Article on the Atari Audio Regulator SENSE mod

[D_Harris]

Well... it depends. Less on a regulated line than an unregulated one. But typically it should be in in millivolts (10s or maybe 100s of mV), usually not in volts.

I guess I'd be concerned about the filter caps if the AC ripple is in excess of, say, 5% of the DC value on a regulated supply. For unregulated, perhaps up to 10% or 15% would be OK.

Ok. I might have written that wrong.

I just retested using the game board with the blown components. The little red light on the game board is working again and the coin door and control panel lights still work, but I get only a tiny amount of monitor glow with zero on the tube.

I set the AR to +5V exactly and got all the following readings from both ARII PCBs:

ARII PCB #1:
AR PCB = +5VDC & 1.3mVAC
Game PCB = +4.87VDC & 1.1mVAC
---------------------------------
AR PCB = -8.50VDC & 1.1mVAC


ARII PCB #2:
AR PCB = +5VDC & 1.4mVAC
Game PCB = +4.89VDC & 1.4mVAC
---------------------------------
AR PCB = -5.20VDC & 1.4mVAC


I guess I should get two rebuild kits from Bob Roberts anyway. (And of course, I'll disable the Sense Circuit).

Thanks.

Darren Harris
Staten Island, New York.

 

[xefned]

the unspoken result of this mod, not mentioned

I just found bit_slicer's article on the ARII sense mod. Very well written and much appreciated on this end.

If I understand correctly, after performing the mod, the sense circuity is still active and still attempting to adjust the voltage regulation as needed, it just always gets the onboard 5v and doesn't respond to a voltage drop at the game PCB. So that all makes sense.

Sorry to bump this old topic, but I feel like this should be mentioned.

Assuming you're experiencing a natural voltage drop from the wire resistance from ARII to game board and voltage drop in the edge connector, let's say for example .5 v...

This mod ensures you'll always be sending a steady 4.5v to your game board. Right?

YMMV depending on your voltage drop of course. I think I would prefer to keep the sense mod intact and beef up the power connector to the board.

 

[MTPPC]

..
This mod ensures you'll always be sending a steady 4.5v to your game board. Right?

No. You measure the voltage at the board and adjust it to 5.05 with the pot on the AR.

 

[xefned]

No. You measure the voltage at the board and adjust it to 5.05 with the pot on the AR.

OK, thanks. I mistakenly thought the sense circuitry would self-adjust that back down to 5.0v. I might give it a try in that case.

 

[gamefixer]

FWIW, so long as your edge connector is in good shape and you connect the female connector correctly this mod is a complete waste of time.