Sony GDM-F520 Text Ghosting

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Gunslinger3333

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I recently purchased a mint Sony GDM-F520 22" CRT from a reputable online seller a few months ago and have been pleased with the display until a few days ago. It has developed an annoying habit of echoing text and vertical lines intermittently. The only way to describe it is that it will ghost or echo text and vertical lines to the right about 4-5 times gradually fading out. It is only noticable on high contrast backgrounds like white and black. Lowering the resolution down helps to make the ghosting less noticable. I have read that this ghosting is caused by signal bounce (ringing) within the VGA cable. I am using the Sony factory cable and switching to a Radio Shack cable with ferrite cores didn't help either. Any thoughts on how to figure out if the monitor, VGA cable or video card is the culprit? Thanks.
 
Since it would be the least invasive thing to do, I would try a different cable first. I would recommend one of these.

By the way, from whom did you buy the monitor?
 
Well I already tried using a brand new Radio Shack VGA cable, but it didn't help any. I am running a 8800GTX with DVI outputs with a DVI-VGA adapter. I wonder if that adapter is causing some kind of impedance within the signal path? I think I might just get a straight DVI-A to VGA cable and rule that out. Oh, I got it from a certified Sony CRT tech on ebay. I sent him an email so hopefully he can figure out what is going on. The weird thing is that it is not constant but comes and goes intermittently, moving the cable around doesn't seem to have any effect. It sucks because the picture quality of this GDM-F520 is flawless other than that small glitch.
 
Well I'm afraid it's a known 'bug' and/or problem. Call it whatever you want but it is extremely (too) common for this monitor. Read a few article on the web you'll see what I mean...Sony shot themselves in the foot with this one. It could have been one of the best CRT ever if their engineer had a f* brain.
 
Koslov said:
Well I'm afraid it's a known 'bug' and/or problem. Call it whatever you want but it is extremely (too) common for this monitor. Read a few article on the web you'll see what I mean...Sony shot themselves in the foot with this one. It could have been one of the best CRT ever if their engineer had a f* brain.
Click to expand...

Inch per inch, it is the best consumer CRT ever.

Sadly, reliability is certainly an issue though with the latter Sony CRT products.

If it's not a bad cable, try the other input (5 BNC)...
 
I thought about doing that. This GDM-F520 has five inputs on the rear near the VGA input. Do I need the 5BNC cable or the 3BNC? Also what is the difference between RGB and BNC cables? I like to game at extreme resolutions like 2048X1536@85Hz, will the BNC cables limit my ability to play at those high resolutions? Thanks


I think this is what I need since my 8800GTX has only DVI outputs.

http://www.computercablestore.com/2_Meter_DVI_A_to_5_BNC_Ca_PID1339.aspx
 
Gunslinger3333 said:
I thought about doing that. This GDM-F520 has five inputs on the rear near the VGA input. Do I need the 5BNC cable or the 3BNC? Also what is the difference between RGB and BNC cables? I like to game at extreme resolutions like 2048X1536@85Hz, will the BNC cables limit my ability to play at those high resolutions? Thanks


I think this is what I need since my 8800GTX has only DVI outputs.

http://www.computercablestore.com/2_Meter_DVI_A_to_5_BNC_Ca_PID1339.aspx
Click to expand...

That type of cable is the one. And BNC is traditionally the higher end cable solution over VGA, though individual cable quality varies of course...
 
Gunslinger3333 said:
I recently purchased a mint Sony GDM-F520 22" CRT from a reputable online seller a few months ago and have been pleased with the display until a few days ago. It has developed an annoying habit of echoing text and vertical lines intermittently. The only way to describe it is that it will ghost or echo text and vertical lines to the right about 4-5 times gradually fading out. It is only noticable on high contrast backgrounds like white and black. Lowering the resolution down helps to make the ghosting less noticable. I have read that this ghosting is caused by signal bounce (ringing) within the VGA cable. I am using the Sony factory cable and switching to a Radio Shack cable with ferrite cores didn't help either. Any thoughts on how to figure out if the monitor, VGA cable or video card is the culprit? Thanks.
Click to expand...

I have two F520s and they both do this from time to time and have since they were new.

It's a side effect of bandwidth becoming limited somewhere in the signal path. What you are seeing is "ringing" from a voltage transition which exceeds the analog bandwidth of the signal path. I've found that simply touching the HD15 or wiggling the cable (once) makes it clear.

I suggest that you run frequencies as low as you can "stand" for your application to minimize the chances of this happening. Just because the monitor can do 120Hz refresh at your favorite resolution doesn't mean you need to use it that way. I generally use all modes at 70Hz. My normal desktop is 1600x1200 and I use 2048x1536 for photo work.

In the past I've opened the monitors looking for cold solder joints or poor interconnects between boards but have never found anything. High quality 5BNC cables would still have the problem from time to time but reseating them at the PC or BNC end fixed things up. Although I consider this an annoyance, it isn't a major one. Most CRTs probably aren't sharp enough to even resolve this issue, and DVI-D operated panels won't have this problem since they use all digital signaling.

It may be the mechanical characteristics of the connectors themselves.
 
You are correct, I can eliminate the ghosting by reaching behind the monitor and applying slight pressure to the HD15 connector on the back of the CRT, thanks. Any ideas on a permanent fix for this?
 
