Excellent... fingers are crossed!
Now, do you see what I meant 20 days and 9 forum pages ago?
DogP
hahah!! Just think of me next time
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Excellent... fingers are crossed!
Now, do you see what I meant 20 days and 9 forum pages ago?
DogP
Oh, and does the game actually reboot, or does the monitor just go dark and then come back. Did you make sure your anode is properly seated in the tube (both prongs in the hole in the tube)?
When looking for arcs, I find it's best to turn the lights out and stare at the back of the monitor... it should be really easy to spot in the dark. You can also look at the metal (usually near the flyback) for burn marks where the spark is arcing to.
DogP
It does seem strange that the monitor would cause a reboot of the game board... did you make sure that your grounds are attached to the monitor frame and everything?
Another test that would be worthwhile is to unplug the monitor and make sure it doesn't reboot (obviously you'd have to listen to the game sounds rather than watch the screen). It's possible that there's a problem with the transformer in the bottom of your cabinet or something.
DogP
Awesome- I will bust out the multi meter and get to work- thanks!Definitely check power... in particular I'd check the fuses/fuse holders and edge connector. They tend to get dirty/oxidized and need to be cleaned, and also sometimes simply wear out (pins lose their "springiness").
I quickly scanned the thread, and it looks like you still have the original transformer, not a switching power supply, so you should have 7V AC (pins 3/C and 4/D) and 12V AC (pins 19/W and 20/X) going into the game PCB, which is rectified to DC on the board. Each of those AC lines has a fuse in-line (5A fuses for 7V and 1A fuses for 12V). You can use a multimeter to check AC at various points (transformer, fuse holders, edge connector, etc)... or you can start by looking for +5V DC at the game PCB, and if that's not present, work your way backwards.
DogP
Ok this is nuts- resurrecting this again- I never actually got to testing stuff from that last post- work/kids/everything just got too busy..Awesome- I will bust out the multi meter and get to work- thanks!
Pac-Man hardware takes in AC voltage at the board edge, the AC voltage is rectified to DC on the game board. so I would test the rectifier diodes on the +12V side (search for a board pinout if you don't know where this is) cause they're probably shorted. why they're shorted you'll probably have to dig a little deeper. I don't know how to test it for shorts accurately besides the "backwards" diode check with meter (red lead on ground, touch black lead to find junction drops), but the amplifier IC isn't pleasant to remove. the heatsink is plastered in multiple legs worth of solder to ground. I've found the LM1877N to be a great replacement because it doesn't run monumentally hot and from hours of running a Ms. Pac-Man with it, I didn't find it needed the heatsink anymore.Ok this is nuts- resurrecting this again- I never actually got to testing stuff from that last post- work/kids/everything just got too busy..
But I am getting to it now!!
So I just tested the fuses, and the two 12V 1A fuses were both blown... So I grabbed more at HD and after replacing them, the two new ones both blow immediately after powering on the machine. All other fuses are fine..
Also I tried putting in good new 12V 1A fuses and disconnecting the edge connector before powering on and they didn't blow in that cases- so it looks like back to something on the board.
What where do I need to start looking for a short that would be blasting those fuses?
(I can also say that when powered on with the two 12V 1A fuses blown- if I turn the brightnes up on the monitor I can get the screen close to white so the monitor is still working fine)
Thanks for the plan of attack- given how much of an oddysey it was for me to complete the multiple repairs needed to the game board and monitor myself last time with just my soldering iron, multi-meter, no real bench setup to work on (just the machine itself), and how much free time I have now, I just sort of gave in and sent the board to @madrits to repair :/ .Pac-Man hardware takes in AC voltage at the board edge, the AC voltage is rectified to DC on the game board. so I would test the rectifier diodes on the +12V side (search for a board pinout if you don't know where this is) cause they're probably shorted. why they're shorted you'll probably have to dig a little deeper. I don't know how to test it for shorts accurately besides the "backwards" diode check with meter (red lead on ground, touch black lead to find junction drops), but the amplifier IC isn't pleasant to remove. the heatsink is plastered in multiple legs worth of solder to ground. I've found the LM1877N to be a great replacement because it doesn't run monumentally hot and from hours of running a Ms. Pac-Man with it, I didn't find it needed the heatsink anymore.
while you're in there, these games are very old now and it's effectively mandatory to replace the caps on the game board.
hopefully you can figure it out. I also don't know the diode part numbers but you can probably find them in the game manual.
@madrits is greatThanks
Thanks for the plan of attack- given how much of an oddysey it was for me to complete the multiple repairs needed to the game board and monitor myself last time with just my soldering iron, multi-meter, no real bench setup to work on (just the machine itself), and how much free time I have now, I just sort of gave in and sent the board to @madrits to repair :/ .