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 Post subject: PVM 1444QM how to fix vertical bowing problem
PostPosted: Fri Mar 13, 2020 2:59 am 



Joined: 20 Nov 2019
Posts: 34
Location: Australia
Hi all,
I recently got a 1444QM pvm which was supposed to be perfectly working but arrived with a bowing problem down the right hand side.

From searching around i'm told this can be corrected via the service menu or adjustable pots.
This set has no osd or any kind of service menu but does have adjustable pots inside.

These are shown on page 18 of the service Manuel here.
https://www.manualslib.com/manual/12736 ... 444qm.html

I'm hoping the answer is obvious, i'm new to pvms and have only really worked with consumer crts so far.

Thanks

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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Fri Mar 13, 2020 8:16 am 


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Joined: 04 Sep 2013
Posts: 291
Location: Portugal
Looks like a "pincushion" problem.

If you try the 505 potentiometer you should be able to fix it. Try 509 also (depend on how the rest of the image look like, can't tell by your Picture)


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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Fri Mar 13, 2020 11:23 am 



Joined: 20 Nov 2019
Posts: 34
Location: Australia
_rm_ wrote:
Looks like a "pincushion" problem.

If you try the 505 potentiometer you should be able to fix it. Try 509 also (depend on how the rest of the image look like, can't tell by your Picture)


Sounds promising.
Here's some test pattern photos showing the problem better. Let me know what you think and ill try making the adjustments. Ignore the bad picture quality on screen, it's just a poor composite connection as that was all i had at the time.

Image

Image

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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Tue Mar 17, 2020 11:01 pm 



Joined: 20 Nov 2019
Posts: 34
Location: Australia
Ok I adjusted RV505 and corrected the pin cushion problem but the picture is also off centre as seen in the photos. RV502 H. CENT should be able to correct this but for some reason it's in a hard to reach spot under the tube. Why would it be in such a difficult spot? There's no way it'd be safe to adjust it while the tv is running. Even the main set of potentiometers aren't particularly safe sitting right next to the flyback. Are you not supposed to not have the tv running when making screen adjustments like this??

https://www.manualslib.com/manual/12736 ... =18#manual


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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Wed Mar 18, 2020 1:17 am 



Joined: 02 Feb 2005
Posts: 322
Perhaps it's possible to withdraw the board (or the tray it's on) a little for a more comfortable access. In any case don't try to adjust it with a metal screwdriver or this is what will likely happen:

https://www.reddit.com/r/crtgaming/comm ... urning_on/
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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Wed Mar 18, 2020 8:38 am 


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Joined: 04 Sep 2013
Posts: 291
Location: Portugal
MKL wrote:
Perhaps it's possible to withdraw the board (or the tray it's on) a little for a more comfortable access. In any case don't try to adjust it with a metal screwdriver or this is what will likely happen:

https://www.reddit.com/r/crtgaming/comm ... urning_on/


Exactly this!

Usually pro monitors like PVM's have this possibility for easy access.

Make sure you test if this is possible with the monitor off and don't take any chances while it's on.


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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Wed Mar 18, 2020 11:01 am 



Joined: 20 Nov 2019
Posts: 34
Location: Australia
Great thanks guys. I managed to slide the board out a few inches and adjust it using a flat head i wrapped in electrical tape. I turned the tv off each time i turned it. Only one geometry problem left but i don't think i can fix it without affecting the rest of the screen.

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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Tue Mar 24, 2020 10:46 pm 



Joined: 09 Jan 2019
Posts: 13
You should replace just few caps near the flyback on deflection area and Pin Amp and this sort all your issue...It is an easy board, not doublesided i will report the caps and theyr position if you need. I must check on my monitor.


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 Post subject: Re: PVM 1444QM how to fix vertical bowing problem
PostPosted: Sun Mar 29, 2020 7:52 am 



Joined: 20 Nov 2019
Posts: 34
Location: Australia
Leoraider wrote:
You should replace just few caps near the flyback on deflection area and Pin Amp and this sort all your issue...It is an easy board, not doublesided i will report the caps and theyr position if you need. I must check on my monitor.

Thanks. I am just trying to work out which caps you mean.

Is this the spot on the main board A?
https://www.manualslib.com/manual/12736 ... =37#manual

This page onwards shows the schematic for the board A
https://www.manualslib.com/manual/12736 ... =42#manual


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