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CRT (Makvision) image is a large bluish blob. Dead, or repairable?
Baldbull:
Makvision/Weiya M2929D4G-TS
Tube A68EMN021X121
The monitor powers on and displays an image for a few moments.... the image quickly morphs into the images I've included. Any ideas?
SOLVED - There was an intermittent short in the picture tube between the blue pin and heater pin(s).
grantspain:
looks like blue gun is full on, could be drive transistor or tube- desolder blue gun pin on crt socket to prove
the red blob is either down to requiring a degauss or the purity rings are set wrong
Baldbull:
--- Quote from: grantspain on June 05, 2020, 04:01:47 am ---looks like blue gun is full on, could be drive transistor or tube- desolder blue gun pin on crt socket to prove
the red blob is either down to requiring a degauss or the purity rings are set wrong
--- End quote ---
Here's another pic... Depending on how long it sits or your viewing angle, can like slightly different.
On this one, you can see the edges come in a bit.
grantspain:
looks like more than one issue to me, if that discolouration does not go with degaussing then its either the yoke moved or purity ring not set correctly or the shadow mask is damaged in the tube
again like i said before the blue gun looks to be fully firing-desolder blue gun pin
Baldbull:
--- Quote from: grantspain on June 05, 2020, 11:22:03 am ---looks like more than one issue to me, if that discolouration does not go with degaussing then its either the yoke moved or purity ring not set correctly or the shadow mask is damaged in the tube
again like i said before the blue gun looks to be fully firing-desolder blue gun pin
--- End quote ---
The monitor had not been moved since installation many years ago.. if that's any help.
It was working fine.. until one day.. it simply wasn't.
Once powering up.. there is image for a moment.. then it slowly morphs into what you see above.... takes 5-10 seconds. The image may influence the colors displayed a bit -- the actual image displayed is mostly blue.
Degaussing has zero effect.