MitchO
Active member
OK, that shouldn't be too hard. I'll post again after I take a look.
Mitch
Mitch
22V1001 uneven brightness
- Thread starter MitchO
- Start date
MitchO
Active member
OK, I verfied the polarity on all of the caps and retouched a couple of the solder joints that looked possibly suspect. No change. 
Mitch
Mitch
MitchO
Active member
I decided to mess around with this again.
After doing some checking I noticed that the regulator was running at around 60V where the manual said it should be at 73V. I adjusted it up to 73V and now the brightess is nice and even across the monitor. Unfortunately, the picture is now larger than the screen and I can't adjust it back down. I went ahead and adjusted the voltage back down to where I could see all of the picture (around 63V). The uneven brightness issue is back but it's barely noticable now.
So is running this down at 63V going to cause any problems and why is it doing that?
Mitch
After doing some checking I noticed that the regulator was running at around 60V where the manual said it should be at 73V. I adjusted it up to 73V and now the brightess is nice and even across the monitor. Unfortunately, the picture is now larger than the screen and I can't adjust it back down. I went ahead and adjusted the voltage back down to where I could see all of the picture (around 63V). The uneven brightness issue is back but it's barely noticable now.
So is running this down at 63V going to cause any problems and why is it doing that?
Mitch
73 volts is the input operating voltage of the flyback. There should be some size adjustments on the chassis. Is it too big horizontally...or vertically...or both?
Edward
Edward
MitchO
Active member
Both. I couldn't get any of the adjustments to change the size except one of the V linearity pots would change the V size on the side closest to the coin door. The other V linearity pot and the H width coil didn't seem to do anything.
Mitch
The two V linearity pots arn't really size adjustments pots...they adjust, well, the linearity. Let's see, how can I explain linearity.....say you have a cross-hair pattern on the screen. The boxes that are formed from the cross-hairs (ideally) should all be the same size. Say the "boxes" on the far right hand side of the screen are "stretched" about one inch larger than the boxes on the far left hand side of the screen.....and all the boxes (slightly) decrease with the "stretch" as you visually move from right to left. This is your linearity being off. I know, not the best description....I'm horrible at this kind of stuff.
Vertical size is controlled by pot R256.
Sometimes you can tweek the horizontal with the HORIZ HOLD pot (R108). This will "shift" the image up/down on the screen. You can get more adjustment from the horizontal oscillator (L201...this has to be adjusted with a plastic hex tool). As a last resort....changing the value of C105 will alter the horizontal size, but I would rule out other issues first as this cap really shouldn't be altered (though, yours could be bad).
Edward
MitchO
Active member
Thanks for the info.
Hmm, I'm pretty sure I tried adjusting R256 for the V size and nothing happened but I will verify that. I knew the V linearity was only supposed to be for adjusting the linearity but I was trying all of them to see which ones worked.
The H hold pot R108 and the H oscillator L201 both work but don't do anything for the picture size. I already recapped it, but C105 was not done because it was not an electrolytic. I suppose I could try replacing it and see if that makes any difference. And isn't the width coil L101 supposed to control the H width? I couldn't get it to do anything.
Mitch
A horizontal width coil will adjust an image...maybe 1/2 an inch...if you're lucky. C105 is a polypropylene cap. I doubt that's your problem. When they go, they usually short...and you'll lose all horizontal deflection. It's weird you're having horizontal and vertical issues....two totally separate circuits.
Edward
MitchO
Active member
Forget what I said about R256 not working. It works fine. I don't know why I had problems with it, maybe I was tired at the time and just missed it. I can adjust V width with no problem now.
By staring at one of the horizontal sides while turning L101 I can see it moving very slowly. I adjusted it as far in as it would go and I was able to move the regulator up to 66V. Better but still not at 73V. Also the horizontal picture is a bit off center, not real bad but if I was able to center it I might be able to bump it up another volt or so. Playing with the H oscillator controls L201 and R108 didn't help much if any.
It seems my vertical circuit is fine but my horizontal circuit is still a bit off.
Mitch
By staring at one of the horizontal sides while turning L101 I can see it moving very slowly. I adjusted it as far in as it would go and I was able to move the regulator up to 66V. Better but still not at 73V. Also the horizontal picture is a bit off center, not real bad but if I was able to center it I might be able to bump it up another volt or so. Playing with the H oscillator controls L201 and R108 didn't help much if any.
It seems my vertical circuit is fine but my horizontal circuit is still a bit off.
Mitch
g3n3r1c
Permanently Banned
Bumping this.
did you ever figure out your problem?
My Space Zap is exhibiting the same problem (uneven brightness) and I would really like to get it figured out.
did you ever figure out your problem?
My Space Zap is exhibiting the same problem (uneven brightness) and I would really like to get it figured out.
hatrick
Well-known member
It says right in the post what it was. I'd check to see that your voltage is where it should be.
g3n3r1c
Permanently Banned
It says right in the post what it was. I'd check to see that your voltage is where it should be.
It didn't make a difference with mine
MitchO
Active member
No, I was never able to get it fully resolved. I'm just living with it now.
Mitch
Mitch
g3n3r1c
Permanently Banned
Just an update. I bought a custom cap from DH distributors and it corrected the uneven brightness issue completely. Looks perfect =)
Thanks to whoever posted the link to DH.
Thanks to whoever posted the link to DH.
