Show me the ways of the Pole Position....

TheDrewster

Well-known member

Donor 2012
Joined
Oct 5, 2008
Messages
7,668
Reaction score
314
Location
Reno, Nevada
Right forum now :)

Alright, so I have a client with 2 Pole Positions. We would like to get at least one fixed.

Machine number 1 clicks on and off by itself and an orange wire from the isolation transformer smokes out and the insulation melts and burns.

Machine number 2 starts off with a very slow moving fan, gradually progressing into a rather fast and loud fan. Nothing shows on the screen and the game does not boot.

I have taken both boardsets and tested them to have at least 1 functional boardset, so that narrows it down to the power supplies. I am assuming machine 1 needs a whole new power brick to start off with. But for the second machine, explain to me step by step how to go about replacing the power supply/ARII's or getting the right voltages to the boards. I have heard about using a standard computer ATX power supply. What truth is there to this and how does this work?
 
Last edited:
Wow--2 working Pole Position boardsets? What are the odds on that? :)

Anyway, what you need to do is just unplug the edge connectors from those boards until you get your power issues straightened out. It would be a shame to toast known working PP boardsets on flaky power! It sounds like you have some issues with your ARII boards, which is a very common failure in Atari machines.

The power brick is really simple in these machines.. all you have there are the transformer, a big blue capacitor, a bridge rectifier, a filter, and a few fuses. That's pretty much it. The transformer RARELY fails, but sometimes you will need a new bridge and/or big blue capacitor.

You will find that there are several testing points on the ARII. One of the first ones you should check is the 10.3VDC point (clip a lead to that one, and a lead to 'ground', and put your multimeter in DC mode.) This is the only DC voltage generated by the power brick. If your 10.3VDC is bad, you will probably need a new bridge rectifier or a big blue.

On the machine that is smoking/burning a wire, you might have a bad ground in your ARII. I.e. the ARII *thinks* ground is a voltage that is different than the ground in your power brick--you can test this easily by clipping a lead to the 'ground' on the ARII in question and the metal casing of your power brick. If you don't see zero volts potential, you have a ground issue, and current getting dumped from the ARII to the power brick (or the reverse), hence the smoking/melting wire. If there is a ground problem, some component is blown on your ARII and it will need to be repaired. If you do have a bad ground in your ARII, and you still want to check the 10.3VDC coming out of your power block (you do!), you can trace it back to the unplugged connector feeding the ARII, or just totally remove the power brick from the cabinet and clip your leads directly to the bolts coming out of the big blue. You can just flip the power brick up on its side while testing in this fashion. Make sure you don't grab anything on the power brick while it is plugged in. If your 10.3VDC is bad/low/fluctuating, check the diodes that make your bridge rectifier if they test out fine, it's probably your big blue.

The best way to troubleshoot power on old Atari machines is to start at the power brick and work your way up to all of the ARII voltages..

Ultimately, you will probably end up rebuilding those ARIIs, but you really need to see if the power bricks are feeding the correct DC voltage to them first. You can try shotgunning them with a Bob Roberts kit, or send them to BitSlicer. I hear he does excellent diagnostics and work on ARII boards.
 
Last edited:
The slow moving fan is a bad fan. I had one do the same on my ms pac. It was shot.
 
As 88MPH mentioned, check the bridge rectifier on the power brick. And off course the Big Blues should be replaced if not done so already.
 
Last edited:
Alright, so after a little more probing, I have come to the solid conclusion that the machine #2 has fully working ARII's. I tested them in my cabinet and my game worked with no problem. That means I am safe to assume that the big blue's are at fault, correct? I already ordered 2 blues from Bob, so I am hoping thats all.
 
if the fuse block is original then replace it...mine would cycle on/off from a broken tab on the fuse block.
 
http://www.therealbobroberts.net/apsnotes.html

A new big blue did the trick for me...start there.

5334018423_0af61866c7_b.jpg
 
br

also want to check with the diode function on a meter the diode junction drop on the bridge rectifiers thats more likey the issue, if bad they would be shorted or open when theres supposed to be about .7 v reading when in diode test
 
Back
Top Bottom