TV Issue or Soft15k related? Yellowing of screen and very bright green, dull RB

[jimmy2x2x]

I saw a nice looking 21" Panasonic Quintrix (TX-21AP1) flat screen crt on ebay, I won it thinking it would be excellent for my soft15k setup.

Got it today and Im having a few issues with it, green seems very bright, red and blue seem very dull - Im would have thought a tweak in the service menu (if I could get in!) or maybe internally could sort that out.

But the most worrying issue is that in some games, when the screen brightens or has a lot of white on it the left edge distorts, and this distortion moves up and down the screen depending on bright colours on the screen.

This issue seems to only occur in certain games/resulutions.

Worried that my homemade vga>scart cable might have had a fault, I built another - nothing changed.

Any advice?

cheers

EDIT: the strange thing is, my Sega Saturn is rock solid - no distortion and vivid equal colours.  On a different TV with the same setup, the Soft15k is evenly coloured and no distortion!

[apfelanni]

i have the same issue with my 2o inch tvs using mamescart + soft 15k / avga . one comes with a build in samsung and one with a thomson tube . both do very well with console gaming , no probs at all . if it comes to mamescart ( ati 9200 and 4350 vidcards ) the thomson looks fine ,while the samsung tv shows a blurry and terrible picture. the colors and the brightness are highly unbalanced and cant be adjusted properly in the osd . dunno what causes it . maybe its a problem of the chassis itself , maybe of the groundings or the graphic card.

my workaround is using the grundig/thomson for mamescart and the grundig/samsung with classic console gaming , but i d like 2 know how 2 setup the samsung tv for mamescart + soft 15 k . heard some guys with 50 hertz sony tvs had problems of the same kind . the picture appears 2 be very yellowed.i know the cam isnt the best , but hope it gets u an impression . if anyone comes up with an idea , i m eager 2 listen .

[jimmy2x2x]

I solved my picture pulling problem, by removing a couple of resolutions in soft15k.

Now my intense green/yellowing remains!

Thanks for the info, I have been tweaking everything I can on my set and tried a fresh install and different gfx card (NVidia 6200 and 5200) various drivers etc... Never changes, its not that it looks bad, it just doesn't have the punch I know RGB can deliver, and the imbalance of the colours is hard to get right.

For me the Green is unnaturally bright, like twice the intensity of the Red and Blue (which are both too dark).

I wonder if there is a software solution to this, I have tried playing around with powerstrip colour ramps, driver digital vibrance all sorts - but have yet to find a decent solution.

Its quite tricky for me now, as its hard to test a set with this kind of setup before you buy it, and decent RGB sets of a certain spec, size and condition are getting harder to find.  I don't want a collection of sets that I cant sell and don't work for what I want!

[apfelanni]

as long ure located in europe it shouldnt be much of a problem to get a fitting rgb tv set for a few bucks .  got maybe 40-50 pieces 14-33 inch in storage for arcade purpose ,some for free of the e-junkyard  it should keep me buisy till i m 112 years old . a 5o hertz tv soft 15 compatible with pure flat philips tube ( 4 easy bezeling ) and solid chassis made in germany i found some time ago is this one ( bought a backup , in case the cabbed one fails in 2032 ) :


http://cgi.ebay.de/ws/eBayISAPI.dll?ViewItem&item=160443327874&ssPageName=STRK:MEWNX:IT


hope a tv guy posts a fix for the yellow/green discoloration problem . ps. ur panasonic seem to be a tv of good quality , but i have no experience with panasonic at all . i ll stay with philips - grundig tv types which i know will work with soft 15 rgb input. i wonder what happens if u hook up a mak with an arcade pcb to ur screen .

[jimmy2x2x]

Yes, I am in the UK and sourcing them isnt impossible, but they have to be local as shipping is very expensive.

I choose this Panasonic as I had great results with a soft15k on a widescreen Panasonic (which I gave to a friend recently).

I wanted a 4:3 set for my cabinet project, so I was thrilled when this one was on ebay locally.

I might exchange my current 4:3 back for the old widescreen if I can, then look out for a phillips or grunding as you suggest.

I would love a technical explanation of what is happening with the green/yellow situation, or even better a solution

[SirPeale]

Have you tried the set with a standard signal to rule out set problems?

[jimmy2x2x]

Have you tried the set with a standard signal to rule out set problems?

With my Sega Saturn and PS2 it is glorious, real punchy RGB to kill for.

Ive been looking at this image on the panasonic tv via soft15k



BLUE: perfect until the 3 brightest strips, these are almost the same, very hard to see any graduation at all
GREEN: even graduation throughout, although it seems to be way too bright
RED: This looks like a spread of earthy brown rather than cherry red, the last 3 bright strips seem to go darker rather than lighter

EDIT: I have swapped this problematic set for my old Panasonic widescreen CRT, this gives me a much better image although Its the wrong shape for my intended cabinet!

