24" Widescreen CRT (FW900) From Ebay arrived,Comments.

LAGRUNAUER

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745
I believe that's what the service manual is saying, that the risk to the unit comes when degaussing is done with it being on. Can't say for certain right now because I don't have it handy. But yes, so long as you degauss the screen while the unit is OFF - you should be fine.

We were always instructed to stay away from this procedure... Like I said, we have done some trials with some success, but if someone is going to try it out, it is at their own risk.

UV!
 

jbltecnicspro

Supreme [H]ardness
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We were always instructed to stay away from this procedure... Like I said, we have done some trials with some success, but if someone is going to try it out, it is at their own risk.

UV!

Is this one of those things where you kind of do it as a last-ditch effort? Nothing else is working, so we may as well trying and hand degauss the unit?
 

LAGRUNAUER

Gawd
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Dec 7, 2006
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745
Is this one of those things where you kind of do it as a last-ditch effort? Nothing else is working, so we may as well trying and hand degauss the unit?

There are many way to demagnetize CRTs. Degaussing coil is the easiest way but it may not work on some tubes, and it may end up making the matter worst.

That's why I said, "try it at your own risk"...

UV!
 

atwix

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why is that cats like computers? They like the heat? The radiation? Or just you sitting there? :D
 

Ashratt

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I ran 1600x1024 @110Hz; i think you can squeeze out a bit more if you play around with the timings
edit: oh and 1680x1050@96
it all depends on the ramdac (which should be 400mhz) and the max. horizontal/vertical sync frequency of the monitor
 

pr0ton

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Hi unklevito, I see you quited on shipping entirely, bad experiences I presume.

Too bad, how expensive are the calibration tools :D?
 

spacediver

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I ran 1280x800 @ 140hz for quake, and recently switched to 960x600@ 160 hz. jaw dropping smoothness.

Not sure what the max res for 120 hz is.
 

spacediver

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Hard to say. Related question. Assuming equal pixel clock, would having a lower resolution with a higher refresh be worse, better, or the same as a higher resolution with a lower refresh?

I guess this is equivalent to asking which is more liable to be stressed due to high signal frequency: deflection circuitry or video amplifier circuitry.
 

rabidz7

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What is the highest refresh rate a FW900 can do at 2048x1280?
What about 1920x1200?
What about 1840x1150?
What about 1760x1100?
 

flod

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Hard to say. Related question. Assuming equal pixel clock, would having a lower resolution with a higher refresh be worse, better, or the same as a higher resolution with a lower refresh?

I guess this is equivalent to asking which is more liable to be stressed due to high signal frequency: deflection circuitry or video amplifier circuitry.

my guess is the deflection circuitry and the fbt



for the maximum allowable resolution/refresh rate, usually the limiting factor is the horizontal scan rate which is the vertical refresh rate times the total number of vertical lines (which is slightly greater than the vertical res)
 

LAGRUNAUER

Gawd
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Dec 7, 2006
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745
Hi unklevito, I see you quited on shipping entirely, bad experiences I presume.

Too bad, how expensive are the calibration tools :D?

NO! We ship worldwide, but eBay, which owns PayPal, has a credit card shipping policy and we no longer accept credit cards for payments. That is why my GDM-FW900 monitor listings on eBay shows as "local pickup only" but if you read the add it gives you the packing and shipping option.

As to the calibrations tools, I only have laboratory grade equipment. However, I do have an extra Sencore CP5000 calibration pods including the calibration program available. PM me if you are interested.

Hope this helps...

UV!
 

flod

Gawd
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YES!!!!

I do not recommend any "forced" resolutions and timings other than the VESA recommended for the unit.

UV!

do you know how it scales? for example would 800x600@170hz cause some part to wear out twice as fast as 800x600@85hz would?
 

LAGRUNAUER

Gawd
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Dec 7, 2006
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745
do you know how it scales? for example would 800x600@170hz cause some part to wear out twice as fast as 800x600@85hz would?

