IBM 2124 Monitor

[Charlie Bress]

This monitor is my son's and is not at my location.
He called with the following symptoms.
No display (except for a very brief showing of the start up screen, then
blank).
The power on led flashes between bright to dim and is always green, not
the yellow
that indicates the system is "asleep".

I suspect something in the power supply has gone awry.
Does any one have any info on the type of supplies, nominal voltages,
and the like. I will be at his house in a few days and will bring along
a DVM, soldering iron, and high hopes.
I have done board level repairs, but have never looked inside this
family
of monitors and will be groping along.

Any and all help will be appreciated.

--
Charlie

To reply delete "noless" from userid

[Jerry G.]

The best suggestion I can give is to varify that the powersupply is
working correctly. If not, then also check the horiz output
transistor.

I have seen the flyback go bad in these types of monitors. When this
happens the horiz output usualy goes down with it.

Unfortunatly the parts for an IBM monitor are very hard to get. They
don't like to sell the parts. I did find out that ViewSonic, and
Sony will sell parts and service manuals. I would buy one of these
makes if I were shoppping for a computer monitor.

--

Jerry Greenberg

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Electronic Components, And Navigation Compasses

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"Charlie Bress" <cbress...@earthlink.net> wrote in message
news:390A41D9...@earthlink.net...

[Tom MacIntyre]

There's a 220pF capacitor, 2kV, that fails in these. It's just off the
HOT collector. Replace with a 3kV or higher capacitor. Fix up the
solder connections in the general area also.

Tom

[u1061771156]

In article <390A41D9...@earthlink.net>, Charlie Bress wrote:
>No display (except for a very brief showing of the start up screen, then
>blank).
>The power on led flashes between bright to dim and is always green, not
>the yellow
>that indicates the system is "asleep".
>
>I suspect something in the power supply has gone awry.
>Does any one have any info on the type of supplies, nominal voltages,
>and the like. I will be at his house in a few days and will bring along
>a DVM, soldering iron, and high hopes.
>I have done board level repairs, but have never looked inside this
>family of monitors and will be groping along.

>Charlie

I fixed one of these recently. The LED throbbed green, it basically
indicated that the psu came on, tripped out due to overcurrent, and
repeated at about 2Hz.

This was due to a shorted cap, next to the where the scan yoke cable
plugs into the PCB. C335 220pF 2KV. I'm told it's a common failure
on this model. In my case it blew the B+ regulator device Q317 2SK2161
and the scan controller chip. If yours comes up momentarily before
cutting out, then maybe the cap's only leaking so far?

Search for my userid on deja for the full story...

Regards,
Mike.