CRT re-furb pages

[Gordon @ Convergent AV]

Hi Guys,

Hope no-one takes offence to this. I've started my article about how I'm cleaning up my Sony1270q DATA projector over at my web site.

First part's there now and I hope to get some time before Christmas to go to the next stage. This one's about re-setting and cleaning inside and tubes etc....If you have a s/h crt you may find it interesting.

Here's a direct link instead of having to trawl through the rest of the site.

Gordon

http://www.convergent-av.co.uk/pr031.htm

[Roland @ B4]

Good one Gordon. Keep it going.

[Mark Grant]

Nice site Gordon

Reminds me of the time about 2 years ago when I rescued an old Electrohome 8500 CRT from a Skip in London.

Three of them had been thrown out by an IT guy

I drove home from London up to Yorkshire with a big grin

It had a bit of burning on the tubes, but worked OK.

If I had found a good online resource for CRT tweaking, I would have kept it, and had a go, but I was not allowed to install it in the lounge , so sold it, and had to buy a DLP in the end.

I sold the 8500 for about £200, I must have been mad, knowing what I know now
Easy come, easy go.


Looking forward to the next site update Gordon!

If I could find a CRT with long throw lenses, I could install one at the back of my lounge, but need a throw distance of about 15 feet, and want a screen width of about 7 feet?

Mark G.

[jrwood]

Thats an interesting read , I still wish CRT's were much much smaller though. Do you recommend anyone poking around in CRT's? as I've always thought that CRT's should only be opened and fiddled with my experts due to the enormous voltages in these devices.

The reason I say that is I have a Dell 1626HT (going from memory) 21" CRT (Sony Tube) monitor with a strange problem. Basically the monitor when you first switch it on is fine and the picture is fantastic. However after about 2-3 minutes the blue 'gun?' turns off and therefore white becomes yellow and so forth. If I switch the Dell monitor off and then back on again all red/green/blue guns are on but then about 5 to 40 seconds later the blue gun turns off again. I think I had it on once for a bit and noticed the blue gun came back on for about a minute then off again, very strange problem indeed!.

It's out of warranty but I would like to replace this monitor I picked up cheaply as my current 20" isn't a Sony tube and I prefer the image quality of this Dell monitor if only the blue gun stayed on!. I did open up the Dell monitor case but all I could see was a massive metal grill covering all the components and couldnt really get to anything. I might try it again tonight though and use a duster buster to blow out all the filth in it see if that helps

James

[Gordon @ Convergent AV]

James:

If you read the article it does say in rather large typeface
WARNING: LETHAL VOLTAGES.....WARNING...IMMINENT DEATH...
or words to that effect.

I STRONGLY advise getting a professional to do these things for you if you are at all concerned or wary. Not all of what's going to happen is achievable by the man in the street. Removing the lenses and cleanig is a doddle though. Sticking your hands inside and adjusting magnets etc when it's on is not for the faint of heart. I take no responsibility for accidents.

Sounds to me like you have a dry joint or component over heating. I'd expect a TV engineer could get it working pretty quick.

Gordon

[jrwood]

Yeah I think I will take it to a computer shop and see if they can fix it, some offer a free service if they can't fix the monitor. I would of had a fiddle myself except there is no way I`m going to take off that metal cage which covers all the insides of this monitor completely .

I've seen quite a few 15" and 17" monitors insides and usually you can get to the boards. I have in the past replaced blown fuses on these types of small Dell monitors about 6 years ago when they had a faulty batch.

James

[Roland @ B4]

Unless you can be sure what you are doing it is sooooooo easy to knacker something. Most Barcos have a heat sink that is live 240 volts.

The worst shock was listening to a focus unit a bit too close. 34,000 volts onto your earlobe stings like hell.

Most of the damage people do is switching on when not every thing has been connected. If you do fiddle check it and check it again before you switch it back on.

James
Try turning your montior upside down or giving it a bit of a knock. If the blue comes back on should be repairable.




Now where did that screw come from - oh well it works!

[jrwood]

Well Ive just turned the beast upside down on the floor and plugged in my old laptop. After about 2 mins the blue gun turned off (I presume) and white on the desktop became yellow. I banged it and apart from the screen doing a sort of 'degauss' wobble the blue gun didnt 'wakeup'. However I watched it for a bit longer and after about 3 minutes the blue gun came back on .

Anyway Ive replaced the monitor cable that came with the Dell 1626HT and used the duster buster just now although I suspect its probably a dry joint. However it was in an office environment before so could be incredibly dusty inside!.

I`ll leave it upside down all night and see how it fairs

James

[jrwood]

Well the 21" monitor has been upside down all night and the blue gun is still off, its come on a few times when Ive randomly checked it tonight. It's a bit of a strange problem, but hopefully easily fixed by either a computer shop or tv repairman.

James

[jrwood]

Hmm strange things here!, I just had a look at the monitor and the laptop has gone into standby mode so no signal to the monitor. If there is no signal the monitor displays a diagnostic panel about 1/6th of the screen size with red/green/blue bar showing each of the primary colours. I noticed the colour was ok so I pressed a few keys on the laptop to 'wake' it up and after a bit the monitor screen lost its 'blue gun' again so white became yellow.

As it's time for bed I've just unplugged the laptop and left the monitor on and after about 30 seconds this diagnostic screen is now displaying the blue gun and white is now white

Where is Scully & Mulder when you need them

James

[Roland @ B4]

Is this a hard wired cable?
If not swap the red and blue over.

Does it have BNC inputs as well?

could be a simple as a broken lead

[jrwood]

The monitor has D-SUB and BNC connector inputs and its a seperate cable for both. Im sure I tried a BNC cable before and it had the same 'intermittant blue gun' problem but I will leave it plugged in tonight with a BNC cable when I get home from work.

It's a pity I cant get to the back connector plate with the monitor case off as Im pretty sure that is the root of the problem.

Will have a play tonight as lugging this 21" FST trinitron baby to a shop is a pain.

James

p.s considering it has the two faint lines to 'stabilise' the picture its very faint, probably the best stabilisation wires Ive ever seen as a friend has quite noticable thick lines on his, not sure why they all cant be like this as some of the iiyama 17" monitors Ive seen have quite noticable stabilisation wires.

[squid]

are you sure it's the monitor and not the output of the laptop that is the problem . i would try swaping the blue and red over with the bnc imputs and see it the red gos instead of the blue befor going to get the mon fixed .

[jrwood]

No I've tried it with about 4 PC's and the monitor exhibits the same symptoms on all of them. However tonight if I get time I will try the BNC cable and swap over the red/blue connectors and see what happens

thanks
James

[Mark Grant]

Gordon mentions on his site, having difficulty finding Isopropanol alcohol to use for cleaning.

The cheapest UK source I have found is CPC.

IPA is available in Aerosols for those hard to reach places, or in bottles, 250ml up to 1 litre etc, cheap as well.


CPC website is no use, but the catalogue is excellent, and a must have for any DIY/Tweaker that can get their hands on one.

Mark G.