DigiTech dsp128+ let the smoke out

[UnluckyFett]

soooo c29 let the smoke out and I don't know the value. anyone have one that you can open up and tell me what value it is?

thanks

[Chuck H]

That cap failing may or may not be the problem. What caused it to fail? You can attempt a repair with failed component replacement but don't hold too much hope in that. It's much more likely that the cap failed because of a less obvious problem with the power supply or a circuit that controls it.

[Jazz P Bass]

I would try contacting Digitech.

(801) 566-8800
support@digitech.com

[UnluckyFett]

I sent an email to digitech and now I wait. I havent done much troubleshooting on it yet. It was given to me and my friend said it had an error code so I plugged it in and the display seems fine all the controls work but I havent put signal through it. there's 4 caps in parallel and this one failed. I want to get some voltages but the smoke is pretty bad so I think I'm going to pull the cap and try. I have a crate blue voodoo on my bench right now so its not really priority

[UnluckyFett]

ok got the schem from DigiTech. c29 says 10 T. I'm assuming 10uf tantalum? its electrolytic. its connected to the -12v supply,-v pin on I believe the d/a converter the positive side connects to ground and the + leg of an op amp. I'm going to guess electolytics in the PS.

[Jazz P Bass]

It appears that the cap is a coupling cap from the DAC to the opamp.

I don't know what the 'T' stands for but coupling caps on opamp circuits are usually electrolytic.

It may have simply been a bad cap and/or the DAC / opamp is bad.

For sure check the -12 volt supply.

You should be able to see the DAC signal coming out of the IC pin.

[g1]

It appears that the cap is a coupling cap from the DAC to the opamp.

I got the impression it's actually a de-coupling cap for the DAC ? Minus end to -12V line, + end to ground. The op amp + leg is I assume an input, and coincidentally also tied to ground so irrelevant?
I would just clip it out and see how the unit responds.
If it is tantalum, I expect it to be bead shaped, can you post pic?

[doctor]

If capacitor smokes, it is internally shorted. Remove it and check V= (-12) V. If this voltage is in range (-11.5)÷(-12.5)V, replace defected capacitor with new one 10uF having working voltage not less than 16V (20V is more preferable).