Forcing the unit to sync non-recommended resolutions and timings forces the guns and wears the cathode (by "poisoning" - oxide build up contamination -) faster.

UV!
 

jrodefeld

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Jun 7, 2014
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I just got an FW900 locally. I am having a few issues and I need your advice.

In the first place, it is clear that this monitor has the "brightness" issue where things appear washed out and blacks are gray even with brightness at 0. So I am assuming I have to lower the G2 voltage. Do I have to use WinDAS for that or is there another way?

I heard that you can simply adjust a "screw" on the flyback which will lower the G2 and restore proper blacks. I don't know how to do this or if this is even safe to do.

Also I wanted to first try the Image Restoration feature, but it doesn't work. Every time I go to perform the image restoration, it starts for about a minute or less and then the whole monitor goes to standby. I just have to turn the monitor back on and nothing has changed.

What is going on here? I have ordered a USB to TTL cable for doing a proper WINDAS calibration but I'd really like to get the blacks looking right as soon as possible. Is there anything that can be done? And why can't I get the Image Restoration to work?

Any advice would be very much appreciated.
 

flod

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Forcing the unit to sync non-recommended resolutions and timings forces the guns and wears the cathode (by "poisoning" - oxide build up contamination -) faster.

UV!

I appreciate your advice but unfortunately there are stubborn people including myself who will force resolutions/rates regardless. the reason is that we use CRTs for gaming, and forcing the refresh rate to, for instance 150hz, results in much better motion quality than the recommended 85hz.

now what we'd like to know is how the rate of wear scales with the resolution and refresh rate. this would help us determine a safe compromise between pushing the rates and wearing out the monitor excessively. for example, perhaps at 110khz horizontal scan, the rate of wear increases by 50%, but at 120khz the rate of wear quadruples. with this knowledge, we'd use refresh rates that keep the horizontal scan rate below 110khz in order to experience good motion quality without excessively wearing out the monitor.

I just got an FW900 locally. I am having a few issues and I need your advice.

In the first place, it is clear that this monitor has the "brightness" issue where things appear washed out and blacks are gray even with brightness at 0. So I am assuming I have to lower the G2 voltage. Do I have to use WinDAS for that or is there another way?

I heard that you can simply adjust a "screw" on the flyback which will lower the G2 and restore proper blacks. I don't know how to do this or if this is even safe to do.

Also I wanted to first try the Image Restoration feature, but it doesn't work. Every time I go to perform the image restoration, it starts for about a minute or less and then the whole monitor goes to standby. I just have to turn the monitor back on and nothing has changed.

What is going on here? I have ordered a USB to TTL cable for doing a proper WINDAS calibration but I'd really like to get the blacks looking right as soon as possible. Is there anything that can be done? And why can't I get the Image Restoration to work?

Any advice would be very much appreciated.

you should do the full white point balance procedure. see spacediver's guide: http://hardforum.com/showthread.php?t=1830788. you'll need to purchase a dtp94 (~30$ on ebay) or some other colorimeter
I didn't see any g2 screw on the flyback of my fw900.

also if you haven't already, make sure to look at the monitor in a dark room to make sure what you're seeing isn't just ambient light reflecting off the phosphors.

until you get your cable and perform the calibration in windas, you can try decreasing the brightness in the OSD... though it's possible that your black will still look bad even with brightness at 0.
 
Last edited:

spacediver

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I appreciate your advice but unfortunately there are stubborn people including myself who will force resolutions/rates regardless. the reason is that we use CRTs for gaming, and forcing the refresh rate to, for instance 150hz, results in much better motion quality than the recommended 85hz.

