WG K7000, Focus wondering in & out?

[lettuce]

Im having a problem with my 25" WG K7000 Monitor, the picture doesnt seem to stay in focus, it will be fine one minute and then it will go out of focus and then 15 seconds later go back in focus, also the left and right side of the screen never seems to be as sharp/in focus as the middle of the picture. Anybody know what the problem is and if it can be fixed???, i believe Kens the man for this?

[Ken Layton]

Two things to check:

First thing to do is unsolder and remove the tube socket from the neckboard. Now that it's off the board there a couple of hidden tabs at the square end of the socket where the single thick wire goes in. These tabs release the end of the socket to get to the soldered end of that thick focus voltage wire. Sometimes the solder has gone bad and merely needs to be resoldered.

Second thing to check is the flyback transformer very closely for hairline cracks or signs of arcing anywhere on it. You usually have to unsolder it and remove it to examine it. Also the flyback is typically very dirty and I usually clean it off with a rag and some 409 cleaner. Those cracks usually appear near the focus or screen controls and you need to look very closely with a magnifier glass. Any signs cracking at all then throw that flyback away and buy a new one as they are only about $27 (or less if on sale). The flyback generates the focus voltage. My experience over the years has shown that 90% of the time a focus problem will be due to the flyback being bad. The other 10% of the time it will be bad solder on the focus wire inside the tube socket or a bad picture tube (in that order).

[lettuce]

Thanks for the reply Ken, the 2 suggestions you listed sound a bit out of my league, so i would have to get a profesional involved. One thing i did notice was, that im using a ArcadeVGA card, on the card there is a jumper setting for PAL or NTSC, when the monitor was on PAL i dont think the focus went in and out, but i have it on NTSC at the moment and its defently doing it now. Any ideas why it would do it on one jumper setting and not the other?

[SirPeale]

Where do you live?

[dabone]

The pal/ntsc jumper is for tv out only.

It has nothing to do with the rgb signal.



Later,
dabone

[lettuce]

Where do you live?

Bedfordshire in the UK mate

[SirPeale]

The pal/ntsc jumper is for tv out only.

It has nothing to do with the rgb signal.

I'm not so sure.  He lives in the UK, in which most video devices accept a PAL, and not an NTSC signal.  I'd swap it back to PAL if it was working that way.

Of course, I don't know if the PAL/NTSC applies to arcade monitors, but it stands to reason seeing how it's all about the refresh rate.

[lettuce]

Would just your bog standard TV repair man be able to fix the focus problem?

[dabone]

He should be, I had one that was doing that, I ended up replacing the flyback.

(You also might want to check your b+ voltage)


Troubleshooting guide is over at.

http://slot-tech-ftp.serveftp.com:8080/technical_department/


Later,
dabone