old sunn st15 not working,

[sadboy]

Hi everyone looking for some help with my amp problem.power is fine and think jack is fine but no sound from speaker. Any advice , schematics from anyone. Yhanks for any help

[J M Fahey]

Write Fender and ask for the schematic.
It should probably be close to a Squier 15 of the same era.
Not sure about your troubleshooting experience.
You´ll need to do some testing and measuring for us, otherwise it´s a wild guessing game.

[Enzo]

OOps, you said old and I was thinking 1970s.


Tes, those are probably similar to a Fender, so many of those little amps are all the same.

No sound?

Does the headphones jack work? That jack cuts out the speaker, so it could be the cause. If the phones work, that is the issue.

It may not be identical, but I'll bet my lunch money it is darn close to this:

[Audiotexan]

Link didnt work for me Enzo.. might have to zip that one :/

[Enzo]

Crap. I don't zip them. (don't know how anyway) I find if I alter the file it works, so I use the "add text" feature to put my initials on the page. That is what the NZO is on them.

[J M Fahey]

Thanks Enzo.
This Squier uses a uPC1188 chip amp which was used by Fender *everywhere* , up to 25/30W amps if I remember well.

This "Sunn" *might* be somewhat newer and use some TDA2030 or similar, only Sadboy can open his and confirm (and maybe post a couple gut pictures).

[sadboy]

Thanks for the 8nfo guys iam going to have a look at it again and maybe get some pictures etc to give you all a better idea of what it is.Thanks Enzo and Jaun. I think fender bought sunn and issued this amp it is basically the exact same as a squire etc.Thanks for your paitence with a newbie, I am an electrician so will test out board etc though not used to component level. Cheers.