Tech: Tempest question

[Cassidy Nolen]

Hi all, usually I try to answer, now I need some help!

 

Just got a Tempest (dream come true after all these years) and I saw I

did not have 5 Volts. Game has been in storage for a few years, so I

cleaned things up and disconnected boards. With main boards

disconnected, there is 5 volts. When it is hooked up, less than one.

 

Swapped out another AR2 I knew was good, and it burned up R29 (10 ohm) within a second or two.

Replaced that one on the original AR2 and the same thing happened.

 

What the heck is going on? Any ideas where to start? I noticed some

cold solder joints on the interconnect pins, but that would not cause

this to happen, right? I have 10.5 or so DCVolts going into the AR2,

at a total loss where to go from here.

 

 

Cassidy

[AlanD]

Well I have never seen the problem before on a Tempest but sounds like a short somewhere in the 5V circuit. My suggestions are:

 

1. Resolder all the interconnect pins. Gregg Woodcock's guide lists this as a preliminary step in troubleshooting a Tempest and I can agree with that.

 

2. Unplug the Aux PCB and leave in just the main PCB with nothing else plugged in (monitor, etc) and try it and see if R29 fries. You can at least eliminate it down to one board or the other.

 

3. Check all those filter caps around the board. I have several times seen them twisted into a short on other boardsets and always the power supply died quick.

 

4. Possibly wire in a switching power supply for them short term since most of them will instantly shutdown from a short.

 

Well that is all I can suggest. Let me know if there is any other assistance I can offer.

Alan