[NJARC] 3RP1 CR tube/Heathkit HO-10 Monitor Scope

[John Ruccolo]

Hi Scott,

It's NEVER easy with you, is it? ;-)

Pardon the pun, but in the future you should resist the temptation to "re-resistor" a piece of gear. That HO-10 is fairly modern, and most if not all of the resistors were probably still good (within tolerance, or at least close).

Think about it -- you didn't "re-resistor" that 70-plus year old Hallicrafters SX-16, why do it to a piece of gear only half that age?

The more parts you replace, the better your chances of making a silly wiring error that can be *extremely* difficult for you (OR YOUR FREINDS) to catch. By all means, get rid if the paper caps. But resistors are usually presumed innocent until proven guilty.


Folks, feel free to chime in.


Regards,

John R.



--- On Wed, 8/12/09, Scott Roberts <ng19delta at yahoo.com> wrote:

> From: Scott Roberts <ng19delta at yahoo.com>
> Subject: [NJARC] 3RP1 CR tube/Heathkit HO-10 Monitor Scope
> To: "NJARC Radio Club" <njarc at mailman.qth.net>
> Date: Wednesday, August 12, 2009, 1:22 PM
> Just remember 
> Reply = Poster
> Reply All = Everyone
> 
> _________________________________________________________
> Wow... Long Subject line...
> 
> Anyway, Simple question: First(as usual) the backstory:
> 
> I purchased the HO-10 scope with a couple known problems,
> so I decided to follow advice from a guy who works on them
> and not only recap, but re-resistor the whole item. No
> problem, simple stuff. However, in so doing, when I went to
> remove the CRT tube (3RP1) the base cap pulled off the
> wires! It was held very tightly by the socket, and literally
> pulled off the end: the adhesive had given up the ghost, and
> they pulled free of the solder, or the very ends of the
> wires came off.
> 
> So now I have an unkeyed tube with a bunch of good
> condition wires, and a cap to refit.
> 
> Looking at the schematic, would it be correct to assume
> that the only two wires I could read continuity between
> would be the heater connections? I looked over the schematic
> and found pins 5 & 11 were not used by the tube itself,
> and I determined where the gaps between wires were spaced to
> go to the pins on either side. I then looked at the line
> burned into the screen, and determined orientation, and
> checked alignment with the cap. It appeared to be correct,
> and my thought was that I could confirm by checking
> continuity through the heater, as it would be the only place
> I would find it. I assembled the cap to the tube after
> cleaning, fluxing & tinning the leads, just have to find
> my Duco cement to glue the base.
> 
> Simply put, is my above assumption correct?
> 
> 
> Thanks!
> Scott
> ______________________________________________________________
> NJARC mailing list
> Home: http://mailman.qth.net/mailman/listinfo/njarc
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:NJARC at mailman.qth.net
> 
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>