Hello,
This is an update to an earlier topic I started about no 5volt logic.
I now have the +5vdc getting to the board. However, I severed many of the +5vdc traces to isolate areas of the board. In the lower right corner of the board around ic chips U50, U28 and Q51, I am getting (point) .3 or .5vdc at pins 16 on the chips and .3vdc at the collector side of transistor Q51. When I disconnect the -12vdc grey wire at 1J18, the stray voltage disappears.??? I thought U48 was suspect, but all it’s outputs check out against a working sys 9 machine. I also disconnected power to U47 audio amp.
Feel like I’m chasing a ghost, Any help is much appreciated.
Thank you,
Matt