-forum.com/...hlight=Fishman

Of all the Fishman threads, most never got this far into the repairs, while this one did, and I found the schematics that Fishman had sent the forum member, which I've attached here:

LoudboxPerformerPowerAmpRev3&4Schematics (1).pdf

I've only attempted to work on one of their amps, and while usually successful on gear, this one was beyond the funding of the owner to pursue, so I gave it back to him to have it sent back to Fishman for service. Hopefully you'll find what you need here in the doc's and the post, along with help from those here who have succeeded in restoring these. I'm guessing with twice the voltage attempted by the power supply to the circuitry, you've lost the power amp(s) to some extent (tweeter amp looks to be a power amp IC), and perhaps preamp IC's, though they're all fed thru IC regulators. Hopefully the regulators survived. The power xfmr would do it's best to put out what the mains voltage suggested, so there was, no doubt, excess voltage applied to supply caps, and the system went down after it left your shop.

And, welcome to the Forum! Good luck!

[The Dude]

I would think that the voltage conversion must involve something else aside from just soldering a jumper. I would think that it may now be wired for both 120 and 240V operation, which would not be good.
Maybe post what you drew up for the power transformer primary side.

^^^^^^ That. I don't see how just adding a jumper could reconfigure a primary for 240V. There almost has to be more to it than that.

[g1]

If it matches the schematics nevetslab linked in post #5, the jumpers labelled 120V would need to be removed.
But I think there will also be other damage that needs to be attended to.

[Enzo]

Im at my wits end, a visual inspection shows that nothing seems to be out of place and the components look alright.

Hi

Visual inspection is important, as it can reveal burnt parts, but the vast majority of bad parts look no different from good ones.


SMPS can be universal. Some will take anything from 90v to 300v without modification. But more common are the 120/240 type, and indeed, it is often just a matter of one jumper wire. In 240v mode, the mains are directly rectified by a bridge to make about 340vDC. In 120v mode, one side of the mains goes to the center of a stacked cap. SO it alternately charges the top cap, then the bottom cap to about 170vDC.


HAving said that, places with 240v may have different rules for little film caps in the mains circuits than 120v. Even in plain old transformer run guitar amps, if we replace a 240v with 120v transformer, there are minor changes like that.

Hopefully it opens, but I attached the schematic for a Fender Passport model with SMPS. Page 6 I think. See the 240/120 switch?

[Enzo]

Wait... rereading, I see no SMPS reference. How did I make that assumption?


Oh well, I am old...


In the #5 drawing, you either mount the one 240v jumper OR the two 120v jumpers. NOT BOTH.

[AlexRG46]

Thanks for all the responses, they've been helpful. I did also remove the 120V jumper before soldering the 240V jumper. If I'm understanding it correctly, is it possible that the primary side caps may not have been able to handle the 240V instead of 120V?
I'll check the voltage ratings of the caps when I go to work later.
Ive drawn up the schematic, I just need to measure the values of the inductors as well. The Load resistor represents the transformer in the schematic
https://imgur.com/nsiM93k

[g1]

Ok, so you got the primary jumpers all correct then.
Yes, the main caps and other things will all have been exposed to double the AC voltage on the secondaries of the power transformer when the unit first had 240V applied in error.

[J M Fahey]

You have to remove *two* 120V jumpers, not just one.