3 T15's with the same issue, 1 with a different one

[jefftd]

Hey Tim,

I've recently built 4 T15's, but all of them are non-functional.

Three of them power up fine, test fine for the ±18v points, and have the phantom power test fine, but don't pass sound. One passes white noise when the trim knob is rotated, but otherwise doesn't work.

I know I installed U5 and U6 backwards at first, and have since corrected that issue. Here's a spreadsheet with the readouts of U1-4's pins - I'm hoping that I don't have to replace every single one of them, so if you could let me know which look suspect it'd be most appreciated.



The last T15 has given issues from day 1 - U5 and U6 were installed correctly, but U3 has blown three times now (replaced each time). I'd post a DMM reading for the pins on the rest of the U's, but they flip back and forth between two numbers and never stabilize. It's built identically to the rest of the units, and all of the components match up to the BOM/schematic, so I'm totally confused as to where to go from here with it.

Thanks!

[jefftd]

I'm too new a member to include a URL with that post, apparently. Here's the spreadsheet mentioned:

http://dl.dropbox.com/u/392637/T15Troubleshooting.xls

[tpryan]

Can you post a few clear, well-lit photos of the boards, both top and bottom?

[jefftd]

Sure - here's a .zip folder with them all. I can also upload higher res versions if you need, but it'll end up being about a 50mb file.

http://dl.dropbox.com/u/392637/JeffTD%2 ... %20xls.zip

[jefftd]

Tim, have you had a chance to look at the pictures? I hate to nag, just trying to avoid multiple Mouser orders if I can.

[jefftd]

Could I please get some kind of assistance on this? Thanks!

[tpryan]

All I can tell you is pack them up and send them in. Please send an e-mail to rma@seventhcircleaudio.com for return instructions.