[Updated 1/15]Colors configuration and darkness on PVM-20L2

[Nintendude94]

Hello all,

After months of searching in my area for a PVM I decided to take a chance on a relatively cheap 2005 PVM-20L2 on eBay. Upon getting it and hooking up my Genesis, SNES, and PS1 with RGB Scart I noticed that the colors were quite off (first noticed that Sonic looked purple instead of blue) and everything was very dark. I fiddled around in the menus to adjust the color temperature gain and bias.

I'm new to the PVM scene and wasn't really sure what I was doing even after scouring the internet for information. The gain and bias controls can be adjusted for red, green, and blue. These values seem to go up to slightly over 1000, but I have no frame of reference as to where these should be. Right now I have them set between 600-800 for gain and 300-400 for bias. The colors definitely look better than they did when I got it, but a lot of games have an overwhelming reddish tint.

I'm not sure if it's related, but on certain games or in certain areas of a game, the image is so dark it's hard or impossible to see what's going on at all. I have the brightness knob and brightness setting in the menu set as high as they'll go.

https://m.imgur.com/a/CAWU3 here is a gallery of images off the monitor.

As you can (hopefully) see, some games like Ristar look pretty spot on. However, Castlevania 4 is dark and overly red compared to normal. MGS is so dark I can't make out much of anything. Earthworm Jim looks mostly OK, but the tires and the conveyer belt (on right in first picture) are practically invisible.

So does anyone have any advice for me with these issues? Is the image darkness related to the colors? Am I setting any of these values too high/low? Anything I should be wary of? I haven't messed with the innards of the monitor, as that is a last resort for me.

Any help is appreciated! Thank you all!

[SamIAm]

Welcome!

Get yourself the 240p test suite for whatever system you can (Dreamcast is best).

Load up the color bars test.

"Gain" will affect the brightness levels on the right side, while "bias" will affect the darkness levels on the left side. Obviously, you want everything to be balanced and even, including the grey/white as true grey/white and not tinted.

Also note that there should be a general "brightness" control, and you'll want to balance that in as well. The pluge screen is very useful for this.

[kel]

If the brightness dial on the front and the brightness settings in the service menu aren't enough then you will need to open the back up and turn the G2 pot on the neck board. Make sure the monitor is turned off each time you turn it just to be safe. It is very close to lots of high voltage parts and it is just too easy to touch something you shouldn't IMHO. If I remember correctly depending on which way it is turned (too bright or too dark) it will add a red tint to the image so it may solve both of your problems if you are lucky.

[Nintendude94]

Thanks for the responses!

@SamIAm:
I'm familiar with the 240p test suite, but don't have it. It looks like the Dreamcast is the only version I could easily access right now. I currently don't have a way to hook my Dreamcast up with anything other than composite video and I had been adjusting my monitor with RGB prior. Does it make a difference what input I'm adjusting for? I would normally assume that adjusting colors using one input would be good enough, but I noticed that composite allow adjustment of Phase/Chroma and RGB does not; they seem slightly different?

@kel:
Alright. I'll have to pick up a set of ceramic screw drivers. I'm assuming if I do this I should set the brightness knob and service menu brightness setting to thier defaults beforehand?

[kel]

Why would you need some ceramic screw drivers? You only need a Phillips head screw driver for the outer casing screws and a flat head or something similar to pop out the plastic tabs also on the outer casing. Then you can turn the G2 pot on the neck board with your fingers.

Yes you should set everything back to how it was before including the gain and bias settings as turning the G2 pot will hopefully get rid of the red tint also.

[Nintendude94]

Why would you need some ceramic screw drivers? You only need a Phillips head screw driver for the outer casing screws and a flat head or something similar to pop out the plastic tabs also on the outer casing. Then you can turn the G2 pot on the neck board with your fingers.

Yes you should set everything back to how it was before including the gain and bias settings as turning the G2 pot will hopefully get rid of the red tint also.

Oh, ok. I was under the impression that this would be a small metal screw.

I've ordered a component hookup for my Wii and will run 240p test suite with it. Should be able to try this fix Wednesday. I'll update with my results after.

[kel]

Nah, as far as I remember it is easily big enough to turn by hand. You can't miss it, it's almost like a dial. It has an open slot on the top so I used a long plastic ruler to get more precision due to the leverage when looking for that sweet spot.

[Einzelherz]

I would just like to state beforehand that I would only open the set up to get at the insides as a completely last resort.

Your brightness, contrast, and color settings are all probably messed up, considering you touched them yourself without a colorimeter. I did the same thing to my 14L5 trying to chase a too-green screen and subsequently had to buy a colorimeter to get it back to where it should be.

