Fender ain't Rumblin'. Faulty amplifier.

ThisIsWeird

Hi.

Fender Rumble 100. 

Symptoms - it's 'dead'. Now't - not a flicker.

Found an exploded SMT cap, C357.

Problem - no idea of its value. Or what could have caused it.

Fender are seemingly reluctant to release schematics, tho' I will contact them to ask if they'll at least provide some info. I'll also try some Fender forums.

Anyone here just happen to have any ideas?!

Cheers.

ThisIsWeird

Oooooh - http://www.fmicassets.com/Damroot/Original/10002/Rumble 100 V3 Schematics-Diagrams.pdf

C357 is 0.015 and 630V (yikes - why so high?)

What notation will 0.015 be in? 0.015 of a Farad?

cerebus

Do you know the value of c359 ?

I would match it to that and pray!

You might need some conductive paint too to get it working again 

ThisIsWeird

Thanks, Cerebus.

Yes, I'll be doing that, but would like to be as informed as possible before doing so.

You may have missed by second post above? I found a link to the schematic, and it's shown as 0.015 and 630V. (An astonishingly high voltage capability!)

What will the 0.015 value be, do you reckon - 0.015 Farad?

ThisIsWeird

Ah, it does say "2. ALL UNPOLARIZED CAPACITORS IN uF, 10% OR BETTER; 50V MINIMUM."

So 0.015uF by the looks. Would a blown - ie missing - one of these really prevent the PSU from operating at all? Ie, make it 'dead'? I suspect replacing this cap won't be the end of matters...

Jono111

Probably the rectifier behind the cap

ThisIsWeird

Thanks.

I could swap the rect and the cap easily - and would do so if I felt there was a reasonable chance of it being enough. Suspect summat else has gone wrong, tho', that gave the cap a good blast of volts, so debating whether to go for it, or pass it on to a more knowledgable person. Good chance it needs proper gear and knowledge...

ThisIsWeird

Update - I whimped out and sold it on.

I was sooo tempted to swap the rectifier, but if that hadn't worked I'd have been a bit stuck, and would then have an amp that was tampered with, as well as faulty. Instead, I sold it on to a more skilled person as 'spares or repair', complete with pic of the blown cap, so I hope he has success.

Heedtheadvice

Probably a wise move if you do not have the ability to properly diagnose and repair - especially with the problem being in the high voltage power supply section. However it could well have been cheap to have it repaired given a competent person....