dead capacitor in powered mixing desk

B

boy_davey

New Member

• Jun 13, 2013

• #1

Hi there I have a problem with my mixing desk and only a basic knowledge of electronics (from a sound engineering degree a very long time ago) and was pointed in your direction! please be gentle

The internal 15A fuse blew at a gig in a village hall with some suspicious sockets, the problem is when it went it appears to have melted the side of what i think must be a smoothing capacitor. So i cannot read the value and replace it.

As i can't find schematics my question is: is there a way to find the correct value? or are there some ways i could narrow it down.

is a big ask so thanks for any advice in advance

 

alec_t

Well-Known Member

Most Helpful Member

• Jun 13, 2013

• #2

Welcome to the forum!

it appears to have melted the side of what i think must be a smoothing capacitor

Click to expand...

Chicken or egg? It's possible the capacitor failed (they commonly burst open) and took the fuse with it.

is there a way to find the correct value?

Click to expand...

Tell us the make/model/etc of the desk. Someone here may then be able to tell you the value. If that fails you could measure the cap dimensions and look in online catalogues for something similar to give a clue.

 

R

ronnieboy1

New Member

• Jun 14, 2013

• #3

you may have had pure ac straight on the smoothing cap if a diode went short circuit. I suspect a diode short somewhere or other. its likely at 15a the fuse was killed and didnt die.

 

B

boy_davey

New Member

• Jun 14, 2013

• #4

cool. Its a Phonic Powerpod K-12 1000W into two channels at 4Ohms. from whats left of the cap its 20mm ish in diameter black disc type if that narrows down the variety a little.

 

alec_t

Well-Known Member

Most Helpful Member

• Jun 14, 2013

• #5

If that 20mm diam thing is only a few mm thick then it may not be a cap. Could be a TVS (transient voltage suppressor)/thermistor. Can you post a sharp close-up gif/png image of that part of the circuit?

 

B

boy_davey

New Member

• Jun 18, 2013

• #6

here is the little fella in question, don't know if thats a bit too close to see

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Jun 19, 2013

• #7

Notice just to the right there are two designations on the board (C918 and Cxxx) - what is the designation of the failed component?, 'C' means it's a capacitor.

 

alec_t

Well-Known Member

Most Helpful Member

• Jun 19, 2013

• #8

The components adjacent the fried one look like part of the mains input section, so my money would be on the fried one being a mains-rated MOV (varistor); perhaps one of these?
https://uk.mouser.com/ProductDetail...=sGAEpiMZZMuQmL5N8IqpX0BIQnsmcWeGTViHp/wSnxg=

 

remon7

Active Member

• Aug 9, 2013

• #9

Sounds very interesting and helpful! Thanks for sharing boy_davey.
I think you want to calculated capacitance Or measurement capacitor. now i'm sharing with you Powerful tool of capacitor and all electronics components measurements powerful tools.
**broken link removed**
www.muzique.com/schem/caps.htm
and Youtube videos for your help guide
www.youtube.com/watch?v=oVUDwSUsbGI‎
Thanks waiting for hearing your sound.

 

remon7

Active Member

• Aug 11, 2013

• #10

Hello I need some like of Online circuit setup diagram work like as breadboard. have u any online breadboard then i can solve any circuit setup easily ...

Thanks