Battlezone

scottmaggie

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So my Battlezone has decided to give me a headache. It is playing blind but is not the monitor. Story thus far:

In test mode I get a repeating long low tone. When RAM is working it would be a short low tone and a long high tone for a bad RAM. The long low tone repeats indefinitely (more then 10x).

What make this even stranger is I can pull any RAM and then the test works perfectly. Short low beeps until it finds the missing RAM and then a longer high beep!

I have moved and swapped all the RAM and tested all in another game. I don't know if the RAM issue is or is related to the game playing blind.

Any clues guys?


NOTES:
All test points are reading correctly.
Braze high score kit is installed and all roms are removed.
ARII is rebuilt and with sense mod (and tested in another game)
19V2000 is also rebuilt (and tested in another game)
Game boards have all new caps
There's also a new big blue
Game was working perfectly
 
If only...

If only I'd read ahead for once before running to post! :0)

The continuous long low tone in test mode means a bad ROM at B/C3 which also would prevent an image.

Hope that's the end of the repairs but first I'll test the 2 vid ROM in a working Battlezone...
 
update

The video roms are now tested good. I replaced the 2 sockets and no change. Playing blind and self test beepeing a B/C2 video ROM error.

Any assistance is appreciated...
 
If the RAM is known-good, and the game things it bad, it's time to consider address decoding and any buffers/transcievers in the address and data busses.
 
This thread seemed to end nowhere so I'll bump it as my issue seems similar :p

I have a battlezone boardset I'm repairing for someone. I've fixed it to the point where I believe I'm seeing the same as Scott above.

The game now plays blind (*1). In self-test I get a constant repeating low tone, low, silence, low, silence, low .... for ever. I'm assuming this is the "you will hear a continuous low tone" as described in the manual for a VROM B/C3 failure [I must have a different interpretation of the meaning of "continuous low" than Atari does]

The problem is, as far as my Fluke 9010 is concerned, the ROMS/RAMS are all good. I've loop tested the 036422-01 and it passes fine in circuit. Obviously verifies fine out of circuit also.

There is clearly an issue in the vector circuitry as I can see the DAC inputs are not correct (I already fixed some obvious unrelated faults in the analog side)

The self-test and the Fluke are both reporting from the perspective of the cpu, so I'm curious on the discrepancy. I'm wondering if the constant repeating low tone signifies something additional other than a VROM B/C3 failure?

1: the only issue with it playing blind, there was an obvious error in the tank motion sound, goes away when a known good aux board is swapped in but that doesn't change any of the above
 
What does test mode give you with the known good aux board?

Same sounds, or different?

Same error in test mode with the known good aux board ("but that doesn't change any of the above"). Constantly repeating low tone. The issue is clearly with the AVG board.
 
The tank motion sound is just an aux problem. The engine sound is generated by a dedicated circuit rather than the Pokey, see the schems. Could be a stuck enable line coming from the LS273 at M2 (possibly shorted to something keeping it high, also). It could also be the master sound enable 4066 switch at L6, but usually when that sticks on, you'll hear other sounds at the wrong times as well (like radar during attract mode, etc).

You might want to look at the decoding logic for the ROMs. Also, I'm not sure what speed the Fluke tests the bus at, versus what the game runs at, so you could have a marginal part, which the Fluke sees as ok, but isn't working right at full speed. The tones are giving you info, but it sometimes takes a little effort to figure out what that is, exactly.

Also, throw a logic probe on CPU pin 40 (RESET) during test mode. Are you getting a reset when the tone repeats?
 
The tank motion sound is just an aux problem.
Yes, I know.

Also, throw a logic probe on CPU pin 40 (RESET) during test mode. Are you getting a reset when the tone repeats?

Isn't this the definition of the constantly repeating low tone? That the cpu is being reset? This is the behavior I've always seen on known working boards if I swap in a 'bad' ROM in place of B/C3. Anyways, yes, with the bad board I'm debugging, in self-test the cpu is constantly being reset. In normal mode it's obviously not as the game plays fine.

Everything points to B/C3 being bad from the perspective of self-test but not from the perspective of the Fluke. Clearly they are testing things differently, somehow. If I get time this weekend I'll hook up my LA and write some C code to see what is actually being read off the VROM at B/C3 when self-test is being run and when the Fluke computes the signature, see how they compare.
 
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It's not clear to me if the low tone you're hearing is a continuous one from a bad ROM that's being reset, or if it's part of a longer RAM error code, that's also being reset, or not reported fully (e.g., if the high tone is missing, from some other audio-related issue).

I don't think the test mode issues a reset when it normally finishes a RAM code. It just repeats the test.

Dumb question - what happens when you replace the B/C3 ROM? If replacing the ROM isn't fixing it, it's either a bus issue, or decoder issue. Did you scope each line? You might have one with a slow edge, where it's not getting fully high or low at speed, but the Fluke is testing it at a slower speed, so it's working in that case. (Basically an analog issue.) Verifying that all lines have clear sharp edges might lend some insight.
 
It's not clear to me if the low tone you're hearing is a continuous one from a bad ROM that's being reset, or if it's part of a longer RAM error code, that's also being reset, or not reported fully (e.g., if the high tone is missing, from some other audio-related issue).
I don't think it could be a bad ROM, as failures of such are not normally reported aurally. You're right of course, it could be a bad RAM but for some reason it's being reset during the announcement that the first RAM is good.

As I said, if I replace the ROM at B/C3 on a working board with a bad ROM I get the exact same behaviour but this doesn't preclude the above RAM scenario (though it seems unlikely).

Dumb question - what happens when you replace the B/C3 ROM? If replacing the ROM isn't fixing it
With a known good one. No difference.

Did you scope each line? You might have one with a slow edge, where it's not getting fully high or low at speed, but the Fluke is testing it at a slower speed, so it's working in that case. (Basically an analog issue.) Verifying that all lines have clear sharp edges might lend some insight.
No not yet. I'll look at it more tonight. I was mostly curious to verify I wasn't spacing on something obvious before dumping more time into it.
 
I don't think it could be a bad ROM, as failures of such are not normally reported aurally. You're right of course, it could be a bad RAM but for some reason it's being reset during the announcement that the first RAM is good.


From the manual, ROM test section:

"If ROM or PROM B/C3 is bad, you will hear a continuous low tone, and the program
may be unable to display a screen image."


My guess is it's not seeing the ROM, then the VG is timing out, and it's resetting.

Bus or decoder issue.
 
From the manual, ROM test section:

"If ROM or PROM B/C3 is bad, you will hear a continuous low tone, and the program
may be unable to display a screen image."
We're misunderstanding each other. You said "It's not clear to me if the low tone you're hearing is a continuous one from a bad ROM that's being reset".

I assumed, since it was obvious that B/C3 was an option -- we'd been discussing it -- that you were referring to a different ROM.

Bus or decoder issue.

Seems like it. It's mostly interesting that the Fluke bus and ROM tests think everything is A-OK.
 
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