Pole Position Issue

wraywray

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have a issue with the power block. i am getting 6vac at fuse f3 and 8.o vac/4vdc at the big blues. the big blues are new and i replaced the rectifier. i am only getting 2.3 volts to the ar's , nothing is booting. i have done the 5volt mod using the switching ps so the board is getting 4.8 volts as the ps is high as it can go (even at that i should get something on the monitor but i am getting nothing but this blank scrren, no sounds or anything). i need some help on what to do. i have tested and tested and tested. changed items i thought were bad but i am getting no where. any help would be greatly appreciated
 

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The switcher mod should let the board boot. The ars would be needed for sound, but you should be getting picture. Is it possible that the monitor is adjusted in such a way that everything is washed out to a dull grey?

(I've been working with wraywray in email, since I repaired his PP pcb, but it looks like he has some cabinet wiring issues too, someone who is more familiar with PP may be able to chime in.)
 
if you're using a screw terminal power supply, you need one for each board. meaning you need 2 for Pole Position. that's way too much draw for a single one. I also encourage you use at least 3 pairs of +5/ground across each board. Atari made incredibly inefficient hardware and the fact they had power tunneling through an edge connector blows my mind.

that's probably about 85% of all problems with Pole Position. you can nerf the +5 output on the AR2 by removing the 3055 transistor, thus making it exclusively an amplifier.
 
I'll put in a second switcher and add some additional +5mods. I only have 1 going to both boards so I'll add 2 more per board. If this works and the game boots then I will still have a sound issue since the Ars aren't getting power. I swapped monitors and messed with the adjustments and got the the same results. I just can't understand why the power at the big blues is so low
 
AC passes through a bridge rectifier underneath the power brick before it hits the Big Blue filter caps. I suppose if the bridge is leaky it'll result in low voltage. I don't think these are prone to burning up but inspect all the wiring running from the transformer. check all wiring going from the transformer to the Big Blue.

you should have close to 14V at the 10.3 test point. there's a pair of resistors that were undersized when the AR2s were made, there's beefier replacements available. if these burn up, you'll lose voltage across them. I think they're for the +5 line though, not the +12.

you could alternatively do away with using the AR2 completely by scalping a pair of PC speakers for the amplifier board inside them. how you rig up the sound signal off the board to those I don't know how to do though, I'm sure there's a tutorial somewhere.
 
ok i have added the extra switcher. voltage at the main board is 5.1 and on the video is 5.0. i have the transformer block on its side so i am getting 13.4 volts on the 10.3 test point on the ar. i am getting no video and no sound. i am lost on where to go with this. i have inspected the harness and anything else i have thought of or been recommended to look at, and everything looks good to me. i have check the continuity etc... any other ideas before i give up and just ditch this project or spend money buying replacements?
 
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