Arcade Collecting > Pinball
Gottlieb System 80b switch matrix question
ed12:
hi
the roit will cause a host of problem's
if u have a multimeter go to vdc and u can see the line's strobe and u can see the return's ie up to 5 but not nessarly 5 i find 2.5 then drop to 0 vdc
if the line's are working right u can clearly see the :strobimg-effect:
a latch high low line is not what u want on the input output side of the
interface chip's ie z11/12/13/14
as they are buffer's 1 side is high the other is low
u will want a ref.handbook and or use nte to cross them over and snag there pdf's,1 sure tell trick on the riot chip's,is the _enable line toggling..
this is a cause for concern..now if u have a batt in this unit,for testing remove 1 lead,them your machine will not keep scoring values
until u fix the matrix,and yes the slam tilt circuit is a cause for problem's
u have 1 on the door,1on the playfield,2 on the side wall of the cabinet
ed
brad808:
So tonight I disconnected everything except the power, and display plugs. The only other thing I connected was an alligator clip so the board saw the slam switch closed. On all pins that I probed I can see voltage but not anything "moving". The voltages are simply sitting at the same value for as long as I hold the meter there. I tried with both analog meter and digital meter to see if there were problems with the digital not reading fast enough.
Are there other spots I can stick my meter to see the strobbing effect so I make sure I'm not missing it somehow? Will the other riot chips be strobbing? If all voltages remain at a constant voltage does that indicate a bad riot chip?
This is what my repair guide says
--- Quote ---MISSING STROBES FROM THE CPU
Testing strobes from the CPU will indicate if the problems are CPU or connector related. Often the connector is usally the problem, but there are a few other checks to do.
The following chart will tell you which strobes you might be missing:
Strobe #0 at connector J5-2 and J6-1 and chip Z12-2, start at U4-24
Strobe #1 at connector J5-3 and J6-2 and chip Z12-6, start at U4-23
Strobe #2 at connector J5-4 and J6-3 and chip Z11-12, start at U4-22
Strobe #3 at connector J5-5 and J6-4 and chip Z11-10, start at U4-21
Strobe #4 at connector J5-6 and J6-5 and chip Z11- 6, start at U4-19
Strobe #5 at connector J5-7 and J6-6 and chip Z11- 4, start at U4-18
Strobe #6 at connector J6-7 and chip Z11- 2, start at U4-17
Strobe #7 at connector J5-8 and J6-8 and chip Z11- 8, start at U4-16
The strobe will be at both connectors (except Strobe 6) and will indicate if you have a connector or CPU problem. Move back to chip Z11 or 12. Then move back to U4 to the start of the matrix.
EXAMPLE: missing entire row of switch 40-44. (follow along with CPU schematic)
This indicates a missing strobe #4. Start at connector J5-6 and J6-5 (no strobe is seen), so then move on to chip Z11-6 (no storbe seen), then move on to U4-19 (strobe seen). At this point you need to make sure the strobe is making it from U4 to Z11. This strobe goes into Z11-5 (see schematic) and should be there if at U4-19. A strobe at Z11-5, but not Z11-6 would indicate a bad Z11 which would need to be replaced. No strobe at U4-19 would indicate a bad U4- RIOT (common).
A strobe found at the Z11 and Z12 as listed above, but not at J5 or J6 would probably indicate a bad connector. You are attempting to probe the connector itself or the wire in the harness, so any flawed connector pin would not get the signal from the CPU board to the connector.
--- End quote ---
It would seem that I wouldn't be missing all the strobes. Most people would have a bad pin or two from the riot chip and not the entire chip?
ed12:
hi
a little logic order is in need here
the riot chip's are >pia's<,they were made by both rockwell and motorola
plus intel,search the web and find what is called the i/o line's
this is were data is sent to the chip and returned from the chip
it is a 40 pin chip...1 or 3 bad line's mean's the chip is done,for the simple fact it is latching up,the olny way to tell is to remove the chip's that interface it and the diode's,leave them out,power up,if u find a high switch and or a none strobbing port,u can conculde u have a blown riot..
ed
brad808:
OK I replaced u4 riot chip and got the game back up running again. All switches are working now :applaud: (cross fingers it doesn't crap out on me in a few more games). What a pain it was trouble shooting that thing. It seemed everytime I turned the machine on there was a different problem. Thanks for all the help.
One thing I've noticed is when I first got the machine upon boot up it would scroll "hollywood's finest" and then start showing high scores across the bottom. As of right now it comes up as just 0's but plays fine and shows credits etc fine. When I start the game it scrolls "the heat is on" as normal. Might be something simple but I'd like to sort that out as well.
Edit: Just a dip switch :banghead:
So looks like just u4 riot caused me a ton of trouble
ed12:
hi
congrads :):)
now enjoy the game
i once did a sc on a 80b where the switch riot was shot because some clown in toronto thought u could use :duct-tape: on the back of the board
to isolate it.... :banghead: :banghead: :banghead:
ed
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