How Many Screens Have You "Accidentally Cracked" ?

[ReeceyBurger123]

Just wandering people how many Crt, Lcd, Pdp or Oled screens have you cracked accidentally ? This could be when repairing the display or just pure harsh luck.

I can proudly say in all 322 Tvs I have repaired (so far) I have never accidentally cracked a single display Of course some that haven't been economically repairable have met the sole of my foot lol

[eccerr0r]

Re: How Many Screens Have You "Accidentally Cracked" ?

1. I dropped a CRT monitor.
It wasn't as spectacular as I thought it would be.

[Pentium4]

Re: How Many Screens Have You "Accidentally Cracked" ?

Zero
I find it amazing when you look on ebay and craiglist, to see how many "AS IS" units are because the screen is shattered. For TVs and monitors. I just don't know how it happens on such a large scale.

[xelectech]

Re: How Many Screens Have You "Accidentally Cracked" ?

Hm, just one so far. It was back in the mid 80's and I was carrying a so-called portable table model out to the customer's car. The thing must have weighed a good 75 lbs., the handle was at the top of the set - and it pulled free from the set. Probably busted some of the other tubes, too, talk about a downer .

[momaka]

Re: How Many Screens Have You "Accidentally Cracked" ?

I never cracked any either. Then again, I don't do that much work on LCD TVs and monitors. Only have repaired like 11 or so LCDs total.

As for CRT - how do you crack that?!
These things are tough to break. Even a story with pictures of one guy here (on BCN) accidentally having his 100 lbs (~45 Kg) 24" CRT roll down the stairs a full story and still working afterwards.

I just don't know how it happens on such a large scale.

Well, for LCDs (especially TVs), the Wii-mote usually does it.
https://www.youtube.com/watch?v=a07W2t2wcRA&t=4m55s

[eccerr0r]

Re: How Many Screens Have You "Accidentally Cracked" ?

I just dropped it from 3-4 ft when it slipped from my fingers, it fell straight down to the floor oriented the way you'd view it. Something caused a vibration and the stem cracked, letting the air in. At least I got a flyback transformer out of it to play with...

I don't see myself breaking an LCD yet. Knock on wood. I bet my phones or laptop may be the first one...

[ReeceyBurger123]

Re: How Many Screens Have You "Accidentally Cracked" ?

Lol

[diif]

Re: How Many Screens Have You "Accidentally Cracked" ?

Just two on my Galaxy S3 and i managed to fcuk up a screen on a HP laptop. I didn't realise the LED circuitry was stuck to the bezel when I removed it and it tore the ribbon cable.

[stj]

Re: How Many Screens Have You "Accidentally Cracked" ?

i have seen small crt's dropped so hard that the scan-coils have ripped the neck off the back of the tube!

usually on portable test gear that came down a ladder faster than the engineer!

[momaka]

Re: How Many Screens Have You "Accidentally Cracked" ?

I just dropped it from 3-4 ft when it slipped from my fingers, it fell straight down to the floor oriented the way you'd view it.

Interesting.
The front of the screen is usually the toughest part of the CRT.
https://www.youtube.com/watch?v=4el9omevmIs&t=2m51s

[Spork Schivago]

Re: How Many Screens Have You "Accidentally Cracked" ?

Usually the tablets / cell phones we get are already cracked. We have an Asus Memo Pad 8 (or maybe 7?) and we need to remove the digitizer and screen to clean it. There's water inside. My wife is a lot better at removing screens than I am. It's been awhile since she removed a good screen so she practiced on an old broken tablet we had. She didn't realize the screen adhesive was really strong and cracked the screen on the old broken one! Thankfully it wasn't the production one. Anyway, what she does now, she uses my Weller WHA900 Hot Air Rework Station to melt the adhesive a bit and uses these little suction cups to lift up the screen without bending the plastic.

[eccerr0r]

Re: How Many Screens Have You "Accidentally Cracked" ?

Interesting.
The front of the screen is usually the toughest part of the CRT.
https://www.youtube.com/watch?v=4el9omevmIs&t=2m51s

Eh no, not face down or up, the monitor is in the "normal" position how one would normally use a CRT. The neck is the weakest portion and it hit something internal and broke.

[stj]

Re: How Many Screens Have You "Accidentally Cracked" ?

more likely the weight of the neck-pcb did it.

[momaka]

Re: How Many Screens Have You "Accidentally Cracked" ?

Eh no, not face down or up, the monitor is in the "normal" position how one would normally use a CRT.

Ah, okay. Now I understand what you meant when you said, "it fell straight down to the floor oriented the way you'd view it."

more likely the weight of the neck-pcb did it.

Agreed.
Either that or the yoke/focus/deflection coils assembly. Lots of copper in those, so they do weight a lot. It's one of the things the copper scrappers around here always take.

[eccerr0r]

Re: How Many Screens Have You "Accidentally Cracked" ?

Indeed quite possibly it was the gun drivers pcb attached to the end, then again, there are the people who had it survive drops. The yoke probably would be OK as it's getting to the bell which is quite a bit stronger - in my case the yoke was intact.

It was a 17" shadowmask monitor. I guess I wasn't too upset about it though I had bought it new. It was starting to have vertical amp noise introduced...alas you all can guess why...



BAD CAPS...

I still have a 19" (shadowmask) and 21" (Trinitron) CRT monitors, a 19" CRT TV, a 5" CRT TV, and a 3" oscope left with CRTs. That's not including the 0.5" CRT in this borked Hi-8 video camera I have (I acquired it broken...)

[momaka]

Re: How Many Screens Have You "Accidentally Cracked" ?

That's not including the 0.5" CRT

Half inch? LOL! That is so tiny.
I am guessing that is for the viewfinder?

[eccerr0r]

Re: How Many Screens Have You "Accidentally Cracked" ?

Yes, the viewfinder is a half or 3/4" CRT in there... Not so funny after you find out they're real... The "eyepiece" has a lens on it to magnify the screen too

It unfortunately is a black and white tube, but what can you ask for when the the screen is that small.

The aspect ratio (screen size vs length) you can guess is pretty bad, just to make sure linearity is good with simple electronics... The tube is about 3 inches long with the about half inch face.

Another thing I was wondering, what voltage is needed for these tiny CRTs? I'd guess that maybe 3KV is enough to get the cathode ray going for a tube this small. With the voltage this low I'd imagine that generating x rays is kind of hard...

[stj]

Re: How Many Screens Have You "Accidentally Cracked" ?

if you play with one, the power to the HV circuit is usually 9v

[eccerr0r]

Re: How Many Screens Have You "Accidentally Cracked" ?

Yeah I see the tiny "flyback" (but I'm not sure if it's "really" a flyback vs a discrete switching PSU)... The voltage in probably is working as the CRT is lighting up just fine (screen starts up with random lines as if the cathode control is messed up along with the sweep circuitry, and then after warming up a bit the screen is all white.)

This circuit was made in 1995 or so. Sounds like it very well could be in the danger zone...

Alas still trying to figure out how to get the PCB out of the case. The CRT is loose when the case is open but the PCB is either glued or I can't find where it's being attached...

[TechGeek]

Re: How Many Screens Have You "Accidentally Cracked" ?

if you play with one, the power to the HV circuit is usually 9v

9kV or 9VDC?