ms pac no video

[death69inc]

forgive me if this is the wrong section feel free to move it but please let me know where it went so next time ill know

either case
I have a video problem have been working of and on for a while now

pac played blind

referenced the PAC trouble shooting guide

replaced just about every ic listed that can cause no screen issues

still have 2 i think I need to order as i do not have any in stock
about to program a whole prom set and eprom set just to see if it will help

2nd issue i replaced the caps with a kit from bob and well I made a noob mistake i cant believe i did but i did
had  3 extra caps (for daughter board i did not know at time ) noticed a cap next to the lm 377 amp so i replaced it ..........
fired it up no sound was a little mad  rechecked all my caps to make sure they where correct sure enough that one was wrong value shakes head
replace original back in place no sound both speaker wires now have +5 volts running through them
fig i blew the lm 377 but was wondering what anyone else thinks i should try 1st if not that as I cant seem to get the heatsink to desolder
either case i assume it still plays blind but i have n o clue as sound is gone now lol

sorry for the run on sentences

not the best at board lvl repairs I'm more a change part out guy and most i fix but a few I have yet to fix and this is one of them


still have all ic's i pulled and caps for that matter just in case

[SirPeale]

1) stop throwing random parts at it. If you can't handle the repair, give it to someone you can. 

2) All you've said is the parts you're tossing at the Pac-Man board, but you haven't mentioned a word about the monitor.  If it's playing blind, that sounds like a monitor issue, not a board issue.

[Kevin Mullins]

  2) All you've said is the parts you're tossing at the Pac-Man board, but you haven't mentioned a word about the monitor.  If it's playing blind, that sounds like a monitor issue, not a board issue.

Ditto.....

Have you tested the monitor with any other game or test rig ?
Is there neck glow, high voltage static or any other signs of life from the monitor itself ?
If you turn the SCREEN up on the flyback does the screen start to turn white/bright ?

[death69inc]

sorry since i didnt mention a monitor issue I thought you would know its fine

in the cab pcb has no video
in the test rig pcb has no video

no broken traces not a scratch on it

does have one of those test board addons but it wont do me any good as there no video to see

well I figured if the service manual says symtoms of each ic i replaced was no video so it was not random, thought it would fix the issue it did not so far
also crystal replaced basically if i had it in stock adn it said issue caused by no video i replaced

but 3 of the proms also state to cause same issue I do have the proms in stock but got pissy with the board and stopped for awhile

usually do nto have problems with game boards guess i have been lucky most all issues have been amps or eproms sockets etc or broken traces

but this one not so much

[RayB]

So is that YES, there is glow in the monitor neck? YES, there is static sound from the monitor? YES, screen goes bright if you turn up the "SCREEN" knob?

[death69inc]

the monitor is fine currently on my test rig and it is fine  (it is not working on cab monitor nor my test rig monitor is what i mean)

rig monitor works 100% with all other games used on it

it is not a monitor issue it is a video issue

as state
in the cab pcb has no video
in the test rig pcb has no video

PCB is playing blind
monitor is fine

[death69inc]

just bought another ms pac board
not getting anywhere with this one
maybe after i replace the eproms and roms it will be good
i noticed a few ms pacs that had extra eproms on them and no longer needed the aux board
woudl be nice to have as this board has a diagnostic addon board and who know it might be the dead and causing the issue shrugs