What would a short during testing do?

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Diamondj421

Well-known member
Joined
Sep 24, 2016
Messages
162
I’m currently troubleshooting a SoundSkulptor MP5.66 tube mic preamp. I was taking measurements to send to JPK (their owner) to see if I had gotten the right replacement for an OpAmp that I had broken. Pardon my lack of proper terminology but the OpAmp is an 8-DIP IC (IC with 8 legs) and despite JPKs endless warnings about shorting it while getting the measurements, I’m 75% sure that the probe made contact between pins 2 and 3. I’m not positive that this did anything horrific but I’ve been trying to check the circuits continuity and when I connect the cables to 0v and V+, I get the tone and then it’s gone. If I wait and test again, same thing so with my minimal knowledge I’m assuming it’s a bad capacitor? Is that possible? I’m guessing that the test signal is going through the circuit but then the capacitor maxes out/fills (can’t think of term) and so the test tone stops? Then when I test again after the capacitor drains the same thing happens again? I could be wayyyyy off on this.
 
Diamondj421 said:
I’m currently troubleshooting a SoundSkulptor MP5.66 tube mic preamp. I was taking measurements to send to JPK (their owner) to see if I had gotten the right replacement for an OpAmp that I had broken. Pardon my lack of proper terminology but the OpAmp is an 8-DIP IC (IC with 8 legs) and despite JPKs endless warnings about shorting it while getting the measurements, I’m 75% sure that the probe made contact between pins 2 and 3. I’m not positive that this did anything horrific but I’ve been trying to check the circuits continuity and when I connect the cables to 0v and V+, I get the tone and then it’s gone. If I wait and test again, same thing so with my minimal knowledge I’m assuming it’s a bad capacitor? Is that possible? I’m guessing that the test signal is going through the circuit but then the capacitor maxes out/fills (can’t think of term) and so the test tone stops? Then when I test again after the capacitor drains the same thing happens again? I could be wayyyyy off on this.

Do the test without the IC. Also, what is the IC in question? All of the DIP-8 op amps I know of have voltage on pin 4 and either pin 7 or 8, depending if it's single or dual. Shorting pins 2 and 3 shouldn't do anything unless you had the IC in backwards, which would ruin an IC chip. You may also have a bad solder joint or misplaced component.

Thanks!

Paul
 
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