Fried op amp(s)

[thom]

I've built the following spring reverb unit:



I'm happy with the result, great sound with my tank.

I then decided to add a 3pdt switch I had lying around, and that's when fireworks started.



Pin 1 wired to pin 2

Pin 3 wired to pin 8

Input tip to pin 8

Output pin to pin 6

PCB input to 5

PCB output to 9

It seems to be ok initially, then I turn the switch off, unplug the adapter (unfused at the moment), plug it again and switch on, and the 5532 is no more.
The first one bubbled away in a cloud of smoke, the second one split in half in a shower of sparks.

Never had that problem before wiring the 3pdt as above.

What am I doing wrong?

[italianguy63]

What's on pin 4?

Do you have the switch turned 90 degrees?

[teemuk]

Waht's  the purpose of the switch? Bypass? Seems like an awfully complex method to wire it.

I tried to sketch the wiring arrangement according to your description but frankly I didn't seem to make much sense? Are you sure its done right?

Can you actually post a picture what you did with the switch wiring and a pic what you tried to do with it.

[thom]

I just tried to wire like the center stage reverb (http://www.generalguitargadgets.com/pdf/ggg_sc_reverb_lo3.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a)

Here's what I did:



(ignore the dodgy layout, I'm still new at working from schematics)

[dwmorrin]

Unless you rotated the switch and somehow got the LED connection into the in/out... I don't think the switch wiring is a problem.
R4 and R11 should be protecting you from most erroneous connections.
Is the +/-15 present? Perhaps something changed with the power supply when you did the switch.

[duck_arse]

switch pin 4 looks to me to be wired to pin 3 of the IC. with the led connected to switch pin 7, there will be trouble, surely.

[thom]

The second frying happened without the led (I thought I'd eliminate that possibility after the first failure), so it must be something else.

I've put in a new IC now and rewired the reverb without the switch, and all is fine (unplugged at mains a couple of times no problem).

[dwmorrin]

I see one possible clue between your original post and the layout post.
You originally stated that output jack goes to pin 6 and effect out goes to pin 9 (which makes sense).
In your layout picture, you've reversed those connections... and they don't make sense. Whether or not you actually did that, or if that could fry an opamp is another question...

[thom]

Well spotted, my layout is incorrect.
I think I may have discovered a new way of diposing of unwanted op amps...

I'll try the correct wiring, I have a few 5532 to spare 

[thom]

It turns out dwmorrin was right, all's fine and dandy now.
Thanks!