angs1957 Posted June 14, 2015 Share Posted June 14, 2015 Had a weird problem with Playboy Basically the machine would not fire up after playing it a few hours before, not mine so I felt a bit bad, after a few checks noticed that the power supply was not giving the correct voltages it was only out .5 to .8 volt D.C so the MPU wasn't firing up. Cut a long story short it turned out that the common ground points were not interlinked between boards, was only getting partial readings then no readings then some readings so it was weird, anyway temporarily placed a common point and wamabalama it fired up, why these were not fitted initially I will never know, anyway might help someone else. Link to comment Share on other sites More sharing options...
wiredoug Posted June 14, 2015 Share Posted June 14, 2015 sorry but can i call gibberish? this is rubbish.. The metal backplane in the headbox is the common ground. Do you mean the braid from the cabinet to the headbox was missing? Link to comment Share on other sites More sharing options...
angs1957 Posted June 14, 2015 Author Share Posted June 14, 2015 No everything was in tack as it should be, with the check points at the power supply it pointed to a bridge rectifier, so I thought, I believe that the common ground was floating causing a ripple effect instead of allowing true D.C. , the fix was easy, just used a jumper lead for now, what else could it have been? Do you have any suggestions :D Link to comment Share on other sites More sharing options...
Railways Posted June 14, 2015 Share Posted June 14, 2015 I'm only guessing but in between all that messing around you may have fixed one problem but bought to light the most common problem with these old girls which is the Rectifier board mounted above the transformer in the headbox. The original boards are waaaaaay past the use by date. Link to comment Share on other sites More sharing options...
Rich Posted June 14, 2015 Share Posted June 14, 2015 Read somewhere of failure of the metal backplane and the later Bally foil type soft cardboard backplane and a simple 'daisy chain' connecting the all the grounds is a reliable and easy fix. Link to comment Share on other sites More sharing options...
angs1957 Posted June 15, 2015 Author Share Posted June 15, 2015 I just thought I would raise the issue in the hope it helps someone else :D Link to comment Share on other sites More sharing options...
Mitchjjam Posted June 16, 2015 Share Posted June 16, 2015 Good comments and interesting to read. Never worked on this pinball but all makes some sense. Sent from my iPad using Tapatalk Link to comment Share on other sites More sharing options...
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