Sony BVM 20F1E washed out blacks issues.

[Remistewart]

Hey all, I'm having a bit of trouble concerning the brightness of my BVM 20F1E monitor!

This is not to do with the level of contrast (ie. the whites) but literally the brightness (the blacks). When I turn on and leave the monitor running on channel 99 (pure black signal), the screen eventually goes from a rich black to a light greenish-grey over 5-10 minutes. During this time I have the brightness set on minimum to ensure I'm getting absolutely no signal. I specifically went into the internal signal to check it wasn't a problem with my console cable set up.

Despite this the rest of the settings seem perfect. The colours are fantastic, the contrast level is great (particularly after installing 75 ohm resistors on the outputs) and now its just the light grey blacks that are driving me a bit loony

This could be completely normal with this monitor, although I have discovered no information through extensive research of the subject... my comparison is with my PVM 20L4 which maintains its rich deep black colour despite how long its been on, giving an absolutely phenomenal dynamic range. The BVM has a total of 55K hours, maybe this has washed out the monitor over time?

Looking forward to hearing your thoughts!

Thanks!

Remi

[Remistewart]

Here is an example image to give you a flavour of what I mean!

Thanks!

[Hoagtech]

Yes. By my naked eye it looks like the green gain is set too high and affecting your black level. This is adjusted on my Sony wega by accessing the service menu, on my GameCube travel LCD, It is under the plastic casing their are white plastic screws by using a Phillips I could adjust these pots to turn up and down gamma, saturation, and one for each color gain.

I would first Google how to access your service manual or look for the plastic "pots" under the casing.

You could try the 90's Sony code: on your remote (with the tv turned off) press "display" then "5" then "volume plus" then "power" you'll know your in when you see a series or weird text and number pop up all over the screen.

[Remistewart]

Hey Hoagtech, thanks for your suggestion!

The BVM came with a remote unit BKM-10R which I've used extensively in a futile attempt to solve the problem... tried all the gains and offset changes, brightness, sub contrast... maintenance menu with ultra sub controls and still the blacks remain this light murky green. When putting in a SMPTE colour bar signal, i can't even differentiate between lower than black and black rectangles as it blends into one grey level regardless of the brightness input.

You say the pots under the casing may be the issue? Could I lower the black level further by adjusting this? Is this a dangerous procedure for an un-mechanical minded person such as myself? I'm even a bit spooked to take the case off in case i get zapped! Does the BVM-20F1E even have pots I can tweak? Or could it simply be on its way to CRT heaven?

Cheers!

[Hoagtech]

No I would not worry about taking the casing off. If your new I would not reccomend discharging it just stay away from the back magnet and neck in general. It would be s great opportunity to vacuum out or spray the dust and if any fans exist these can be cleaned and either graphite or lithium grease on the rotor would make it sound much whiter and move more air. Look for the pots connected to a plastic piece or on the side of the neck. If you don't find any. Simply put the. Asking back on. But chances are because of its low latency range it will be there

[Ed Oscuro]

Vacuums have been linked with static electricity generation, and I don't think there's much inside this series monitor to manually tweak.

You should grab a copy of the operation manual.

One setting which is possibly related is called SUB BRIGHT on many Sony monitors of this time, but I don't see it listed here. That setting had the effect of brightening or darkening the black level.

What you might try is reloading the factory data, a process described on page 48 of the manual. It's likely this is the result of some kind of aging, but this will hopefully rule out user error.

[Skips]

It almost looks like the green bias (not gain) is too high. Increasing the gain would not do that but setting the bias too high might. You need to check the setup menu AND the service menu. The values can be different in both of them so even if you looked in one you still need to go back and check the other. Instead of doing a factory reset I would find a value chart on what they are set to from the factory and go off that. If it were a PVM id agree with Ed and say reset it however BVM's are in a whole new level of picky than the PVM's. Faulting components such as capacitors on the RGB or deflection boards can cause the monitor to have issues after a factory reset (I don't know why I just know they do). Pasky had a problem when resetting his D20F1U. It worked fine until after he reset it and it caused problems with the colors or something. I am not sure if Pasky was able to fix it or not or what component specifically was faulting. I asked Saveonpat (who is a retired Sony Pro technician) and he confirmed this. I think the stock values will be in the service manual.

[Ed Oscuro]

That's available from the menus and not the front panel, right? Was thinking of that setting but couldn't remember the name.

[Remistewart]

Hey all, big thank you for your suggestions! Already tried a factory reset on the deflection board and RGB Analogue board (backed up all the values) I've tried changing the bias too, but the background remains the same. I even tried turned off all red, green and blue guns from the remote and everything except the green-grey background vanished.

Strangely enough, when I turn it off for a couple of minutes and back on again, the blacks look gorgeous - but only for a minute or two. I sat staring at the 0% black signal after a restart and watched the green quickly ease its way in over 5 minutes.

I'm fearing this truly is just a dodgy tube at this stage! When I set it to under-scan and widescreen, you can see it go from true black on the edges where the phosphors aren't hitting to the smudgy green described.

[Ed Oscuro]

Unless something's wrong in one of the electron guns, the screen is fine, since it's showing things properly.

Some other component is failing, I think.

[Skips]

I would try to find a cheap RGB amp board replacement. Make sure its not something simple like that. If you look around you can get them for $30 or so. They are connected directly to the neck board so a funky RGB card might cause slight issues like this.

[Remistewart]

Hmmm, it's promising to know it may be related to a small replaceable component. Only problem is the only experience I have with computers is changing a memory card/hard drive . I took a look inside the monitor just now and went pale with how tightly set up it is in there, not to mention touching be wrong bit and you're toast.

Does replacing the RGB amp require an intermediate/advanced level of CRT undsrstanding/soldering experience? I'm a beginner at both. Is it worth I attempt a fix or is it likely I'll cause more damage than good with no experience?

[Remistewart]

Ah forgot to say - I turned it on in a blackout room a moment ago with the brightness on minimum and it was as dark as it should be. Within moments, I saw two lights in the top left and right hand corner flickering, following which the whole screen quickly increased in brightness.

[Skips]

Its pretty easy to do. You unscrew the four screws holding on the plate in the back that contains the manufacture date and other information and remove it so you can see the neckboard. Next you unscrew the screws on the RGB card so it can be removed. There are three cables going into the RGB board from the neck board, simply disconnect them and remove the card. Just do the process in reverse to put a new one in.

[Remistewart]

Awesome, so the RGB amp board is on the RGB card itself? Are these components safe to touch with bare hands?

Considering I still get the same issue even when on the internal 0% black signal signal channel 99, could the RGB amp board potentially be causing this problem on that channel too? Apologies if I sound totally dense, it's all an exciting and new science to me

[CPC6128]

I have the problem a little similar on a sony BVM-14.
At the end of a few hours the image became green and then almost black, it was necessary to push the luminosity at the most to perceive something.
Since it take some minutes only.
I disassembled the monitor with a friend technician and having tried everything, we found the problem which resulted from the Power Supply block.
Power Supply (A-1316-258-D) is easy has to change on the BVM, but it is necessary to find one cheap!

[Remistewart]

Oohhhh dear oh dear oh dear! Now the overload light is switching on a few seconds after I turn the monitor on. Every time. I've got the brightness and contrast at minimum value. Hearing a pretty grating sound from inside the monitor around where the neck board/RGB card is. Has anybody experienced a similar problem and found a fix for themselves?
Thanks!