Posted by JosephKK on 11/11/07 06:22

jakdedert jakdedert@bellsouth.net posted to rec.photo.digital:

> Igor wrote:
>> On Tue, 6 Nov 2007 12:20:43 -0700, "Bob Myers"
>> <nospamplease@address.invalid> wrote:
>>
>> <snip>
>>
>>> And realistically, a CRT monitor cannot be "refurbished"
>>> without replacement of the tube. <snip>
>>
>> Would replacing the tube be prohibitively expensive?
>> --
>
> When they quit making them (soon), and when NOS runs out
> (eventually),
> yes...depending on your definition of 'prohibitive'. Just when the
> above will happen is a guess; but crt plants world-wide are shutting
> down NOW. Most models--and there are thousands--are probably not
> easily available even now, due to the fact that crt replacement
> hasn't been a
> common procedure for decades. Given the hour or so required for
> alignment of a new crt, it's long been more economical to replace
> the entire set except in specialty or industrial applications.

What hour of alignment or so are you talking about? That has not been
necessary since the early 1980's. Even late 1980's projection sets
did auto-alignment. It is a result of manufacturing the deflection
yoke on the tube. It makes the process less expensive and improves
the picture quality.


>
> That said, if a demand exists, someone will fill the vacuum. It's
> still a question of price.
>
> Most other parts of a monitor are stock, replaceable (or
> rebuildable)
> devices. Building new crt's is not something easily taken up as a
> 'cottage' industry.
>
> In early-tv hobby circles, crt's are reportedly still 'refurbished'.
> This involves opening the glass envelope and replacing the electron
> gun assembly (all the electrical parts in the neck of the tube),
> then
> evacuating and resealing the tube. This cottage industry is largely
> dependent on availability of NOS replacement 'guns' or electron beam
> assemblies, and the reported cost for doing a monochrome crt is
> around
> $250. Of course, this depends on the availability of replacement
> parts.
>
> A color unit will cost more...and all is dependent on the condition
> of rest of the tube--shadow mask and screen phosphors--being worthy
> of the
> effort. Even these problems can be overcome, but again, price is
> the issue.
>

Correct, but not necessarily for the reasons you are considering.
Even in the 1940's very few amature radio types tried to construct
their own vacuum tubes. Even then the changes in the ration of labor
cost and materials cost were changing. The infrastructure cost for
constructing semiconductor devices is hideously more so.


> I did an extensive web search and was unable to definitively locate
> a
> price for the above. I found a few that claim to do the work, but
> require a request for quote. I'm sure it wouldn't be cheap.....
>
> jak
>
>> "Those of us whose brains did not die in college are
>> actually stunned by just how stupid academic ideas
>> are." -- Robert W. Whitaker, http://readbob.com/
>>

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