For the vintage computer collector though, replacing
picture tubes is generally done with used tubes from
something else. A lot of monochrome tubes are pretty
much interchangeable. Save junk terminals with decent
tubes, they might come in handy. Also, don't overlook
TV's - the picture tubes in 12" black and white TV's
I rememebr about 20 years ago I needed a new CRT for a somewhat rare
(even then) terminal. After phoniug round a dozen CRT stockists, and
getting the same story from every one ('12" black and white TVs are not
worth repairing if the tube goes, so we don't stock them'), I finally
realised the cheapest way to get a CRT (even then) was to buy a cheap TV
and take the CRT out of it. Oh, and add some interesting components to
the junk box as a by-product.
make a pretty good replacement for many computers,
I've used a TV tube in a TRS-80 Model III. Also, one
time when I was bored, I transplanted the tube from an
IBM 5151 display into a 12" Zenith black and white TV
set. It worked fine, although the long persistance
phosphor and WordPerfect screen burn made TV unusual.
The things to look out for in swapping tubes is the
physical mounting, the neck size, and base. Typically,
if the base matches up, the yoke fits and you can bolt
it in there, it should work. Modifying mountings is OK
In gneeral, for small mono CRTs, there are thin-neck ones with a modified
B7G base (7 piu, the 'modification' being the seal-off tube in the
centre) and a 12V-ish heater and thicker nexk ones with a B8H base (8 pin
with a plastic locating hey in the middle round the seal-off tube) and a
6.3V heater. Virtually all computer monitor/terminal CRTs have a 90 dgree
deflection angle (some late-model portable TVs over here used 115 degree
tubes, those are not useful in computer terminals). And in each category
they're pretty much interchangeable. You may need to tweak the anode
voltages to get the best picture, but it should work anyway.
-tony