Tempest spinner quit

chas010

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My Tempest is acting up again. It had been sitting unused for a bit and when fired up to play the other day it had no spinner function. Everything works but the spinner so I thought it would be a simple fix...
I checked all the connections, tried a different encoder pcb board and swapped in a different aux board on the pcb and nothing. Anything else im missing?
 
Pretty sure spinner control goes through one of the Pokeys on the smaller main PCB... not sure which Pokey it is though.
 
Found some info here...



Gregg Woodcock said:
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).

Grabbed from here:
http://users.rcn.com/jenison/mars/trouble/man/atari/game/tempest.html
 
Thanks Jeff!
I went back into the test screen and didnt have any failed chip codes :confused:
So for kicks I tried an opto off my championship sprint cp and poof it worked!! My spare encoder board was bad I guess I should buy stock in those things :D.
Jason
 
Thanks Jeff!
I went back into the test screen and didnt have any failed chip codes :confused:
So for kicks I tried an opto off my championship sprint cp and poof it worked!! My spare encoder board was bad I guess I should buy stock in those things :D.
Jason

Jason,
B4 you toss that board, check it for cold solder joints and/or dirt on the optics!
cheers
/Tim
 
DON'T toss the encoder boards! The optics are really easy to replace and only cost a buck or two.
 
For the record / future search...

You can swap the two POKEY (C012294B-01) on the Tempest AUX PCB located at B/C2 and C/D2 to see if the problem follows the chip change. If your Tempest spinner is not working, swapping the POKEY should leave you with a working spinner but a non-functional fire/zap button combo. The same goes for sounds. A swap should yield different sounds working and working sounds missing if one of the POKEY has failed.

On a Tempest UR the POKEY are responsible for the spinner, start p1, start p2, fire and superzap as well as audio. With a cocktail you add the second fire 2, superzap 2 and spinner.


POKEY B/C2 (#1)
------------------
Spinner 1
Spinner 2 (cocktail)
Audio Out


POKEY C/D2 (#2)
------------------
Start 1
Start 2
Fire 1
Fire 2 (cocktail)
Superzap 1
Superzap 2 (cocktail)
Audio Out
 
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For the record / future search...

You can swap the two POKEY (C012294B-01) on the Tempest AUX PCB located at B/C2 and C/D2 to see if the problem follows the chip change. If your Tempest spinner is not working, swapping the POKEY should leave you with a working spinner but a non-functional fire/zap button combo. The same goes for sounds. A swap should yield different sounds working and working sounds missing if one of the POKEY has failed.

On a Tempest UR the POKEY are responsible for the spinner, start p1, start p2, fire and superzap as well as audio. With a cocktail you add the second fire 2, superzap 2 and spinner.


POKEY B/C2 (#1)
------------------
Spinner 1
Spinner 2 (cocktail)
Audio Out


POKEY C/D2 (#2)
------------------
Start 1
Start 2
Fire 1
Fire 2 (cocktail)
Superzap 1
Superzap 2 (cocktail)
Audio Out

Resurrecting this thread to document a problem I am having.
Display is fine.
Sound seems fine.
1p and 2p buttons flash at normal rate and can start game
can start game but no spinner input
fire button acts like it is held down. (even if control panel harness is disconnected)
super zapper button works normally.

So, swapped in some different pokeys. No change.

Tried a couple other Aux boards from other Tempest PCBs.
Aux Board #1 : everything looks and sounds fine, but no spinner and fire button acts like it is being held down
Aux Board #2: Displays alpha-numerics fine, but the playfield is all wrong. Can play the game, spinner is recognized as well as the other buttons. (this rules out the spinner as a problem and it obviously is having some problem with the math to display the vectors for the "well". All the objects (flipper, tanks, etc.. ) display correctly, but are in the wrong places.

Aux board #3: s[pot killer, will deal with it later.
 

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Hehe thanks. One day I hope to be able to legitimately necro-bump a thread where all of the original participants have been banned for one reason or another.
 
So I managed to get the Aux board #2 working fine. Just needed a couple chips from Aux #3 (which was throwing up the spot killer anyways).

Now, with a fully working boardset, I was able to probe D6 (LS157) on both aux boards. I figured that since I am having problems with the Spinner AND the Fire button, that the D6 was common to both POKEYS (on the input side).

On the working controls board, Pins 7 & 12 were HIGH, but on the Non-working board, those 2 pins were being held low. The other pins matched.

