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Main => Monitor/Video Forum => Topic started by: skynaps on February 26, 2013, 10:10:44 pm

Title: Flicker/jumping/bouncing screen (v-hold?) problem
Post by: skynaps on February 26, 2013, 10:10:44 pm
I purchased a cabinet with a relatively new Pentranic Model 1127, 288-S26A in it. I have an ArcadeVGA 3000 and J-PAC running to it. A lot of screen jumping/vertical rolling then bouncing and settling occurs whenever larger shifts in color and/or light appear. (When transitioning between new screens for example, and flashy events.)

The picture, even with its left corner green shift (needs to be degaussed), looks beautiful and sharp otherwise. I've tried playing with the brightness and v. hold and h. hold and all of the knobs to varying degrees and nothing seems to stop this major problem (though turning the brightness WAY down seems to help it a very minor amount). Could it be damaged (maybe during transport) and what can I do to fix this?
Title: Re: Flicker/jumping/bouncing screen (v-hold?) problem
Post by: sandheaver on February 26, 2013, 10:20:47 pm
The monitor should degauss each time you turn it on.  Or, at least once every 4-5 times you power it up. 

Check the V-Hold pot and sweep the knob through its full motion a few times.  All the way left, all the way right.  If there is a little mote of dust in there, holding the contacts apart slightly, this motion should clear it.

Try that and let us know if it helps.
Title: Re: Flicker/jumping/bouncing screen (v-hold?) problem
Post by: skynaps on February 26, 2013, 10:52:16 pm
That definitely helped a significant amount! That V-Hold pot was nestled in there and I wasn't aware of it's existence. I'm new to this.

There is still, however, some roll/jump on the brighter flashing parts. Is this normal? I'm still going to continue adjusting, but shouldn't everything hold even when there are huge flashing moments?
Title: Re: Flicker/jumping/bouncing screen (v-hold?) problem
Post by: skynaps on February 28, 2013, 03:55:04 pm
Alright, I was informed that I may have to adjust the B+ due to the problem still persisting even after adjusting the V pot (which helped a ton, but there is still lots of jump on bright flashes and some screen transitions). I was told this may be a voltage issue. Now I found the B+ marking on the board itself, which is hooked to a harness (white wire) into the flyback board with the other dials, but there is no B+ dial that I can see so far.

I'm attaching photos of the chasis. How do I adjust this?
Title: Re: Flicker/jumping/bouncing screen (v-hold?) problem
Post by: grantspain on February 28, 2013, 06:30:30 pm
don't touch the b+ unless you know the meter points and exact voltage it needs to be

what might help is if you remove that metal washer from shorting to the video decoder ic on the neck card
Title: Re: Flicker/jumping/bouncing screen (v-hold?) problem
Post by: skynaps on February 28, 2013, 06:41:38 pm
I did notice that washer after posting the pictures and I removed it post-haste.

How do I find the meter points and necessary voltage?