I know this doesn't address your fundamental question, but I don't think 960x600@ 160 hz, for example is non standard - it syncs perfectly and uses VESA timings, from what I understand.
 

jrodefeld

n00b
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Jun 7, 2014
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I appreciate your advice but unfortunately there are stubborn people including myself who will force resolutions/rates regardless. the reason is that we use CRTs for gaming, and forcing the refresh rate to, for instance 150hz, results in much better motion quality than the recommended 85hz.

now what we'd like to know is how the rate of wear scales with the resolution and refresh rate. this would help us determine a safe compromise between pushing the rates and wearing out the monitor excessively. for example, perhaps at 110khz horizontal scan, the rate of wear increases by 50%, but at 120khz the rate of wear quadruples. with this knowledge, we'd use refresh rates that keep the horizontal scan rate below 110khz in order to experience good motion quality without excessively wearing out the monitor.



you should do the full white point balance procedure. see spacediver's guide: http://hardforum.com/showthread.php?t=1830788. you'll need to purchase a dtp94 (~30$ on ebay) or some other colorimeter
I didn't see any g2 screw on the flyback of my fw900.

also if you haven't already, make sure to look at the monitor in a dark room to make sure what you're seeing isn't just ambient light reflecting off the phosphors.

until you get your cable and perform the calibration in windas, you can try decreasing the brightness in the OSD... though it's possible that your black will still look bad even with brightness at 0.

I appreciate the advice. I'm sure lowering the G2 voltage will fix the problem. But what about the Image Restoration issue? Why does it fail and go into standby? That is probably the more concerning issue right now.

I jumped at the chance to get this monitor locally even knowing that there were some problems that I saw with the image. These are just so hard to find now and I've always wanted one. I'm just hoping I can get it's performance back to where it should be. With the brightness issue, the image is definitely not that impressive yet.

Anyone else have advice about the Image Restoration feature? Why would it go into standby less than thirty seconds after starting?
 

spacediver

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Total guess, but it might be an ABL issue (auto brightness limiter). If your display has drifted too much, then some of the demands on the monitor used during the image restoration may be pushing the luminance too high, which would in turn shut it down. Does the screen go really bright before it shuts down? Also could be that the ABL was set for too low a threshold. Best thing to do is do a white point balance in WinDAS to restore as much function as possible and see what happens.
 

flod

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maybe this has been answered before... but what exactly does "image restoration" do?
 

spacediver

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some sort of drift compensation. The circuitry probably tries to guess how much drift has occurred by using certain combinations of voltages and somehow measuring the output, and then making adjustments based on that. Not sure how the feedback works or if it is indeed feedback based.
 

flod

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but what does it adjust? does it change anything not changed in the wpb procedure?
 

spacediver

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I believe it adjusts G2, and possibly some of the other things that WinDAS adjusts.

The service manual doesn't give much, but the notion of lost brilliance probably has to do with drifting black level.

The colors of most display monitors tend to gradually lose brilliance over several years of service. The IMAGE RESTORATION feature found in the EASY and sRGB menus allows you to restore the color to the original factory quality levels.
 

flod

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should work but youll have to open the case to plug those individual pins in. fortunately the fw900 has a hole in the back for the ttl port so you can put the cover back on; the usb side should be small enough to thread through the hole
 

spacediver

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Just got an FW900 in great condition, lightly used. Antiglare still on so will do some comparison experiments :)

Brings my total to four FW900s, 3 of which are in working condition. I have a problem :p

dfzjhw.jpg
 

spacediver

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old buddy of mine bought it a few months ago, and I calibrated it for him. He wanted to let go of it (nothing to do with the quality of the monitor), so he sold it to me, along with a new in the box DTP-94 for $250 (which included him driving it over). Looking forward to seeing the first pass slider value in WinDAS on this puppy :)
 

flod

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nice!
what's wrong with the one not in working condition?
The AG coating on the F520 tubes is built into the glass. Not all the 15X and 16X tubes have AG coating built into the glass. Some have the AG film on it and the best way to find out is to open the case and look for a small round sticker on the tube that reads "F" which means film.

Hope this helps...

UV!
i think that my cpd-g520p has the coating built in. i'll take it apart and look.

i'd be interested to see whether the fw900's film has an antireflective (like the interference type) coating on it. judging from the untinted reflection of the light from that picture, it looks like it doesn't, but it could just be overexposure.
 
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