[R-390] Tube removal

[Barry]

Yes, I'm familiar with those. I thought I had a pair of them hanging on the back of my R390 but I was mistaken. 

Thanks, 
Barry - N4BUQ 

> From: "wc4g at knology.net" <donwc4g at gmail.com>
> To: "Barry" <n4buq at knology.net>
> Cc: "Tisha Hayes" <tisha.hayes at gmail.com>, "R-390 Mailing List"
> <r-390 at mailman.qth.net>
> Sent: Thursday, January 6, 2022 11:16:48 AM
> Subject: Re: [R-390] Tube removal

> Barry and all, here are the tube pullers we all really want!
> I am continuing to look.
> Regards,
> Don WC4G

> On Thu, Jan 6, 2022 at 11:13 AM Barry < [ mailto:n4buq at knology.net |
> n4buq at knology.net ] > wrote:

>> In a pinch (no pun intended), I would think that a pair of common kitchen
>> scissor-style tongs with some shrink wrap or thin rubber tubing wrapped around
>> the ends would work as well.

>> I have some of the older Tektronix items (Type 106, Type 191 as well as a Type
>> 184 which uses nuvistors). The 106 and 191 have tubes with IERC shields. I
>> tried to remove one of those shields in the 106 and I simply could not pull it
>> loose. I've used IERC shields before and they can be tough to pull when they're
>> locked to the tube base (which they should be to work properly) but I simply
>> could not pull hard enough to remove them in the 106!

>> Thanks,
>> Barry - N4BUQ

>> ----- Original Message -----
>> > From: "Tisha Hayes" < [ mailto:tisha.hayes at gmail.com | tisha.hayes at gmail.com ] >
>>> To: "R-390 Mailing List" < [ mailto:r-390 at mailman.qth.net |
>> > r-390 at mailman.qth.net ] >
>> > Sent: Thursday, January 6, 2022 9:52:34 AM
>> > Subject: [R-390] Tube removal

>> > Those "Chinese finger-puzzle" type of grips are still used but on cables;
>> > You will find them for suspending coax cables inside of cellular towers
>> > from the top and along the midspan. They are known as "Kellum grips".

>> > Now, a Kellum grip used for cabling might be a bit too "aggressive" but
>> > glass is amazingly resilient when forces are applied equally around their
>> > radius. You would need to find a light-duty one.

>> > The gorilla tape is a great idea; You can always remove the adhesive from
>> > Gorilla tape with the universal solvent... WD-40.

>> > Another alternative would be to find an "IERC tube shield". Those are as
>> > rare as hen's-teeth and quite valuable in the tube-radio market. They are a
>> > black metallic shield that slides down over the top of a tube and are used
>> > for shielding and thermal dissipation. They have beryllium-copper
>> > fingerstock inside of the shields that tightly grabs the tube glass and
>> > couples the heat to the metal shield. If you could slide an IERC shield
>> > down over the tube you could then grab the top lip of the shield with a
>> > pair of needle-nose pliers and rock the tube up and out of the socket in a
>> > confined space.

>> > A bunch of years past I did a writeup on the thermal improvements in a
>> > Hammarlund SP-600 (posted on a different list) between unshielded tubes,
>> > silver-metallic shielded tubes and IERC shielded tubes on an SP-600 that
>> > was installed in a closed cabinet. It involved thermocouples attached to
>> > the chassis and key components in multiple locations, regulated AC
>> > supplies, temperature controlled rooms and a few weeks of data collection.
>> > The end result was that the IERC shields did knock down the temperature of
>> > the chassis by an average of 5c to 15c. The purpose was in how such
>> > temperature reduction would have on extending the life of components like
>> > electrolytic capacitors and on frequency drift of the receiver. I do not
>> > even have the writeup or data any more; it was lost in one of the many hard
>> > drive failures that we all experience with computers.

>> > I did end up buying a significant quantity of IERC shields and they are
>> > still installed on my SP-600-JX17, R-390A and the much despised (by me)
>> > CV-591 SSB converter.

>> > *Ms. Tisha Hayes*

>> > *AA4HA*
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