Some Battlezone questions

fcjim

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Hi, and thanks in advance! I am working on my current project, a Battlezone. It seems like this game in general has a lot of gremlins, but unlike many of the BZs I've been reading about, I got lucky because after a quick repair to the power cord mine fired right up. I've been doing a lot of searching and reading about it but haven't stumbled across discussion of my particular problems... sorry if I missed the answer to my questions somewhere.

I've been doing mainly cosmetic and control panel work to it, and I haven't done any of the usually-recommended BZ stuff to the electrical bits (reflowing interconnect, replace edge connectors, cap kit, etc) because like I said it's mostly working, and for the moment I'm taking a "if it ain't broke don't fix it" approach. So the answer to the "what have you done already" question is "pretty much nothing."

I have three questions I'd love to get some feedback on. First, there is a pot on the AR board which I believe is to adjust +5v. There are at least three 5+ test points on the main board, and one more on the smaller auxiliary board. If I adjust it to +5.00 at the closest test point (the one near the edge connector) on the main board, it reads low at the aux board, and if it's set to +5.00 at the aux board it's about +5.25 on the main board. I'm thinking I should set it to +5.00 at the aux board (the furthest test point from the power source that I can find), but I'm worried that would be too high at the main board. What's the correct way to measure and set this voltage? Is it normal for this voltage to differ that much at different points, or does that tell me there's an issue with the AR board?

The second problem is with the monitor, which I have virtually no experience with at all. In the test grid, I can't seem to get it aligned using the XBIP and YBIP pots on the PCB (see photo). When I use the pots to line it up on the top and one side, it's out of alignment on the bottom and the other side, and vice versa. I've messed slightly with the little metal tabs on the yoke, these move the entire image around but they don't seem to affect this issue. When I plugged this monitor into my Asteroids Deluxe, the test screen looked fine and everything lined up perfectly, which I tend to think eliminates the monitor itself as the source of the problem... but that means I have no idea what IS causing it. The monitor is a G05-802.

The other issue with the monitor is that during gameplay it pulsates, especially noticeable in the upper corner where the score and extra tanks are displayed. It seems to kind of come and go depending on where the enemy tank is, sometimes the pulsing is prominent and other times it's minimal. I did try to get a video of this but it didn't come out very good, I can try again later to get a better one if just saying "pulsate" isn't enough to go on, which I figure it probably isn't.

Any help or suggestions on these questions would be appreciated. Thanks!
 

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Sounds like you need to re-cap the monitor, it's never a bad idea, and it's one of the #1 things to do since you aren't sure the last time it's been serviced. This may take care of most if not all of your issues you are mentioning.

The X and Y bip will adjust the diamond pattern so that it touches on all sides of the bounding box. Or as close as possible. What you will also find is that when the highscores are displayed you may notice that the text is slanted one way or the other. So I always get the bip close, and then adjust so that the high score text is verticle.
 
I've messed slightly with the little metal tabs on the yoke, these move the entire image around but they don't seem to affect this issue.

Plez don't do anything with the yoke ever again, it is for your own good.
 
I've messed slightly with the little metal tabs on the yoke, these move the entire image around but they don't seem to affect this issue.

Plez don't do anything with the yoke ever again, it is for your own good.

Why do you say that? Because I will screw up the monitor, or because I will get zapped? I admit I don't know enough about monitors to avoid the former (I did mark the position of the tabs so I could set it back the way it was), but I do know enough to avoid the latter. Thanks for the advice in either case though!

The X and Y bip will adjust the diamond pattern so that it touches on all sides of the bounding box. Or as close as possible. What you will also find is that when the highscores are displayed you may notice that the text is slanted one way or the other. So I always get the bip close, and then adjust so that the high score text is verticle

I did notice the way the bip pots made the high scores diagonal, I've got them pretty much up-and-down right now. The edges of the diamond pattern extend past the edge of the box on two sides no matter how I adjust it, and I think that shows up in gameplay when the vectors don't always match up perfectly. Would a cap kit tighten that up so the tips of the diamond could be adjusted more perfectly?

It sounds like recapping this monitor is worth doing one way or the other, but when the same monitor looked fine in the Asteroids it made me wonder if the alignment issue was being caused by something else.
 
