Tempest Issues

starfighter2

Member
Joined
Sep 22, 2009
Messages
657
Reaction score
8
Location
Derry, New Hampshire
I have display issues with a tempest that I got not working. the game seems to play blind, cannot see anything in test mode. The following was the things I tried today. If anyone has an idea wht to look at next I would appriciate any recommendations.

1. Test the Tempest monitor: was able to connect to my start wars arcade game with WG6100 game and the video was really good. So the monitor should not be the issue.
2. Test tempest board with star wars WG6100 monitor. Get the same issues
3. Test tempest board with aux board connected. The only thing that will display is the tempest logo that starts of small then grows with three different colors. Other than that nothing
4. Put into test mode, will not display anything.
5. Increase screen, see only dot and can see red spot killer lot on
6. There was a low hum, so since I had a cap kit for the ARII, did that, no more hum but no change to the video. I also reflowed all the connectors on the ARII board
7. Reflowed connectors on the aux and main board, no change
8. Also had a backup CPU and changes that, no change
9. Tested without the aux board in test mode, no video
10. Tested all the ROMs on the main board all checksums are the same except 113 which in MAME is 00028392 and the ROM 000282A9, but I saved the rom to the zip file and MAME played the game with no issues.
11. Also one of the transistors in the video output section was bad, replaced that with no change.
12. Tested to verify that both ground and power rails had continuity for all columns
13. On the board I get the following voltages:
a. +5 tab = 5.06
b. -6.8 tab = 6.77
c. -15 tab = -15.31
d. X out tab = -2.03
e. Y out = .45
f. +15 tab = 15.10
g. DAC +5 tab = 5.06

Let me know if you have any other thoughts on what and how to test next
 
I hope on b) -6.8 you forgot the '-' if not that is an issue.

It looks like the program just halts and this can be a number of issues. I would use use a logic probe and check several chips to see what is doing what when this thing stops. The clock chips, ram chips, and roms are a good start. Pay close attention to any and all counters. I don't own a vector yet but this one is next on my list, after a Carnival. I want to see what one of them games looks like on my scope. That was one of my favorite games and it just doesn't play right, for me on mame.
 
Have you replaced (or swapped) the big blue yet?

The big blue cap should be filtering ripple, if it is not, some Atari boards are really touchy about this.

Since you have a Star Wars on hand to work with, swap the big blue cap near the transformer at the bottom of the cab - only a few screws - won't hurt anything to try..

Good luck!
 
check the dips, especially n13 #1,2,7,8

1on 2off 7off 8on=demo mode

1off 2off 7off 8on=freeze mode

May be a simple fix but don't think so. Worth a shot.

Found some more info for you;

I tried a different link to AndysArcade.de and got some kind of warning message about 'hacking site' When I went to get the schematics. Here is some good info on the Tempest and it assumes the power supply is good and monitor. Hope this helps you

http://www.kfu.com/~nsayer/games/tempest.html
 
Last edited:
Tempest Board issue, Need Help


I have a tempest board that is not working. I know I have a good WG6100 since I have tested in a star wars game I have. I have updated the AR board with Bob Roberts kit and added a big blue. I get 5 volts on the board but the video is all messed up. Looks like lighting strikes. I ensured the ROMS all have the appropriate checksums, The RAMS have been replaced. Did some reading on KLOV and from recommendations tried to shotgun the video section with new chips (all 4 TL082, 2 LF13201N, 1 DAC08CN, and the MC1495 chips) and pots and replaced the CPU (6502). I also tried to test the TTL chips with the inverse diode check. If anything looked under 4 volts I compared with an existing chip I had. So I am running out of ideas.

Please let me know what else I can try or if there is someone out there that repairs these boards.
 

I have a tempest board that is not working. I know I have a good WG6100 since I have tested in a star wars game I have. I have updated the AR board with Bob Roberts kit and added a big blue. I get 5 volts on the board but the video is all messed up. Looks like lighting strikes. I ensured the ROMS all have the appropriate checksums, The RAMS have been replaced. Did some reading on KLOV and from recommendations tried to shotgun the video section with new chips (all 4 TL082, 2 LF13201N, 1 DAC08CN, and the MC1495 chips) and pots and replaced the CPU (6502). I also tried to test the TTL chips with the inverse diode check. If anything looked under 4 volts I compared with an existing chip I had. So I am running out of ideas.

Please let me know what else I can try or if there is someone out there that repairs these boards.


Try your hand at a logic probe and FIND the problem and not just guess at what parts may or may not be bad. It may take a long time at first, trying to understand the circuits, but it gets very easy after a few repairs.

My guess, just from other reading on the forums here, would be the math box. Now you are going to want to know what that is right?

Mathbox
I haven't got the slightest idea how the Mathbox works. Its purpose is to do the 3D computations necessary for the perspective view of the game.

This little tidbit comes from Gregg Woodcock:

The [...] 4 socketed 40-pin chips on the math box (at locations E2, F/H2, J2 and K/L2 on Tempest) are called "transistor array"s by the manual and the chips themselves carry only the Atari part number 137004-001 on them in an attempt to hide their true identity (to keep people from making illegal copies of the game?) They are really 2901 bit-slice ALUs, which were very popular and are fairly commonly available. They were made by AMD and a number of other vendors. In a technical sense the part really is a transistor array, but calling it that serves no purpose other than obfuscation. These go bad every now and then and will generate an "M" on the self-test screen. NOTE: the "M" is a generic "M"ath box failure indicator and does not necessarily indicate that an ALU is bad; lots of failures cause the "M" indicator to appear but one of the most frequent causes is bad ALUs (Note: The most frequent cause I've seen is the interboard cable failing. Check that first, as it's a lot easier to fix -- Nick). The cheapest place I have found for these is:

B.G. Micro, Inc 800.276.2206 (AMD2901 ALUs $1.50 each)

For reference, B.G. sells two kinds of "2901" chips so be careful not to order the 14 pin chips ($0.55 each) because you can't use them.

*Copied from this link*

http://www.kfu.com/~nsayer/games/tempest.html
 
I don't beleive it is the math box but do have the chips to replace them if need be. The reason is that the same issue shows in the test mode as in regular mode. The math box is on the aux board I beleive. I was told that I could test without that aux board as long as long as I was only in test mode. If that is true, then the math box is not available and I get the same result no mater if I have the aux board connected or not.

Any other ideas?
 
I don't beleive it is the math box but do have the chips to replace them if need be. The reason is that the same issue shows in the test mode as in regular mode. The math box is on the aux board I beleive. I was told that I could test without that aux board as long as long as I was only in test mode. If that is true, then the math box is not available and I get the same result no mater if I have the aux board connected or not.

Any other ideas?

Logic probe......I don't own a tempest yet but I keep looking for one, I want to look at that game on my scope.

You might just read through the link I posted above, it has lots of info on that game.
 
Back
Top Bottom