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

[John Ruccolo]

Scott,

>From your note, it sounded like you were done already, and then the "CRT Incident" happened.

BTW, did you test the power xformer on that HO-10 first? They have a reputation for failing.


JR

--- On Thu, 8/13/09, Scott Roberts <ng19delta at yahoo.com> wrote:

> From: Scott Roberts <ng19delta at yahoo.com>
> Subject: Re: [NJARC] 3RP1 CR tube/Heathkit HO-10 Monitor Scope
> To: "NJARC Radio Club" <njarc at mailman.qth.net>, "John Ruccolo" <jr6v6gt at yahoo.com>
> Date: Thursday, August 13, 2009, 10:56 PM
> Thanks John.
> 
>  Mention it AFTER I start why dontcha!... LOL... However,
> it has helped expose several defects with the unit: I found
> one resistor which had obviously overheated the wire next to
> it, as I found them welded together... I also found a
> broken(clean in half!) resistor in one spot, and a couple
> other things. I am just annoyed I forgot to order the 3
> .22/600 caps I needed for it when I placed a large
> electrolytic order with Just Radios. (I can't use
> electrolytics in place of paper caps I'm sure...) I am also
> starting to swap in X-Y caps on the 120AC line on most of my
> machines. 
> 
> I found one problem with my shop: I have been getting bits
> together for so many different radios, I lost track of what
> goes to whom! So I spent last night after work sorting caps
> (mylar, electrolytics, and those little flat ones John likes
> to supply us with ;)) into little plastic buckets labeled
> for each radio. It is now a very organized little pile of
> caps :) I have about 6 radios/components & power
> supplies to recap!
> 
> Scott
> 
> 
> 
> --- On Thu, 8/13/09, John Ruccolo <jr6v6gt at yahoo.com>
> wrote:
> 
> > From: John Ruccolo <jr6v6gt at yahoo.com>
> > Subject: Re: [NJARC] 3RP1 CR tube/Heathkit HO-10
> Monitor Scope
> > To: "NJARC Radio Club" <njarc at mailman.qth.net>,
> "Scott Roberts" <ng19delta at yahoo.com>
> > Date: Thursday, August 13, 2009, 9:26 PM
> > 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
> > >
> >
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