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Deadringer II opamp issues

Started by Cevin, December 26, 2014, 05:05:20 AM

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Cevin

OK... I'm stumped.  I just finished a deadringer II build and I'm debugging it.  I've traced the signal to the input of the first stage of the opamp (pin 3).  Now all of my signal tracing/voltage readings are from legs of the IC, not through the socket or the solder on the bottom of the board.  I get signal on the input (pin 3) but not the output (pin 1) nor the inverted input (pin 2).  The other opamp (pins 5,6,and 7) have nothing either.  If I measure the voltage between pin 8 (Vcc+) and ground, I get 9v.  If I measure the voltage between pin 8 (Vcc+) and pin 4 (Vcc) I get 8.5-9v.  So, I traded out the JRC4558 IC with another from the same batch.  Same readings.  I traded the IC out with a TL072, same readings.  I even tried a 1458, with the same readings.  What am I missing here?

lincolnic

Quote from: Cevin on December 26, 2014, 05:05:20 AM
If I measure the voltage between pin 8 (Vcc+) and ground, I get 9v.

Do you have a short between power and ground somewhere?

Cevin

It seems like there would be less or no voltage between vcc+ and ground if that were the case. But just to make sure, I looked at the board and I see no solder bridges and DMMed all the components up to that point and they all give back the right readings.

lincolnic

Sorry, I misread your initial post. My fault!