Advice for a toasted wall-wart?

[bodega]

Hello Prodigy,

I was wondering if anybody had any suggestions on what to do with this wall-wart that I seem to have fried.

As you can see, it's a pretty simple one - 4 diodes, 4 caps, 2 trannies and some heatsink.

Last time I used it I had plugged it in wrong and before I got a chance to use it I could smell that something had burnt. Is it the diodes that would have give up the ghost? Or perhaps the caps?

FWIW it's a +/-15v Elpac that I was using to power some modular synth units.

Much thanks in advance!
Matthew

 

[Biasrocks]

Check the voltages that your getting, it's mostly likely a one of the voltage regulators that popped.

Mark

 

[audiox]

Or thermal fuse in the primary circuit, but that is easy to measure. If it is ok, then measure the secondary AC voltage and DC voltages before and after the regulator.

EDIT: And be carefull with the mains voltage!

 

[JohnRoberts]

+1 probably thermal fuse in transformer, if so not very easy to fix, but you may be lucky so ohm out the primary, check voltages. Most regulators have protection built in so they should be hard to kill...

JR

 

[mad.ax]

If it appears to be the thermal fuse (primary testing as open) then there are chances that you will find it under the first layers of yellow tape right where the two black wires are... If so, replace it, put some new adhesive tape, end you're done...

Axel

 

[owel]

Isn't the whole point of a "thermal fuse" is to protect you in case of a transformer overheating. 

If there is an increase in temperature beyond the specs of the transformer, the thermal fuse goes out first before the trafo causes a fire.

I don't think these "thermal fuse" are meant to be fixable (other than rebuilding the trafo).

Time to get a new one.

 

[CJ]

off topic:

this thing has saved my bacon more than once,

why? because there are seven, count em, seven ways to win!

but i really need one amp.  China can you help me?  Tommy can you feel me?

 

[JohnRoberts]

Isn't the whole point of a "thermal fuse" is to protect you in case of a transformer overheating. 

If there is an increase in temperature beyond the specs of the transformer, the thermal fuse goes out first before the trafo causes a fire.

I don't think these "thermal fuse" are meant to be fixable (other than rebuilding the trafo).

Time to get a new one.

+1.. wall wart thermal fuses are not generally considered user serviceable....

The thermal fuse did it's job and may have prevented more than a bad smell.

JR

 

[AnalogPackrat]

Isn't the whole point of a "thermal fuse" is to protect you in case of a transformer overheating. 

If there is an increase in temperature beyond the specs of the transformer, the thermal fuse goes out first before the trafo causes a fire.

I don't think these "thermal fuse" are meant to be fixable (other than rebuilding the trafo).

Time to get a new one.

+1.. wall wart thermal fuses are not generally considered user serviceable....

The thermal fuse did it's job and may have prevented more than a bad smell.

???
"User serviceability" is often user dependent.  This is a DIY forum, right?  How many of us have not only opened, but repaired something with a "No User Serviceable Parts Inside" label (or "Danger, High Voltage," or "Breaking this seal will void warranty," or whatever)?  If the thermal fuse is outside the winding it may be accessible and repairable.  Wouldn't that be preferred to tossing it all in a landfill and buying a cheap Chinese POS replacement?

A P

 

[CJ]

look for an end to wall warts as we " go green"

they are horrendous from an enviro standpoint, waste of power, heat generation, zillions into landfill,

have you seen that mound of cell phones that they plow under at the dump?











































i just realized that i spent an hour of my life on something that costs a buck at the surplus,

talk I cheap and i must get mine wholesale, 

 

[bodega]

Just to clarify, this isn't a one-buck item. If you can find a +/-15v wallwart for that, you're a lucky person! This one cost me $60-70, including shipping n all that.

That said, I'm having a *$&# of a time prying out the pcb, to allow me to measure the secondary. It's kind of shattering around the edges. I get the feeling they waxed it in there.

So there you go: it's a p.o.s, but an expensive p.o.s.

 

[kazper]

The PCB may be still screwed down to the case.  Press on the label for soft spots and if you find one there is probably a screw hole. If it's toast or beyond repair, get a pcb from the boards for your +/- 15V and use a common transformer. It will be serviceable then.