WG25k7193 Issues

[Nipedley]

I've just recently installed a new 25k7193 board onto a tube (some of you may remember it from last year =)).
Turns on fine, a picture appears, but theres a really loud staticy sound coming from the back of the monitor (that shouldnt be there) and there are distortions in the picture that seem to correspond with the noise. I cant see any anode arcing, so I'm not sure what else to check for or what could be wrong.
Any ideas?

[Ken Layton]

Are the tube and yoke correct for that chassis?

[Nipedley]

It was a wg 25k7193 originally (the board fried) so I just got a replacement, so I assume there wouldnt be any problems with that... It's strange, the static only starts about 4 seconds after the picture appears and seems to be random. I'm at a loss

[grantspain]

whats the condition of the insulation paint around the the anode cap insert?

[Nipedley]

It looks fine to me, I havent touched it since the old board came off and that worked fine until it fried =).

I'm sure its not an anode issue though because today i went out to test it, and theres no static. But! Theres no noticeable picture, either, just a white colour of varying intensity. LOPT trouble or is this something else? Kinda sucks because I bought the replacement as a drop-in, so I wouldnt have to do more work -_- Sigh. The last one died because of a dead LOPT as well.

[grantspain]

if you get any kind of pic then its not likely to be lopti,somehow the signal is missing either the signal from the pc/gameboard or a connection problem on the monitor.double check the neck card is fully home and check you have a ground on the neck card

[Nipedley]

It seems to vary whether the monitor will just display a white picture (which fades in/out a lot) or whether it displays the proper picture (with some horizontal lines going across) and makes awful noises. I've checked the connections and they're all fine..

I'm willing to buy (another -_-) replacement chassis for this thing. Does anyone know of a source for reliable K7000 25" monitor replacement chassis?

[Ken Layton]

It's very possible the flyback is leaking high voltage either from a hairline crack in the plastic casing or a crack/internal arcing around the focus & screen controls on the flyback.

Naturally when you trade chassis even between the same model number, you still need to adjust the screen, focus, brightness, contrast, etc.

[modessitt]

Check to make sure one of the neck pins didn't miss it's hole on the neck board and get bent against the neck instead.

Turn the lights off and watch the chassis when it's doing it and see if you see a flash.

[Nipedley]

I like that idea, I'll give it a shot later on tonight when it gets darker.

I just gave it another go and this time it gave me a mix of the white background and a really fuzzy picture with short bursts of static. This is getting strange o.O I caught it on video (I'll try and get a screencap). If it is a crack in the flyback, is that fixable? I had it shipped from the US -> UK so I suppose thats possible.

[grantspain]

if it turns out to be the lopti you should be able to get one in the u.k,possibly from either suzo,brent or grandata
they are very easy to replace

[Nipedley]

It's getting clearer now, as the static gets louder and more frequent the picture begins to really show up. When I can't hear the static, the picture goes and a white background takes over... So whenever theres the static (sparking?) the more intense it gets, the more correct the picture gets.

I take it that means there is a hairline crack in the lopt, unless anything else could be causing a spark like that?

If so, any way to fix a hairline crack or do I have to replace the lopt altogether? Thanks for the sources grant =)

[grantspain]

sometimes you can get away with using a bit of araldite on the crack but i have only ever seen that work once and many years ago
does physical manipulation of the chassis make any affect?e.g tapping it with a screwdriver handle

[Nipedley]

Bit of a newbie at this thing to have the courage to try that while it's on xD. I might give it a go... I'm going to see if I can see a spark when it gets darker. That should clear things up =)

By the way, on my post above I edited in a link to a video of the monitor. You can hear the static a bit on it as well, as it gets more intense when the pictures clearer.

[grantspain]

it does look like the lopti,its possibly breaking down internally
try turning down the screen volts first

[Nipedley]

I'm pretty sure it is. The screen wildly varies in brightness and focus, and I'm still getting the static/crackling corresponding to distortions in the screen. I've found a replacement K7000 lopt for £26 but..

If possible I'd like to just go for a new replacement board. What chassis are suitable replacements for 25" k7000's? I dont mind importing from usa/anywhere so long as I can get this damn thing up!

[Nipedley]

o.o Is this a miracle or a fluke? Is it possible that the parts just needed a bit of warm up?

Now my only trouble is the horizontal lines across the screen... I bet I'll be back to square 1 tomorrow, though.

Incase it DOES actually keep working, any idea on the horizontal lines? They're static, not moving. I thought maybe a bit of h-sync tweaking, but I can't find the control on the remote board o.O

[grantspain]

they are called flyback lines caused by the screen volts being set too high(which i told you in a previous post)-look at the lopti/flyback you will see two adjustments(screen volts and focus),you need to turn the screen volts down until you loose the flyback lines
if your picture is then too dark you need to use the brightness/contrast and colour pots to correct the quality

[ac3]

Hey Nipedley what is the best way to contact you?. I sent you an email but it got returned. It's regarding Mega-Tech stuff. While on that note this might interest you. 







ac3.