Pole Position ARII Regulator boards - why two!!?

PolePosition 2

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Hi Klovarians,

Most if not all retro video games appear to have just one ARII Regulator board, except Pole Position which has two

Also has two big blues!! ....

Also Atari's Pole Position and Pole Position II utilize a two-PCB board design: one for the CPU and one for the video output, so, is this why there are two regular boards?

Or, maybe, does one serve as an audio regulator as I've heard them referred to as Audio Regulator boards?

Anyway, what I'd like to understand is why two and what do they individually do?

Thanks

Paul
 
Pole Position is especially power hungry. So two power supplies. And yes, the AR is also used as an audio amplifier.

Firefox has the exact same setup.
 
To be more exact, each PCB, the VID and CPU take approximately +5V @ 4A. That is near the limit for the discrete linear regulator (and edge connector pins). So, two ARII are needed - one for each board. (As time progressed, and newer games / boards needed more power, Atari did start to use switching power supplies and dedicated audio amps instead of their "tried and true" Audio/Regs. For PP in 1982, they used what they knew and had available - you could argue it was a good available technical solution that was also cost-effective).

Here, on the bench you can see the approximate loading of a working pair ->

PPII_LOAD3.md.jpg


The advantages of using two ARII for power/audio are shown in the schematics. Each ARII needs a dedicated Big Blue to reduce ripple and provide the required bulk, so since the power brick only has one, another was added.

 
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Well, wasn't it only FF and I,R that used their custom switcher for logic and monitor? They learned quickly. LOL
Yup. They did that, realized it was hot garbage, and then went back to linear supplies with the AR3 lol
 
Yes, the AR3 uses two 2N3055 pass devices, so it likely can process twice the power of the AR2.
So, you could assume you could get perhaps +5V @ 10A from that linear supply.
 
Having looked more closely I can see how one big blue on the power supply supplies one ARII board and the other Big blue powers the other ARII.

Each ARII cable loom coming off of J7 then merge and form part of the wiring loom to the edge connector with one side doing pins 1-22 and the other 23-44 of the edge connector.

Thanks for all the comments Klovs
 
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