Build Your Own Arcade Controls Forum

Main => Monitor/Video Forum => Topic started by: kardenm on March 26, 2010, 01:01:38 pm

Title: model 688-20(pentranic?), dim screen
Post by: kardenm on March 26, 2010, 01:01:38 pm

I have a monitor with a dark/dim screen (no brightness). Board is labled model 688-20". Is this a Pentranic?  Picture tube is a 20" Hitachi. What is likely cause of the dim/dark picture?   :dunno

Title: Re: model 688-20(pentranic?), dim screen
Post by: codecrank on March 26, 2010, 01:37:41 pm

first, try adjusting the various pots / knobs on the board and flyback.

Here is a good intro video.

http://www.youtube.com/user/varcadegames#p/u/10/MUL5TiUYAss (http://www.youtube.com/user/varcadegames#p/u/10/MUL5TiUYAss)

Title: Re: model 688-20(pentranic?), dim screen
Post by: kardenm on March 26, 2010, 02:16:30 pm

Sorry. Should have told you I alredy tried all the adjustments including ones on the flyback. Still cannot identify the make of the board from the suggested web sites (still trying).

Title: Re: model 688-20(pentranic?), dim screen
Post by: lilshawn on March 26, 2010, 02:22:10 pm

if you take a few photos and post them, someone here has probably seen/has it.

Title: Re: model 688-20(pentranic?), dim screen
Post by: grantspain on March 26, 2010, 04:22:30 pm

i have a schem for the 888 chassis and i would change c407 10uf 250v cap-not 100% sure if your chassis is the same

Title: Re: model 688-20(pentranic?), dim screen
Post by: kardenm on April 08, 2010, 10:11:54 am

Finally got back to this one. I did suceed in getting a near perfect picture through a combination of adjustments including flyback-screen.  Main problem seemed to be a pot in middle of board labled only VR901.

Also this chasis is a Pentranic model 688.

Thanks for the help. On to the next one.