Pro Football thread this aint!
Update on this... I eventually sourced another board guaranteed 100% working. Well the CPU booted but the board itself was not 100% working.
I have several problems with this machine.
Flipper relay does not pull in and so ground is lost.. i can activate flippers by bypassing the relay at the power board connectors...
I also have several solenoids that do not fire.. they have power to coils and work in test mode but not in game mode. Is a bit hard to determine whether this is a CPU or Driver problem... if its a driver fault then i have all three 4724 IC's failed.. this is very unlikely and so the CPU gets tested.
I downloaded a test Eprom from Flipperfan here....
http://www.flipper-pinball-fan.be/I find that this site has quite a bit of usefull stuff on it that cant be found anywhere else.. also includes an ATARI repair guide .. something that is pretty hard to come by.
Anyway, Beaky burnt me the test Eprom ( many thanks mate
)... in fact twice!
Today whilst both young kids were asleep i quickly tested the board... flipperfan's instructions can be a bit scratchy, but you can work out whats meant to be going on.He tells you to test only 3 outputs to IC38.. but there are 8 on this chip and all are used so i tested them all. Glad i did cos at pin 9 CN10 i have no output signal.
This goes back to IC38 pin9 where signal is present.
This chip has been replaced on this board and a socket installed also. Zac games can be tricky to work on as the tracks lift with too much heat, plus i find that the joins between the solder pads and traces are very easy to break... too much heat and this will give way... too little and it snaps.
For this reason ALL repairs MUST be buzzed out before being installed back into the game again. The output of this IC ( my dreaded 3081 transistor arrays) cannot be tested as they are open collector and so current must pass for the output to be tested. Without a test Eprom, all you can do is replace this chip in the hope that it will rectify your fault... if it doesnt, its easy to assume that all is OK here.
The Eprom identifies a signal missing.
A quick check on schematics reveals that this output is ROW 7 for solenoid contacts... Ok is looking promising!
But then the kids ( well one of them) woke up and so my work stops there.
When i get the chance, ill fix the broken trace and install the board.. may well have the solenoids firing.... maybe flippers too?
Im getting closer to having this sucker nailed!
