Seventh Circle Audio

[wacktrucks]

just got finished building 2 t15s and neither of them are working.

one is passing signal but very quietly and very distorted.

the second one is doing nothing.

everything seems to be in the right place any ideas?

[tpryan]

Are you absolutely sure that all the ICs are oriented correctly?

Are you getting +/-18v at the test points?

What's the voltage at U1, pin 6?

[wacktrucks]

i am pretty sure they are all in the right direction. the notches line up and U2 the circle should be in the same location as the others correct? upper right corner?

I am Getting

1st t-15 U1 pin 7: +17.7 and pin 4 is -17.8
2nd t-15 U1 pin 7: +17.7 and pin 4 is -17.8

Pin 6 is

1st t-15 0.0
2nd t-15 -16.6


i measured all the ics and there are some other voltages that aren't the same. do you want those?

thanks so much

[tpryan]

Right-click the photo on this page: http://www.seventhcircleaudio.com/T15/T15R13/t15_about.htm

Click "view image" or the equivalent and zoom in so you can see the IC orientation.

[wacktrucks]

nope all the ics are in the right locations and the right way around.

[tpryan]

Can you post similar photos of your boards?

[wacktrucks]

only had time to take pictures of the first one.

[tpryan]

Looks OK from the top, how about the bottom?

[wacktrucks]

here are the backsides

[tpryan]

That's not the best looking job - too much solder on many joints, some possibly cold - but nothing blatantly wrong. Do you have access to a scope or signal tracer? That might prove useful for T15-1. The board with -16V at pin 6 probably has a damaged IC.