I have a non-working Tempest I picked up last year. Finally getting around to figuring out what all is wrong with it. I am new to this hobby, but pretty comfortable around electronics.
This is what is happening:
I adjusted the pot on the regulator board and I'm getting +5.5VDC on the +5 REG output, but only +4.4 on the PCB. I couldn't read anything with the negative lead on GND on the regulator and positive on +5 REG on the PCB connector. Schematics mention measuring the voltage between GND on the regulator and main PCB. I did this, and it was +50VDC. This seems alarmingly high, but I don't know what it means.
+5 REG lines on the harness have some repairs and I think those wires need to be replaced. Not sure how to do this — Looks like I can get some new end connectors (Molex?), solder or crimp to a new wire and string it through?
On the other hand, it feels like the regulator might be a problem. Topping out at +5.5 feels strange, and it's also responsible for sound, which is another symptom.
Ideas?
This is what is happening:
- P1/P2 button lights on, but the game is 100% dead otherwise.
- Spot killer off.
- LCDs CR2/CR1 on the main and aux boards are on. I think these are just power indicators, but I'm not sure. Is that correct?
- Loud hum from the speaker, no other sound. Sounds like a ground loop. Read that a bad big blue could cause hums, but I don't know if this would manifest this way. Stops if I disconnect J5, so it isn't (directly) the main power supply.
- Nothing in test mode.
I adjusted the pot on the regulator board and I'm getting +5.5VDC on the +5 REG output, but only +4.4 on the PCB. I couldn't read anything with the negative lead on GND on the regulator and positive on +5 REG on the PCB connector. Schematics mention measuring the voltage between GND on the regulator and main PCB. I did this, and it was +50VDC. This seems alarmingly high, but I don't know what it means.
+5 REG lines on the harness have some repairs and I think those wires need to be replaced. Not sure how to do this — Looks like I can get some new end connectors (Molex?), solder or crimp to a new wire and string it through?
On the other hand, it feels like the regulator might be a problem. Topping out at +5.5 feels strange, and it's also responsible for sound, which is another symptom.
Ideas?



