[kfaiman]

Long story short... I accidentally passed 110VAC straight through to my Gilmore Dynamic amp's 16VDC input!

ZAP!

After plugging my power cables in the RIGHT places this time, I said a little prayer and flipped the switch.
The amp still made "noise," but the audio was garbled and staticky.
I popped the lid, and found the OPA227s burning hot.
I replaced them, but the replacement OPA227s burn up as well.

Can anyone please help me troubleshoot?

Much appreciated,
Ken

... I'm still kicking myself over this. DOH!

 

[[AK]Zip]

Please post a picture of the top.

-Alex-

 

[kfaiman]

Aside from the crappy soldering, I didn't notice any burnt components...

Picture w/ OPA227s removed. Cut traces were re-wired on reverse.

 

[MisterX]

I would be willing to bet that every one of the transistors is fried.

 

[Pars]

I would agree. Certainly the FETs are toast. The only thing I see that remotely looks fried is the blue metal film resistor, but that could just be the light. The rest of the resistors are probably fine (not much consolation...).

 

[Polaris111688]

Replace the transistors, bud.

 

[kfaiman]

Thanks everyone.

I will replace all the transistors and give it another try.
Any recommendations on where to purchase 2SA1015 and 2SC1815 transistors?
Most places seem to be sold out.

 

[MisterX]

Quote:

Any recommendations on where to purchase 2SA1015 and 2SC1815 transistors?

I got a bunch of those that you can have... just drop me a PM with your address and I will send them out in the morning.
Did you happen to notice if the LEDs were dead or not after you replaced the op-amps for the servo?

Try forum member dgardner if you need a source for the JFETs

http://www.djgardner.com/headphone/gilmore/

 

[mrdelayer]

Just out of curiosity, how did you manage to get 110VAC into the 16VDC input?

 

[kfaiman]

Valid question.

I have a three Hammond box setup (Gilmore power supply, DAC power supply, DAC/amp combo).
Two non-descript 5-pin XLR umbilicals connect the Gilmore PS to the other two.
The first connects the Gilmore PS to the DAC PS, sending 110VAC and returning +5VDC.
The second connects the Gilmore PS to the DAC/amp, sending +5VDC (from DAC PS) and +/-16.4VDC (to amp).
I accidently mixed up the connections.

Note to self: Color code my connectors.

 

[Pars]

Quote:

Originally Posted by kfaiman /img/forum/go_quote.gif Valid question. <snipped> Note to self: Color code my connectors.

Better note to self... never use the same type of connector for different applications... make it impossible to mix up.

 

[Emon]

I think it's a bit of a stretch to say all the transistors are fried. Then again, determining the exact problem might take more time and effort than just replacing all of them.

 

[rsaavedra]

Man sorry for the accident. Very recently I received a suggestion precisely about not using (as I was planning to) XLR connectors for bringing DC power from the PSUs to my amp boards box. After what happened to you I'm glad that I eventually went for some especial 4 pin connectors, so there's no chance I'll mix anything up, I thought that certainly it could always happen, just a matter of time. The ones I got are these:

Rephrasing Murphy's law, if you leave any backdoor for an accident to happen, sooner or later it might happen, just a matter of time. Better to make it impossible to happen in the first place.

Good luck with the repairs, btw why do you say crappy soldering in your boards? Looks ok to me

 

[kfaiman]

I replaced every transistor on the audio board. The OPA227P opamps still get scorching hot to the touch within 5 seconds.

All the original red LEDs still light up, but I'll try replacing those tonight. Could the LEDs cause the opamps to heat up like that? Maybe their matching is off after being zapped?

Just to make sure, I also checked the power supply output. It's a rock solid +-16.28vdc under load.

 

[FallenAngel]

Did you change the opamp?