So....per the Ls157 datasheet
with pins 1 & 15 LOW, that means that "A"s are selected and should be on the output.

Pin 7 goes to pin 10 on the POKEY at C/D2. Pulled the POKEY and checked to see if the line was grounded. Checked out OK. With pin 5 High, the output on Pin 7 should also be high, so that's a problem

Similarly, with pin 14 high, the output on 12 should have been high. With power off, i checked it to make sure it wasn't shorted to the ground.

I'm going to replace the LS157 at D6 and retest.
 
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Did you try swapping the Pokeys first? They are a common issue on these for control problems. Just to rule out the simple stuff first, before you start probing.
 
Did you try swapping the Pokeys first? They are a common issue on these for control problems. Just to rule out the simple stuff first, before you start probing.

Yep, got a dozen or more of them here. The observed differences between the working and non-working Aux board jive with the spinner output and fire button both being held low on the output of that LS157.

It appears that chip isn't really needed for an upright game. Only function (as far as I can tell) is to select which side controls are active on a cocktail gaime.
 
Yep, got a dozen or more of them here. The observed differences between the working and non-working Aux board jive with the spinner output and fire button both being held low on the output of that LS157.

It appears that chip isn't really needed for an upright game. Only function (as far as I can tell) is to select which side controls are active on a cocktail gaime.


Ok. No errors in test mode?

BTW, the other side of D6 is used by the other Pokey for the Fire and Zap controls. (See the schematics for the other Pokey.)

However the issue might not be those chips themselves. I'm not a Pokey guru, but I wonder if the outputs pof those chips may be being help low by the Pokey, depending on the state the Pokey is in, depending on how the Pokey is being controlled, depending on if/how the Pokey is being properly controlled by the CPU. (In other words, it could be an issue with the CPU talking to the Pokey, which could be due to plenty of other stuff on the aux board.)
 
Success.

Ok. No errors in test mode?

BTW, the other side of D6 is used by the other Pokey for the Fire and Zap controls. (See the schematics for the other Pokey.)

However the issue might not be those chips themselves. I'm not a Pokey guru, but I wonder if the outputs pof those chips may be being help low by the Pokey, depending on the state the Pokey is in, depending on how the Pokey is being controlled, depending on if/how the Pokey is being properly controlled by the CPU. (In other words, it could be an issue with the CPU talking to the Pokey, which could be due to plenty of other stuff on the aux board.)

Maybe, maybe not, but replaced LS157 at D6 and works like a champ now.
I had done some other checks that led me to believe that it probably was just the 157. Letting it run for a while now.

As far as the POKEY and the rate counter could see, the fire button was being held in and the spinner wasn't pulsing at all.

Hopefully can get another of the 2 main boards sorted out and have 2 functional Tempest's by the end of the week!
 

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Cool. Glad you got that sorted out. You could have confirmed that the Pokey wasn't pulling them low by just removing the Pokey, and rechecking (which maybe you did). Input chips do go bad as well, but it's also easy to be misled with these (ask me how I know). So it's good to have multiple checks before assuming a stuck chip is bad.
 
Cool. Glad you got that sorted out. You could have confirmed that the Pokey wasn't pulling them low by just removing the Pokey, and rechecking (which maybe you did). Input chips do go bad as well, but it's also easy to be misled with these (ask me how I know). So it's good to have multiple checks before assuming a stuck chip is bad.

Yep, that is one of the things that I did to increase my confidence that it wasn't the POKEY.

Speaking of POKEYS, what is the best/easiest way to go thru a stack of them and have a reasonable assurance they work? Tempest? Centipede?
 
Yep, that is one of the things that I did to increase my confidence that it wasn't the POKEY.

Speaking of POKEYS, what is the best/easiest way to go thru a stack of them and have a reasonable assurance they work? Tempest? Centipede?


There's no easy way, as different boards use different functions, and none uses all of them (so Pokeys that have some issues can technically still be used in other boards, in some rare cases).

There is a homebrew Atari 7800-based Pokey tester, which is pretty slick, and that's the only actual available tester I know of, if you want to test all functionality. (And even then you still need human interaction to do it, as you need to actually check all of the sounds with your ear, given that there's no way for a computer to do that.) Link:

https://www.youtube.com/watch?v=8JuQ-NoocCQ

In lieu of that, the best bet is to just test one in the board you want to use it in (and play test to verify that everything that it needs to do works properly.)
 
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