tempest problems

jroberts86

New member
Joined
Oct 23, 2010
Messages
8
Reaction score
0
Location
California
I have an arcade (stand-up) Tempest. It played great for a couple years but now has some problems and I am not sure what to try. A bit of an electronics noob, but I have worked on and fixed many pinball machines.

What it does varies a lot:
--turn on, screen black. start buttons flashing red. Nothing happens when start buttons pressed.
--turn on, screen comes on, bright, but upside down or inverted. after some time, it may change to normal view, or scrambled.
--sometimes the text is slanted up and to the right in the top right corner of the monitor
--sometimes the playfield (the geometric shape) is off to the left and very compact
--sometimes it actually plays, but not so much
--sometimes it seems to warm up, but not so much (I have been messing with it off and on for awhile--time to get serious).

I tried test mode, I get a partial white box with a bunch of square o's and ones intersecting them, but it does not look too coherent.

In the back I have tried to reseat connectors and boards with no effect. No obvious cracked solder joints but I need to look carefully.

The large boards on the lower right have a tag that says working, Feb 2004, recapped electrolytics, and the small square board right behind the monitor has a tag that says recapped and working 2003.

I have looked around the site, but it is a bit over whelming.

Any help on where to focus my effort is appreciated and also what real hazards to I need to think about from energized caps if I start pulling stuff out.

Thanks,

Jeff in Nor Cal

(PS any local who comes to help me trouble shoot and fix will be rewarded with fine wine from Entropy Cellars)
 
Start by downloading the PDF manual, and schematics.

Next check your voltages
Re-flow header connectors
re-seat roms

After that, you may have luck trying to swap the socketed parts, but you really need some testing equipment to go much further.

You might want to snap off a few pics of the test mode and post them.
 
What city are you in? Just curious. I'm in Martinez. Anyway, yes...voltages first. Low +5 can cause all manner of odd behavior. As can the big blue capacitor in the bottom of the cabinet. If you are close enough you can try your board in my Tempest.
 
What city are you in? Just curious. I'm in Martinez. Anyway, yes...voltages first. Low +5 can cause all manner of odd behavior. As can the big blue capacitor in the bottom of the cabinet. If you are close enough you can try your board in my Tempest.

I am near Livermore. I checked the voltage it was 4.88 and tweaked it to 5.00. No change in behavior. Will try to get a screen shot. Currently, on turn on, the graphics is upside down (not reversed in a mirror image).

Jeff
 
Upside down is something you would normally see if the aux board was not plugged in. Well in test mode. Cocktail mode is what causes the image to go upside down between player 1 and 2 on the sit down version. That signal come from the aux, so its most likely a bad interconnect cable signal. I would reflow the header pins.
 
Ok back home so I have schematics now. Check the Pokey at B/C2 on the aux board. Look for +5v on pin 10. If it's grounded you will get the upside down picture. This signal goes to edge connector pin C on the aux board.
 
Not to hyjack the thread or anything, but can a Tempest board be tested with only a single scope or b/w monitor? Would I be able to use a b/w power brick to supply the proper voltages?
 
Ok back home so I have schematics now. Check the Pokey at B/C2 on the aux board. Look for +5v on pin 10. If it's grounded you will get the upside down picture. This signal goes to edge connector pin C on the aux board.

thanks, I am away this week will try this this weekend.
 
Not to hyjack the thread or anything, but can a Tempest board be tested with only a single scope or b/w monitor? Would I be able to use a b/w power brick to supply the proper voltages?

Not sure what you mean by single scope, I assume a scope with only one input. So No, you need a scope with dual inputs, and an xy mode. Preferable a scope with a Z so you can add the z blanking signal as well.

You can use an B/W monitor, you just need to feed the B/w signal from Tempest to it, or combine the RBG there are threads on this subject.

No you can't use a B/W brick to power a Tempest. It has different voltages for the color XY monitor.
 
Thats what I meant...I have an xy scope I've been using to mess with some Asteroids boards. Was wondering if that would do to troubleshoot a tempest board in a pinch.

I guess I gotta download the tempest manual...is there a bw output on it? That would be awesome (For testing purposes anyway).

EDIT: Found the answer on page 57 of the vector monitor faq...pretty easy to do the combine rgb trick! Sweet!
 
Last edited:
Yes you can use the X Y mode on a scope. You can also use it to check video signals in normal mode. Typically 1v-5v per division, around 5ms

B/W Edge connector 11 never used it though. Video ground is M
 
back and making progress

Ok, so I was away for awhile and am now back to fixing this thing.

Apparently adjusting the voltage, cleaning the boards, and reseating all connnectors has it working normally again. But I have thought so before, I will give it a few days.

Next question is how do I adjust the position of the screen image. I don't see a procedure in the manual (tm190). Biggest problem is the image is too far to the right. Secondary problems are that the parallel lines in the distance cross (they should get closer in perspective, but not cross) and the images curves up and to the right in the upper right (just enough to notice).

Advice on the procedure or appropriate manual location appreciated.

Jeff
 
The linearity, size, and center pots probably all need adjusting. The procedure is specific, random tweaking will probably not do it for you.

The procedure is in one of the manuals, I forget which, all available on the net. Make sure you do this using the diagnostic patterns available through the self test/slam switch method. Using the game attraction mode isn't good enough. You'll need a mirror too so you can adjust while you watch.
 
thanks!

Thanks Laz. That worked. Game is very good again. No problems with inverted screens etc for several days now.
 
more trouble

So after spending a couple good sessions using tips and info from this forum the machine was fixed. solid, fun. Actually rewarding to fix it the first two times... Thanks.

I did fix it intending to sell. So I moved it from the game 'barn' to a more convenient garage location. Moved it in my truck, all of 100 meters, and it no longer works. NBothing lights up except the top light. No buttons or screen image. I can probably fix it, but my question is: When selling these machines, the buyer comes, machine is fine. They buy it and take it home. It probably won't work. Any one else dealt with this? Now I am weighing this issue and considering selling as is or parting it out.

I am in the bay area. If someone here wants it, a reasonable offer will take it away.

Jeff
 
Usually when this happens, it's caused either from:

a) interlock switch on back door no longer actuating
b) loose fuse clip
c) loose connector

Open it up and look for something obvious...
 
It's something simple for sure. Never part out a working Tempest!

Check the harnesses. They had cable ties attaching them to the pc board when they were made. They're usually missing and it won't transport properly. It cold be as simple as re-seating the harnesses.
 
Back
Top Bottom