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tv/monitor color gone -Viewsonic 29ga    
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PostPosted: Tue Feb 06, 2007 3:50 am    Post subject: tv/monitor color gone -Viewsonic 29ga Reply with quote

Hi - First off, I like the info on the site. I'm an arcade game collector who does a lot of his own repairs, and basically am just frustrated by a lot of the same pittle things going wrong, looking for cheap/free/local help.

I noticed your page said "live in the KC area?" Sort of - I can haul it in with no problem. my troublemaker is a Viewsonic 29GA - 1997 29 inch tv/monitor with displays up to 1600x1200 at 60hz. Lots of inputs, including old mac monitor inputs. (and VGA ones too). One day, I heard a sssssPOP! and my green went completely out. now I figured with a sound that loud, I could look at the board and see where the bad part would be located, order it, repair, done. I haven't done anything but shelve the unit since that happened (about a year ago) and would love to have it repaired.
(I have the manual, but not the schematic)

I also have a 50" hitachi with a slight convergence on red gun problem. someone worked on it 4 separate times and got it watchable, but you still cannot play Halo on it, if you get my drift - one corner is pretty misaligned (my red actually does a slight 's' when making a straight line of white in the bottom left.)

...And I also have arcade chassis' for 25" standard resolution arcade games with slight problems - one had a fold about 2 inches down from the top, but after a cap kit, it's a "crease". Another is a horizontal bar after a move, and a third is a blowing a fuse every time we fire it up. Frustrating, but fixable. WGk7000(2), Yeh-Wa 826HR, WGk4900 for a 25" (maybe a 5500 or 4500, I can't remember the number off hand).

I got some money to fix these, and some have been sitting for quite some time - I see you are probably swamped out and I 'm at my wits end with the chassis.

I've bookmarked this site, but I'd love to talk to you on the phone, about some of the other big projects I mentioned. Thanks for any help you might have for me. Sorry for dumping too much on my first post (probably out of category as well) won't happen again.

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Joined: 28 Dec 2006
Posts: 2879
Location: Overland Park, KS

PostPosted: Tue Feb 06, 2007 6:28 am    Post subject: Reply with quote

Wow, sometimes when it rains, it pours. I live in Olathe. I'd suggest registering your user name and giving me a private message if you want to get ahold of me.

I remember your user name from the klov forums. Glad to see you here.

I'll try and do a little research on your problems if I can. I know the Hitachi TV would be the easiest for me. I'm curious what was worked on, and if you can get me a model number... I can be very helpful.

Joined: 28 Dec 2006
Posts: 2879
Location: Overland Park, KS

PostPosted: Tue Feb 06, 2007 11:46 am    Post subject: Reply with quote

I can't seem to find any good information on the Viewsonic 29ga monitor. I don't have much experience with monitor repair... my extent would be repairing cracked solder joints, and turning up screen voltages.

Yeah, I would start with looking for the burnt components, and I would probably test the CRT itself next, then follow up by measuring the voltage on the neckboard that is driving the green. Then I'd probably try to cut some traces on the CRT neckboard and see if switching it with the red circuit still resulted in no-green or no-red. After that, I'm not sure what else I'd look for.

Joined: 07 Feb 2007
Posts: 1
Location: NE Kansas

PostPosted: Wed Feb 07, 2007 2:44 am    Post subject: Reply with quote

All registered. :D

The monitor back when released was $4000 and was used for businesses as a display unit for office room presentations - before the little projectors got popular. It has at least 5 inputs, mac & pc monitor inputs, and some coax & RCA (red white yellow & s-video) inputs. It's the crispest monitor I've ever seen, and did 1024x768 @ 75 hz with call of duty on a PC - quite beautiful.

When the green went away, I was watching TV and I heard a ssss-POP like a capacitor popping. Once the sound happened, no Green.

It still works fine other than that. I bought it off of ebay, and it was freighted here, since it weighs right at 150 pounds. It is a solid brick of death. At the moment, it's off the floor on a shelf, nothing plugged into it.

Aside of that, anyone repair monitor chassis? simple problems, but I don't want to chuck another 100 bucks for a replacement one when I should be able to get it repaired for parts cheap. One has a horizontal line across (still see the color and motion in the line), one was folded about 1/4 th the top screen, I bot a capkit and unfolded it, now there's a crease where the fold originally was. And one is blowing it's main board fuse as soon as you turn it on every time. All 25", 2 of them are WGk7000.

OH- the hitachi was bought as a 50" tetris, worked on for a number of times, but not completely fixed. Looks good, but not perfect. Also there is very slight burn, not a ton like other projection 50" videogame screens. Mine has Street fighter Alpha 3 embedded faintly in the bkgnd when everything is white.

Again, thank you for the welcome. :D

Joined: 28 Dec 2006
Posts: 2879
Location: Overland Park, KS

PostPosted: Wed Feb 07, 2007 8:48 am    Post subject: Reply with quote

Yeah, I would also suspect a capacitor on the viewsonic monitor based on what you’ve said. Open that bad boy up and take a look. It should be easy to spot if it is a blown Cap.

Arcade monitors are not my strong suit. I can usually figure out the ones from the ‘80s, because they are quite simple and have a lot in common with TVs. The newer multi-frequency arcade monitors are much more sophisticated. There is some info available at http://www.wellsgardner.com/pdf/Spec/K7000.pdf There is also some other pdfs available there. Those aren’t schematics, but they show the adjustments that can be made.

The one that was folded, and now is creased. Make sure your electrolytic caps are soldered using correct polarity. I know that some of the PCB boards have the polarity marked incorrectly. The only way to confirm that (without a schematic) would be to turn it on and test with a multimeter. If everything is installed correctly, then it’s just a matter of figuring out which component on the board is outside of its tolerance. I’m not sure where the crease is, but I would try adjusting the pots on the board to see if it makes any difference. Measure your B+ and tell me what it is. Also explain the where the crease is to me.

The one that is blowing the fuse: I would suspect is a shorted transistor. Probably the H.O.T. You have to remove them from the board to test them. A Transistor tester is available at Radio shack for ~$20.

The one with the horizontal line: Check the Vertical Output Transistor for shorts, or an open resistor/capacitor very near it.

Just FYI, I’ll probably move this discussion to the Non-TV forum section soon.

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