Swapping CRTs

From: Wayne M. Smith <wmsmith_at_earthlink.net>
Date: Sat Oct 21 17:58:35 2000

> > I have an IBM System 23 with a badly burned screen.
> > The CRT is a 12 inch monochrome green screen. Does
> > anyone know whether I can replace the CRT with the
12"
> > green monitor CRT that came with the original IBM
PC
> > (and which are easy to find)? The model no. of
that
> > monitor is 5131?
>
> IIRC the IBM PC MDA monitor is a 5151, not a 5131,
but anyway...
>
> How many pins does the System 23 CRT have? If it's
got 7 pins in a
> 'modified B7G' arrangement -- like a 7 pin miniature
valve with a
> seal-off tube in the middle and _no_ plastic shell
with a locator, then
> it's likely to work
>
> Basically, there are 2 common classes of monochrome
CRT. 7 pin (modified
> B7G) with a 12V heater or 8 pin (B8H) with a 6.3V
heater. Within a class
> you're likely to have few problems swapping them.
>
> Keep the yoke with the monitor it goes with -- these
are much less
> generic than CRTs. Undo the clamp around the back end
of the yoke and
> carefully silde the yoke off towards the back of the
monitor. Don't force
> it -- if it won't come off easily, take the clamp
right off, and use a
> screwdriver to _carefully_ spread the slits in the
yoke's clamp tube to
> free it.
>
> -tony

It's the same 7-pin arrangement according to my
maintenance documentation (I haven't opened up the unit
yet). The documentation also indicates that the CRT is
interchangeable with several other models, which is
encouraging. BTW, you're right, it's a 5151 not a
5131. Thanks for the excellent help.

-W
Received on Sat Oct 21 2000 - 17:58:35 BST