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-

[Derf]

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

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-

I used the linked service manual and a picture someone took of the real 2030 service manual to create this diagram. Red values are values I measured with a multimeter at these points. For the variable resistors, I measured each side.



The only thing that really stands out to me is the two points in the service manual marked +12V and they are not 12V. Also, it appears that cranking either the PINAMP (RV552) or PIN PHASE (RV553, RV554) to one side is not changing the image as expected either. Could IC552 be bad perhaps?

[MKL]

How's the picture width? Narrower or wider than the screen borders? Left and right edges are vertically straight or bowed in (like an hourglass)?

[etb]

I recently had a similar issue with the h-center POT.
I used a continuity tester to find any resistors associated to the POT and check/replace them as well.
The service manual would be really handy about now, I know the UK model is somewhat compatible but there are differences, especially with the input board since it has a scart connector.