I did notice the way the bip pots made the high scores diagonal, I've got them pretty much up-and-down right now. The edges of the diamond pattern extend past the edge of the box on two sides no matter how I adjust it, and I think that shows up in gameplay when the vectors don't always match up perfectly. Would a cap kit tighten that up so the tips of the diamond could be adjusted more perfectly?

Probably not.
 
update: no steps forward, two steps back

Well, I purchased and installed a cap kit for this monitor. It didn't seem to make much difference... the extra-life tanks still pulsed (although it may be a bit less than before, tough to tell) and the vectors on both the play screen and test pattern screen still had issues aligning properly. But I did get the monitor back together and working at least as well as before, so I'm counting that as a small victory.

I have been reading a lot about Battlezone issues, so next I decided to try reflowing the interconnect and re-seating the chips on the main board and the aux board. None of the ICs seemed particularly loose, but I gently pressed them down a bit just to make sure. Now, nothing happens at all. The board gets power, the spot killler is on, no light on the start button, no sounds, no nothing. Once the coin counter flipped a number of times, but it only did this once. I disconnected the aux board, to see if I could get the main board to fire up just to the test screen, but no joy there either. So there's definitely a problem on the main board, and I have some more reading to do.

Any suggestions on where to start would be appreciated! And can anybody advise me on the power adjust question I had originally? Thanks!

EDIT: I have it back working the way it was before. I removed one of the chips from the board, and when I re-set it in the socket, a pin bent in that I hadn't noticed. Straightened it out, reinstalled it to the board, and we're back to square one... another small victory.
 
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I have the same pulsating on mine . Planned on changing the 4 pots on the main PCB . could not find the right ones at Bob Roberts . Not sure if will help anyways
 
I get a little pulsating at times as well.

It seems to be worse in the few minutes after the game is powered up.
 
got it to stop pulsating . the voltage regulator on the main board VR3 was putting 22 volts not 15 . so check the 5 15 and -15volt test points . bottom right of the board . now to fix the graphics are a little jacked mountains don,t sit right. hope it helps you
 
got it to stop pulsating . the voltage regulator on the main board VR3 was putting 22 volts not 15 . so check the 5 15 and -15volt test points . bottom right of the board . now to fix the graphics are a little jacked mountains don,t sit right. hope it helps you

Thanks ory! That's a good suggestion, I had checked the +5 at different points but hadn't checked other voltages. Turns out they were all within .5v... the +5 was at 5.4, +15 was at 15.4 and the -15 was at -15.5. Not sure if those are high enough to cause the problem or not, but I wasn't getting anything near 22v.

I just received an A/R rebuild kit from Bob Roberts so I'm gonna go ahead and do that this weekend and see if that changes anything. I did notice just now that two of the caps that are supposed to be 3300uf on that A/R board are 4700uf on my BZ... not sure that would cause a problem but I figure that means somebody's probably monkeyed with it before I got to it, so redoing that board is the next step.

I too have a problem with the mountains... on mine, the mountain range on the right kinda floats above the horizon. When I move the tank to the right, that range will pop into place about 2/3 across the screen, and the new range moving in on the right will be floating too high. I figured that was a symptom of the vector end-alignment issue I have, but I'm not sure about that. The caps on the main and aux board look to have been changed at some point too, so perhaps my next next step will be to swap them out for new and see what that changes. I'll let you know if I get my mountains to sit where they're supposed to.
 
PCB repair?

I thought about making this question a new thread, because it may end up being more PCB tech-y than the general questions earlier in the thread, but decided to try it here first to see if anybody has an answer before starting something new.

This morning I was busy replacing the capacitors on my BZ boards when I noticed something that may or may not be weird. At some point, somebody has soldered a couple capacitors in series with a couple resistors, and capacitors had also been soldered directly onto the legs of an IC chip.

The pics are of the bottom right corner of the main BZ board, in the area of the X/YSIZE and BIP adjustments. The resistor at R83 has a ceramic cap soldered in series with it, and the resistor at R69 has a little green cap added in series as well. In both photos you can hopefully make out the little brownish things -- presumably also caps, but it's tough to make out what is written on them -- attached directly to the legs of the ICs.

Is there any chance this was done at the factory, or is it more likely a repair attempt of some sort? And if so, what could the person have been trying to accomplish here? Should I remove these and put it back the way the schematic in the manual indicates it's supposed to be, or leave it alone?

Thanks!
 

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