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SS Bally Help lamp driver problem

Johnnyo

Johnnyo

Not such a well known member.
10 Years
Joined
Jul 21, 2011
Messages
382
Location
Hertfordshire
Really need you help here this is driving me nuts.
I have lost all feature lamps associated with U3 on the lamp driver board uploadfromtaptalk1434822959232.JPG
I have replaced U3with a new
CD4514 to no avail still no lights
I have also checked every SCR and all test Ok with my DMM, all lamps on U1,2&4 are good and no other faults show on the game. Have been over the schematics and noticed U10 on the mpu board may have something to do with the address/data lines for the lamps on U3 swapped PIAs U10/U11 no difference
Any one have some ideas as I have none left.

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Last edited:
when I had a similar fault,it turned out to be a dodgy pin header connector,try reflowing the header pins
 
Thanks for the reply Steve done this several months ago but will go over it again.

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Just got some connectors off Andy but I had all the lamps prior to removing the board to replace two of the smaller Scr s when I replaced the board some of the lamps controlled by U3 flickered and promptly died hence me thinking U3 was fried.


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The only other thing that could have happened is that some of the lampholders in the centre of the playfield are very close to coils in the droptarget assemblies could have shorted and stuck 43v down the lamp line.

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Yes but it controls all the red lamps on pacmans maze and they all work

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7.2v on the common line. forgot to mention if I ground the anode of the Scr the lamps that don't light do light

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Sorry Carl I didn't thank you for trying to help me the other night again sincere apologies.

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i know some things ,but i was getting a bit drunk and getting out of my depth.
did you see the thread on this site .one of the links was saying about pulling out J1 one the mpu to see if you have 7 flashes on the board ?

really nice pin you have there !!
 
The mpu is booting up no problem the fault is about 14 or so feature lamps refuse to light all controlled by U3 decoder chip on the lamp board.

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Recheck connection on j2 / j3 ,lightly sand pins with ruff sandpaper ,recheck U3 chip work buzz test the socket etc !
 
Done that Carl and buzzed out every pin on u3 to the back of the board all joints ok
 
Just got back from a week away very nice it was too.

Worked on it today and finally cracked it, buzzed out all the relevant connections and found one line on J1 lamp driver board not making connection pin 5 data line to U3 great cracked it.

I thought plugged it back in switched on now loads of lamps constantly on.

Oh despair :-( head scratching etc
Back to the schematics found I put the new terminal in the wrong hole fifth from top instead of fith from bottom swapped around bingo lights now working.:-)

Still had a few not working but they were soon sorted bad headers on J3 as you said check, now all sorted only downer put a new chip in U3 for nothing.

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Thanks for your input Carl much appreciated.
.

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Nice detective work. Probably stepping away from it for a week and then coming back to it fresh helped.

Would love a M&MPM. Still kicking myself for missing out on a project last year :( Still, can't complain. I'm now the owner of an ultra-rare super-mint GOLD BALL that has actually turned out to be great fun to play :D

At least you've got a spare chip for when it does get fried with a 43V short ;)
 
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