"Spark" sounds in CRT

Q

quantum112

Limp Gawd
Joined
Jan 20, 2010
Messages
392
Hi, I have an EIZO T966 21" CRT, great monitor, the picture is amazing. However, it seems to have something of an issue: after running for 6-7 minutes, it starts to emit some kind of "clicking" and "sparking" sounds. They aren't really that loud, but with the monitor fully closed up, sitting about 2 feet in front, I can hear them.

Every now and then, this spark will also be accompanied by a split-second change in brightness - it will go down just enough to be noticeable, and very rarely, they may cause the focus of the screen to go somewhat blurry too, this happens about once in 2 days or so. It all lasts for a fraction of a second though.

The snaps vary in loudness, and sometimes there will be 2-3 within a minute, other times it will go for 10 minutes being completely silent. There is however, absolutely no visual sign of any kind of sparking or arcing anywhere, neither from the flyback, or the HV anode.
The only thing glowing is this here tube that I have marked on the bottom picture, I am not sure if this is supposed to be glowing but it does all the time while the monitor is on.



So most of this "snapping" seems to come from the marked area, the CRT neck. Not sure if this means anything, but I'd appreciate if someone who knows more about these monitors could tell me what this means.I'd like to repair it if it is possible before any more serious damage occurs, because I'd like to keep this monitor for at least another few years until laser TV becomes more common, the picture quality is that good.

Thanks
 
Quantum:

If it sounds like arcing, it probably is. It could be between elements of the CRT from the area you highlighted, or between windings of the deflection coils (the area circled). The area in the square is supposed to glow. That is the cathode. It needs to be hot to emit electrons.

If it is the CRT you may want to give this monitor last rites before it dies. In my experience, CRTs are either not repairable or are cost prohibitive to repair or replace.

There is another possible cause, the HV power supply. Maybe producing momentary over voltage conditions. It depends on the value of you monitor and your skill level, whether it is practical to repair.

I crapped away several hours troubleshooting one of my Veiwsonic PS790 monitors that died a couple of years ago. Replacement parts alone made repair of the HV impractical. I still have two PS790s. I'm using one of them to type this message. When they die, I won't try to repair them unless it is something simple like a broken connector. They are 12 years old and not worth much. But I will always have fond memories of them.:)

Regards,
ArTcher
 
Keep in mind that CRTs operate with some very high voltages, so this is not a good place to play. Seriously do not go poking arround with the thing fired up, and be carful even with it powered off. When my Sony GDM-F500 was arcing like you describe, I took it to a authorized services center and they told me it was unfixable. I replaced it with 2 GDM-F520s right before they quit making them. These displays were worth what they cost.

Dave
 
Thanks Dave:

I should have mentioned that. The second anode on the CRT is usually around 20,000 volts and can kill you. Plus it stays charged after the power is turned off. Sometimes it will stay dangerous for days. It must be discharged before servicing. Also there are other high voltages for the deflector coils. I was bit by HV a couple of times in the past. It didn't kill me, it just felt like it did.

Artcher
 
In an attempt to be slightly more encouraging ... I remember an arcing/sparking sound in the first Heathkit TV that I built. As I (very vaguely) recall, I investigated with Heathkit and was persuaded that it was not a problem - unfortunately, I've long since forgot the reason/rationale (perhaps a few trace impurities inside the tube that are being blown away ?). In any event, if this is a relatively new CRT and/or if the sparking/popping frequency/magnitude does not increase over time ... I wouldn't give up on it just yet. (The Heathkit TV survived for a -long- time, and the sparking/popping decreased over time ... :)
 
TheArTcher said:
I should have mentioned that. The second anode on the CRT is usually around 20,000 volts and can kill you.
Click to expand...

"Why do they call it a fly-back transformer?"
"Guess what happens if you touch it..."

On a more serious note, if he does have to replace the whole thing, is there any place still selling decent CRT monitors?
 
Hi guys, thanks for all of the input. Yes, I am well aware of the dangers of working around inside a CRT, but I do take great precautions, I have already adjusted the focus on the flyback on this monitor a couple of months ago and 2-3 days ago have cleaned the entire inside of the monitor (you can tell from that picture) - as far as I could reach. There was quite a bit of dust everywhere, especially around the HV anode, and although there is still some of that black silicone grease around the cap, is it possible dust may have gotten inside and is causing trouble?

If so, would it be worth to try to discharge the anode (I've read how, big screw driver, attach crocodile clip to metal bit and ground to chassis, touch anode, hold for 1 minute, repeat 3-4 times?) and clean the contacts on the place it plugs in and the anode itself?

