Dragon's Lair Fans - Arcade Lifestyle

General Chat => Technical Area => Topic started by: neocps1 on September 21, 2013, 07:46:44 AM

Title: wei ya 825h
Post by: neocps1 on September 21, 2013, 07:46:44 AM

Hello,

As anyone information on these chassis ? I have bought one on ebay and it is working, but suffers
from a strange problem.

Basically, when there are lots of graphics elements onscreen, the colors are darker, and
when the screen should be dark, I can almost see the raster as If the G2/Screen was set too high.

The contrast doesn't seem to be regulated. I have made some researches on google and it may be
related to the chassis power supply which is too weak to handle correctly high voltage when
 for example, the picture is full white which it will display grey...

Any idea on how to fix this ?

thank you

Title: Re: wei ya 825h
Post by: DarthNuno on September 21, 2013, 09:13:28 AM

I've the same symptoms on my Space Harrier monitor : the contrast changes following the colors displayed, depending also of the size of the areas color changes. It's annoying during the game, but it's strong during the tittle screen, when the logo 'Space Harrier' comes from back to front. I think a capkit will fix that, but just too lazy have too many others things to do first  ::)

Title: Re: wei ya 825h
Post by: PaulSwan on September 21, 2013, 04:44:41 PM

I had what sounds like a similar issue on a Hantarex 900E that was fixed with a cap kit:

(http://www.zzzaccaria.com/images/Projects/MoneyMoneyRestoration/SAM_1286w.JPG)

Paul.

Title: Re: wei ya 825h
Post by: Etienne MacGyver on September 21, 2013, 05:51:10 PM

those are called Jailbars i believe ?

Many times (almost Always)  that is a capacitor related problem

Title: Re: wei ya 825h
Post by: PaulSwan on September 21, 2013, 06:39:25 PM

There is some bleed interference also but I mean the fade in brightness from top to bottom. They look like jail bars on this picture because of the building windows :)
This is another picture of the same chassis:
(http://www.zzzaccaria.com/images/Projects/MoneyMoneyRestoration/SAM_1287w.JPG)

A cap kit is your friend for the weird ones ;)

Paul.

Title: Re: wei ya 825h
Post by: neocps1 on September 23, 2013, 04:38:00 PM

thank you but the chassis is new and I have the same issue with another identical chassis (new too).

How can a chassis psu can be too weak to drive the monitor when there are high contrasts ?

Under dimension power transistors or capacitors ?

Title: Re: wei ya 825h
Post by: PaulSwan on September 23, 2013, 05:51:45 PM

Do you have it connected to a correctly rated isolation transformer?
If you have a multi meter, measure the AC input voltage to the monitor when it's displaying full brightness and see how it compares to it's rated AC input voltage.

Paul.

Title: Re: wei ya 825h
Post by: neocps1 on September 24, 2013, 10:24:28 AM

Yes, it is connected to an isolation transformer taken from an old sega model 2 cabinet.
It was used to power the 110vac nanao monitor.

Also, I tested with a 220/110 transformer also and same issue