Help with a Battlezone...no picture

Trakkur

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Hey there folks,

The arcade where I work has a Battlezone that is out of commission, it is playing blind. All sounds and controls work but there is no picture at all.

A tech wizard that I work with took the PCBs (main and aux) a few weeks ago and fixed them. When we reinstalled them in the game it worked for a few days, but then went back to playing blind again.

The transistors have all been checked and are good. They are not grounded to the chassis either. The fuses on the monitor (deflection?) board are all good as well.

At this point my thought is that we are possible dealing with a power supply issue, which I'll have to check.

I'd be willing to listen to any other suggestions.

Thanks.
 
If it's playing blind, it's likely not a power issue, but that's easy to check. You also need to figure out if it's a game board or monitor problem. It's very common for monitors to blow after a few days or weeks, once a game board is repaired, if the monitor is not also overhauled at the same time. (Has the monitor been capped and reflowed?)

Check to make sure you are getting +15V, -15V, +12V, and -5V on the game board. There are test points for each, all just below the edge connector on the main board.

If those are all good, take a DMM and measure the AC and DC voltages on the XOUT and YOUT test points on the main board, and report them here (4 values total).

Also, is the red spot killer LED lit on the monitor's deflection board? If so, does anything happen when you press the reset button on the game board?

Providing all of the above info will help narrow down where the problem is.
 
Andrew,

I will check the voltages later tonight when I go into the shop. I forgot to mention that the spot killer on the deflection board IS lit. I have not tried the reset button...but will later on as well.

Thanks
 
Andrew,

To answer your questions on this Battlezone unit

1) The deflection board has not been reflowed or capped recently.


2) Here are the voltages that I just read on the main board:

+15V = 15.23
-15V = -15.49
+12V = 11.93
-5V = -5.06
+15v = 15.23 -- all which seem fine to me.

3) Readings for test points on main board:

DC: XOUT = -121.1 YOUT = .822
AC: XOUT = .031 YOUT = .114

..and just because I measured it by mistake, ZOUT: DC = -4.4 AC = .005

4) The spot killer on the deflection board IS lit.

5) I looked and looked but could NOT find any reset button on the main board. Where is that located? I'm trying to find it on schematics and manuals but no luck so far.

:::EDIT::: I found where the reset button *should* be - someone has removed it, so no go for that check.

Thanks again for the assist. I look forward to your response.


***Additional information***

I flipped on the test switch, and waited a few seconds. After which I was given a set of long high pitched tones, that just kept repeating. Based on the manual this would seem to indicate RAM failure on ALL chips...which I find highly unlikely given that the unit had been working up until a few weeks ago -- although I can't argue with the test results. I'm thinking perhaps the harness has an issue maybe? I tried moving it around, cleaned the contacts and got no change in the test pattern sounds and still no picture...yet it DOES play blind, so I can't imagine it's a RAM issues. My next step will be to pull the deflection board and reflow/recap it to see if I get anywhere.
 
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The self test beeps a certain number of tones, which indicates which RAM chip is bad. There should be a series of low tones, followed by a high tone. The number of the high tone indicates the bad RAM. What sequence of tones are you hearing?

If it's continuous high tones, then the first bad RAM is J2 (i.e., the high tone is the 1st one, and it's repeating). You would want to replace that one, then see if the codes change.

The XOUT and YOUT voltages you reported indicate that the board isn't putting out X or Y signals to the monitor. This is also supported by the fact that the spot killer LED is on, which happens when the monitor isn't getting signal (as the spot killer circuit shuts down the monitor, so you don't burn a hole in the center of your tube when there are no deflection signals coming from the game board).

This is at least a game board problem. You could theoretically have a monitor problem also, but for now, I would leave the monitor alone, and focus on the game board. Once we can get it outputting XY signals (which you will be able to measure as an AC voltage with the DMM), we can focus on the monitor, if it's still not working. You should re-cap and reflow the monitor boards eventually, but you don't want to do it now, as if you mess it up in any way, you will end up with two problems instead of one (which is much harder to troubleshoot).

It's possible the entire vector generator section of the board isn't working, which would explain why neither the X nor Y channels are generating any output signals. The RAM error beeps are the key right now, and you want to focus on figuring out what's going on there, before looking at anything else. (And yes, it's possible for bad RAM in the video section to cause it to play blind, and not generate video signals, while the CPU is playing the game properly.)

What is the exact pattern of beeps you're getting in test mode? Also, do you get different behavior if you flip the test switch on after it's already powered up, versus if you power it on with the test switch enabled?
 
Thanks Andrew.

I only tried the test switch with the game powered on, and when I did that I get a high pitched long tone, followed by the same tone and more. It just keep repeating. I'll try with the game off, flip the switch then power up.

I have some RAM in stock, but they are from a Robotron, I'll have to check if Battlezone uses those or not. Of course I don't know if they are good or not, we knew that we had some bad RAM and replaced all of them. We really do need to get a RAM tester.

I'll check this again when I return to the shop either or tomorrow.


The self test beeps a certain number of tones, which indicates which RAM chip is bad. There should be a series of low tones, followed by a high tone. The number of the high tone indicates the bad RAM. What sequence of tones are you hearing?

If it's continuous high tones, then the first bad RAM is J2 (i.e., the high tone is the 1st one, and it's repeating). You would want to replace that one, then see if the codes change.