Afaik if you're in RGB/Component, the knobs on the front don't do anything. And they should be all in their neutral (high point) spot when adjusting the set.

Here are my settings for my L2MD on the RGB/Component channel if you want to try them. Write down what you have before changing anything.

Main menu:
Status - Color temp D65, Comp level beta 7.5, ntsc setup 7.5
User preset - Off, contrast 50, bright 0

Service menu:
Signal - Level - Sub bright - 108, (these next ones I believe do nothing on this channel) C level - 27, Y level - 16, Y delay - 0, Sub chroma - 58, Sub phase - 57
Signal - White Balance - Sub contrast 90, Sub bright - 108, Color temp - D65, Gain - R737/G600/B352, Bias - R703/G400/B300

These were calibrated through RGB (which means they are slightly off with a component signal) and specific to my set, obviously, so they may do nothing for you. When you mess with the bias and gain though, try to not adjust green. Once you've set your contrast/brightness, the green channel maintains that level. So if you were to raise green your contrast/brightness would increase.

[22point8]

Green gain should be 700 and green bias should be 512 or 400 depending on model (check service manual). Component level should be n10/smpte unless you are using a betacam deck.

[Einzelherz]

I had to lower my green gain because red had to be too high for D65. And my monitor can't change its comp level.

[Nintendude94]

I will set these values back later tonight. I am a little confused though. When I changed the gain and bias it was through the main menu (not service) with the color temp set to User instead of D65. Won't changing color temp back to D65 set the gain/bias (I'm assuming this since you can't change gain/bias unless color temp is set to User). If that's that case, do I just set the color temp back to D65 and then make modifications in the service menu instead of the main menu?

[kamiboy]

Before all the fancy stuff, did you try a simple factory reset?

[Nintendude94]

Before all the fancy stuff, did you try a simple factory reset?

I have not. If I remember, I've read mixed opinions on this? Is there anything to be wary of when doing it? What all does it reset?

[kamiboy]

If your settings are already fucked then there is nothing to fear, just do it.

[Einzelherz]

If your settings are already fucked then there is nothing to fear, just do it.

If they're truly crap, Kamiboy is right. I didn't think of the factory reset.

[Nintendude94]

After doing a factory restore, everything looks like it did when I first got it. So it's still very red and dark.

http://m.imgur.com/a/vwshx

The darker image is right after the factory reset. In the brighter picture I turned up the brightness/contrast knobs, just so you could see it a bit better.

[kamiboy]

You sure about those SCART to BNC cables you using? Try hooking up your systems using composite and S-Video to see any differences.

If the strange colours persist then your set is damaged somehow.

[mikejmoffitt]

You might want to raise the SCREEN control on the flyback / Neck "C" board, and simultaneously lower contrast.

[SamIAm]

I'm going to second checking all of your cables. That darkness is quite extreme.

If you open up your PVM and start tweaking pots, I humbly suggest taking notes to record where everything was originally. I consistently find that that kind of thing is harder to remember than I anticipate when I start out.

I'd take a long look at any electrolytic capacitors you can see, and carefully scrutinize both the top and bottom for signs of bulging. If the problem is related to a faulty part, it's probably one of these. My BVM is much older than your PVM, but it was loaded with bad capacitors when I got it. Some of them live quite stressful lives.

[Nintendude94]

Composite gave me the same dark/red results. I'll open it up tomorrow and check for damages and try turning the G2 pot. Not feeling too confident it's going to help though.

[Einzelherz]

Semi dumb question: assuming you've maxed out your brightness settings, have you checked that the knob on the front does anything? Just thinking there's a slim chance that it's stuck low?

[BazookaBen]

My guess is that his inputs aren't terminated properly. The outputs and inputs can be damaged in transportation, damaging the termination circuit. That's what happened to the original BKM-129X card in my 20L2.

[Nintendude94]

@Einzelherz:
The two last pictures I posted were with the front brightness/contrast knobs set to the middle and max settings. What do you mean by "stuck low"?

@BazookaBen:
Would it affect the picture that dramatically? Either way, I can order some terminators to rule out the auto termination is/isn't working.

[Einzelherz]

I mean like it's a potentiometer and maybe it's failing? e.g. 50% is actually 1% or something.

And I'm assuming you've tried S-Video and it looks the same as well.

[BazookaBen]

@BazookaBen:
Would it affect the picture that dramatically? Either way, I can order some terminators to rule out the auto termination is/isn't working.

Terminators might work as long as the outputs are fully connected internally.

