Hi everybody! I have a question for you.
I'm trying to repair a sys7 mpu with the above errore code. This "8" is driving me Crazy..
Comparing signals with a working (with working I mean "zero" than go off as per manual), they are the same! Error code could be a bad CMOS or a bad memory protect circuit. Since the signals of ICs of mem circuit are ok, I try ti change several 5101 but nothing better happens. The eight Is always in front of me. With Leon, the test passed so.. where is the problem?!
In fact, with board installed, I cannot change audits from the coin door, so I think the problem Is correct.. something is protecting the values on the memory..
The mem protect circuit is composed by two ICs: a 4071 and 7408.
Thanks in advance for helping me!
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Thanks for the answers!
The only difference between boards Is that the working one doesn't have the IC2 74125 and all diodes & dip switches on the left.
With the working one is possibile to change settings, no with the other.
With Leon the test Is fine (blinking, 1-2-3, blinking). The board does the complete booting and It is possibile to play.. but no change audits..