Working on a Mr and Mrs Pac, LEDed it, no problems with anything except the GI. The GI flickers, not terribly, but it's definately noticeable.
I noticed that during the display test, the GI flashes on all even numbers. It also causes a number of controlled lamps to flash during the test as well. Thinking some sort of leakage current, through a common point.
I'm using comet bulbs, and haven't had problems with them in any other GI situations.
Anyone know of any solutions?
Check the power supply connection for burnt connectors or cold solder joints on the power supply board. I suppose there could be an intermittent short in the GI circuit, so maybe a bad LED or one of the lamp connections is touching something else.
Quoted from Zsuttle:Power supply board checks out, no burning and I had repinned it before. Unfortunately I'm running the original MPU, I may order a replacement to give it a shot unless anyone can think of anything else.
do you have a frequency test feature on your DMM? Check Hz at the 555 timer pin 3. Also check the value of R21. If someone put an MPU originally in a six digit game, the LED triac controlled GI lamps will flicker (the display are probably flickering too if this is the case). This game has extra displays and extra triac drivers making it extremely sensitive to interupt timings.
GI on this game is controlled by the lamp flasher board. The small rectangular board should be under the playfield. It uses a 555 load bulb mounted nearby. If this bulb is missing or has been replaced by an led the GI will function erratically. The lamp flasher is controlled by a switched lamp SCR so it's normal to have flashing GI in lamp test.
Quoted from barakandl:do you have a frequency test feature on your DMM? Check Hz at the 555 timer pin 3. Also check the value of R21. If someone put an MPU originally in a six digit game, the LED triac controlled GI lamps will flicker (the display are probably flickering too if this is the case). This game has extra displays and extra triac drivers making it extremely sensitive to interupt timings.
Sorry for the late reply, holiday times are always so busy around here. Frequency was reading around 408Hz, R21 checked out at 23k. Displays aren't particularly flickering (though they do if you look at them closely)
Quoted from BigAl56:GI on this game is controlled by the lamp flasher board. The small rectangular board should be under the playfield. It uses a 555 load bulb mounted nearby. If this bulb is missing or has been replaced by an led the GI will function erratically. The lamp flasher is controlled by a switched lamp SCR so it's normal to have flashing GI in lamp test.
There appear to be 3 bulbs underside of the playfield, one right next to the lamp flasher board, one next to the solenoid expander board, and another one up by the pop bumpers, all three of the are good.
That display interrupt is probably not happening at the best time making the GI triac flicker. This game in particular is sensitive, specially with led GI lamps.
If it really bugs you try changing the resistor to a trim pot wired like a variable resistor or tinker with the resistor value, probably slightly lower resistance, like maybe 20k.
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