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YaYaLanD

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Hello !

i bought in october 2019, 2 9“ sony 9042QM PVM.
One was always black and white. I managed to solve the problem after a deep cleaning and some soldering reflow here and there where the solders were looking suspicious.

the other one has a screwed image on the left and right side with some king of wiggling on the sides.
The wiggling is more and more visible if i turn brightness all the way up. And tends to disappear but not completely, when the brightness is very low.

please take a look at the picture.

what i tried so far.

i swapped the B board and the D board from the working unit to the non working one.
nothing had changed.

please refer to the attached link for the service manual
https://www.manualslib.com/download/1282003/Sony-Trinitron-Pvm-8042q.html


as per the manual, D board deals with
H oscillation freq, screen phase, H/V BLK, H/V deflection, H/V delay, while B bord deals with primary colors matrix, burst gate width, VXO, NTSC/PAL/SECAM, chroma pulse.

When i swapped the boards, the working unit had still its beautiful Picture.

now i start thinking that the P board which contains the EHT has a problem. Maybe the EHT itself ?

do you guys can give me a path to follow ?
Can i swap P board to test ? Isn’t it dangerous for the tube ?
What should i do next ?

i didn’t touch any Of the potentiometers.

thanks for any comment or any help.

5bokK3d.jpg


xMlw0pv.jpg
 
Repair done. The filtering capacitor was dead. This was causing the electron beam to wiggle as seen in the pictures.

i did a full recap.
 
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