i have a bally -35 mpu that at power on, only gets the first flicker. if i jump pins 39 and 40 of cpu, usually it resets and proceeds with all of the flashes and boots properly.

any idea what makes it sometimes boot normally and sometimes stop after the first flicker?

thanks in advance.

happens on both the bench and in game. im not certain tho if my bench power setup requires a manual reset of board because of its initial power speed, or if its the board.
i should mention driver board capacitors are new.

most times, but not everytime. and also since first post, i replaced U2 socket hoping somehow that was the issue, and it booted up twice in game fine. then it started stopping at two flashes. i switched out U8 and U19 (they are both already socketed), it booted up fine a couple times, but now it wont get past initial flicker, even when i jump cpu pins.

ill check that asap. i replaced all the reset components a few months ago, while attempting to get this board to flicker, i think i still have some extra components i got extra of. i may have another VR1.

thanks for responding.

its actually very pretty clean looking. no real signs of corrosion. a small amount of green paint has been sanded off both lower corners but components dont look affected.

i recieved this board in a game as untested. its replacement battery is one of those disk capacitor looking things. im not familiar with those yet.

all but the U16 chip are socketed. repair work looks fine. not sloppy.

This is the second board to unreliably boot in this game. but both boards are in questionable shape so im not really sure at all if its the boards or something in game creating the unreliability.

i found more VR1s, ill replace it tomorrow just to make certain its not that.

if these are not high enough resolution, I can take them again with my wifes iPhone this evening...

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thanks for inspecting pics.

bare copper is bare. I can tin it tonight.

you could be onto something with the chips. ive switched out most of them when working on my other -35, and that board boots up unreliably as well.

roms are newly burnt, and other chips were from a reputable vendor as a bally 35 mpu set. so i didn't expect them to be wonky. ive replaced most of the sockets, but not all. so possibly issues from one i haven't replace yet?

is there any possibility of the super capacitor creating issues after being totally empty for a long time?

ill check q5 tonite, but fairly certain its the angle of pic.

if it is a wonky chip or socket, would i be correct to assume its not U6 U9 or U11 because i do get a flicker reliably?

again, thanks for the help

I sadly don't have a third board to switch with (time to get another project lol), but do have other chips. I will switch out what I can, and also replace any remaining sockets I did not replace myself.

ill post back with any updates, hopefully positive news.

thanks for the info, I have some good leads to go on now.

alright, so when i got to the board today, it was consistently booting on the bench. That made me wonder if it was a power issue. In the game, I checked all test points on driver board and mpu, and they were all correct. i connected the rest of the cables, and the game booted up correctly, but then crashed after about a minute.

I then replaced VR1. the one i took out read 0 volts in both directions.

Game was then consistently getting the first flicker, but would not get the first flash, even when jumping the cpu pins.

I burned a new U6, and now it boots up correctly. i got it into attract mode multiple times, and played for about ten minutes. turned it off, and back on and it went to attract mode again.'

holding my breath but it seems okay now.

@quench thanks a lot for the leads. i really appreciate it.