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 Post subject: pvm 1442qm + rgbpi sync issue
PostPosted: Thu Oct 24, 2019 4:56 pm 



Joined: 09 Jan 2019
Posts: 7
Hi, I'm experiencing a strange problem with this monitor and rasberry + rgbpi. There is an obvious timing problem because the resulting image is distorted and rolls vertically. I am using a bnc rgb + csync to scart which works great on other monitors like jvc tm-h1750gc. Furthermore, the same rgb pi system works great both on 2130qm and on a lower end brother 1440qm, the latter are equipped with scart eu rgb input. Have you any advice?


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 Post subject: Re: pvm 1442qm + rgbpi sync issue
PostPosted: Wed Oct 30, 2019 5:24 pm 



Joined: 09 Jan 2019
Posts: 7
Here is the solutuion.

1) weird but true, the ext sync must be connect to sync Out and not on Sync In as usual, this is on both 1444qm and 1442qm, the R,G,B on " IN" connectors. On front panel must set analog rgb and ext sync.
2)edit the cfg on RGBpi OS for games and os menu, change v.sync pulse from 5 to 0

all fixed!

Tested ps2 (240p/480i) and ps3 (480i/576i) on both 1442qm and 1444qm I confirm that the sync must be connected to ext sync Out connector.


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 Post subject: Re: pvm 1442qm + rgbpi sync issue
PostPosted: Thu Oct 31, 2019 9:17 pm 



Joined: 21 Oct 2019
Posts: 8
Hi,

The reason for sync out socket working and sync in not working is that the sync out socket is a special type that when a plug is inserted, it disconnects a 75R resistor that otherwise links the signal to ground (you can see the inside of the "Out" BNCs look a little different to the others). The actualy connectors are wired directly in parallel - the only difference is this resistor disconnection. Hence I suspect your Pi setup cannot source the current to drive into a 75R load, so by going into Sync Out you are then presenting it with a high impedance load.

Hope this info may be of use to someone somewhere.


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 Post subject: Re: pvm 1442qm + rgbpi sync issue
PostPosted: Fri Nov 01, 2019 7:38 pm 



Joined: 09 Jan 2019
Posts: 7
phosphor wrote:
Hi,

The reason for sync out socket working and sync in not working is that the sync out socket is a special type that when a plug is inserted, it disconnects a 75R resistor that otherwise links the signal to ground (you can see the inside of the "Out" BNCs look a little different to the others). The actualy connectors are wired directly in parallel - the only difference is this resistor disconnection. Hence I suspect your Pi setup cannot source the current to drive into a 75R load, so by going into Sync Out you are then presenting it with a high impedance load.

Hope this info may be of use to someone somewhere.


and you have explained everything perfectly and for this I thank you, you have avoided me to reopen the monitor to make some verifications, I have always supported that the "In "and "Out" were connected. I had purchased some BNC 75 ohm terminator plugs but at this point I think they won't work (they still not have arrive but on the way).
I'm just wondering if using sync on the "out socket" for consoles and rasberry can cause issues or losing something or not in image quality.


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 Post subject: Re: pvm 1442qm + rgbpi sync issue
PostPosted: Wed Nov 06, 2019 7:50 pm 



Joined: 09 Jan 2019
Posts: 7
1444qm have the same issues but on Both ext sync connectors (IN, or Out) , the image cannot be stable by using v. Hold pot and rolling vertically. No sync issue on 1440qm wich have rgb on scart connector.


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