soldering iron blew up! & ts7 now not working

[hershey]

Hello all,
Was modding a ts7 pedal and putting the soldering to the coupling cap section 1uf caps and the there was bright blue bang! and the soldering iron died (the pedal was on  at the time by 9 v battery).
The pedal no longer works in bypass or effected either so I thought I fried the nearby trannys 1815. I measured voltage across them and they appear o.k.
Possible that I killed the 1uf caps?

[Incubus]

Depends what the soldering iron was touching when it happened.

I think the tip of the iron is earthed, so if the ts7 was on at the time, you probably shorted whichever component you touched, to earth.

[Fret Wire]

(the pedal was on  at the time by 9 v battery).

You've probably figured it out by now, but don't work on pedals while they are on (powered up). Especially with AC powered pedals!!! And don't forget to remove batteries or power supplys before any disassembly or work begins.

[Peter Snowberg]

Welcome to the forum.

When your iron died it's quite possible that a very large voltage spike was injected into your pedal. It probably wouldn't have made a difference if the effct was on or off. A 40V JFET is just no match for a multi-hundred volt spike. When you get big bursts of power like that, the inductance of the element and the cord all combine to create an environment that is very unfriendly to low voltage components.

The good news is that the pedal should be fairly easy to fix. Your next step will be to build an audio proble (see the FAQ section) and trace how far the signal gets. The zap could have killed anything (or multiple things).

Here's a schematic minus the switching logic http://bryant02.home.att.net/schematics/TS7.gif

If you don't have a more complete schematic, you might want to start by looking for sound (using the audio probe) at the reverse parallel diode pair. That will divide the circuit roughly in half. If there is no sound there, try following the signal path toward the input jack until you hear something, or follow the signal from the input towards the diodes.

My guess is that either the switching JFETs are toast, or the input buffer died.

Good luck!

[hershey]

Thanks everyone for your kind assistance!
Yeah I was unaware I had the pedal on.
But yeah it gave me a big shock to see a bright blue spark then bang" and then the section of the board blackened as a result!
I figured it's either the buffer or jfets as I hear the hiss when I crank the gain, treble ot level.

[hershey]

O.k. made myself a cool little audio probe. Works great for debugging, and from using found one of the 1815  jfets was fried.

So used a bs170 replacements and it works, but now when I switch b/w bypass and effect I only the get  effected signal with lower output.
I replaced the other jfet with bs170 and it works like above.

So buffered bypass is not working??

[jrc4558]

1815 is NOT a j-fet. It's a BJT. 2SC1815, pinout - BEC(bace is not the central pin).
Use exactly those those, they are buffers, i think.