Sony PVM display issue

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Retro Mecano
Posts: 2
Joined: Sun Jan 02, 2022 9:25 pm

Sony PVM display issue

Post by Retro Mecano »

Hello,

New to this forum, but my googling during past weeks led me here..

So i got a PVM 20M2E wich had some geometry and 3 Horizontal lines issue. Long story short i recapped the C585 and C572 as recommended in RetroTech videos.

The 3 horizontal lines disappeared. Did further adjustements in service menu, some focus pot tweak and the result was absolutly amazing.

Played happily my Snes through Scart/bnc for 1h or 2.. the the picture just disappeared.. sound still worked.

Restarted, changed the console, changed the input via component, composite, another cable, another machine..nothing. only sound.

Strange thing is that the menu still shows uo perfectly.
The Monitor seems to get a signal when powering on the console, but no display.
Here's what i did so far:

- I followed up the service lenu to reset each value to default.
- recheked all caps on PSU, Neck, Motherboard, I/O board.
- reflowed few solders even knowing they were fine..
- measured output voltage on PSU. Fine. Neck board. Fine..

Spent 2 weeks troubleshouting and i cant figure out what the f*** is going on.

Any help please?

Thanks
Odyssey113
Posts: 9
Joined: Wed Jun 29, 2022 4:15 pm

Re: Sony PVM display issue

Post by Odyssey113 »

Retro Mecano wrote:Hello,

New to this forum, but my googling during past weeks led me here..

So i got a PVM 20M2E wich had some geometry and 3 Horizontal lines issue. Long story short i recapped the C585 and C572 as recommended in RetroTech videos.

The 3 horizontal lines disappeared. Did further adjustements in service menu, some focus pot tweak and the result was absolutly amazing.

Played happily my Snes through Scart/bnc for 1h or 2.. the the picture just disappeared.. sound still worked.

Restarted, changed the console, changed the input via component, composite, another cable, another machine..nothing. only sound.

Strange thing is that the menu still shows uo perfectly.
The Monitor seems to get a signal when powering on the console, but no display.
Here's what i did so far:

- I followed up the service lenu to reset each value to default.
- recheked all caps on PSU, Neck, Motherboard, I/O board.
- reflowed few solders even knowing they were fine..
- measured output voltage on PSU. Fine. Neck board. Fine..

Spent 2 weeks troubleshouting and i cant figure out what the f*** is going on.

Any help please?

Thanks
I'm not sure I have advice to offer as much as I would be curious to ask if you have a picture of these 3 horizontal lines issue? I recently RGB modded a 27S42 tv and I have an issue that sounds similar to what you're describing, having three horizontal lines across the screen, however the issue is very subtle and can usually only be seen on pure white or light grey screens. I've also verified that the issue exists even on my composite only signal so I can kind of assume it's not to do with the mod itself, although I honestly didn't test much on this TV before I modded it.

I uploaded a picture to show where the lines appear on my tv, just drawing in the location since it's hard to say i'll even be able to capture them on screen.

https://imgur.com/a/53zkoSf

I'm just trying to identify if my issue is a cap issue, since it sounded like that initially fixed your problem.
fernan1234
Posts: 2175
Joined: Mon Aug 14, 2017 8:34 pm

Re: Sony PVM display issue

Post by fernan1234 »

Retro Mecano wrote:Strange thing is that the menu still shows uo perfectly.
The Monitor seems to get a signal when powering on the console, but no display.
Well the good thing is that you don't have a dead tube, and you still get a raster so that rules out a lot of things related to the neckboard, flyback, power.

Sounds like the issue is somewhere in the boards that process all the video inputs. Could it be that a bit of solder landed somewhere and caused a short? I'd do a careful inspection of the motherboard and I/O board, following the traces from the video inputs.

Odyssey113 wrote:having three horizontal lines across the screen, however the issue is very subtle and can usually only be seen on pure white or light grey screens.
If you were only talking about two lines, and especially based on your picture, I would be sure it's just the two damper wires that hold the aperture grille and which are totally normal on Sony/Trinitron tubes. But no idea about why you see a third line across the middle. Either way, that's a totally different matter from the "three line" problem TC had which is three R G B lines that appear on the effective area and with varying distance between them around the top part of the screen, and they're always a sign of failing caps. Normal behavior is for those lines to be close together and in the overscan area.
Retro Mecano
Posts: 2
Joined: Sun Jan 02, 2022 9:25 pm

Re: Sony PVM display issue

Post by Retro Mecano »

I had the same thought actually, so i already checked the coonnection on the motherboard nearby I/O board, and they where fine, no shorts, no extra soldering etc.. i even went to dissolder the whole I/O pcb from the shield and inspect inside for the same problems.

Everything was fine.. my problem is that i dont know how the video input is processed through the chips. There's a lot of them and cannot figure out how to follow up the signal at least with my multimeter. Sadly i do not know how to handle (yet) an oscilloscope and i dont have one.
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