Two different issues with Sony PVM's (14N1U)

[chuckster]

Hey guys, I recently hit up a local TV station, and I am getting quite a few PVMs over the next few days. I have three as of now (A PVM-1380 from 1993 as well as the two PVM-14N1U models, both mfg. March 1997), and both of the latter have issues with the picture, hoping you can help.

The first has green flickery dots when I connect a straight RCA>BNC connector. I have tried on the SNES, GC, and Dreamcast. I have also verified both input lines have he issue.

It looks like this:

S-video oddly enough removes the dots, but pus a green wavy line beside some graphics. Don't have a good photo of that.

The second has more of a general color issue, but I haven't been able to fix it with the menu system, or with a factory reset. This picture is noticeably more yellow, and somewhat dimmer than the first, or the JVC monitor I use as reference. I think it's more of a color temp issue than just a weak tube (which the 1380 has), it looks like this (ignore the gunk on the screen, I haven't cleaned them in my haste to test):

Any way to correct the color temp/shift? Maybe an internal pot or through a more advanced menu? This seems like an easier fix than the first issue.

I am excited to get the PVMs, the JVC monitor I got is only 13", but works flawlessly. I hope I can get these Sony's up to snuff. I am hoping to get about 8 more of these in the next couple weeks. Any information on general repair and restoration would be very much appreciated.

[Anapan]

It looks like your sync is coming through the Green channel (Sync on green) and causing problems. You may need an in-line sync stripper/cleaner (LM1881). There are 2 pre-built sync strippers/cleaners that I know of (or you just buy the LM1881 chip yourself and build the circuit from scratch):

http://retrorgb.com/store.html - Sync in SCART board (needs a +/- 5V 5-10Ma power source - USB type power)

http://arcadeforge.net/Scaler-and-Strik ... e::15.html - Sync Strike comes with a power source and runs through a SCART interface to provide a separate sync source.

On your PVMs these are the black external sync inputs when you pump the signal into their BNC connectors.

I have two of the RetroRGB circuit boards that I've never used. I got the problem solved with a dual female SCART coupler that I soldered a USB adapter into SCART pin8 using a Retro Gaming Cables sync stripper Framemeister adapter. I'd be happy to send one of them for cost of shipping.

[chuckster]

Hey there, I appreciate the info, are you sure it's a sync issue, since only one monitor exhibits a unique issue? I figured that any issue like that would affect both monitors.

Also, I was considering this cable for RGB output from my Genesis (https://www.retrogamingcables.co.uk/gam ... -rca-sound) and would supposedly use one of these to connect to the monitor (https://www.retrogamingcables.co.uk/fem ... m-monitors), but my issue is I only have one BNC connector per line on each of the four monitors I received, though the cable seems to breakout into four connectors for RGB+Sync. Do I need 3-4 BNC connectors for RGB? Am I stuck with composite/S-video if I only have on per line?

[theclaw]

The purest form of RGB isolates each signal. On PVMs you'll see a row of separate BNC plugs for red, green, blue, and sync.

So yes, that's correct. 14N1U is not an RGB monitor.

[Anapan]

No, I'm not sure it's a sync issue, just my best guess. It just looks like problems I've had before with combined sync on a couple of displays.

Those cables should do what you want - I'd recommend going with the CSYNC option rather than the Composite+sync cable for the Genesis one.

[chuckster]

The purest form of RGB isolates each signal. On PVMs you'll see a row of separate BNC plugs for red, green, blue, and sync.

So yes, that's correct. 14N1U is not an RGB monitor.

Well Foohey! Thanks for that, beggars can't be choosers I suppose, so the hunt continues! I really like the picture I get from these little guys, the one that works well is better than my 20" flat Sanyo CRT without calibration! I think 20-24" is the sweet spot for decent size and the space taken up by a CRT anyway. I hear that PVMs over 20" begin to lose a bit of consistency in build quality. I will use these guys as test subjects for figuring out the service menu and which pots do what (I can only find distantly related service manuals so far). I was able to adjust a few things that improved each monitor by opening it up and tweaking a few pots already.

No, I'm not sure it's a sync issue, just my best guess. It just looks like problems I've had before with combined sync on a couple of displays.

Those cables should do what you want - I'd recommend going with the CSYNC option rather than the Composite+sync cable for the Genesis one.

Thanks for the CSYNC tip. I think that may be the case since with S-video (which appears to carry sync as well), the problems are cleared up. I will have a true RGB monitor soon though, I'm on the hunt. I will pick up the CSYNC cable when the time comes though, as per your tip.

I am becoming very interested in displays now that I have began working on the inside of these PVMs, I really want a Commodore 1701 to compare these to, since it's size is comparable. Also looking into a HD Trinitron/Diamondtron/Sonictron PC monitor for PC emulators. I figure this is easier (if more expensive) than running the PC to a CRT TV.

[theclaw]

No, I'm not sure it's a sync issue, just my best guess. It just looks like problems I've had before with combined sync on a couple of displays.

Those cables should do what you want - I'd recommend going with the CSYNC option rather than the Composite+sync cable for the Genesis one.

How would that work? The monitor has no csync input jack, only composite and s-video.

[Anapan]

Ohhyeah, without a sync-stripper it's the wrong cable . I did not actually look these monitors up (saw PVM and have had similar-looking issues with fully equipped RGB and YPbPr displays). Then thinking to which cable I bought while having a powered -inline sync stripper because it was the final solution for my XRGB setup... I was just actually drunk-posting on my phone. I'm by no means an expert but with enough beers I can think I am.