[vcf-midatlantic] Museum report: terminals

systems_glitch systems.glitch at gmail.com
Mon Jul 9 14:35:02 EDT 2018

If you don't like the idea of heat gunning a tube, there are other methods:
I've seen them floated off over an extended period in room-temperature
water, or heated by placing face-up in the sun with a black trash bag over
the front.

I've done the heat gun method, you don't need to get it crazy hot, and in
my experience the PVA layer pretty much peels off, if you do it right. It
leaves slimy residue on the safety glass and the tube, but this comes off
with alcohol. I stuck my CRTs in a 5-gallon bucket and only heated the face
of it. It would've been uncomfortable to hold the safety glass, but not so
hot as to burn you.


On Mon, Jul 9, 2018 at 2:23 PM, Herb Johnson via vcf-midatlantic <
vcf-midatlantic at lists.vcfed.org> wrote:

> On 7/9/2018 1:04 PM, Evan Koblentz wrote:
>> Well, Evan asked me to come in on Sunday, to review the terminals and
>>> inventory them. ...I'll send Evan a more detailed report, but he has the
>>> list and location-of information I compiled Sunday.
>> We definitely picked the right person for this job! Thanks again Herb for
>> the detailed report you gave me yesterday.
> To be clear, I gave Evan on Sunday a list of terminals and shelf
> locations. Today he got my detailed report by email, and my comments as
> posted here.
> Jonathan Gevaryahu wrote:
> These CRT tubes don't have to be replaced, the CRTs can be very carefully
>> heatgunned to remove the front protective glass cover and scrape out the
>> 'cataract' goo. I think Ian has done it to a few of them already?
> Ethan Dicks also described this process. Also here's where someone
> describe it to me:
> http://www.retrotechnology.com/restore/adm3a_nick.html
> I'll be blunt to be brief. A heatgun on a messy, gooey, HOT, CRT is too
> dangerous and takes too long, in my opinion. I won't do it. Ian and others
> may do such things. "There are old pilots, there are bold pilots, but there
> aren't many old, bold pilots."
> Private email to me:
> Hey Herb: where can one get replacement CRTs for "tens of dollars"?
>>  I'm looking to repair an H19 that is otherwise in good shape but  the
>> CRT seems to be bad. Tx.
> Rebuilt CRT's for common CRT's say 12-inch, seem to be under $100, maybe
> well under. Try
> https://cathoderaytubes.com
> Used CRT's, say salvaged from other computers, are less. About "bad", you
> weren't specific. Heath H89's and H19's use the same CRT. (Zenith Z89,
> Z19), so look for another unit. I have extra Heath CRT's, I'll get back to
> ya on that.
> But the common problem with those models, is poor contact at the CRT
> socket and pins for the high-current filament. See if the filament is
> "lit", if not see if wriggling the socket changes your results. YOu can
> tell me privately about other CRT problems.
> Herb "Cathode Ray" Johnson
> --
> Herbert R. Johnson, New Jersey in the USA
> http://www.retrotechnology.com OR .net
> preserve, recover, restore 1970's computing
> email: hjohnson AT retrotechnology DOT com
> or try later herbjohnson AT retrotechnology DOT info

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