G05 (Asteroids) - vertical jitters

jehuie

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Ok, I spoke to soon in my previous post. After I replaced the fuse and adjusted the brightness my monitor looked great for 5 or 6 games. Then I turned it off and came back to it. Now it has a bad case of the jitters. It looks like it is jumping up and down vertically. Just little jittery jumps. I have not yet done a cap-kit on it. Will a cap-kit likely fix this kind of problem?

Or perhaps I just have a loose connections somewhere since it was looking so nice earlier? What do you guys think? Thanks again!
 
Too often caps are mentioned as the "fix it all" solution, which it isn't.

Jitters often indicate bad potmeters or contacts.

Yeah, but when you've already got the chassis out for repairing the joints and checking the pots... it'd be crazy to not just go ahead and do a little "Spring cleaning" and redoing the caps and cleaning the HV diode. Only takes an extra 15-20 mins or so and will help out in the end. I think Bob Roberts sells a full rebuild kit (I should be able to remember this, I JUST ordered one a couple of weeks ago) for something like $11, that's the caps and can transistors...

Caps are an over used excuse though... I hate asking for monitor help because I know the first 4-5 responses will be able the caps... even if you JUST did a cap kit, they'll still tell you to redo the cap kit. Going into HV shutdown? Cap kit... completely ignore the transistors and IC on a normal monitor... Missing green? Cap kit... don't bother with the drive transistor and resistors on the neck (or the IC on some monitors)... Monitor won't come on... fuse blows, cap kit, cap kit... don't bother with the bridge or the hot, or the degaussing coil.

Granted, most of the time cap kits are needed... don't get me wrong, but they really are used as a "fix all".

I have a Battle Zone that was having REALLY bad video issues (BAD jitter and loss of video signal all together from time to time)... I spent a good couple of hours checking and double checking the chassis and HV section of the monitor... ended up being a bad RAM on the game itself that was causing the video issues.

He mentioned in another thread that he's getting weird results from his test mode... I'd clear that up first before I bother pulling the monitor... unless it's already pulled, then just reflow everything and clean the pots (can of contact cleaner sells at Home Depot for about $2.99 a can). If/when you order new RAM in for the board, if needed, go ahead and toss a cap/rebuild kit in with the order... might as well also get a cap kit for the game PCBs as well... never hurts.
 
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Don't get me wrong, i dont think a cap kit will fix his problem, but troubleshooting a monitor that has not been capped IS a waste of time. His problem is more likely to be filter caps or pots. But first things first, cap it and reflow solder. If the game is a keeper, and it sounds like it is, then it will get capped eventually, so why not do it BEFORE wasting a bunch of time troubleshooting ?
 
I just bought Bob's cap kit for my G05 and had I known it didn't include the 2 big caps in the picture I would have ordered them from him too. Some people say don't fix what isn't broken, but when I do a cap kit I like to replace all the caps just to be safe.

mon12.jpg


That's just an FYI though, not a recommendation. Ordering 2 caps from anywhere isn't really cost effective- in case you wanted to replace them.
 
Thanks guys. For the record, I already bought a cap-kit as well as the deflection transistors before doing anything. While I was waiting for it to come in I noticed the blown fuse and with a little tweaking it all looked great. So I haven't pulled the monitor at all.

I thought about it being a pot issue as well. It almost looks like a vertical hold pot that's slightly out of adjustment. But I don't think the G05 has a vertical hold pot. Or at least I don't see anything like that. Or else I would try just adjusting it to see if I can fix the problem. Although, the problem seems to have mysteriously disappeared again for the moment at least.
 
cleaning the HV diode

This caught my eye, is it normal for there to be problems with the HV diode connection? I have an Asteroids Deluxe that was working beautifully until one day I turned it on and the screen image was extra large and breathing. I thought HV diodes die slowly, can they just "burn out"? Or is it likely I have a bad connection? Haven't checked anything out yet, but the deflection board has been capped but the HV board has not.

Not trying to hijack, we can go to a new thread if needed.
 
This caught my eye, is it normal for there to be problems with the HV diode connection? I have an Asteroids Deluxe that was working beautifully until one day I turned it on and the screen image was extra large and breathing. I thought HV diodes die slowly, can they just "burn out"? Or is it likely I have a bad connection? Haven't checked anything out yet, but the deflection board has been capped but the HV board has not.

