Gravitar vector alignment issues

eightbitwhit

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Donor 2012, 2015
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Greetings everyone,

I recently pulled my Gravitar out of stoage to put it into rotation in my gameroom and noticed that when I turn it on, I tend to get what I can only describe as 'vector alignment' issues where the lines drawn on the screen don't line up properly and the screen looks 'shifted'.

Here's some pics of what I'm talking about:

WP_20121209_016%20(Custom).jpg


WP_20121209_017%20(Custom).jpg


WP_20121209_018%20(Custom).jpg


If I power cycle the game quickly (like a rapid off/on switch; all within a second) then the game will almost always start back up lined up just fine and looking like what you see in the following pictures. Alignment looks good, but it appears that some of the vectors are 'weak'.

I'm pretty concerned about what potential damage is being done by the shotgun power cycle procedure... so far it has (mostly) produced the desired result of clearing up the game, but I'm expecting the whole situation to go *poof* at some point if I continue doing this....

WP_20121209_021%20(Custom).jpg


WP_20121209_020%20(Custom).jpg


I'd appreciate any comments on what is wrong. To my knowledge, nothing in the game has ever been repaired/replaced, so it's pretty safe to say everything is original. I picked up the game from the original owner, so it's been HUO since delivery.

Thanks!
 
There's three things I'd do. BTW, don't sweat it too much, you're not going to destroy anything, it may burn a few things up but it's things you need to work on anyways, lol.


1. Replace the Big Blue in the power brick in the bottom. It's a filter capacitor that keeps A/C ripple out of all your power voltages. It may be your problem. Even if it isn't, it needs to be replaced so you have a nice clean power line.

2. Rebuild the A/R power supply that runs the game board. You can get a rebuild kit (and the Big Blue in the power brick) from Bob Roberts. Again, this will get your voltages going to the game board nice and clean.

3. Rebuild the monitor. Vector monitors, in my opinion, are easier to rebuild than rasters, if they're already working. There's also a vector F.A.Q. out there that makes troubleshooting pretty damn easy. Bob sells a rebuild kit for the monitor as well.

I'd do those three, in that order, and check the game after each to make sure you haven't screwed anything up. OR, send the individual pieces out to someone on here to rebuild for you. If you can do it yourself, though, it won't cost much and you'll learn how to fix your game in the future.
 
Oh, and another thing you can do, that doesnt' cost anything but isn't really preventative mainentenance, is to clean the edge connector on the game board. That may be your problem as well.
 
Oh, and another thing you can do, that doesnt' cost anything but isn't really preventative mainentenance, is to clean the edge connector on the game board. That may be your problem as well.

Hey man, thanks for the detailed response. This will be the first vector that I've ever worked on, so although I'm handy with a soldering iron and more than willing to do everything you mentioned above with the power supply and the monitor chassis, I'm just not familiar enough with vectors yet to call a problem.

What is the best way to clean the edge connector 'fingers'? In the past, I've used a pencil eraser. Is that still a good and recommended way?
 
I had this issue before in my Black Widow (same board) and it was the big blue but I'm also siding with what LionsArcade has to say to help solid up your machine. I would also suggest the LV2000 for the monitor too.
 
I had this issue before in my Black Widow (same board) and it was the big blue but I'm also siding with what LionsArcade has to say to help solid up your machine. I would also suggest the LV2000 for the monitor too.

Understood completely. I just read up on the LV2000, and it looks like very cheap insurance, especially to do while you are 'in there'.

Thanks for the heads up on this as well - both you and LyonsArcade have given me a good 'punch list' of items to tackle.
 
Well good man if you've worked on games, you'll find out that these things aren't as bad as they seem. Also the vector monitors have seperate boards that are easily removed, so you can rebuild one piece at a time. High Voltage/Neckboard/Deflection Board.

Eraser works great. Use something like a file or something though on the actual housing, get those pins nice and shiny.

Looks like freeplayinc though had a similar issue and it was the Big Blue, it's kind of a classic symptom I believe of a failing Big Blue (game doing crazy shit, resetting makes it work sometimes, etc.)
 
