Can I repair this Small Stone EH4800 Phase Shifter that I fried with 18v?

[sirdavy]

I plugged the wrong DC plug into my Small Stone and all I get out of it now is very quiet white noise/hiss. I'm fairly handy with a soldering iron, but most of the components are smd...is there any chance I could fix it myself? In the photo you can see there are some burn marks around a component near the 9v socket. It's labelled FB3, which I think means an inductor?

[theehman]

Try jumpering the inductor with a wire and see if that fixes it.  It won't hurt anything to not have it in the circuit.

[antonis]

In case of fried item indeed is an inductor, one of its legs should be connected to +9V jack where the other one to C19..
(although, 100pF cap seems rather small for such a filter configuration..)

[sirdavy]

Try jumpering the inductor with a wire and see if that fixes it.  It won't hurt anything to not have it in the circuit.

I tried this and the LED lights up. I gave the inductor a poke with a pencil and it's broken off the board, leaving the LED lit. No sound coming though.

One of the large through board caps (right in the middle) is a 16v/220uf - any chance it's that? I could swap that one fairly easily.

[sirdavy]

In case of fried item indeed is an inductor, one of its legs should be connected to +9V jack where the other one to C19..
(although, 100pF cap seems rather small for such a filter configuration..)

So I should try jumpering from one pad of the inductor to one pad of this cap, and it should leap both?

[antonis]

So I should try jumpering from one pad of the inductor to one pad of this cap, and it should leap both?

No..!! 

C19 shunts +9V to GND, forming a LPF with inductor(?) so you don't want to short +9V to GND..
(Consider fried inductor in place of R1 and C19 in place of C13 on schematic below..)

Most possible is some +9V break around fried item resulting into power interrupted supply..

[sirdavy]

Thank you. What would you say, in this circuit, would be most vulnerable to 18v, and might have blown?

[antonis]

There are some items, especially SMD polarized caps like 47μF one right next to 1N4001 diode, which can't withstand the 18V supply..

[sirdavy]

Would jumpering across this capacitor - and other components - make the pedal show signs of life?

[antonis]

You have the nasty habbit to indiscriminately jumper items..
(it might be OK for some series items but a prospective disaster for shunt ones..)

Probably 47μF cap is a reservoir/filter one, meaning it's placed across +9V & GND..
By jumpering fried item AND that cap you effectively short your power supply (it smells like smoke..)


P.S.
In case of that particular cap is damaged, it's most possible to be "open" (out of the circuit) so there is no working issue..
(possibly a small supply voltage ripple and/or hum but let it be for the moment..)

[sirdavy]

Thank you, Antonis. I will get my multimeter out and go around testing the components that way instead.