by oneandasixtenth on Mon Sep 12, 2011 10:28 pm
eric I might try this what do you think?
Do NOT try servicing a machine with "A hand full of fuses"!
That is a fairly good way to blow a transformer or worse. Better way to go is to replace the fuse with a small wattage 115 volt bulb. Use a 25 watt bulb for this application. Now, remove the power supply plug and unplug ALL the displays. Hook the light bulb across the fuse holder, then turn on the game. Light bulb should glow, but not a full intensity. If dim that's good. Next turn game off, hook up power supply, BUT disconnect other cables from the power supply (right side and top cables), plug in again, light should be NO brighter. Might be briefly lit, but will dim down almost immediatly.
Now turn game off again, plug in half the displays, test, turn off and plug in other half, test. If the bulb glows brighter at any point (and I do mean BRIGHTER) then you have found the area and just disconnect/connect things until you find the guilty party. You can, if the lamp test passes all the displays and the unloaded power supply, then connect up the right cable (not the top) and test again. If bright with all displays connected remove half and test ... Lastly try the MPU board, but by now you should have found the short.
This will work for both transformers, but you might try removing the fuses from the front fuse panel and test after replacing each one. The test process depends on the problem.
Oh, and if the lamp is bright with nothing connected to the transformer, it is probably bad, but make sure all circuits from the transformer are disconnected, including bridge rectifiers.
This test process also works great for solid state amplifiers and monitors...