Asteroids G05

[FrizzleFried]

I have an asteroids that was jittery... much of the screen had a slight shake to it. I recapped it today hoping to rectify the situation and it's the same. I have the jitters mostly at the score and down down where it says 1979 Atari (when its on screen). Sometimes it gets worse, other times not so bad. I also notice that the asteroids/ufo's sort of stretch and then squeeze as they go up/down on the screen... but just barely.

Any ideas?

...could it be the Big Blue?

 

[modessitt]

When you recapped it, did you replace the big caps? Is this a -801 or -802? And didn't you have another post here about this same problem within the past month?

 

[FrizzleFried]

When you recapped it, did you replace the big caps? Is this a -801 or -802? And didn't you have another post here about this same problem within the past month?

The big "filter" caps didn't get replaced... only what came in the Bob Roberts kit. It's the -802 and no, I think that is the Sanyo 20EZ with the jitters I posted about.

I think.

 

[ELutz]

Is the cover on the high voltage cage? That will sometimes cause jitters if it's missing.

Edward

 

[FrizzleFried]

Is the cover on the high voltage cage? That will sometimes cause jitters if it's missing.

Edward

Yes sir... cover is present and accounted for.

 

[FrizzleFried]

So...replacing the filter caps is recommended? How about Big Blue?

 

[ELutz]

So...replacing the filter caps is recommended? How about Big Blue?

Either one of those (could) be causing the problem......or, they might not be the problem at all.

The asteroids/ufo squeezing and stretching sounds like a separate issue. Maybe someone has messed with the linearity pots on the deflection board.

Edward

 

[Blades]

So...replacing the filter caps is recommended? How about Big Blue?

Hey Frizz, I had the EXACT or Close to the same problems with my Asteroids Cocktail G05 monitor. The big caps didn't come with the kit,(was a little pissed off about that). So I ordered and replaced those and replaced Big Blue. That pretty much took care of my problems of the jitters and "Breathing" effect that I was getting. Couldn't hurt.

Hopefully this helps you.



;

 

[HudsonArcade]

Either one of those (could) be causing the problem......or, they might not be the problem at all.

The filter caps really only see 60Hz, so they're probably not the problem... the caps that get hit with high frequency, high current signals are the ones that tend to go...

 

[FrizzleFried]

...any suggestion on where to look if not the filter caps? What's your opinion of the big blue being the culprit? Anything else to look at?

 

[FrizzleFried]

Well, a big blue replacement didn't help. I still get the jitters (though I can now tell, the jitters is actually the screen shrinking and expanding vertically...like I am losing vertical deflection for a 1/10 of a second and then back again...

I have a hypothesis... there are two pots on the PCB itself that appear to control X and Y screen size.... what is the chance that one of those pots are bad?

Anyone know what "size" pot I need to buy?

Any other suggestion? Those two filter caps will cost me $17.00 shipped from Bob... is it work it to try to replace them?

I still have the situation where the screen seems to produce normal sized vectors at the bottom, top, and middle, but about 1/3 up from the bottom and 1/3 down from the top, the vectors squeeze VERTICALLY about 10-15% or so as they travel through those areas...then expand back to normal in the middle, top and bottom. Same happens with the UFOs and my ship.

 

[That80sGuy]

I see my post got nuked in the site data base crash Friz. I will dig out my manual. I'm almost 100% certain its the vertical chip in the vid output section. Like I said..the Asteroids I picked up did the exact same thing only on the horizontal output.

 

[FrizzleFried]

I see my post got nuked in the site data base crash Friz. I will dig out my manual. I'm almost 100% certain its the vertical chip in the vid output section. Like I said..the Asteroids I picked up did the exact same thing only on the horizontal output.

Was it this chip:

http://www.arcadechips.com/product_info.php?products_id=99

Thanks!

 

[80scoinops]

Curious as to the outcome of this one, have the exact same issues FF described. Recapped the monitor boards and recapped the Asteroids PCB, no change.

Was leaning toward transistor replacement as a possible next step, did the chip turn out to be the culprit?

 

[FrizzleFried]

Curious as to the outcome of this one, have the exact same issues FF described. Recapped the monitor boards and recapped the Asteroids PCB, no change.

Was leaning toward transistor replacement as a possible next step, did the chip turn out to be the culprit?

Actually, once I adjusted the linearity pots the shaking stopped. My guess is that one of the pots is starting to go... but it hasn't come back.

 

[80scoinops]

The X pot won't adjust the edges of the screen into view. Bad pot, or is something else causing the horizontal expansion of the image? Image size stays the same no matter how long it's left on.

Center of the screen also is washed out now while edges are nice and bright. I don't recall that it was doing that before.

 

[orion3311]

I have one doing the same thing and I believe its the pots...messed with them and it went away for a while. I believe Bob Roberts sells a pot kit for that monitor.