5200 console won't register joystick moves

[shadow460]

OK, here's the deal: I have this 5200 that boots up just fine but it won't register any joystick moves except up and left. It registers left when the stick is pushed all the way down. Pushing left or even centering the stick simply makes the player move up. This affects ports 1 and 2, but I haven't checked 3 and 4. Turning R132, the pokey adjustment pot, does nothing.

 

The controllers work fine on another console. I looked at the service manual and it says to try replacing the Pokey first. I did that and had the same result, so I swapped it back. The next thing it says to replace is the GTIA (U5), then it says to check voltages at Q11 to Q14.

 

What's the likely culprit here? I'd been thinking I needed to trace out the circuit path to R132, but I had no idea the GTIA had anything to do with this.

[ApolloBoy]

Have you checked the pot itself?

[Osgeld]

my rule of thumb is if anything analog and old goes weird check the caps

[shadow460]

I didn't take an ohmmeter to the pot. I did think about that but I just haven't opened the console back up yet. First I have to find another 12 volt power supply.

[ApolloBoy]

my rule of thumb is if anything analog and old goes weird check the caps

The 5200 has very few electrolytic caps in its design so I doubt that's the issue.