Star Wars issue...

modessitt

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Game belongs to a customer. Noticed something wrong while there for a pinball delivery. Haven't even looked inside the cab, as the customer wasn't there to authorize additional work.

Turn the game on and hear "The Force will be with you" like normal. Attract screen runs, but when the "STAR WARS" is supposed to scroll up, it just has a glow from the upper right corner. The green words come out fine, and towards the end of this part of the attract screen, there is some weird graphics lines and what not in the upper right-hand corner, like the STAR WARS logo is up there but mostly off the screen. All the other attract screens (high score list, etc) are fine.

When you start a game, you get the normal EASY MEDIUM HARD select screen, with the little Death Stars. You move your cross-hairs and hit your button to select. Music starts fine, you have your scores and shields on top, you have your X-Wing guns on both sides top and bottom, your cross-hairs move around, and you can fire to the cross-hairs using all four buttons. BUT - there are no tie-fighters, star field, or Death Star in the background. After about 5-6 seconds, you hear, 'I'm going in!', as it's supposed to go into the trench on the Death Star, but there is no trench or Death Star. You can fire all you want, but the game will just sit there forever with nothing to do and you don't get killed by anything. You get this no matter what difficulty setting you choose.

So - what's the likely problem? Bad ROM? Bad RAM? Chip sockets/dirty legs?

The customer complained last time when I fixed his Asteroids because he thought it was fine (hadn't played it in a month) and it had a bad DAC. So - we left it as-is for him to see the problem and then we'll fix it. Just figured I'd start thinking about it now....
 
I have a board set that is doing the somewhat of the same thing. I haven't got around to fixing it yet but this is the information I found for when I get into my repair.

• Some video, but no enemy ships or stars.

Check the matrix processor and divider circuits by obtaining
the Mathbox Tests display with the game in the Self Test
Mode as described in Chapter 2 of the Operators
Manual. If the BAD MATH READY LINE message appears
and the math ready line is stuck low, the result
will be some video but no enemy ships or stars. If the
BAD MATH READY LINE message appears and the
math ready line is stuck high, the screen will be completely
blank in game mode (but will function during
Self-Test).

• Everything seems to work, but there are no
stars in the space wave, and all the dots on the
ground in the Tower wave come from the same
point.


Check the pseudo-random number generator
at locations 4D, 5B, 5C, and 5D on the Main PCB. Make
sure the 3-MHz clock is present and that PRNGCLR is
not permanently low. PRNGCLR is made low by a
hardware reset and made high by the microprocessor.
If the program is not running, the pseudo random
number generator will remain cleared. If the pseudo-random
number generator is working, connect a
2.2-kilohm resistor from pin 13 of the integrated circuit
at location 5D to pin 1 of connector J16 and listen
for white noise.
 
This problem has been discussed many times on the vectorlist and RGVAC newsgroups. I have never had a SW board do this so I do not recall the exact fix. I would search vectorlist and google for the symptoms you describe because I know it has come up before and I bet some of the discussions are still online.
 
This problem has been discussed many times on the vectorlist and RGVAC newsgroups. I have never had a SW board do this so I do not recall the exact fix. I would search vectorlist and google for the symptoms you describe because I know it has come up before and I bet some of the discussions are still online.

Good idea. I don't know why I keep forgetting about Vectorlist....
 
I have this exact problem (plus some garbled audio, which I think I have an answer to from another thread). Did you find a solution to this?
 
Customer apparently hasn't noticed it yet, so I haven't touched it....
 
Well, customer finally noticed it. I'll be picking it up this week to check it out...
 
Twice now I have seen issues where there was no enemies on the screen and it turned out to be one of those small custom chips on the main board, forget the location and I am at work, but there are 4 of them in a row with the Atari logo on them, i can look up the location of them if needed.


edit: they are socketed.
 
Twice now I have seen issues where there was no enemies on the screen and it turned out to be one of those small custom chips on the main board, forget the location and I am at work, but there are 4 of them in a row with the Atari logo on them, i can look up the location of them if needed.


edit: they are socketed.

Those are bi-polar PROMs.....They come blank, and are programmed....like an EPROM. And yes, I've seen bad ones cause that problem too.

Edward
 
I've seen lots of SW boards with this problem.....usually one of the Math Proms but not always. I find #110 seems to fail more often than the others for some reason. They get very hot. Maybe attaching some small alloy heatsinks to the top would help prolong their life.
 
Is this something I can burn (or have burned by a local) myself? data hard to get?

Possible to reuse the bad one (erase and reprogram) or must it be replaced?
 
Is this something I can burn (or have burned by a local) myself? data hard to get?

Possible to reuse the bad one (erase and reprogram) or must it be replaced?

Bi-polar PROMs are a one time program chip.....no erasing and reprogramming. Some programmers can program them.....but not all (a lot of the more popular ones with collectors can't.....my Pocket Programmer 3 can't). I get my PROMs from Steph (hobbyroms), very reasonable prices.

Regarding the file data.....it's in the MAME files....I believe it's on ionpool.net.....a lot of people have those files and could e-mail them to you if need be.

Also, as mentioned previously in this thread.....the AVG chip can also cause this issue (and any of the support logic in all this). The 4 PROMs and the AVG chip are all socketed. I have a working Star Wars machine I just swap these chips into for quick and easy testing. None of these chips are exactly....cheap. You can get the AVG chip from ArcadeShop, if needed. It is a CUSTOM Atari chip (unlike the PROMs, which are not....even though people keep saying they are:D).

Edward
 
Are the cockpit and upright boards compatible? I have a semi-functioning cockpit, and could swap some chips from it...
 
I have a SW boardset that has the issue with the star field missing and grouped together in a line, but the problem is intermittent. When it does happen, you can "fix" it by putting the game in test and then back to gameplay. It is not any of the socketed chips, I know that for sure.
 
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