Need to repair many IBM G74 Monitor, Model #6547-0AN [Repair]

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From: ferkee on 12 Apr 2005 13:14

I am part of an I.T. shop for a company that has many many many of these
IBM G74 monitors. They are gradually starting to all have problems

1. Very dark - Brightness/Contrast controls are not effective and
are maxed out
2. Display wider than screen - Width adjustment has very little
effect

We have so many, but I'd like to figure out what to look for and how to
repair them. I'm really starting to feel stupid and wasteful when we
are told to just "junk 'em" and get another. They're fantastic
monitors. I am sure the company (or at least the organization that I
support) would be somewhat impressed if I could repair them with little
trouble and expense.

The other rather embarrassing fact is that I have a EE degree! It was
almost all book-smarts if you know what I mean and was not really
electronics, per se. I have not been in the electronics nor the
engineering world since 1991! I have a FLUKE DMM (at home...don't have
the model # with me) and I have soldering tools. I actually have access
to an entire workforce of component people (our value add shop), but I'd
like to eventually do this myself.

Can anybody help me here?

Thanks,
John

PS, I'm in the DFW area (Dallas/Fort Worth, Texas)

--
ferkee

From: NSM on 12 Apr 2005 21:59

From: James Sweet on 12 Apr 2005 23:27

"ferkee" <ferkee.1necxm(a)news.diybanter.com> wrote in message
news:ferkee.1necxm(a)news.diybanter.com...
>
> I am part of an I.T. shop for a company that has many many many of these
> IBM G74 monitors. They are gradually starting to all have problems
>
> 1. Very dark - Brightness/Contrast controls are not effective and
> are maxed out
> 2. Display wider than screen - Width adjustment has very little
> effect
>
> We have so many, but I'd like to figure out what to look for and how to
> repair them. I'm really starting to feel stupid and wasteful when we
> are told to just "junk 'em" and get another. They're fantastic
> monitors. I am sure the company (or at least the organization that I
> support) would be somewhat impressed if I could repair them with little
> trouble and expense.
>
> The other rather embarrassing fact is that I have a EE degree! It was
> almost all book-smarts if you know what I mean and was not really
> electronics, per se. I have not been in the electronics nor the
> engineering world since 1991! I have a FLUKE DMM (at home...don't have
> the model # with me) and I have soldering tools. I actually have access
> to an entire workforce of component people (our value add shop), but I'd
> like to eventually do this myself.
>
> Can anybody help me here?
>
>
> Thanks,
> John
>
> PS, I'm in the DFW area (Dallas/Fort Worth, Texas)
>
>
> --
> ferkee

For the brightness problem, look at the heater in the neck of the tube, is
it glowing normally? If not then you might have a bad capacitor in the power
supply. If the heater is ok and HV is present, chances are the tube is shot.

For the width issue look for a bad capacitor somewhere around the horizontal
section.

Oh and do NOT under any circumstances try to adjust out either of the faults
unless you want to make the monitor not worth repairing.

From: Franc Zabkar on 13 Apr 2005 03:58

On Tue, 12 Apr 2005 18:14:37 +0100, ferkee
<ferkee.1necxm(a)news.diybanter.com> put finger to keyboard and
composed:

>
>I am part of an I.T. shop for a company that has many many many of these
>IBM G74 monitors. They are gradually starting to all have problems
>
>1. Very dark - Brightness/Contrast controls are not effective and
>are maxed out
>2. Display wider than screen - Width adjustment has very little
>effect

According to the Google Groups archives, the width problem is due to a
3.3uF non polarized 65V capacitor.

http://groups-beta.google.com/group/sci.electronics.repair/msg/3c5efd6875333540?dmode=source

- Franc Zabkar
--
Please remove one 's' from my address when replying by email.

From: Tom MacIntyre on 13 Apr 2005 16:13

On Tue, 12 Apr 2005 18:14:37 +0100, ferkee
<ferkee.1necxm(a)news.diybanter.com> wrote:

>
>I am part of an I.T. shop for a company that has many many many of these
>IBM G74 monitors. They are gradually starting to all have problems
>
>1. Very dark - Brightness/Contrast controls are not effective and
>are maxed out

Do they have Samsung blue-label CRT's? If so, that's the problem.

Tom

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