Anyone have a Running Galaga Bootleg MGG-703A ?

papapopop

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Hi,
working on a bootleg Galaga labeled MGG-703A(CPU) and MGG-703B(video) makes me crazy. Sometimes it runs, sometimes I get different RAM errors sometimes it hangs up after 10 minutes. I use a test equipment plugged in as cpu1 so I can stop the cpu1 and test the RAMs and they are all OK. I am not sure if I have the right ROMs or have another hardware failure.Does anyone have a running pcb or known good roms and send the file to me ? I made some tests with namco roms, galaga bootleg roms and I always get no positive results. Or anyone an idea on which area of the pcb to look ?
In my repair career I never thought about dropping a pcb out of the window,this time I thought about it.
Thanks for help
Greets to All
 
The Galaga bootlegs are known for having poor ROM sockets, might explain why your problems are intermittent if your loosing a few connections here and there.
 
Hi,
I know the bad IC-sockets. Made all of them new, took the goldplated sockets with machine pins. Therefore I changed all 74LS367 (8 pieces) and soldered a new 50 pin connector cable instead of the interboard connector plug.
Your idea sounds good, will have a closer look again to the signals. But I don't trust my ROMs.
Greets
 
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