PVM-2030 Pinamp rheostat doesn't do anything

[Derf]

I have a PVM-2030 where the pinamp rheostat (RV552) is not changing the image on screen. Measuring the rheostat with a multimeter, I can observe the value changes properly (e.g. from 5.5kohm to 16kohm). The whole deflection (D) board has been recapped and I've reflowed all the nearby joints in either direction from the rheostat and made sure resistors have continuity.

I am using a SNES hooked up via RGB.

Closest service manual online is the PVM-2130, which is slightly different.
https://ia601508.us.archive.org/0/items ... Manual.pdf (D board on Page 23)

Any ideas?

[fidde_se]

Something wrong with Q1519 (2SC2785) or IC552 (UPC4558C/NJM4558D) maybe? The ic is getting power?
Q553

[Stuararton]

If the rheostat's resistance changes correctly, the issue might be further down the signal path—possibly a failed transistor or op-amp tied to the pinamp circuit. Maybe trace RV552 to its next component and test for proper voltage or signal response?

-Monkey Mart-