PVM-8040 V. linearity adjustment maxed

[rcboosted]

I hope this is the right place to ask questions about PVM servicing and adjustments.

I picked up a PVM-8040, which is an 8" lower end PVM with no service menu I believe. All the geometry adjustments are done with pots. I pulled up the grid using 240p suite, and the squares at the bottom are shorter than the ones on top. From my limited knowledge, this should be adjusted via vertical linearity adjustment (V.LINE). Well, after maxing it out, it's still shorter at the bottom. I tried playing with vertical center and vertical size with no avail.

There's 1 more setting in the service manual called U/V Size. Which I take it to mean Upper vertical size. So perhaps it can shorten the top of the screen and allow everything to be short and then I can adjust vertical size to bring them back? Problem is, that pot is not populated on the PCB.

So question is, is this a case of degraded capacitor since the pots were maxed out? Can I simply add a pot to the empty spot and gain adjustment that way or is the hardware to do that not even present on this lower end PVM? What else can I do?

 

[Joko3]

Does it look okay when it runs games?

 

[rcboosted]

If it's side scrolling mostly, it looks sort of ok. But vertical shooter or vertical movement makes things shrink and grow as they move around, can be a bit distracting.

 

[Joko3]

That's a bummer. I use one of these little monitors almost every day with my supergun and quite like it. It was supposed to be just a temporary hold-me-over unit, but I'm so used to it now that I don't need anything else at the moment.

 

[rcboosted]

That's a bummer. I use one of these little monitors almost every day with my supergun and quite like it. It was supposed to be just a temporary hold-me-over unit, but I'm so used to it now that I don't need anything else at the moment.

I see it in one of your posts! It seems perfect for testing. Thank you for the shopping service btw, I might have some questions for you later in PM on that if you don't mind.

 

[rcboosted]

Just to close the loop, I recapped the D Board and linearity issue was resolved. I ran into a V lock issue after recapping where it won't V lock and just kept scrolling. Turns out during recap I nicked the D501 diode responsible for V sync. Replacing that fixed the V lock issue.