[Heathkit] Need A One Ohm Variable Resistor

Mon Sep 30 14:00:38 EDT 2013

As I indicated earlier, I have two originals, 595-1092-02 and
595-1092-05. Both show the 1 ohm variable. Pictorial 2-8, page 23, shows
a good representation of the pot which basically is a small pot with ears
so that you can mount it flush on the chassis. Also, these iterations of
the manual have one additional capacitor and several resistor values have
changed from the schematic that's floating everywhere around the web. I
serious doubt that Heathkit would choose, after five iterations of the
manual, to change the pot to a fixed value. Line voltage variations and
component aging make the use of an adjustive high current control a
definite advantage.

Pete, wa2cwa
http://www.manualman.com

On Mon, 30 Sep 2013 10:26:18 -0500 "Gary H. Harmon, Jr."
<gharmon at idworld.net> writes:
> IP-28 manual number 595-1092-05 dated 1969 shows R-14, the ONE ohm 
> variable
> resistor, part number 11-124, as the HIGH CURRENT LIMIT control.  A
> schematic I got off the web shows R-14 as a .18 ohm resistor with no 
> pot.
> Unfortunately, there is no date on the schematic.  It would be 
> interesting
> to know if the variable or fixed resistor is the later version.
> 
> 73,
> 
> Gary H. Harmon, Jr. - K5JWK
> 6003 Archwood
> San Antonio, TX 78239-1504
> 210.657.1549h / 210.884.6926c/t
> 
> "Retirement means every day is a Saturday except Sunday"
> http://www.grissomroadcoc.org
> 
> 
> -----Original Message-----
> From: heathkit-bounces at mailman.qth.net
> [mailto:heathkit-bounces at mailman.qth.net] On Behalf Of 
> manualman at juno.com
> Sent: Sunday, September 29, 2013 2:38 PM
> To: krkaplan at cox.net
> Cc: heathkit at mailman.qth.net
> Subject: Re: [Heathkit] Need A One Ohm Variable Resistor
> 
> You all have to remember that the Heathkit schematics are directly 
> related
> to the manual they came out of. The majority of the Heathkit manuals 
> have a
> specific "595-xxxx" associated with them. If changes were applied to 
> the
> design of a piece of equipment or changes applied to the manual to 
> reflect
> printed errors or clarification of assembly processes which required 
> the
> manual to updated, a suffix dash number, "595-xxxx-01"
> was added to the manual code. With each iteration of the manual, the 
> suffix
> "dash code" (-01, -02, -03, etc.) was increased. From what I can see 
> that is
> floating around the web, (i.e. same schematic in multiple places 
> around the
> web) you all probably have the original or first design released 
> for
> manufacture. I have here several original IP-28 manuals labeled 
> 595-1092-02
> and 595-1092-05 and they both have the "High Current Control" (1 ohm 
> pot)
> and take note that there were several other component additions to 
> the
> circuit. To answer your question Ken, the R designation is R14, Part 
> Number
> 11-124. As Heathkit progressed through the years, they also decided 
> to also
> include the specific manual part code on their schematics and 
> external
> Illustration Booklets. This also helped reduce the confusion of 
> multiple
> documents or diagrams having different information. Unfortunately, 
> there is
> no way to tell by physically looking at a piece of Heathkit 
> equipment what
> manual iteration it applies to since Heathkit also issued separate 
> service
> bulletins to update a piece of equipment and sometimes they even 
> included
> separate update manual pages with the manual that came with the 
> original kit
> to update the manual and the kit building process.
> 
> Pete, wa2cwa
> http://www.manualman.com
> 
> On Sun, 29 Sep 2013 11:23:05 -0700 Ken Kaplan <krkaplan at cox.net> 
> writes:
> > Pete,
> > Do you know the R number? Perhaps my schematic is incorrect? R13 
> is 
> > the
> > 100 ohm "Current Control" pot. I don't see a "High Current 
> Control".
> > 
> > Thanks,
> > Ken
> > 
> > On 9/28/2013 7:23 PM, manualman at juno.com wrote:
> > > In the IP-28, the 1 ohm variable is used for "high current
> > control".
> > > Clearly marked on the schematic.
> > >
> > > Pete, wa2cwa
> > > http://www.manualman.com
> > >
> > > On Sat, 28 Sep 2013 21:27:23 -0400 Bill Cromwell
> > <wrcromwell at gmail.com>
> > > writes:
> > >> On 09/28/2013 09:03 PM, W. Harris wrote:
> > >>> Don't think I have ever seen a one ohm pot, but then there 
> are
> > >> lots of things I have never seen.
> > >>>
> > >>> Bill - K5MIL
> > >>>
> > >>>
> > >> Hi,
> > >>
> > >> I saw one that was less than an ohm in some solid state audio
> > gear.
> > >> It
> > >> was worn out and I could not find a replacement. I used the 
> thing
> > as
> > >> a
> > >> parts mule after that.
> > >>
> > >> 73,
> > >>
> > >> Bill  KU8H
> > 
> > 
> 
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