The XOUT and YOUT voltages you reported indicate that the board isn't putting out X or Y signals to the monitor. This is also supported by the fact that the spot killer LED is on, which happens when the monitor isn't getting signal (as the spot killer circuit shuts down the monitor, so you don't burn a hole in the center of your tube when there are no deflection signals coming from the game board).

This is at least a game board problem. You could theoretically have a monitor problem also, but for now, I would leave the monitor alone, and focus on the game board. Once we can get it outputting XY signals (which you will be able to measure as an AC voltage with the DMM), we can focus on the monitor, if it's still not working. You should re-cap and reflow the monitor boards eventually, but you don't want to do it now, as if you mess it up in any way, you will end up with two problems instead of one (which is much harder to troubleshoot).

It's possible the entire vector generator section of the board isn't working, which would explain why neither the X nor Y channels are generating any output signals. The RAM error beeps are the key right now, and you want to focus on figuring out what's going on there, before looking at anything else. (And yes, it's possible for bad RAM in the video section to cause it to play blind, and not generate video signals, while the CPU is playing the game properly.)

What is the exact pattern of beeps you're getting in test mode? Also, do you get different behavior if you flip the test switch on after it's already powered up, versus if you power it on with the test switch enabled?
 
Thanks Andrew.

I only tried the test switch with the game powered on, and when I did that I get a high pitched long tone, followed by the same tone and more. It just keep repeating. I'll try with the game off, flip the switch then power up.

I have some RAM in stock, but they are from a Robotron, I'll have to check if Battlezone uses those or not. Of course I don't know if they are good or not, we knew that we had some bad RAM and replaced all of them. We really do need to get a RAM tester.

I'll check this again when I return to the shop either or tomorrow.



Yeah, that XOUT = -121.1 value I assumed was a typo. (Maybe your meter was in mV?)

Either way, it's the AC values that tell us that there are no signals present. When there are, you should see something roughly in the 2-3V AC range.

Robotron uses different RAM. You need 2114 for BZ (and about 90% of Atari games, so they're good to have around).
 
I'll check the XOUT again just to be sure - and regarding the RAM issue.

Could it be something else? I know I don't have any of that in stock - and I'm having a hard time believing that the RAM is suddenly bad - and certainly not ALL of them.

It was working just a short time before -- but I suppose it is possible however unlikely.


Yeah, that XOUT = -121.1 value I assumed was a typo. (Maybe your meter was in mV?)

Either way, it's the AC values that tell us that there are no signals present. When there are, you should see something roughly in the 2-3V AC range.

Robotron uses different RAM. You need 2114 for BZ (and about 90% of Atari games, so they're good to have around).
 
For the 2114 RAM - which other Atari games use it? I have plenty on the floor. I'd like to pull from those working machines and test to be sure before I order replacements.
 
I'll check the XOUT again just to be sure - and regarding the RAM issue.

Could it be something else? I know I don't have any of that in stock - and I'm having a hard time believing that the RAM is suddenly bad - and certainly not ALL of them.

It was working just a short time before -- but I suppose it is possible however unlikely.



What leads you to believe that it's all of the RAM? The self-test only indicates one bad chip at a time.

One high beep indicates the self test sees an issue with J2. Once you change that, you should either get a different code (which indicates another chip), or no codes, and just a short beep indicating self tests complete.
 
Ah, ok. I misread the manual on that.

Which other Atari games use the 2114 RAM? I'll swap from a working machine to this one and see.

What leads you to believe that it's all of the RAM? The self-test only indicates one bad chip at a time.

One high beep indicates the self test sees an issue with J2. Once you change that, you should either get a different code (which indicates another chip), or no codes, and just a short beep indicating self tests complete.
 
Ah, ok. I misread the manual on that.

Which other Atari games use the 2114 RAM? I'll swap from a working machine to this one and see.


Asteroids, Asteroids Deluxe, Battlezone, Space Duel, Tempest, to name a few. I'm not as familiar with the rasters, but I'm sure there are others. Just look on the boards you have.

They might also be labeled as 9114's, which are the same thing.
 
OK, thanks. I'm hesitant to touch anything in our Asteroids or Asteroids Deluxe since they have never given me any grief - and Tempest because it has been a LOAD of work over the last year and has been solid for the past 3-4 months. Space Duel is the one I'll use - its in our back room and doesn't see a lot of play...good candidate. :)

Thanks for the information.
 
If any of them have had the RAMs socketed, it's really no big deal to pop one out.

But if they're soldered, then yeah, you probably don't want to mess with working boards. Better to just order a few 2114's from ebay.
 
I took a look last night and the 2114 RAM chips in this particular BattleZone are soldered to the board. I'm not going to take a socketed chip from a working machine and put it into this one...not worth the time and risk.

We're going to order ram and I'll fix the BZ that way.

Stay tuned.
 
::UPDATE::

A couple days after my post on this issue with BZ the strangest thing happened...

The machine was turned on (along with the rest of the units in the arcade) and viola! It was working suddenly, without any intervention from anyone - other than my tinkering around in the cabinet and testing for a few days.

...and it has now been running for over a week with no more issues. I can't explain it -- perhaps it has a power supply issue? I guess...

I'd be interested in the thoughts of those more experienced in this forum.

Thanks,
-Rob
 
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