One input is oversaturated on PVM-20L2

[BazookaBen]

I just picked up a PVM-20L2, which has one built in RGB input, and an RGB input in an expansion slot (called Option 1 on the monitor). Video from the expansion slot is WAY oversaturated. RGB is the worst, but component is bad too. I can adjust the chroma knob to fix component video, but the chroma knob doesn't work in RGB mode for some reason.

On the built-in RGB input, RGB looks great. Actually, on that input component mode's color is a little weak, and I have to boost the chroma a little bit. So both video types are less saturated on the input, just RGB is right where it needs to be.

Has anyone seen this issue before? Any clue on a way to fix it?

This isn't a problem with my 20M2MDU, both inputs look identical in all modes. With that I never need to touch the chroma knob.

I'm thinking about taking this back and just getting another 20M2MDU, or an Olympus OEV 203 (which seems to be a rebranded 20M2MDU). My original intention was to rotate the 20L2 with my 20m2mdu so I don't wear out one tube too fast. I thought the 20L2 would be a good one to own since it's a newer model.

[alamone]

I prefer the older M2U model, seems to be more tolerant of variance in sync whereas the L5 model that I tried was very picky. I think the multiformat PVMs have less scan range tolerance.
I don't know about the chroma problem but I never had a problem with my M2U.

[BazookaBen]

L2's are actually 15hz only.

The tube was pretty bright compared to the other L2's I looked at, so I don't think it's worn out. Maybe something's off in the expansion card? I did realize the BNC connectors were bent, like they had been banged up against something. I had to bend them back to get my leads on there.

[Unseen]

I just picked up a PVM-20L2, which has one built in RGB input, and an RGB input in an expansion slot (called Option 1 on the monitor). Video from the expansion slot is WAY oversaturated. RGB is the worst, but component is bad too.

Since you mentioned that the BNC connectors were bent it might be a problem with the input termination? (I could be completely wrong here...)

Usually the termination should be on and auto-disable if something is connected to the output jack, but bending the jack may have damaged that feature. If you have some 75 ohm BNC terminators available (or suitable substitutes) you could try if that helps, alternatively you could check if the picture gets even worse if you connect anything to the output jacks, for example a BNC-Cinch adapter.

[BazookaBen]

usually the termination should be on and auto-disable if something is connected to the output jack, but bending the jack may have damaged that feature. If you have some 75 ohm BNC terminators available (or suitable substitutes) you could try if that helps, alternatively you could check if the picture gets even worse if you connect anything to the output jacks, for example a BNC-Cinch adapter.

I'll give that a shot later. I noticed the connectors were moving a little when I was bending them back in shape. I may have broken one of the grounds.

[BazookaBen]

Fixed it!

Unseen was right. Turns out the BKM 129x module was bent more than I originally noticed, and the solder pads for the R and B signals were broken from the PCB. So that means that terminating the output plugs did nothing, because they are at the end of those broken circuits. I had to scratch away at some of the traces and solder directly to them. Now my picture is perfect again! Identical to the built-in RGB input.

So thanks again Unseen. I'm still curious as to why chroma adjustment is disabled in RGB mode though.

[nyder]

Fixed it!

Unseen was right. Turns out the BKM 129x module was bent more than I originally noticed, and the solder pads for the R and B signals were broken from the PCB. So that means that terminating the output plugs did nothing, because they are at the end of those broken circuits. I had to scratch away at some of the traces and solder directly to them. Now my picture is perfect again! Identical to the built-in RGB input.

So thanks again Unseen. I'm still curious as to why chroma adjustment is disabled in RGB mode though.

Nice work finding and fixing the problem, I think chroma only works for composite and component. Only brightness and contrast work for me on my l2 and 1354Q.

Nyd

[BazookaBen]

Nice work finding and fixing the problem, I think chroma only works for composite and component. Only brightness and contrast work for me on my l2 and 1354Q.

How does component video look on your L2? I have to boost chroma for the colors to look right. It's pretty obvious on my Wii's menu. The blue lines and other colors just aren't as vibrant.

[Ed Oscuro]

Ah, for once the post update announcement (three just while I was composing this!) saved me.

So I'll just change a bit, but the basic idea I still had is the same:

Take a look at the entries in the first and fourth basic menus. The first one should list stuff like Beta 7.5 (I think this setting is more or less explained here) - listed twice on mine. This actually might not be the right setting for what we want, so I'll have a look again later. Overall it's more important to have it look right, though, since the rest of the stuff we're using (including ambient lighting) is hardly reference.

Possibly more important is what's listed in the fourth menu. I believe it should list two RGB systems, and you can change these options. On mine, both are set to the RGB EXT option, though options like COMP INT are possible too (four options total, from combinations of RGB or COMP, and INT or EXT).

I'm looking in the direction of there perhaps being a mismatch between input types somewhere. That said, there's only a single screen for internally setting the options on brightness, contrast, volume, etc. (as distinct from using the front panel knobs) and I wonder that just using two different systems - say COMP INT in one slot and RGB EXT for the other - would really cause this much trouble. But certainly there would be some difference if you have a system set to COMP when you really want it set to RGB. Sometime I'll have to look at a system that really outputs both RGB and component to check for color differences when switching these options.

[BazookaBen]

I didn't really understand half of what was said in that link, but one of the guys mentioned changing the "Comp Level" setting to Beta 0 instead of 7.5. I'd like to try that but there doesn't seem to be a way to change it. Maybe service menu only? I have no idea how to get into that, and I can't find a service manual anywhere.

I'd also like to see if I can change any options on how the L2 handles sync. It's not working well with my Extron RGB right now.

[Ed Oscuro]

Actually, I think the link within the link - leading to Bob Zelin's post here - indicates what that's all about. Probably Beta 7.5 is just fine - it certainly is fine for what I'm seeing - and if you're seeing it then you should be good to go as well. I think Beta 0 is actually a setting for digital Beta DVRs with some weirdness for the digital age.

If anything is important here it would have to be the INT/EXT and RGB/COMP settings.

[BazookaBen]

Ok, that makes sense. Not a big deal, because I can leave the chroma knob set for component video and it has no effect on RGB.

As far as the INT/EXT and RGB/COMP settings go, I have one input set for comp/int and the other set for rgb/ext. Doesn't cause a problem on my other PVM, the M2MDU, when I have it set up the same way. So I have no idea why my L2 behaves differently.

Anyway, do you have a service manual for the L2 series by any chance? Or do you at least know how to get into the service menu? I'd at least like to scroll through it and see what's in there.

[Ed Oscuro]

Try matching the INT/EXT and RGB/COMP settings and see what happens. This is the least destructive of your options, and I'd try it before the service menu. But it does stand to reason that having one dedicated to RGB and one to component should be fine, which is what it sounds like you've done. Maybe it's something to do with the specific inputs you're comparing, or possibly the selection of internal or external?

As for the service menu, I believe it should be the same as outlined in this post -
http://shmups.system11.org/viewtopic.ph ... 95#p886395

[Unseen]

I'm still curious as to why chroma adjustment is disabled in RGB mode though.

That's probably because adjusting the color saturation on an RGB signal directly would require a circuit that converts it to component (YPbPr) and back to RGB. For a component signal changing the saturation requires just changing the amplitude of the two color signals, but if doing the same with all three RGB signals just changes their contrast.