Not trying to hijack, we can go to a new thread if needed.

I was emailing back and forth with Bob Roberts, he mentioned that over time the grease they use on the ends of the diode will run, build up, and sometimes cause a little leakage. So, I've added that to my monitor routine when I run across it now (so far, 2 monitors). I just took them out, washed them in a some soap and water, dried them in the over on low for a few minutes, regreased them and put them back in. Figure they'll probably be okay for another couple of dozen years.

White line on the diode goes towards the anode cup.
 
After reading the above links, it seems that discharging via the screwdriver method could hurt the diode, if there's ever a pop. For all those experienced with a G05- how do you discharge it? I only have a screwdriver and not the proper tool. Is it necessary? If so where do you buy one, and are they expensive?
 
After reading the above links, it seems that discharging via the screwdriver method could hurt the diode, if there's ever a pop. For all those experienced with a G05- how do you discharge it? I only have a screwdriver and not the proper tool. Is it necessary? If so where do you buy one, and are they expensive?

... call me crazy, but I just don't discharge 'em.

I -think- you can use a lightbulb and discharge them through that, but don't quote me on that... I'm tired, pissed off, and tired.
 
Bob Roberts response....

After reading the above links, it seems that discharging via the screwdriver method could hurt the diode, if there's ever a pop. For all those experienced with a G05- how do you discharge it? I only have a screwdriver and not the proper tool. Is it necessary? If so where do you buy one, and are they expensive?


You know, I've asked Bob Roberts that same question when I was recapping my GO5. And he told me ... well let me see if I have that email.... yep here it is:


I asked him this:

Also would your Safeback Discharger kit be safe for discharging this
monitor? I read in the B&W Vector FAQ, that it can cause the HV Rectifier
Diode to fail if you don't use Ten 100K-Ohm resistors in series. Is that
necessary? I've discharged raster monitors before(without resistors),
however I don't know if you need to have the recommended resistors in place
for a vector monitor. What do you think? Will your discharge kit work just
as well for this vector monitor?




Bob Roberts responded with this response:

Basic electricity 101 as taught since the days of Edison until now:

"Electricity ALWAYS seeks the easiest path to ground! It does not "care" how

it gets there. If you or your equipment create that path, you will be
placing yourself (and possibly others) in a life threatening situation."

So... if you don't hold onto the ground wire with one hand & touch the metal

frame with the other it will not go through you to get to it's objective nor
will it go through a diode, or any other component, unless you put it in the
path to ground. In the case of discharging a monitor with a Safeback, it's
absurd to think that the electricity with a nice solid path to ground is
going to somehow allow part of it's charge to go in reverse looking for a
much harder path to ground.... yet... the inet stories still grow such as
the one about ketchup containing the HIV virus!

For a common sense view... while the monitor is on there is a constant

17,000 to 22,000 volts applied directly to that HV diode.... not just the
small residual charge left in the CRT.





So there you have it. It makes sense and I've had no problem discharging it with a screwdriver and a wire. Bob knows his sh*t that is for sure.


;
 
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So there you have it. It makes sense and I've had no problem discharging it with a screwdriver and a wire. Bob knows his sh*t that is for sure.


;

Makes sense. I trust Bob too. I've already discharged it twice with the screwdriver method and didn't get a pop either time.

... call me crazy, but I just don't discharge 'em.

I -think- you can use a lightbulb and discharge them through that, but don't quote me on that... I'm tired, pissed off, and tired.

Actually the first time I unplugged all the cables from the deflection board before discharging the monitor, and nothing happened. I figured since the flyback wasn't on the deflection that it wouldn't hurt. I know it may have been wrong, but the monitor still works... well at least gives me a spot killer.
 
Well, back to the original topic. I tried swapping both the X and Y pots on the game board. My theory was that if it was a problem with the pot then it would change the jitters from being vertical to horizontal. But swapping them had no affect at all. It still jumps vertically.

I saw a few other threads on this same problem. People recommended checking a bunch of things. But nobody every posted what actually fixed the problem. I guess I'll start running through the various recommendations and see what happens.
 
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