[solved] Trying to repair a SONY PVM 9042QM

[YaYaLanD]

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.

 

[YaYaLanD]

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.