First posting - not sure to the rules Of the forum but adding to this topic since it may be related.

I just pushed to 3 my pinball collection by buying a Tri-zone, a system 6 machine. It does not boot up. I have 2 LEDs on constant with play field on. No display lights although from an angle I can see there is power going to them.

When I first fired it up, I had some numbers going to the displays that eventually went away.

My question this: I have checked the voltages and I am only getting 9 Volts DC in the 12V unregulated supply, both on the MPU board and on the power board. The 5V is good. The F5 fuse and the C15 capacitor all have 9 V going to them.

Any ideas on what could be limiting the voltage from reaching the 12V dc?

Thanks,

Indigestion

Thanks for the response and intel. Here is further results of the ongoing investigation.

Now I disconnected all the connectors to the Power board except for the input F1 and F2. I have removed the F2 and F3 fuses. Now When I power on, I get the 12v DC unregulated on the 6 pin! What does that tell you?

However, when I do a diode check on the D7 and D8 diodes, I am getting .4V with DMM in diode setting in both directions. I am seeing that malady on both diodes.

I may also have a grounding problem. I swear I am getting a current from the rails to my fingers and got a reasonable shock one time I touched the metal surrounding the transformer.

What is your best prognosis? Buy a new PS board? Buy a new set of diode?

Thanks,

indegestion