[vcf-midatlantic] Museum report: terminals

[Herb Johnson]

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