PVM-20M4U Screen Troubles

[StarmanJSP]

Hello all,

I bought this thing of beauty last summer and had no problems with it whatsoever until this past Saturday. I was in the middle of some PS1 gaming when these black blobs suddenly pop up in both corners at the top of the screen, mildly squishing the picture. After I turned it off and left it alone for a little over an hour, this is what happens whenever I turn it back on.

https://youtu.be/b-NNoShaqco

After a couple of minutes, the screen settles down into these two curved black borders.



After a minute the borders split and slowly recede into the corners until the bottom clears up and the top goes back to the way it was when the black corners first appeared.



Does anyone have any idea what's causing it and if there's anything I can do to fix it?

[xAzurexEonx]

Any help is going to be very lacking here, as most everyone got their sh*t done and won't advise others.


If nothing got pumped out of place, this could be something as some caps going bad. Since you've been using it with no issues this seems the most likely case. Which is rather good, aside from trying to figure out which cap(s) are going bad. Maybe you'll get lucky and you'll be able to visually see it discolored or bulging.

[DejahThoris]

Have you tried other sources and at least made sure it's definitely the PVM and not the PS1 or cable? Always a good place to start.

[Dochartaigh]

Any help is going to be very lacking here, as most everyone got their sh*t done and won't advise others.

Wow, 7 posts and you're been here for how many weeks? and you're already talking shit on the members? Please grow up or stop coming to this super nice, friendly, and knowledgeable forum - we don't need bitter people like you around.



OP, sorry to thread crap, and sorry I can't be of much help (besides the regular comment of "recap everything" to see if it helps). This forum is my go-to when I need a technical question answered – it's just that not many people were TV repairmen in their past lives so detailed information on how to fix these can be hard to find ANYWHERE online. If you have no luck, my only advice is to find a local TV repair place which has older employees who know how to work on CRT's, or perhaps even a dedicated arcade group in your area might be of some help as they're at least used to common problems with CRT monitors. KLOV forums are also known to be very technical (more so for arcade cabs, but lots of PVM users there as well).

[xAzurexEonx]

Any help is going to be very lacking here, as most everyone got their sh*t done and won't advise others.

Wow, 7 posts and you're been here for how many weeks? and you're already talking shit on the members? Please grow up or stop coming to this super nice, friendly, and knowledgeable forum - we don't need bitter people like you around.



OP, sorry to thread crap, and sorry I can't be of much help (besides the regular comment of "recap everything" to see if it helps). This forum is my go-to when I need a technical question answered – it's just that not many people were TV repairmen in their past lives so detailed information on how to fix these can be hard to find ANYWHERE online. If you have no luck, my only advice is to find a local TV repair place which has older employees who know how to work on CRT's, or perhaps even a dedicated arcade group in your area might be of some help as they're at least used to common problems with CRT monitors. KLOV forums are also known to be very technical (more so for arcade cabs, but lots of PVM users there as well).

haha man oh man. if ever this comment was predictable.

I have 2 20M4Us (1 good, 1 now bad) and when geometry issues arose recapping (not "everything") corrected the issue, so at least I'm advising from experience.

won't even get into all your additional asinine reasons that do not pertain to the fact there has been a massive drop off after the vets got their stuff done. having the only option to hopefully hit a keyword on google search or hunt through pages upon pages to get your answer, since older OPs didn't have the wherewithal to update for those in the future.
you ASSumed I'm new, never needed an account. as I've always dug for most of my info for hours upon hours. you can have the last word on this subject if you wish.

apologizes OP.

[DejahThoris]

I have 2 20M4Us (1 good, 1 now bad) and when geometry issues arose recapping (not "everything") corrected the issue, so at least I'm advising from experience.

Doesn't look like a geometry issue, it looks like a sync issue. Geometry doesn't roll and eventually stabilize. You're advising about an unrelated issue.

And your attitude *is* bad, it's not just one dude's interpretation. Your second post proved it. We have a lot of good tech people on here, and having a bad attitude toward them only serves to drive them away. Please keep to helping OP.

[StarmanJSP]

Thanks for the replies so far, guys. I edited the original post so the pictures I took showed up properly.

To answer DejahThoris's question, I also tried turning on NES and SNES and the screen still has the same distortions. All of my systems, however, are plugged into a system selector which plugs into the PVM with an RGB to BNC cable. Unfortunately I don't have a way of plugging individual system RGB cables into the monitor (I'd need a female RGB plug to BNC which I don't have at the moment), but I just realized I can try using an S-video cable to see how that looks. I suppose it could still be the cables I'm using rather than the PVM itself.

