Bally Doctor Who (Bally, 1992) mini playfield optos errors

[robbo007]

Hello all,

I've got a Dr Who Pinball and I have some issues with the optos on the mini play field.

Originally 2 of the 5 were not working. I was given another opto set which was taken out of another machine. I plugged it all in and only 2 of the optos were working. With a digital camera I see the LEDS seems to light up. Not too bright but there is light.

I then connected the original opto set which had 2 of the 5 not working and now none work?????

I connected it directly to the connector without taking to bits the mini play field to test it, then stuck it correctly into the mini play field. This should not damage the optos right?

Any ideas how I can troubleshoot the problem?

I'm going to stick the second opto set in the mini playfield again and see if I have the same issues.

Thanks in advance.

Rob

 

[pinball_faz]

Before you try all this, make sure the connector from the mini-playfield is good. Check continuity from the PCB to a spot beyond the connector into the main playfield.
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You've tested the LEDs...next test the receivers. Hook up to a DMM and look for a consistent signal out of each. If all give a good reading, then check alignment. The PCB can become warped or the plastic housing that holds the optos. <o></o>
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If you're at this stage, the mini-playfield is probably on your bench. Try lighting each LED and seeing if the Light receiver can pick it up (again using your DMM to interpret the signal). Make sure the room lighting is dark as to not cause a bad reading. Try applying light pressure on the board to alter the light path. The receiver wants a tight light path. If manually warping the harness matters, you may need to replace some parts.<o></o>
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I hope this helps.<o></o>
faz