[jerb]

I'm sure this amp is way past its prime but I remembered that I had a board populated and decided to dust it off and se if I could get it to work.

Now, I'm going through amb's site step by step. The board is fully populated and after a once over I found no solder bridges.

Now for step 6 when I check the voltage across the pins I'm not getting half my supply voltage, I'm getting all of it, a full 24 V.

What could be causing this?

 

[n_maher]

Quote:

Originally Posted by jerb /img/forum/go_quote.gif Now for step 6 when I check the voltage across the pins I'm not getting half my supply voltage, I'm getting all of it, a full 24 V. What could be causing this?

Quote:

Originally Posted by amb Turn on the power. The power LED should glow. Measure the DC voltage across pins 7 and 4 of the opamp. You should get approximately the power supply voltage minus 1.5V to 3V. Also, check the DC voltage between pin 7 of the opamp to IG, as well as between pin 4 and IG. These should be half of the first measurement.

One of the required measurements should yield nearly the full supply voltage (between pins 4 and 7), the other measurement (pin 4 or 7 to IG) should be approximately half. So are you saying that you're getting the full voltage for the second reading? Can't answer your question without knowing a bit more information.

 

[jerb]

oops, I guess I read that wrong. from pins 4 to 7 I'm getting my input voltage... like I should (oops)


thanks for the clarification, I suspect I'll be back though

 

[tomb]

Amb still actively supports the M3 and answers any question within a day on the M3 thread at Headwize.