Sony PVM-M2U20 Blinking/Flickering Screen

[Rock Man]

The TV in question is a Sony PVM M2U20.

Tried the BNC + sync stripper to Female SCART with SCART switchers, Saturn, SNES, and Playstation I kept getting a bouncing screen for everything except for SNES and 3DO! (3DO is in S-Video) Looks like it's a problem restricted to RGB. For Saturn I tried two different RGB SCART cables including one with CSYNC yet the problem persisted. I've notified the seller about this awaiting a response.

https://www.youtube.com/watch?v=gb3Cd9w ... e=youtu.be

What do you guys think though?

I feel like there's a setting in the service mode I can tweak or adjust to stop this. Other Sony TV's had the same issue but if you enter SSMD from the Service Menu and adjust some numbers it fixes it. The problem is there isn't a setting on my PVM labeled SSMD so I have no idea what to look for. No sense in going into Service mode to make adjustments if I have no idea what to look for that would be like shooting in the dark. I could really use you guys help on this one.

[buttersoft]

What model PVM? 1952Q? 20M2U? From memory the models that look like yours don't have have a v-sync dial on the back like the 194X series did... which seems to be where your issue is. Horizontally the picture is holding fine, but it's rolling vertically. Is there any other way to adjust V-hold (or V-freq, or v-sync) perhaps through the service menu?

I'm also confused by the playstation working and then not working. It works by itself, but fails to sync through your SCART switch? Is that what you're showing us in the vid? In which case the problem would seem to be related to your scart switch, no?

What happens when you use composite video for sync?

[Rock Man]

What model PVM? 1952Q? 20M2U? From memory the models that look like yours don't have have a v-sync dial on the back like the 194X series did... which seems to be where your issue is. Horizontally the picture is holding fine, but it's rolling vertically. Is there any other way to adjust V-hold (or V-freq, or v-sync) perhaps through the service menu?

I'm also confused by the playstation working and then not working. It works by itself, but fails to sync through your SCART switch? Is that what you're showing us in the vid? In which case the problem would seem to be related to your scart switch, no?

What happens when you use composite video for sync?

Hi,

This was the SSMD fix I mentioned earlier. It's for a different TV than mine but maybe relevant? The guys TV appears to have the same symptoms as mine.

https://www.youtube.com/watch?v=ZT5ariz5-X0

My TV model is a Sony Trinitron PVM M2U20. I don't believe it has a V sync switch in the back. I will look for V-hold/freq/sync in the in the service menu. Don't recall seeing either of those last time but I'll give it another look. It's true, the PVM rejects my PS1 SCART cable when connected to my Keene Commander SCART switcher but detects & accepts that same cable when it's hooked up raw. Appears to be an isolated case because the PVM let's me play Super Nintendo using that SCART switcher. We can rule out the SCART switcher not working at all with the PVM otherwise it would have rejected all 3 of my consoles SNES/Saturn/PS1 but it accepted 1 of 3.

EDIT: Posted a video of everything I recorded in service mode. I will add it to my first post in the thread. I did find V Hold. Going to mess with it now.

Service Mode: https://www.youtube.com/watch?v=xZ6ljOO ... e=youtu.be

EDIT: I found V Hold tried toying with the numbers it didn't do anything. Apologies for the lighting in the middle, you can still make out the text from the menu.

[buttersoft]

Not good to hear the v-sync adjustment did nothing.

The problem still looks like your SCART switch to me. I understand that the SNES always works, even through the switch, but the problem is not black and white. Different consoles output sync slightly differently, at slightly different levels and timings with different shapes to what should be a square wave. The SCART switch is messing with something, and that slight difference is fine for the SNES, perhaps due to the way it outs sync, but it's reshaping the PS1 sync pulses enough to be a problem. I suppose this doesn't rule out a slightly unusual PS1 SCART cable but those have no components on the sync line IIRC (luma or composite video line). And i it's possible the PVM is aging - you could try recapping the vertical deflection area, but TBH i reckon you'd be chasing ghosts.

It's true, the PVM rejects my PS1 SCART cable when connected to my Keene Commander SCART switcher but detects & accepts that same cable when it's hooked up raw. Appears to be an isolated case because the PVM let's me play Super Nintendo using that SCART switcher. We can rule out the SCART switcher not working at all with the PVM otherwise it would have rejected all 3 of my consoles SNES/Saturn/PS1 but it accepted 1 of 3.

[Rock Man]

Not good to hear the v-sync adjustment did nothing.

The problem still looks like your SCART switch to me. I understand that the SNES always works, even through the switch, but the problem is not black and white. Different consoles output sync slightly differently, at slightly different levels and timings with different shapes to what should be a square wave. The SCART switch is messing with something, and that slight difference is fine for the SNES, perhaps due to the way it outs sync, but it's reshaping the PS1 sync pulses enough to be a problem. I suppose this doesn't rule out a slightly unusual PS1 SCART cable but those have no components on the sync line IIRC (luma or composite video line). And i it's possible the PVM is aging - you could try recapping the vertical deflection area, but TBH i reckon you'd be chasing ghosts.

It's true, the PVM rejects my PS1 SCART cable when connected to my Keene Commander SCART switcher but detects & accepts that same cable when it's hooked up raw. Appears to be an isolated case because the PVM let's me play Super Nintendo using that SCART switcher. We can rule out the SCART switcher not working at all with the PVM otherwise it would have rejected all 3 of my consoles SNES/Saturn/PS1 but it accepted 1 of 3.

So I found another Saturn SCART cable in my basement that actually worked when connected raw however failed once I hooked it up to the switcher. What should I do? I refuse to connect and reconnect my switchers one at a time when I want to play them. I play my retros on the regular, so playing without some kind of switcher or going back to my 1080p VIZIO & XRGB-Mini to play retro consoles on my switches is a non-starter. Once I've tasted that CRT goodness I don't wanna go back! What are some options moving forward? The guy from ebay said the Female SCART to BNC adapter + sync strip extracts a 5v charge from the SCART cable. Do you think my Saturn and PlayStation leads lack that voltage?

I'd like to make the best out of what I bought and utilize that BNC cable. If all that needs to happen is to replace the cables I'm slowly coming around to that argument. However if the issue lies with the consoles themselves and the way they deal with sync? I don't know what to do.

[buttersoft]

Just remember that to a certain extent this discussion is academic. Remote diagnosis in this case is going to prove very little. If i had to pick the most likely fault, i'd go for the SCART switch for sure, but that doesn't mean a new one is automatically going to fix your problem. Ideally you want a second known-working PVM or different SCART switch to try things out, but you may not have that opportunity, i realise.

[Rock Man]

Just remember that to a certain extent this discussion is academic. Remote diagnosis in this case is going to prove very little. If i had to pick the most likely fault, i'd go for the SCART switch for sure, but that doesn't mean a new one is automatically going to fix your problem. Ideally you want a second known-working PVM or different SCART switch to try things out, but you may not have that opportunity, i realise.

I do have a third switcher, my shinybow. It needs a power supply though, once I order that I will test on the pvm. I wish the answers here were clearer. Appreciate your help btw.

[Rock Man]

Update on the PVM crisis. It was the stripper. Turns out all I needed was the normal female SCART/BNC adapter without the stripper. Sucks because the consoles/cords the strip cable did work on added slightly more contrast. If I can source cables compatible with the sync stripper SCART BNC cable that pulls 5v from the consoles SCART I wouldn't mind replacing all my SCART cables with that.