http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Second_flash

Voltages all within tolerance at test points on the MPU.

I get the flicker then two flashes. Replaced the socket and the 5101 - no change. Also tested the continuity points suggested in the pinwiki link - all check out good.

Swapped out known good ICs for all socketed chips (except the game ROMs) as well.

All I haven't done yet is replace the 4011 at U19 as it's suggested that could be a long shot problem.

The Vidiot appears to be working in that I can get the video test to run at least.

Lastly, FWIW, Eldorado games had repaired this back in 94 and verified it's a baby pac MPU (sticker and their tag on the board).

Suggestions?

Bueller?

Bueller??

Bueller???

Booting in both Baby and in my Strikes and Spares using only J4. All socketed chips swapped from working Strikes and Spares, including the 5101. Also had an NVRAM replacement for 5101. No difference.

Turns out the R113 still had the resistor installed, and not a diode. Diode installed, no change. Rested R11, tested fine and and 5+ was getting to U8. Replaced ,U14 U17 and U18 in case damaged by the R113 snafu. No change. Also hit the entire underside of the board with the heat gun in case it was a cold joint I was missing. No change.

I've already tested, twice now, the continuity points on the chart in the link in the first post. Seems like that covers everywhere U8 goes, correct?

Yup. Must be one of those dumbass "Oh, THERE you are!" things. Grrr. . .

Will likely do shortly.

Not a lot of work on it - jumpers were added since, IIRC 32 ROMs are on there now instead of the original 16s. Eldorado Games had worked on it back in 94 and gave it the OK - but I found the resistor where the diode should have been so this does not fill me with confidence.

As far as the new EPROMs - no as they are tested during one of the first two flashes already, and, thus, pass.

EDIT: Just realized I've not tried replacing U19, as suggested in my initial post. Derp. Will do this as well and report back.

Replacing U19 - no change. So, I started to measure voltages going to U19. The 3vdc was only registering at about 1.9v. Followed that back to R136, which was showing 1.9v at each end. Continued to follow to pin 5 of the 6800 - also 1.9v.

Does the 6800 produce this regulated voltage that's falling short of the 3 that is probably required to get the memory write enabled or it produced elsewhere on the board. I see the 3VDC elsewhere in the schems but can't determine where it's generated. I see .3VDC by Q5 and 3.6 by BT1 as well - but presume that's the battery voltage there.

Jumping the "lower" end of R6 to TP7 gets me to 2.9v and board boots and game plays about 90% of the time. Jumpered 5V TP to TP7 and game boots and plays - only did this once as I feared it would damage something with prolonged use. Perhaps adding a resistor to this jumper to get me just over 3v?

Pics. Anything obvious?

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ROMs are tested prior to the 3rd flash, so should be good.

*throws up hands and orders Ultimate MPU*