Reply to "Weak DCS signals, Failed TIU Output Drivers, and Design Solutions devloped under collaboration between AGHR and MTH"

gunrunnerjohn posted:

Norton posted:

Junior, at least two of us, John and myself, have rev Ls that never came with the tiny TVS's. Both of ours continue to work. I have put a scope on mine and it shows full output of 6-8v P-P on all channels. If yours stops working then send it to an MTH tech and have it repaired. For any electronics guy worth his/her salt this is a simple repair.

John, I would suggest doing at least one TIU, yours or your clubs with one channel using MTH's suggested component for a comparison. If theirs fails and yours doesn't then maybe MTH will adopt your fix.

Pete

Pete, I see that Adrian beat me to it, 8V P-P is too low, that indicates that probably two of the four gates in the 244 have already failed.  You should be getting around 14-15V P-P with a properly functioning TIU, see my previous post before and after replacing the 244 for the failing channel.

Post with signal levels before and after repair

I assume to get 14v you are using a transformer on the fixed one set at 20v RMS and a high pass filter to get rid of the 60hz?

I was using a 12v DC wall wart. I will retest with an AC transformer.

Pete