If not, I'm a little afraid to find out how much a local TV repair shop will charge to fix the problem (if it can be fixed), but it may be totally worth it.

[DejahThoris]

but I just realized I can try using an S-video cable to see how that looks.

I'd be interested to see how that turns out. Then at least if it persists you can say "It's definitely the PVM".

If that fixes it, you've got some more narrowing down to do .

[Bratwurst]

From my experience with CRTs, any display that had an issue that either eventually self corrected or shifted over time, suggests that a cap is out of value and eventually warms up closer to its original spec.

[StarmanJSP]

So I didn't actually try the S-video in, but I turned on just the monitor without any of the game systems turned on and just tried navigating the menu on the default "no sync" black background and it was still wonky.

Tomorrow I'll look around and see if there are any local repair shops that are willing to look at this beast.

[xAzurexEonx]

I have 2 20M4Us (1 good, 1 now bad) and when geometry issues arose recapping (not "everything") corrected the issue, so at least I'm advising from experience.

Doesn't look like a geometry issue, it looks like a sync issue. Geometry doesn't roll and eventually stabilize. You're advising about an unrelated issue.

And your attitude *is* bad, it's not just one dude's interpretation. Your second post proved it. We have a lot of good tech people on here, and having a bad attitude toward them only serves to drive them away. Please keep to helping OP.

I did not advice it being a geometry issue. I stated that my comment was not the "recap everything" comment as other user inferred, because I specifically recapped those that affect that issue.

It might look like a sync issue, however you can still see the image. *Most* (pretty much all examples I've seen and experienced) you can not see a distinct image, here you can. Looks far more like a V-hold if we were just going to start throwing out guesses. SO looking for visible damage is not a bad idea.

If you weren't biased yourself you would of easily understood that. You can easily see many unanswered posts and once again you gloss over the rest of my statements, that while info is here, questions are answered, it is buried because once they got what they needed they left. Just because I have a counter viewpoint with reasons I have them makes me bad huh? Pretty much the gist of that second post, that you've proclaimed proves my attitude *IS* bad. So how about YOU keep to helping OP(s) aswell?

[xAzurexEonx]

From my experience with CRTs, any display that had an issue that either eventually self corrected or shifted over time, suggests that a cap is out of value and eventually warms up closer to its original spec.

Agreed. Only reason I suggested the caps check. Especially since he still has a complete image signal (while unstable).

It could even be the caps that go with the "pin amps" + "sexy" etc. So hard to suggest exact but caps can have some tell signs of damage and are very cheap.

[buttersoft]

It could even be the caps that go with the "pin amps" + "sexy" etc. So hard to suggest exact but caps can have some tell signs of damage and are very cheap.

That doesn't look right for geometry, so not pinamp- or sexy-related. The second pic does look more like a sync issue, as DejahThoris notes. That sort of distortion can be symptomatic of pushing sync range slightly beyond the max the set is designed for, though in this case not, obviously. I've also seen it when combining H- and V-sync from a PC outputting 15kHz, and varying the value of resistors in the two lines before combining.

I won't claim to know what exactly is causing it here, but after inspecting for obvious damage, the first thing i would do is try a 1k linear potentiometer in the sync line before it hits the set. Total ghetto fix, and probably won't do anything, but worth a shot, especially if OP can get it done for about $10 or less by someone. Have them make up something that plugs in between the cable end and the PVM - that way you can remove it again. If you're using RGB or another source with a separate sync line, this is. If not, it can't be done this way. It may also be a temporary fix, if whatever is causing the problem now drifts further.

[StarmanJSP]

Thanks for the suggestion, buttersoft.

I do happen to know someone who is electronically inclined, but unfortunately when I approached him about my situation and whether or not he could whip up a potentiometer plug, he simply said I'd be better off just junking my monitor and buying a 4k TV (NO!).

I also wanted to share an observation I made today that will hopefully help narrow down what the issue might be. Those goofy black bars in the corners disappear entirely if I switch the PVM to 16:9 mode.

The picture in full screen mode.


The picture in wide screen mode.


It's not a case of the top and buttom borders obscuring the distortion either. In the top corners, it comes down far enough to where it would interfere with the 16:9 picture, but it doesn't.