What did I just break?

mrsuspend · February 21, 2011, 05:17:12 PM

Oh man... nothing worse that messing up and IT'S YOUR OWN FAULT!!!

I just finished building the Orange Squeezer kit from GGG which turned out quite nicely (see pics), I'd just turned it on and verified it was working well on batteries, although on a regulated power supply there was an annoying keening tone.
I decided to try another PSU, plugged it in, heard a horrible hum and immediately unplugged it. I looked at the power supply and realised I'd given the poor board a dose ov 9 volts AC...
Needless to say the pedal is now quite dead.
Does anyone have any suggestions for me as to how to find out what component(s) have broken? I'm grateful for any pointers!
JD only allows serving of images from his own site so here is the link to his schematic:
http://www.generalguitargadgets.com/pdf/ggg_osq_sc.pdf
/Magnus

Jazznoise · February 21, 2011, 05:35:29 PM

Generaly transistors are the first to go. Check those. Maybe the Op Amp. Last resort would be the diodes.

Govmnt_Lacky · February 21, 2011, 05:38:52 PM

Seeing as you only socketed the op amp, I would try that first. It is a likely culprit and it will be easy. Replace it even if you notice no change.
After that, I recomend audio probing the transistors. Might only be one bad and it would save you some desoldering and resoldering.

Good Luck

mrsuspend · February 21, 2011, 05:44:57 PM

Flashback to me at the workbench a few days ago:
"....maybe I should socket those transistors?... naaah, what could possibly happen...."

Thanks both, sound advice! Unfortunately I'll have to send for parts but I can always look at it in the meantime!

/Magnus

mrsuspend · February 21, 2011, 05:57:48 PM

Quote from: Govmnt_Lacky on February 21, 2011, 05:38:52 PM
After that, I recomend audio probing the transistors.

Where can I learn more about "audio probing"...?

/Magnus

Govmnt_Lacky · February 21, 2011, 06:00:31 PM

Quote from: mrsuspend on February 21, 2011, 05:57:48 PM
Where can I learn more about "audio probing"...?

Search function.... Google.... etc.

mrsuspend · February 21, 2011, 06:04:42 PM

Quote from: Govmnt_Lacky on February 21, 2011, 06:00:31 PM
Quote from: mrsuspend on February 21, 2011, 05:57:48 PM
Where can I learn more about "audio probing"...?

Search function.... Google.... etc.

I deserved those rolling eyes, it was the first hit!

Thanks!

newfish · February 22, 2011, 10:33:55 AM

...at least the hardest component to remove *is* in a socket.

Transistors aren't too difficult to remove if you use a de-solder pump, followed by de-solder braid.

Either way, it's a neat, compact build.

Nicely done.

mrsuspend · February 23, 2011, 08:52:54 AM

Update:
I contacted JD who offered to send me a new IC and transistors for free, including postage from the US to Sweden. Class act.
I'm sure you all know of him but if you don't: http://www.generalguitargadgets.com/

/Magnus

stringsthings · February 24, 2011, 12:05:27 AM

Quote from: mrsuspend on February 21, 2011, 05:17:12 PM

... I decided to try another PSU, plugged it in, heard a horrible hum and immediately unplugged it. I looked at the power supply and realised I'd given the poor board a dose ov 9 volts AC...
Needless to say the pedal is now quite dead.
Does anyone have any suggestions for me as to how to find out what component(s) have broken? I'm grateful for any pointers! ...

1) At this point, be honest about your troubleshooting abilities. In either case, approach the problem of fried parts logically and calmly.

2) Label your PSU's clearly to avoid this problem in the future.

News:

What did I just break?