I picked up a project Space Riders - posted to early SS forum but haven't got much help. I know this is the Middle Earth forum but though maybe someone could give me some advice.

At power on all lights and displays just flash. I checked voltages and I think that is the problem. I am not getting 5vdc on the MPU. I rebuilt the power logic on the mpu - new lm323, new capacitor, and resistor. Still no 5vdc on the board. I checked the incoming connection from the power supply pin 1 at J9 which should read 10vdc. the voltage bounces but 1.61vdc max. I decided to go ahead and replace rectifiers and the two large capacitors on the power supply. That too did not solve the problem.

The fuses on the power supply which should be VAC from the transformer read from 0 to 1.5 or so - assuming I am measuring the VAC correctly. I touched leads on either side of the fuse.

Transformers seldom go bad. Is it a short somewhere? Any advice on what next to check?

Thanks,

Should be DC volts coming off the rectifiers, correct?

I pulled the transformer/power supply unit and checked for continuity across the entire power supply. Everything checked out okay. I double checked the new rectifiers and connections - all is okay. I reinstalled the transformer/power supply unit and checked continuity from the power supply to the MPU board connection and power supply to the auxiliary board- all connections buzz as they should.

Turn the power on, and no volts to the mpu or auxiliary board. No volts coming off the rectifiers or capacitors.

I do have 117volts to the bg cabinet and those lights work. This connection does not go through the transformer.

Is it the transformer? I don't see an easy way to check voltage off the transformer - wire connect underneath it. Transformers seldom go bad so that would be odd.