Yes those were voltages with the power plugged in, game inserted, and no power button pressed before measurements were taken.
I thought the same thing regarding the U6 being faulty so I replaced it with a MC14069B U6 replacement chip from eBay.
Still getting weird readings.
double checked TP15 and with the AC plugged in I’m getting .450V.
Regarding the power pins to the battery terminals, these were the DMM continuity/resistance readings with no power.
- Batt Terminal.
Pins 2+3 have direct connection .8 Ohms.
OL for pin 1
+ Batt Terminal
pin 2 4.8M Ohms
pin 1 2.3M Ohms
pin 3 2.3M Ohms
Looking at the schematic: I wanted to check the power rail. Continuity from pin 1 to anode. Using diode mode .555V anode to cathode, OL cathode to anode.
I used the cathode as the continuity point for the rest of the power rail.
Continuity to cathode of D11 .535V anode to cathode, 2.5V cathode to anode. Continuity to C35, C36, C39 positive, D12 cathode, continuity to C40, C41 positive, continuity to the emitter on Q8, continuity to R74, C44, and R75.
Does anything stick out to you here or should I check through the ground rail?
Jared