The NEW Build Your Own Arcade Controls

Main => Monitor/Video Forum => Topic started by: nipsmg on April 05, 2020, 02:27:27 pm

Title: New k7000 chassis, image a mess
Post by: nipsmg on April 05, 2020, 02:27:27 pm
I just bought a k7000 chassis off ebay that was supposedly completely overhauled and tested, but the images are a mess.

First, I have this discolored spot in the bottom left. I'd thing degaussing would handle this.  I hooked up the cable for the degaussing coil, but I didn't hear it fire on power-on.  Does the direction that connector is plugged in matter? 
(https://i.imgur.com/2gyC83pl.jpg)

Second, I can't get the image to the top of the tube. With the vposition pot turned all the way, the picture gets at best a few inches from the top of the screen.  I can adjust the vsize and get the picture to the top, but the bottom gets very bright and wraps/inverts:

(https://i.imgur.com/bgNCZEZl.jpg)


Also the convergence and colors are off.. but that I can fix myself.

Any help would be appreciated.  thanks.
Title: Re: New k7000 chassis, image a mess
Post by: grantspain on April 05, 2020, 03:47:51 pm
50/60hz pot will probably help the vertical shift issue
check your deflection yoke and purity rings are set correctly
check diodes, resistor and ptc in degauss circuit
Title: Re: New k7000 chassis, image a mess
Post by: nipsmg on April 06, 2020, 08:29:55 am
The color dot was due to purity rings being WAY THE HELL out of whack.

I was able to fix the color using the colorbars from a CPS2 game's test menu, and there was a great convergence chart on Walvisions.com (https://www.walvisions.com/PattPages/1-convergence.html (https://www.walvisions.com/PattPages/1-convergence.html)) that helped me with convergence.  Some convergence issues in the corners but not enough for me to worry about it I don't htink.

I've got some geometry issues (different size squares) that I think can be further fixed by the 60/50hz pot. 
(https://i.imgur.com/c1b3wBAl.jpg)

The last problem is even with the VPos pot turned down to 0, the picture isn't at the top of the screen.  Someone over on the KLOV forums said to replace Q9 (2n3904). I'm going to see how much it bothers me, then potentially replace that transistor if I can't dial it in.

Of course, get the monitor working, and now 75% of my switches aren't firing on the control panel.. all still wired to an (old) ipac 2.  I'm going to do some continuity tests, but that ipac may have finally died.  New one on order should be here soon hopefully.

Title: Re: New k7000 chassis, image a mess
Post by: grantspain on April 06, 2020, 11:00:31 am
what value pot do you have for the vertical position
you should adjust the 50/60hz pot now