TRS-80 Model 12 crt substitution

From: Witchy <>
Date: Wed Mar 3 16:23:10 2004

> -----Original Message-----
> From:
> [] On Behalf Of Ralph E. Dodd
> Sent: 03 March 2004 20:46
> To:
> Subject: TRS-80 Model 12 crt substitution
> Hello,
> I broke the neck off the crt in my TRS-80 Model 12. I have a
> crt from a Model 4. Can I use this in the Model 12 or will it
> cause problems like smoke etc.? Thanks.

If the M12 is anything like the M2 it just uses a standard 12" B&W TV tube.
When my model 2 was 'handled' by airport baggage crews they smashed the
screen to bits, so I replaced it with the screen from a standard old B&W TV.
If that's the case remember to change only the tube itself, ie leave ALL the
wiring behind - you must loosen the holding screw(s) on the yoke (the mass
of copper wiring) and fit it to the 'new' tube. Remember not to tighten too

I'm assuming you also know that if you power up the replacement screen and
it doesn't work you must either discharge the tube with a suitable EHT meter
on the connection to the flyback transformer (very thick wire going to the
back of the screen rather than to the neck) or leave it overnight to
discharge itself before swapping in another one.

Tony will be along soon with some more info :o)


Owner & Webmaster, Binary Dinosaurs - possibly the UK's biggest online computer museum - ex-monthly gothic shenanigans :o(
Received on Wed Mar 03 2004 - 16:23:10 GMT

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