Piershil
It seems you may have a bad U2 on the master display driver board.
It's a UDN6118A chip.
Use the Road Kings schematics for better images.
Peter
(Topic ID: 208405)
Linked Games
High Speed
Williams, 1986
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The UDN6118A are driven to the limit of their voltage capability.
Failure is due sometime.
The UND6118A is one of the few things which can fail.
Lowering the voltage from the power supply is a good idea.
http://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#Display_problems
Replacing two zener diodes to reduce 100V to 91V.
Adding fuses is another idea.
http://www.pinwiki.com/wiki/index.php?title=Williams_System_9_-_11#Bridge_Rectifier_Fuses
Or using my Bridge Board to replace the bridge rectifiers, the big cap and adding the fuses.
http://home.kpn.nl/p.koch3/bridge_board.htm
Available here: http://bigdaddy-enterprises.com/boards/boards-index.htm#newboards (scroll to the near bottom).
And off cource replacing the battery with a NVram.
http://www.pinitech.com/products/6116_nvram.php
or http://nvram.weebly.com/
Quoted from lpnsocal:I'm down to my last issue on this machine, special solenoid #6 top pf flash lamps don't light. PF circuit is good as I tested it using a different solenoid # and the lamps lit during test. I also have connector continuity to the nearest component Q79(TIP122). I checked the Q79 and Q78(2N4401) values against others in the board and got very similar readings. Also local resistors checked out fine too. My guess is to replace both Q78,79 and see what happens, after I order them.
Thanks again for all the help and direction and feel free to chime in on my solenoid problem/solution!
If the transistors are good, check U50 (7402).
These are known to fail.
Did you also replace the power supply caps?
1 week later
Looking at the schematics I see that U50 looks to be working correctly because you grounded pin 1J18-9 and the lamps flash.
The flash lamp switch wire isn't used on the playfield.
The flash lamps are directly controlled via the cpu just like in the test function.
There is another chip (U49) in series with this line to U50 and through to Q78.
Check U49 (7407 hex buffer).
This is asumming the test function for Special Solenoid #6 does not work too.
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