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CRT tube making a static crackly sound


brentos82

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Hi I have a Toshiba 20 inch tube with a new universal Chassis. All working fine but when I turned it on today I notice the tube is making a constant sound kinda sounds like static electricity or like a frying pan sizzling on low. haha . Bit worrying. Its not very loud but it wasn't there before (from memory )

It sounds like its at the back and near the suction cup but hard to tell exactly. Is this bad?

All help appreciated.

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Montior likely arcing around the anode cup. Yes it's bad, but far from disastrous and a very common issue.

 

Discharge the monitor, remove the anode cup, clean the shit out of the cup and the back of the tube with a microfibre cloth and isopropyl alcohol (metho will work in a pinch) and then reseat the anode cup. If it's still arcing, rub some dielectric grease around the anode and then reseat it again, Vaseline will work in place of dielectric grease.

 

Ensure the two prongs inside the anode cup are firmly seated inside the hole, if one is loose, you will get arcing. If there is dust caught under the cap, arcing. If a dog walks past and farts in the direction of your monitor, arcing. You get the picture. Arcing is common, don't stress, just clean and reseat the anode cup.

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If the hook is rusty, or if the anode button itself is rusty inside, feel free to use sandpaper.

 

(I posted in another thread about using spark-plug-grease in preference to vaseline, but i suspect the anode caps are actually made of synthetic rubber, so petroleum-based dielectric substances like vaseline shouldn't hurt.)

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Hey guys so I discharged and cleaned with alcohol. Applied some Vasoline and put the suction cup back in. No improvement. Tried repositioning the suction cup thing and turned it on again.

Some improvement this time.

I forgot to mention I can actually see tiny blue sparks about 6 inches to the left of the suction cup. Not right around the suction cup.

There are less sparks now after cleaning , lets say 2 sparks and the noise is quieter compared to about 10 sparks and a louder noise the first time...

Any thoughts? Should I do it again?

I should also add that the Chassis is brand new from Jomac..maybe 4 weeks old so the suction cap was clean and in good condition.

Edited by brentos82
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Clean it again, then again, then again. Reseat again, again and again.

 

If you cannot get rid of the issue, contact Joey and he may suggesting adjusting some voltage pots on the chassis. The B+ voltage might be too high, which can cause arcing also, but I don't know if that arcing would be present at the anode cup or elsewhere.

 

I had an astro city monitor that always had persistent arcing issues at the anode cup. Only minor, a slight fizzle constantly, but enough to warrant fixing it. It took me a long time of cleaning, reseating, turning the anode cup and using vaseline to get it just right so that it didn't arc. I spent around 3-4 hours one arvo doing it.

 

EDIT: Also, when I say clean it, I mean clean the entire back of the tube, don't just focus on the anode cup. I know it seems silly, but cleaning the entire back of the tube has stopped arcing for me on a number of occasions.

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Hi namastepat

Yeh thanks mate I will give that a go... Does the alcohol go on the back of the tube too or just the back of the suction?

Just to be clear, the sparks I see are no where near the anode cup and they don't look as if they come out from under it. I looked it up on youtube and can't see anything similar to what I am getting. Is it possible the sparks are inside the tube? Could it be I am seeing sparks inside the tube where the aquadag has been scratched away a bit. Or something to do with the grounding strap not being setup properly????

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Wait, hang on, the sparks are not near the anode cup? Sorry, misread your post. I've never had arcing on the back of the tube itself, only at the anode cup. I would still clean the ever living hell out of the tube, isopropyl sprayed on a clean microfibre cloth and then wiping the back of the tube. Even if the aquadag is scratched a bit, it shouldn't cause arcing, not in my experience anyway. All of my tubes have scratched aquadag around the anode cup area due to people discharging the tube over time.
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Yep so just confirming the sparks are about 6 inches to the left of the anode cup. They don't seem to be coming out from under the anode cup otherwise they would be 6 inches long. Instead they are very tiny and blue. Sort of in a straight line and I can't tell if its in front or behind the glass. I'm trying not to get too close and I turn it off once I see them..

The grounding strap is connected to the E pin on the neckbeard and thats all. Is that correct procedure? Sufficient?

I actually have a wooden frame that the CRT is bolted to and then slides down into some grooves . So I don't have a metal frame like most screens. When I discharge the monitor I just hook the alligator clips to the metal parts that the bolts go through.

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Ok gave her a wipe, plugged in a turned on. No sparks, no sizzling noise. There is a very slight hum but it just sounds like an operational type of sound.

Looks like cleaning it solved the trick. Oh and my measurements were out. It was about 3 inches from the cup not 6. So it may have just been small sparks flying out from there.

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