Doctor Who
Bally, 1992I have just picked up a Doctor Who pinball that had some issues with the cpu. I managed to get a couple of games in but the mini playfield eject stopped working (it was working to start with).
I have just put in the repaired cpu and everything is working fine accept the mini playfield r/h eject.
Where is the first place to check with this issue. There is continuity from the under playfield connector to the driver Board plug and the tip102 and tip36 transistors measure ok with my dmm.
Did you check the basics...
Full test, All switches, All solenoids [ could be matrix issue or power issue that you are just not seeing in other aspects of game play]
The connectors under the MPF (most likely the cause of spontaneous issue). Check condition.. replace if not perfect.
Broken wire from connector to optos or broken wire from connector to cpu (less likely the later but it can happen(
The vibrations in the MPF are severe.
Check power at all the testpoints within spec
Cold solder joint on opto component(s)... unfortunately, you need to pull the MPF first. Do you have my whitepaper on the topic?
faz
Quoted from pinball_faz:Did you check the basics...
Full test, All switches, All solenoids [ could be matrix issue or power issue that you are just not seeing in other aspects of game play]
The connectors under the MPF (most likely the cause of spontaneous issue). Check condition.. replace if not perfect.
Broken wire from connector to optos or broken wire from connector to cpu (less likely the later but it can happen(
The vibrations in the MPF are severe.
Check power at all the testpoints within spec
Cold solder joint on opto component(s)... unfortunately, you need to pull the MPF first. Do you have my whitepaper on the topic?
faz
Thanks for your comment. In the end I started checking everything I could without removing the MPF. Everything tested fine so needed to remove the MPF which was an easier job than I thought once I checked the whitepaper on this. I worked my way back to the coil only to find the winding had snapped. I replaced it with a new one got it all back together and it has worked great since.
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Chicago Burbs, IL