Tempest is definitely one of the most talked about vector games on the newsgroup. You may want to check Google first to see what you can find. Here's some links that may help you, also.


Symptom: Deflection overdriven
Between the X-out test point and ground connect 2 6.8 VDC zeners connected in series, banded end to banded end. For the Y-out you use 5.6 VDC zeners.

Symptom: Game "scrunches" in center from player 1 to player 2
Fix: Need to upgrade to version 3 ROMs (see Jess Askey's Tempest Page)

Symptom: Bad POKEYS
Fix: From Gregg Woodcock:
Two of the socketed 40-pin chips on the math box (locations B/C2 and C/D2) are called "Audio I/O N-Channel MOS/LSI Custom Chips" by the manual but at least the schematics refer to them by their "real" name which is "POKEY". The most frequent thing to go bad on the Atari math boxes besides the ROMs are these POKEY chips. The POKEY was designed by the Atari home computer division for the Atari 400 computer. It stands for POt KEYboard controller and it has a sound generator, random number generator, input buffering, and much more all on one chip.

The symptoms of a bad POKEY are that control input or sound output is not normal or missing altogether. The POKEY in Tempest at B/C2 controls the spinner inputs so if your spinner is flakey and the opto-electronics check out (they frequently fail), this is probably your culprit. The self test should be able to confirm the diagnoses. If you see a "P" or "Q" in the middle of the screen then one of the POKEYs is bad (see chart below).

I like to order POKEYs from American Techna-Vision since you get an entire 40 PIN chipset intended for machines in the Atari 8-bit computer line. Besides the POKEY, you get a GTIA, ANTIC, 6502 PIA and 6502 CPU. Order catalog number AK675, "40 Pin Large Scale Integrated Circuit Chip Set". On top of that they have the cheapest shipping, no minimum order (that I am aware of) and accept credit cards. You can also scavenge POKEYs from inside of many Atari 7800 cartridges, most notably Ball Blazer although they are also used in Commando and Summer Games and I suspect that Dig Dug, Dark Chambers and Jinks also have one. The POKEYs are the chips that have the Atari part number "C012294B-01" on them.

B&C ComputerVisions 408.986.9960 (Atari POKEYs $5+$6 S/H)
Best Electronics 408.243.6950 (Atari POKEYs $5? S/H+$4.75 COD; $12 min)
American Techna-Vision 510.352.3787 (Atari POKEYs $14.95; #AK675)

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