Well good man if you've worked on games, you'll find out that these things aren't as bad as they seem. Also the vector monitors have seperate boards that are easily removed, so you can rebuild one piece at a time. High Voltage/Neckboard/Deflection Board.

Eraser works great. Use something like a file or something though on the actual housing, get those pins nice and shiny.

Looks like freeplayinc though had a similar issue and it was the Big Blue, it's kind of a classic symptom I believe of a failing Big Blue (game doing crazy shit, resetting makes it work sometimes, etc.)

Good deal man. I just found the WG 6100 vector FAQ you were talking about, as well. That's a hell of a document that will definitely be some good reading.

Looks like I've got to hit up Bob Roberts now. :)
 
His macdaddy 6100 rebuild kit will fix most dead 6100's... so it's a good way to bulletproof. You'll see all about that in that FAQ too, they've got it down to a science now, lol. I agree too about that LV kit, those are cool. I had a Gravitar that I rebuilt a couple years ago, I had it in my shop on everyday for 8 hours or so for about 6 months. I sold it, and when I got ready to ship it, I looked at the monitor to make sure everything looked good. The resistors I had replaced in the low voltage section were already charred again. the LV kit will probably relieve that, I've never used one though.
 
His macdaddy 6100 rebuild kit will fix most dead 6100's... so it's a good way to bulletproof. You'll see all about that in that FAQ too, they've got it down to a science now, lol. I agree too about that LV kit, those are cool. I had a Gravitar that I rebuilt a couple years ago, I had it in my shop on everyday for 8 hours or so for about 6 months. I sold it, and when I got ready to ship it, I looked at the monitor to make sure everything looked good. The resistors I had replaced in the low voltage section were already charred again. the LV kit will probably relieve that, I've never used one though.

Good deal - I just ordered a couple of the LV2000's (I've got a Tempest, as well, and it'll likely need - and benefit - from everything I'm going to do to the Gravitar) so I figured picking them up now will save me the trouble of piecemealing it later on down the road.

I'm so thankful Bob Roberts is still in the game... we'd be up-the-creek without him.
 
Yeah, really. Especially with those big blues. Try looking around for one of those on Newark.com or something. They're like 3 times the price... or you can buy them on ebay, but they're all as old as the one in your game! If you run the date codes on some of those caps on ebay, they were built in the 70's! So you're taking one out from 1982 that's worn out, and replacing it with one from 1977.
 
Yeah, really. Especially with those big blues. Try looking around for one of those on Newark.com or something. They're like 3 times the price... or you can buy them on ebay, but they're all as old as the one in your game! If you run the date codes on some of those caps on ebay, they were built in the 70's! So you're taking one out from 1982 that's worn out, and replacing it with one from 1977.

Yeah, no doubt. Bob has no equal for our hobby, so it's not even worth the time to check anywhere else first off.
 
Sounds dumb, but try cleaning the edge connector. My Gravitar would do that too until I cleaned and reseated the edge connector. It was actually about the +5 being a tad low and the dirty connector dropped it just enough to cause weirdness.
 
Sounds dumb, but try cleaning the edge connector. My Gravitar would do that too until I cleaned and reseated the edge connector. It was actually about the +5 being a tad low and the dirty connector dropped it just enough to cause weirdness.

OK, fair enough. I'll make sure I do that. Thanks!
 
while all of these are good suggestions, and probably will make your game more reliable, i think your issue isnt related to any of them. Go through self test, make sure you dont have a bad rom (maybe rom x07). Also calibrate the bip settings.
 
Better yet, while you are cleaning your edge connector, consider repinning the socket that mates with the edge connector, namely the power pins and the ground pins.
 
For what it's worth, my PCB comes up with those scrambled vectors about half the time. Power cycling it once clears it up most of the time.

I'll also add that it wouldn't hurt to repin the card edge connector. I haven't done it to my Space Duel/Gravitar, but I have done it to a couple of Ms Pacs and it makes it MUCH more reliable.

Kerry
 
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