I don't really think this CRT is going to die that soon, it was built in July 2003, the picture is so amazing that I have sold my 22" Samsung LCD months ago and I have not regretted that decision once! And frankly this is the only issue it is having. The tube still looks like it has tons of life in it, and the power supply is stable and the picture doesn't breathe around one bit no matter how much black/white screens I alternate. Would just be a shame to bin this thing. Especially if this one little issue could be solved by something simple as cleaning.

What's curious though is that, like I said, it doesn't do this for the first few minutes, but only when it already became moderately warmed up.

Would taking measurements with a voltmeter at certain points give me any further pointers as to whether or not the flyback could be the issue? If it is really inside the CRT I guess I'll just have to live with it.

Oh yeah, it also does have a slight buzzing sound when it runs, can't quite pinpoint from where as I don't wanna get my head too close in there, but then again my PC PSU does it too.
 
I had two GDM-F400s die similar to this fashion. They were "unrepairable" and Sony replaced them with a pair of GDM-F520s (luckily I was within warranty). In my case the "snap" was accompanied by a loss of geometry, a black flash, or a couple of seconds of blurred picture.

Top performance CRTs don't necessarily seem to be made for extended longevity. That being said, my GDM-F520s performed well - I haven't used them since I got my 2490. At the risk of sounding negative, there may be nothing you can do. If you're "lucky", it may be fixable by replacing the flyback which may still be obtainable.
 
I see. Honestly for the past couple of days I've had headphones on so haven't heard the sizzles but the flicker was much rarer, I think it only did it once in the past 4 days. It's not flyback popping though, that is much louder. This sounds like when you turn a TV off and the plastic cools and settles down so you get those pops and clicks in various locations, they're all pretty silent though.
It certainly does not look like it's dying in any way.

Looking at the wallpaper on my desktop right now (this one) the image is so amazing and life-like that I'd say the monitor is brand new if I didn't know it wasn't. It honestly beats every monitor I've had so far in absolute picture quality. That is why I am going to be really sad when it goes, and that is why I am pissed off at the display industry for abandoning CRT's and stuffing us with inferior display technologies for years. Laser, FED, SED, whatever you want (even though I'm not a fan of fixed pixel displays) but please, no LCD's. I've been on an LCD for the past 4 years and I know what I've been missing when I now replay all the games and movies I encountered during those years. There is no comparison. My eyes are always the ultimate judge for me, not reviews, or critics, or "professionals", and certainly not mass opinion (which has been proven wrong countless times). Among the few more intelligent friends who came over and were able to look past the "ugly, bulky beige box" and "CRT is old therefore it's automatically bad" dogma, they admitted that "this thing actually looks pretty freaking amazing".

Why everybody insists on pushing an obviously flawed (in one way or another) and failed-concept display technology to the masses is beyond me, but I assume the reasoning is something along the lines of "yes, we know it's bad, but since we invented it, we may as well milk it for the next 10-15 years, the suckers will never know the difference". Heh. All just my opinion though - I know a lot of folks who are happy with LCDs, even the extremely cheap ones, I wish I could be like them. :rolleyes:

Plan on buying an FW900 next week (pretty good condition, image looks great, I don't think it's seen much use, 2-3 scratches on the AG and plastic, nothing severe), hope these two hold out until a good replacement comes. I'm having my hopes high up for laser monitors. I mean just look at the 75" Mitsubishi LaserVue. If that isn't the ultimate display technology so far, it certainly is the only decent CRT successor. Multiscan, CRT blacks, even better colors, lighter and less power draw than plasma & LCD? Bring it!
 
Woah I just DL that cat for my desktop background in 1080p on this FW900. Thanks for the link, I can make out every hair and whisker, great image!

I never heard of laser monitors before, hope they pan out!
 
Yikes, I wouldnt screw around in there, just too dangerous even if you know what you are doing
 
Yah, back in 2005 my dad who is a Doctor, built his dream house himself, and knows about voltages- almost killed himself fixing a CRT monitor that i TOLD him to throw away (or use for target practice.) He had 2nd degree burns on his hand and heart problems for a few months after that. He was taking his time jumping on to the LCD bandwagon. Please be careful.

LCD's are super duper cheap- and alot safer.
 
Although I've already done a complete cleaning and focus adjustment on this monitor - I appreciate the warning. I am extremely careful around electricity and components, it has not yet had the chance to remind me how dangerous it is.

I don't plan on digging through the insides any more, aside from slightly lowering the G2 voltage to get rid of the retrace lines on startup, but that can be done through the case.
 
lcd and crt have their places. My lcd's place is portrait mode playing second fiddle to my crt, which is for fun mode. Unbeatable setup.
 
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