working process to rejuvinate monitor CRT

[Cher]

My monitor is loosing brightness.

Does anyone have a working process to rejuvinate a CRT without an
actual commercial rejuvinator?

What voltage do I need to clean this out.

Does 700 sound right?

What is the max I can use. In days of old, 700 volt transformers were
plentifull. How about an oil furnace transformer or a neon sign
transformer?

I remember I once used the anode voltage on a 25 inch color tv to fix
it. Had nothing to loose, it was pretty dead - but it actually worked.

This monitor is still functional so I don't want to fry it in the
process.

thanks

 

[mike]

Cher wrote:

My monitor is loosing brightness.

Does anyone have a working process to rejuvinate a CRT without an
actual commercial rejuvinator?

What voltage do I need to clean this out.

Does 700 sound right?

What is the max I can use. In days of old, 700 volt transformers were
plentifull. How about an oil furnace transformer or a neon sign
transformer?

I remember I once used the anode voltage on a 25 inch color tv to fix
it. Had nothing to loose, it was pretty dead - but it actually worked.

This monitor is still functional so I don't want to fry it in the
process.

thanks

Are you sure it's the crt? Most of the "dim" problems I've had were due
to leaky ceramic caps on the crt neck board.
I've had some interesting results fixing crt internal leaks with a stun-gun.
mike

--
Bunch of stuff For Sale and Wanted at the link below.
laptops and parts Test Equipment
Honda CB-125S
TEK Sampling Sweep Plugin and RM564
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/

 

[James Sweet]

"Cher" <ccher@your.place> wrote in message
news:cd5srvoofqlkrj6ad5cbjqim8b95oh8lna@4ax.com...

My monitor is loosing brightness.

Does anyone have a working process to rejuvinate a CRT without an
actual commercial rejuvinator?

What voltage do I need to clean this out.

Does 700 sound right?

What is the max I can use. In days of old, 700 volt transformers were
plentifull. How about an oil furnace transformer or a neon sign
transformer?

I remember I once used the anode voltage on a 25 inch color tv to fix
it. Had nothing to loose, it was pretty dead - but it actually worked.

This monitor is still functional so I don't want to fry it in the
process.

thanks

If the problem is indeed the CRT then it's just worn out, modern tubes don't
rejuve very well, particularly high performance monitor tubes. If you try to
hack something together I can guarantee you'll destroy the tube completely,
you should have a shop with a good quality CRT tester test it first, and if
it's truly bad they can make a last ditch effort to rejuvenate it, but even
then it'll likely die within a few weeks to a month.

 

[Cher]

Well, it comes on very bright since I turned it off with the bright
control full up.
If I turn it down, within a min or 2 it is very dark and I have to
turn the bright back full up.

Can't think of caps causing this. Am I missing something?



On Fri, 21 Nov 2003 16:42:04 -0800, mike <spamme0@juno.com> wrote:

Cher wrote:
My monitor is loosing brightness.

Does anyone have a working process to rejuvinate a CRT without an
actual commercial rejuvinator?

What voltage do I need to clean this out.

Does 700 sound right?

What is the max I can use. In days of old, 700 volt transformers were
plentifull. How about an oil furnace transformer or a neon sign
transformer?

I remember I once used the anode voltage on a 25 inch color tv to fix
it. Had nothing to loose, it was pretty dead - but it actually worked.

This monitor is still functional so I don't want to fry it in the
process.

thanks

Are you sure it's the crt? Most of the "dim" problems I've had were due
to leaky ceramic caps on the crt neck board.
I've had some interesting results fixing crt internal leaks with a stun-gun.
mike

 

[mike]

Cher wrote:

Well, it comes on very bright since I turned it off with the bright
control full up.
If I turn it down, within a min or 2 it is very dark and I have to
turn the bright back full up.

Can't think of caps causing this. Am I missing something?



On Fri, 21 Nov 2003 16:42:04 -0800, mike <spamme0@juno.com> wrote:


Cher wrote:

My monitor is loosing brightness.

Does anyone have a working process to rejuvinate a CRT without an
actual commercial rejuvinator?

What voltage do I need to clean this out.

Does 700 sound right?

What is the max I can use. In days of old, 700 volt transformers were
plentifull. How about an oil furnace transformer or a neon sign
transformer?

I remember I once used the anode voltage on a 25 inch color tv to fix
it. Had nothing to loose, it was pretty dead - but it actually worked.

This monitor is still functional so I don't want to fry it in the
process.

thanks

Are you sure it's the crt? Most of the "dim" problems I've had were due
to leaky ceramic caps on the crt neck board.
I've had some interesting results fixing crt internal leaks with a stun-gun.
mike


Yes, you have the bad cap symptom.

Bad crt typically comes on dim and gets brighter.

It varies by brand. Just replace every ceramic cap that connects to a
crt grid pin. Start with the screen grid cap.
Can't easily test 'em, just replace. They'll be high voltage caps.
Sometimes you can just remove the caps as a test. Will get some ripple
showing
up in the brightness, but that will tell you if it fixes the dim thing.
But your design may be different from what I'm used to. Don't just
disconnect anything unless you're sure of the consequences.

If that doesn't work, start changing electrolytics on the crt neck
board. Assuming the color tint doesn't change, you're looking for bias
voltages that affect all 3 drivers. If you have schematics, you can
start there. Otherwise, just replace all the electrolytics on the neck
board.

Still could be an internal crt short that's temp dependent. Stun-gun
can fix that.

mike

--
Bunch of stuff For Sale and Wanted at the link below.
laptops and parts Test Equipment
Honda CB-125S
TEK Sampling Sweep Plugin and RM564
Tek 2465 $800, ham radio, 30pS pulser
Tektronix Concept Books, spot welding head...
http://www.geocities.com/SiliconValley/Monitor/4710/