Gunslinger3333 said:
You are correct, I can eliminate the ghosting by reaching behind the monitor and applying slight pressure to the HD15 connector on the back of the CRT, thanks. Any ideas on a permanent fix for this?
Click to expand...

Not really (yet, anyways). Mine doesn't suffer from this often enough to warrant anything more than the hunt for cold solder joints and loose internal interconnects.

You may want to be sure that you're using a good video cable with gold contacts. Frankly, I'm not really sure if the jack on the monitor has gold plated contacts because you can't see them.

I forgot to mention that I've also tried a Stabilant-22 clone on the cable and monitor contacts and I don't feel it made any difference.

I find it interesting that when I used 5BNC cables I had to wiggle the HD15 at the PC. Now that I'm using the factory HD15 cable I have to wiggle the HD15 at the monitor.

I'd be interested to see if anyone else has anything more permanent also.
 
i also have F520 and have exactly the same problem

i bought it on december 2003 and it started doing it after some months making my life a hell since then (i gave 1100 euros to buy it brand new back then)

i've sent it to sony service but they sent it back telling me that they couldn't find any problem, typical sony

trust me it's not the cable or the gfx card as i tried many (i also tried a 5bnc cable) - this awful ghosting goes away if you also apply pressure to the power cable of the monitor not only to the hd15, but of course it always comes back all the time

it's really a shame because it ruins the experience, i saw a lot of lcd monitors and i can tell you for sure that nothing can even come close to F520 - that's why i'm desperate because i know that if i'll buy an lcd monitor it will be much worse

if an engineer or someone that knows reads these forums please help us, what is causing this and how can we fix it, this is my last hope for this monitor, if nothing happens i'll put fire on it and burn it, i mean it
 
The guy I bought this GDM-F520 from is a certified Sony CRT tech as well as an electrical engineer. He goes by the name Unklevito on ebay, all he sells is Grade A+ high end Sonys. He would be the person to shed some light on this ghosting problem that seems to affect a large percentage of F520 owners, but Im not sure how often he visits here.

I agree that the Sony GDM-F520 is the best consumer grade CRT ever made. Alot of people will argue that the Sony GDM-C520K Artisan is better, but the F520 has the tighter .22mm dot pitch and a substantially better tube. If you game at 2048x1536 resolution at a rock solid 85Hz there isn't anything that can touch it, image quality wise. I recently bought a BenQ FP241W 24" LCD for the widescreen aspect and it rocks but if you put it next to the F520, there is no comparison especially if your a hardcore gamer.

I had always wanted a F520 back in the day when it was getting the MaximumPC Kickass award year after year but the $1800.00 price for a new unit was beyond my means. I finally got a Grade A+ , fully calibrated unit with less than 200 hours on the tube from Unklevito and am very pleased other than the minor ghosting issue. This CRT really needs a dedicated Hardforum thread, like the Sony FW900 24" CRT has.
 
I've also had my F520s since new, and both had the ghosting problem to some extent or another. In my case, it is by no means a "living hell". Actually, I purchased GDM-F400s in 1999 but both tubes flamed out in exactly the same manner just a couple of months before the warranty expired in 2002. Sony sent back GDM-F520s with a note that the -F400s were "unrepairable". The -F400s had better build, but the -F520 picture is noticeably superior. My first -F520 started having problems with collapsing picture about a year ago so I've set it aside.

I had not previously noticed that pressing on the power connector fixed the ghosting. That definitely makes me want to open it again. When I get the ghosting myself the next time, I'll try manipulating the power connector. I'm going from memory, but the power connector and the signal inputs are not on the same assembly board. It's possible that wiggling any of those rear connectors is actually moving the casing and cleaning a ground point for the signal input board or something, so it's worth a look. The fact that 5BNC and VGA inputs suffer the same ghosting, and "wiggling" fixes it means it is a mechanical problem with an electrical connection. The simplest thing to affect all of the inputs in this way is a ground point.

I will mention again, though, that when I was using a 5BNC cable I would sometimes have to manipulate the video-card end of the cable to clear ghosting. This doesn't point to a consistent problem inside the monitor.

I'd love to find an FW900 in my area (Toronto-ish), it's getting hard to get away from wide-screen aspect.
 
I emailed Luis (Unklevito) and asked him to stop by and take a look at this thread and suggest a permanent fix. I figure that with his help we can narrow down and isolate this problem and maybe fix it. I do agree that it does seem to be a grounding problem that is causing some kind of impedance within the signal path, we just need to find out what connection is faulty.
 
Had the ghosting problem, but with the BNC connection. Fixed it by replacing the BNC assembly inside the monitor.

(This should only be done with extreme caution, however, due to the potentially lethal voltages within computer monitors...)
 
I think I have a lead on this, since I was poking around in my "spare" -F520 tonight. I don't have any pics yet.

The interface module, with the HD15 and BNC connectors on it, has two edge connectors on the bottom. Physically this module is supported by clipping onto the rear ground shield and accepting two screws. More screws go through this module when the full ground cage is attached.

The edge connectors are looser than I'd like, especially considering the frequencies involved. When assembled, these edge connectors are rocked back and forth slightly by wiggling any of the input connectors or the power connector.

I've put some stabilant-22-clone contact enhancer on the male and female connectors in this location. I don't yet have any bright ideas to mechanically stabilize the area.

I don't know if the -FW900 has this problem, or if it is constructed in the same manner.
 
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