Build Your Own Arcade Controls Forum

Software Support => GroovyMAME => Topic started by: Endprodukt on June 20, 2016, 10:52:52 am

Title: black stripe on 15khz (on white pictures)
Post by: Endprodukt on June 20, 2016, 10:52:52 am
https://www.dropbox.com/s/04bs1nsotfyoloh/2016-06-17%2017.39.33.jpg?dl=0 (https://www.dropbox.com/s/04bs1nsotfyoloh/2016-06-17%2017.39.33.jpg?dl=0)

It only occurs on 15khz games on very bright pictures, and not always. Monitor is NOS and in very good shape...problem occured after the switch to the new driver/system.

Any ideas?
Title: Re: black stripe on 15khz (on white pictures)
Post by: Doozer on June 20, 2016, 11:48:37 am

Are you talking about the diagonals stripes? To cure this phenomena you can either try to reduce the screen brightness or turn a bit the screen G2 control on the flyback.
Title: Re: black stripe on 15khz (on white pictures)
Post by: Sledge on June 20, 2016, 05:52:36 pm
No i think he's talking about that black stripe right down the middle of the screen..
Title: Re: black stripe on 15khz (on white pictures)
Post by: Endprodukt on June 21, 2016, 02:20:30 am
Exactly.
Title: Re: black stripe on 15khz (on white pictures)
Post by: Doozer on June 21, 2016, 03:03:38 am

Is the picture blowing, bumping/scaling when it happens or this is completely static? Could you please make a video of the phenomenon?
Title: Re: black stripe on 15khz (on white pictures)
Post by: Endprodukt on June 22, 2016, 05:05:44 am
There you go: https://www.dropbox.com/s/yxo7u7azeeyihkq/2016-06-21%2015.32.02.mp4?dl=0 (https://www.dropbox.com/s/yxo7u7azeeyihkq/2016-06-21%2015.32.02.mp4?dl=0)
Title: Re: black stripe on 15khz (on white pictures)
Post by: Doozer on June 22, 2016, 07:38:01 am
There you go: https://www.dropbox.com/s/yxo7u7azeeyihkq/2016-06-21%2015.32.02.mp4?dl=0 (https://www.dropbox.com/s/yxo7u7azeeyihkq/2016-06-21%2015.32.02.mp4?dl=0)

Thank you for the video. It really helps to understand the issue. I haven't experienced this behaviour before but it is definitely linked to kind of beam cut off when displaying bright white pictures. The 3 colors are impacted and the spot dimension is linked to the picture brightness (visible with single frame step by step). Another element is the perfect alignment of the picture, there is no deformation visible in the surrounding elements during the apparition of the spot. It can be related to some protection (x-ray) mechanism, deflector issue (I doubt) or capacitors.


I am not able to provide you with guidance to get it quickly fixed. Next step is the examination of the signal and the boards. Nevertheless, you might see some enhancements by reducing screen/G2 or brightness, this will put less stress on the fly-back. If the issue gets worst through time, something is starting to die on the board. How old is the PCB? Has it already been upgraded with a capkit?
Title: Re: black stripe on 15khz (on white pictures)
Post by: Endprodukt on June 22, 2016, 05:54:24 pm
As mentioned, this is a nos monitor. It had a bad flyback right from the beginning that we had to replace (exact same type brand new). It worked flawlessly until I switched the computer and went for the latest driver.