(Initial Post Below Now Updated Reflecting All The Tests Performed So Far/Latest Conditions
My TZ resets the instant both flippers are pressed simultaneously (even at 0 points on the DMD with Ball 1 in the shooter lane)…this happened EVERY time without fail--but only when the game is cold (IE--10 out of 10 times.)
But after the game warms up, it doesn't reset despite the 5V rail being at only 4.80V (I thought these games most certainly reset if under the 4.92 V)?
Anyway, I started methodically trouble shooting the problem by going through all the usual steps:
1. Line voltage: 119.9 volts; with the furnace on: only drops to 118.7 V.
2. 5V TP2 on PDB: shows a pathetic 4.80 Volts.
3. 5V on the CPU on EPROM pin 32: no change, 4.80 Volts.
4. Reseated J101 on the PDB and used a pusher: same voltage on pin 32: 4.80 V.
5. Reseated J114 on the PDB and used a pusher: roughly same voltage on pin 32: 4.79 V.
6. Reseated J210 on the CPU and used a pusher: roughly same voltage on pin 32: 4.77 V.
7. Z connector was previously eliminated.
8. 18-Volt TP8 was between varying between 15.75 and 18.5V.
9. Decided to reseat all 5 connections coming out of the transformer, same voltage afterwards: 4.80 V.
10. All PDB ground screws are tight.
11. Earlier thought I might have a failing DMD or Controller Board, swapped in 2 known good parts; still resets when cold.
12. Thermistor: jumpered around it and game still resets when cold.
13. All other connectors in the power box are secure; in-line fuse holder looks fine.
14. All 8 flipper diodes present; no cold solder joints.
15. DMM reading on BR2: reading on positive leg was 9.86V.
16. C5: reads 0.286 with DMM on AC Auto.
Thanks in advance.