"SIOL" bravely wrote to "All" (15 Dec 04 07:31:51)
--- on the heady topic of " What cause CRT blur?"

SI From: "SIOL"

SI "CJT" wrote in message
SI ...

There are several possibilities, including (in no particular order) -

SNIP
aging of the CRT
SNIP

SI How can aging of the CRT result in picture blurring ?

SI I know that kathodes or heaters could wore out or that phosphor could
SI decay, but what effect would cause blurriness ?


The effective interelectrode potentials in the electron gun are
dependant on the beam current. If a gun is too weak the beam doesn't
focus at the right distance anymore.


SI Most of the units I have seen got that way aither due to HV pots (for
SI focus and screen) and due to demagnetisation of the calibration magnets
SI and rings. IOW, nothing that couldn't be trimmed and retweaked...

Modern crt's did away with the colour convergence coils so this can't
be adjusted anymore. It's the price to pay for needing less circuitry.

A*s*i*m*o*v

.... I worked hard to attach the electrodes to it.