Ah well My Quest Continues!

[the end melody]

Hi,

The problems you experienced with the tv set are probably caused by an old/aging/faulty tube.

With use, the tv tube loses the capability of maintaining the balance between the R/G/B beams. That process is called "aging".

I had an arcadevga/scart/mame tv set that behaved in a similar way. The image was superb, but it carried a greenish dominance.

My dad is a TV technician and his advice to the the problem was to get a new tv, because calibrating/recovering the tube wouldn't worth the effort,
considering that the price for a 4:3 crt TV is very low and affordable nowadays.

Fortunately I had a big screen sony 4.3 crt that was nicely converted to mame/gaming purposes.

A little teak in the service menu and it was ready to go.

Again, in the majority of the cases the aging tube is to blame, but I don't rule out other causes that may contribute to the problem.

PM

[jimmy2x2x]

If this was consistent across sources, I would fully agree with you.

In my case, my sega saturn produced excellent vibrant colours.

[the end melody]

Is the tv scart female connector loose by any chance?

Does it show any signs of wear or tear? 

Could the tv scart female connector have any broken/unsoldered circuitboard pins, difficulting RGB signal routing ? 

PM

[Jack Burton]

On all my RGB monitors I've noticed that the video from the S-video and Composite ports looks brighter and more vibrant than the RGB.  

I believe the S-video and composite signals are boosted/amplified a little bit before being displayed.

The RGB must be the raw, unboosted signal.  This can cause it to look "dull" compared directly to S-video.

This is pure conjecture on my part.

However, comparing an arcade monitor running a pcb and my RGB monitor running advancemame in the same resolution, they look exactly the same.  

So it isn't an issue with the RGB video, it's an issue with S-video.  The signal is boosted to look "better", as in brighter/more vibrant, at the cost of color accuracy and definition.  

As far as the intense green/yellow.  I believe RGB just exposes the age of a monitor more than S-video does.  My big monitor has a slight defect in the blue gun, in that it cannot display very dark blues.  On a color bar ramp red and green have full contrast, but blue crushes in the last two levels.

What this means for me is that I can't get a true good yellow in the life bars of SFII. 

BUT, if I hook my PS1 up and play the PSX version I get good yellow bars.  I believe this is because the entire signal has been amped up, and the colors necessary to get that good yellow are now further up in the color scale into the area where my tv can display it. 

[jimmy2x2x]

That sounds more like what was happening for me, with the price of CRT's being so low these days its probably best to source another set rather than spend too much time on solving a problem that doesn't exist on another set.

A software based colour compressor, to tweak min/max values to fall within the best range of your monitor would be excellent for solving these kind of issues, although I have yet to find one!

[apfelanni]

i dont believe it has anything 2 do with tube aging nor some svideo stuff. if 2 oder 3 consoles with 100 % "" rgb "" cable output have a brilliant and fine colored picture and only the mamescart thing doesnt work right, its for sure no defect on the tv . must be some pc hardware related problem . 

[jimmy2x2x]

maybe the PC is outputting a wider range than the consoles?

For example if the maximum range is 0-255

Pc outputs this range, ie 0-255

A console might only output 32-220

This is pure speculation, but might explain some of the behaviour if the TV isnt performing well at the extremes of the max range (0-31) and (220-255) in this example

[Jack Burton]

I've thought sometimes if this thing would do something to help the signal, it's worth looking into:

http://dme.ghost2.net/hdfury/gamma-x/

[the end melody]

Since the aging tube and damaged tv scart connector are possibilities to rule out, I would definitely consider reviewing the vga to scart cable.
In one occasion I had a cable home built that worked perfectly with a particular tv set (sony) but displayed an out of focus picture and some missing colors with a nokia.
This first cable was built according to a schematic/pinout that I found on the internet.
The second cable was built following instructions from Andy (Ultimarc). This cable gives me excellent picture quality (the old RGB color punch) in all tv sets I've used (sony, thomson, nokia and sanyo).

PM
   

[jimmy2x2x]

I have built 2 cables already (see above)

Both perform exactly the same

Do you have a link to the diagram you used, I will check it against mine.

[the end melody]

I had to search the net as I misplaced the drawing I used, but this is exactly it:

http://homepage.ntlworld.com/callum.henderson/basement_boomera_000007.htm

Keep us posted and best of luck!

PM

[jimmy2x2x]

Thanks for that

I have compared the wiring, excluding my additions (auto switching and audio)

There is only one variation, both sync are wired to both scart pins 20 and 16 (standard numbering)

Mine are combined and only go to scart pin 20 (standard numbering)

I will bridge them and report back

[apfelanni]

try the parallel resistor sheme taken from italo forum .