Fried Op-Amp?

[instantaphex]

I'm working on a blue collar overdrive clone.  I'm using a JRC4558D Op-Amp.  My circuit was working fine(ish) on my breadboard yesterday and I haven't touched it until tonight.  Today I plugged in and got no sound.  I checked the circuit for continuity and were good there.  Here are the voltages for the 4558:

Pin 1:    8.75
Pin 2:    8.72
Pin 3:    8.25
Pin 4:    0

Pin 5:    0.12
Pin 6:    8.11
Pin 7:    8.62
Pin 8:    9.43

I checked, double-checked, and triple checked all my breadboard component connections, all good.  I followed the schematic along with my bb.  If I had another op amp I would drop it in and see if I get a anything, but I don't.  I noticed that if I turned my amp all the way up to 12, I could faintly hear my guitar coming through.  Any tips for how to figure out if this IC is dead?

[mistahead]

Something is definately wrong there - the lack of variation between those (and the fact they're all just under the supply voltage) would make me suspect catastrophic short inside the op-amp...

But I'm a noob.

[instantaphex]

Something is definately wrong there - the lack of variation between those (and the fact they're all just under the supply voltage) would make me suspect catastrophic short inside the op-amp...

But I'm a noob.

Should they not be so similar?

One thing I should mention, when I was hooking up my newly soldered AC adapter I accidentally hooked it up wrong and may have seen a small arc coming out of the power bus...

[mistahead]

I would assume to be seeing measurements of half supply voltage on some of those (no datasheets near me and I've been away from my iron for a month) assuming you're not using bi-polar power... so unless you're setup at 18v there is an issue.

Many say visible arcs are a dead-giveaway, I've had CPUs survive visible arcs and not be damaged at all - but I've also had undetectable static destroy less complicated chips...

[instantaphex]

I would assume to be seeing measurements of half supply voltage on some of those (no datasheets near me and I've been away from my iron for a month) assuming you're not using bi-polar power... so unless you're setup at 18v there is an issue.

Many say visible arcs are a dead-giveaway, I've had CPUs survive visible arcs and not be damaged at all - but I've also had undetectable static destroy less complicated chips...

No bi-polar power, and not using 18v.  I guess that means.. hes dead jim.  Oh well, time to order a few more.

[mistahead]

Not necessarily - but I'd suspect it. I know that there are issues - but I'm not so good to say its definately that part (yet).

Someone else can probably confirm or otherwise.

[instantaphex]

I'm open to any suggestions... I just haven't changed anything other than hooking up an AC adapter incorrectly.

[Scruffie]

I and am sure many others here have been the victims of night time breadboard elves stopping a circuit working that did before and hadn't been touched, breadboards can be pains in the ass sometimes.

That looks more like your V.Ref just isn't working... something shorting to somewhere else and messing with the voltages that's hard to spot, or just a poor breadboard connection.

Unless you did something to kill it, shouldn't have died.

[Scruffie]

I'm open to any suggestions... I just haven't changed anything other than hooking up an AC adapter incorrectly.

Oh... if you gave it AC it's dead, or do you mean an AC to DC adapter? If you wired it backwards so ground got 9V and visa versa that would kill it and probably damage any transistors on your board.

Remove the chip and check your voltages at the V.Ref points.

[instantaphex]

I'm open to any suggestions... I just haven't changed anything other than hooking up an AC adapter incorrectly.

Oh... if you gave it AC it's dead, or do you mean an AC to DC adapter? If you wired it backwards so ground got 9V and visa versa that would kill it and probably damage any transistors on your board.

Remove the chip and check your voltages at the V.Ref points.

AC to DC adapter.  But yeah I think I probably wired it backwards.  There are no transistors on my board so I suppose I'm good... could it damage any resistors and/or capacitors?

[duck_arse]

reversing the dc supply is very similar to appling ac volts. you end up with dead silicon. resistors will probably be ok if the smoke stayed in, it won't hurt to chuck out any electro caps, the film caps should be ok.

+1 on remove ic and check Vref.

[instantaphex]

reversing the dc supply is very similar to appling ac volts. you end up with dead silicon. resistors will probably be ok if the smoke stayed in, it won't hurt to chuck out any electro caps, the film caps should be ok.

+1 on remove ic and check Vref.

VREF seems fine.  With a 9v battery I'm getting around 4.45.  With the AC to DC adapter I'm getting slightly higher, but still within the range of what seems normal.

[duck_arse]

sounds like it's time to try a replacement ic.