Wg 25k7197

splattergatz

Well-known member
Joined
Jun 20, 2008
Messages
5,756
Reaction score
52
Location
Belton, Missouri
WG 25K7197 looks like this. you can see game working in background, barely.

the game is a PLASMA SWORD. never heard of it and i really want to play it.

i think the tube may need to be rejuvenated ????? help please !
 

Attachments

  • uhhh 001.jpg
    uhhh 001.jpg
    92.9 KB · Views: 20
Last edited:
I don't think rejuvenating the tube will help. It looks like the blue gun is stuck on (I think just blue, although maybe green as well). That could be a H-K short in the tube, or it could be a problem on the chassis, usually the drive transistor on the neckboard.

The easiest thing to do is to pull the drive transistor off the neckboard and see if it's still stuck on, or if you lose blue. If it's still stuck on, you've got a short in the tube, if it goes away, you've got a chassis problem, likely that drive transistor. You can also check the resistance from the H to Blue K on the tube... it should be open (or high resistance, check H to Red K to get a baseline value).

If it's low resistance, a rejuvenator won't fix the short, but what you can do is create an isolation transformer for the heater by cutting the traces to the heater pins, then take a wire, wrap it around the ferrite flyback core 2.5 times (I think), then solder each end to the heater pins. This creates a transformer to make ~6.3V AC for the heater voltage, but it's AC coupled, so it doesn't affect the picture. The way it's originally connected, it's DC coupled, causing the gun to be grounded (full on).

Oh, and if the tube is shorted, you should test the transistor as well, since a lot of times the shorted tube seems to take out the transistor.

DogP
 
Have you tried turning the SCREEN voltage down on the flyback ?
Contrast, brightness, etc......

A quick Photoshop cleanup of the pic and it doesn't look so "blue", more of just highly washed out.
 

Attachments

  • uhhh 001.jpg
    uhhh 001.jpg
    92.9 KB · Views: 6
thanks for the replies. i turned it on to try your suggestions and there was a click from the yoke i think and the image is gone.

i ohmed the yoke and it seems to be ok. the flyback looks terrible and i made an order from bob for HOT, flyback etc.

in the meantime i will install new transistors on the neck board, hit all the cold solder joints, etc.

thanks people...
 
Back
Top Bottom