Wells Gardner D9200 Issue

[dskillz1]

After about 5 years my Wells Gardner D9200 monitor in my Mame cabinet decided to lose allot of its brightness.  When I try to access the monitor via the OSD panel It doesnt even show up on the screen because its not bright enough to see.  I have been able to turn up the gamma, contrast and brightness in windows up real high and I do get a somewhat decent screen but its distorted a little.  Does anyone know if I need a new part to get this back to normal or a cap kit or something?  I have 0 experience with monitors and heard this is the board to ask.   Any suggestions fellas?

[lilshawn]

if you crank the screen on the flyback, can you see the OSD? if not ,i'd suspect the eeprom has gone in it.

the eeprom stores all the values for the monitor, if it goes south, it will just use zero values for everything.

[MonMotha]

If the EEPROM has been corrupted, you may simply need to reset everything in the hidden ("service") menu.  Unfortunately, I don't remember how to get into it on a D9200.

Agreed: crank screen on the flyback to see if it improves things.  That setting can drift, especially with mechanical vibration or if the cabinet/monitor is moved.  If you turn it up high enough, you should get "retrace lines".  If you keep going, the screen will become fully white.  Don't go any higher.

I think the D9200 may also have a "sub bright" adjustment pot somewhere on the chassis PCB.  It may need adjusted.

Also, be aware of the somewhat inaccurate terminology of monitor settings:
*Brightness is black level.  This controls the input signal level that the monitor regards as "black".  If this is set too low, things that should have color will appear black, but things that should be fully white (or have full intensity with other colors) will still be about right, assuming contrast is set properly.  If brightness is set too high, things that should appear fully black will instead appear gray.
*Contrast (aka "Picture" on some TVs) is white level.  This controls the input signal that the monitor regards as "full intensity".  If this is set too low, colors will appear dim but will still be present, assuming brightness is properly set.  If this is set too high, things that shouldn't be of full intensity will be very bright, and full intensity signals may result in "blooming".  The CRT will suffer burn-in prematurely.

Brightness and contrast do interact some, but the interaction is limited.

The screen control on the flyback behaves much like a very coarse brightness setting.  It predominately affects black levels, not intensity.

I explain all this because a screen with insufficient "brightness" (meaning the picture isn't as "bright" or "intense" as it should be) will frequently instead need an adjustment of the contrast control.  The terminology is unfortunately somewhat archaic and confusing.


A good color bar or gray/color ramp pattern is essential to properly setting brightness/contrast.

There is a definite "correct" setting for brightness: it should be set at the level which makes "black" signals actually appear black, but low intensity gray signals should still appear gray.  A color bar pattern will usually have 2 or 3 steps at the bottom that are intended to be invisible (regarded as black), but it does vary with signal source.

"Correct" setting of the contrast control is a bit more subjective.  The "proper" setting is usually taken to be "as high as you can get it without significant amounts of blooming and such that the top two bars on a 10% step color bar pattern are still distinguishable", but I usually back it down a hair from there as doing so substantially lengthens the lifespan of the tube, and tubes are hard to come by these days.

[lilshawn]

If the EEPROM has been corrupted, you may simply need to reset everything in the hidden ("service") menu.  Unfortunately, I don't remember how to get into it on a D9200.

i think you hold the menu button until the service menu appears.

[smartbomb2084]

You need to hold DOWN and SELECT at the same time.

Be sure to go into the COLOR PALLETTE and set the brightness of the colors.

To SAVE your changes be sure to hit RE (recall) or it won't work.