WG71XX 25" chassis problem, HELP!

LyonsArcade

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Hi Guys!
I hope somebody can help me figure this out. I have a wells 25" monitor that i'm having trouble with. Originally, I had the monitor working fine, but it had a really, really bad spark coming from the flyback which had some cracks in it. I mean like Frankenstein sparks, you couldn't leave it on but a few seconds and you'd have fireworks.

So, I replaced the flyback. Fired it back up, and I now get a really blurry screen. Essentially the monitor is displaying the correct images, but you can't even come close to tuning them in with the screen control. so I checked to make sure I put the correct flyback in, and the numbers match up fine.

I recapped it, it still looks exactly the same. I replaced the hot, it still looks exactly the same. I checked for bad solder joints and reflowed a bunch of resistors, it still looks exactly the same. I replaced IC4 (voltage regulator) and it still looks exactly the same. I replaced the vertical chip on that tall heat sink, (can't remember the ic #) and it still looks exactly the same.

On the large white resistor, i'm getting about 150V on the far side, and 130v on the front side. That sounded about right to me for a 25", although i'm not sure about that 150V.

Anybody have any clue what I should be looking for? I'm thinking I may have a resistor that's opened up, would that be a place to start? I tried another working wg71XX board set on the tube, and it works perfectly.
 

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And just in case you "misspoke" when you said you adjusted the screen control:

You should have a wire going from your flyback to the neck socket. That is your focus wire. If it is not hooked up correctly, or something is wrong with that pin/socket on the neck/neckboard, you'll have focus issues...
 
Yes sorry, I misspoke. the focus control doesn't tune it all the way in for me, the picture above is as good as it gets!

I checked the wire running to the socket, it seems to be making good contact. I didn't splice it, i removed it from the socket and pressed the new one back in then snapped the plastic piece back over it all to hold it in like it's supposed to be.
 
hmm... odd one for sure...

is the neckboard on straight?? It should not be on the back of the tube crooked.

i had a k7000 once that looked all goofy after repairs. It turns out the plastic "guide" on the tube was broken off and i had the damn neckboard plugged on 1 pin off( the pin seperate form the rest was bent!!!!!!!!) Thats pretty unlikely but worth checking out.

Id check the neckboard, make sure you hooked the ground wire back up to the neckboard properly, and again recheck that focus wire.

I guess its possible that you got a krap flyback but ive never seen one doa before(with the exception of a cheap krappy suction cup that split and caused arcing )

I'd also double triple check and make sure you have that red anode wire properly inserted in the tube(after discharging of course)

also look over that chassis and neckboard good for krappy solder joints, (especially around the large resistors/yoke plug area.) Make sure you didnt crack one of the traces/board while removing the old fly..
I did that once... somtimes you gotta wrestle them out so its worth checking out just to make sure.


I guess its also possible theres someething wrong with the tube but i doubt it.

Also where/how did you hookup the other small red wire on the flyback??????

Good luck!
 
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On the two smaller wires that come out of the fly, (not the 2nd anode wire) make sure the thicker of the two is connected directly to the tube socket on the neckboard and the thinner of the two is connected to the neck circuit board. If the two wires are backwards, your screen and focus will be way off!

I've had replacement fly's with the color of the two wires opposite from the original fly, but I don't recall if the K71's were like that. Still, easy to check by wire diameter. Thicker wire is screen/G2, thinner is focus.


D
 
I've looked and looked for bad solder joints, but i'll keep looking. The neckboard is definately on straight, I checked several times for bent pins and such. The suction cup is in good too on the anode. The red wire I did splice because the connector plugs into the neckboard, so I cut, soldered and wrapped the splice. The tube's fine because it works with the other board installed. The ground wire is spliced together and soldered, then wrapped as well.
 
On the two smaller wires that come out of the fly, (not the 2nd anode wire) make sure the thicker of the two is connected directly to the tube socket on the neckboard and the thinner of the two is connected to the neck circuit board. If the two wires are backwards, your screen and focus will be way off!

I've had replacement fly's with the color of the two wires opposite from the original fly, but I don't recall if the K71's were like that. Still, easy to check by wire diameter. Thicker wire is screen/G2, thinner is focus.


D

The colors seem to line up. the thicker is black, as the old one was, and connected to the tube socket... the thinner is red, as the old one was, and connected to the pcb.

Oh and also, the focus pot DOES work, it just doesn't even come close to adjusting it all the way in.
 
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