But on second thought, since you're getting the problem on all inputs, I think termination may not be your problem. But it did really throw off my colors when I had the problem

[Nintendude94]

@Einzelherz:
That's an interesting thought, but I don't know how I'd test for that. I did try S-video with the same result.

@BazookaBen:
I went ahead and ordered a handful of them, but I came to the same conclusion shortly after.

I guess my next step is to open it up tomorrow and see what I can find.

[Nintendude94]

I opened it up, plugged in my Wii with 240p test suite loaded, and started turning the G2 pot. Sadly it didn't make a single difference in the image. Turning it both clockwise and counter-clockwise did absolutely nothing. Here's a gallery of several pictures I took inside:

http://m.imgur.com/a/bavmE

The first image is the G2 Screen pot that I carefully turned with my fingers, although I later noticed there was a hole in the back of the C board to turn the pot with a screwdriver. In the second image I noticed the plastic support for the neck was cracked, so I'm assuming there's some kind of greater damage somewhere. The rest of the images aren't really specific.

The inside was actual pretty darn clean. I didn't see any signs of the capacitors going bad; they looked in great shape (as far as my untrained eye can tell).

Does all that tell anybody anything? Is it hopeless?

[kel]

That's strange. You should definitely see a difference when turning the G2 pot, you wouldn't be able to miss it. For example either so bright that you can even see the retrace lines or so dark that you can barely see anything at all. If the G2 pot doesn't affect the brightness at all then there is definitely something faulty, can't think what it might be off the top of my head though.

I don't think that the plastic support of the neck board being cracked is any indication of greater damage. Those things become very brittle over time and will crack with the slightest movement. The one in my L2 ended up in about 6 pieces. It's more than likely a component gone bad or worst case possibly the flyback transformer gone bad.

EDIT: Maybe you could check the components in the G2 circuit, there's not many from what I can see on the schematic. On board "G" B+ goes to pin 2 on the flyback and then from pin 1 there is a resistor, rectifier diode, capacitor. Then on board "C" there are two more resistors a capacitor and the G2 pot although not in that particular order.

Also inside the Plastic CRT neck connector on the "C" board there are some shorting plates with a gap in between. Not sure what they are or what the proper name is off the top of my head, I am guessing they are some kind of safety measure for the CRT in case for some reason there is a fault and the voltage becomes too high it can then arc across the gap but don't quote me on that. If you carefully unclip the top of the connector and pull it off you can easily check that they are not touching or shorted for any reason. Once when putting it back together I accidentally bent one which made it short. I can't remember what the symptoms where now, could have been a loss of brightness similar to yours, not sure now but I knew what I had done straight way and re-opened it and bent it back into place. If you do attempt this then just bear in mind that when removing the neck board from the CRT neck the plastic support that you mentioned earlier will probably fall to pieces like mine

[mikejmoffitt]

I opened it up, plugged in my Wii with 240p test suite loaded, and started turning the G2 pot. Sadly it didn't make a single difference in the image. Turning it both clockwise and counter-clockwise did absolutely nothing. Here's a gallery of several pictures I took inside:

http://m.imgur.com/a/bavmE

The first image is the G2 Screen pot that I carefully turned with my fingers, although I later noticed there was a hole in the back of the C board to turn the pot with a screwdriver. In the second image I noticed the plastic support for the neck was cracked, so I'm assuming there's some kind of greater damage somewhere. The rest of the images aren't really specific.

The inside was actual pretty darn clean. I didn't see any signs of the capacitors going bad; they looked in great shape (as far as my untrained eye can tell).

Does all that tell anybody anything? Is it hopeless?

In every PVM I've opened, the G2 control is on the neck board. The two controls on the flyback might be separate H and V focus.

[Nintendude94]

Update! So I took my monitor into a local-ish shop for repair and it was indeed an issue with the bias circuitry. My monitor is the correct brightness and the redness seems to be gone now!

I do have a couple more questions though.

The monitor has some kind of chromatic aberation going on (small strip of red/blue on the right/left of everything). This sounds like it might have to do with the focus on the monitor. There are Focus controls in the service menu, but they don't seem to do much. How do I go about adjusting this?

Secondly, the picture doesn't fill the whole screen. This seems to vary among different consoles. There are controls in the service menu to adjust the geometry, but I'm not exactly sure the correct way to do it. With a grid pattern up, are the red parts of the grid supposed to be showing? Should I be doing this on underscan or overscan mode? It also seems to vary between inputs; composite and RGB signals are displayed differently. When I adjust geometry on one input will it affect the other?

Any input is appreciated! Thanks!