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B.M.
23-09-2003, 05:19 PM
Iíve got a Compac S710 17inch monitor, which although the brightness and contrast are flat out on 100 produces a picture one would normally expect if the adjustments were each set at 40.

I thought Iíd tweak the screen adjustment on the fly-back transformer only to find both adjustments appear to be focus?

Can someone point me in the right direction?

Bob

Pheonix
23-09-2003, 05:56 PM
What you are looking for is the A1's which have changed from the manual control you usually use, to automatically contolled by some electronics, to keep the level constant.
So basically the tube is getting tired.
What brand of tube is it?

B.M.
24-09-2003, 10:31 AM
Hi Phoenix,

Yes the tube itself is my worst fear. The other thing that points to the tube is itís very slow to fire up.

The tube is a Samsung, manufactured June 2000, so I would have expected it to last longer than 3 years.

Does not look good does it.

Pheonix
24-09-2003, 10:39 AM
Yeah, samsung haven't got a great name for their CRT's. I still remember several Unisys 15" monitors around the 2yr old mark having stuffed tubes. I have tried to rejuvinate them but have had no success at all with Samsung tubes.

kiwibeat
24-09-2003, 11:11 AM
Sell it asap and get a new bigger one

B.M.
25-09-2003, 09:05 AM
Just one last query. (Iím 90% sure the tube is dying)

Is it possible for a incorrect driver Video Driver to cause a Brightness/Contrast problem of this nature?

Bob

Pheonix
25-09-2003, 09:16 AM
Not that I am aware of. Substitution of another monitor on your PC , or your monitor on another PC should prove that, if you could. At least it would quell any doubts in your mind then.

the highlander
25-09-2003, 10:38 AM
If the onboard controls can't liven up your screen and you have an agp card why not just boost the gamma/ brightness/ contrast with the software app that comes with your card ? Not a elegant solution but better than shining a torch at your screen.

B.M.
25-09-2003, 04:53 PM
The Monitor is the same regardless of computer. Having said that, none of the computers itís been tried on have a specialised driver installed, nor do they have a AGP card.

I see Drivers.com have a driver for it so I might give that a try.

A typical case of a drowning man clutching at straws. :D

FrankS
26-09-2003, 02:41 PM
Have a fossick through
http://www.repairfaq.org/REPAIR/F_monfaq.html

Billy T
26-09-2003, 03:23 PM
Hi B.M.

If you have decided that your CRT is actually dying, there are three things you can do to eke out a little more life. One works better than the other two, and you have to be handy with a soldering iron for all of them!

The CRT heater will almost certainly be supplied by a 1 or 2 turn winding on the HV output transformer. This winding may not be obvious and is likely to be integral with the transformer. Whichever way it is generated, there should be two moderately heavy wires going up to the CRT base from the main circuit board, and if convention hasn't changed too much they will go to pins 4 & 5 on the CRT base, but don't count on it, trace it out for yourself.

Identify those wires and see if there is a resistor or choke in series with either of them. The first option is to increase the voltage supply to the CRT heater element by either shorting out any series choke or resistor. That will supply more energy to the heater thus boosting its emission for a brief but glorious period of time.

Second otion is to disconnect the existing supply and wind your own loop around the ferrite transformer core if you can get to it. Start with two turns and see how it goes. If it is too bright and you get white lines across the crt face at high brightness levels you may have to add a resistor in series to cut the voltage down. Something from 0.22 to 0.47 ohms will do.

Third and by far the best option is to get a 6.3/7.5/8.5 volt filament transformer and wire that in place of the original filament supply. You need to be knwledgeable and handy enough to find the 230 volt supply for the primary, and to hang somewhere safe inside the case, but this works a treat and the 50Hz ac seems to rejuvenate jaded cathodes by heating more broadly across their surface.

If 6.3 volts isn't enough, 7.5 almost always does it ok. Jaycar sell a suitable tapped transformer for $20 as CAT MM-2002. I have used the latter method successfully over the years on a range of TVs and monitors and got years more life in some cases.

Cheers

Billy 8-{) :)