[aprssig] Kenwood TR-7730 backup battery?

Steve Noskowicz noskosteve at yahoo.com
Sun Apr 21 16:51:55 CDT 2013



> Ah, good find, and an interesting idea.  

...Google...

 
> But, the article is a "reprint" 
> from a 73 Magazine article from 1981 (fine print at the
> bottom), 

OK  I did think it looked strange to have a 2012 review of a radio that looked older...

73, Steve, K9DCI  USN (Vet)  MOT (Ret)  Ham (Yet)


> 
> 
> Steve Noskowicz wrote:
> >
> > Try KA1LR.  Perhaps he knows something.  His
> review os only a year old:
> >
> >    http://www.radioaficion.com/HamNews/reviews/kenwood/9440-tr-7730-review-by-ka1lr.html
> >
> >
> > 73, Steve, K9DCI  USN (Vet)  MOT (Ret) 
> Ham (Yet)
> >
> >
> > --- On Sat, 4/20/13, Steve Noskowicz<noskosteve at yahoo.com> wrote:
> >
> >> From: Steve Noskowicz<noskosteve at yahoo.com>
> >> Subject: Re: [aprssig] Kenwood TR-7730 backup
> battery?
> >> To: "TAPR APRS Mailing List"<aprssig at tapr.org>
> >> Date: Saturday, April 20, 2013, 6:14 PM
> >>
> >>
> >> I think that stuff is all poart of the ham's mod.
> >>
> >> 1 -  I can't resolve why it looks like a 4
> pin
> >> connector.
> >>
> >>     I suspect:
> >>
> >> 2 -  the original circuit had nothing to do
> with the
> >> main power input.  He did that mod so he could
> use some
> >> batteries instead of the external TK-1 power widgit
> and
> >> wanted the main power to keep it charged. 
> Nice idea.
> >>    I think there is another path from the
> DC power input
> >> to the micro processor memory supply, but am too
> lazy too
> >> try to trace it out.  This is becauese that
> schematic
> >> looks like the lines are all hand drawn going
> between DC
> >> input and the memory backup connector.. 
> Dunno.
> >>
> >>
> >> 3 - He added the 4k resistor deeper in the
> schematic along
> >> that backup input line .  Don't know why
> because it
> >> appears to say 6V by the backup connector. 
> Perhaps the
> >> TK-1 is a 12 volt wall wart and he wants to frop
> more, so
> >> increased that resistance......?
> >>
> >> Gud Luk.
> >>
> >>
> >> 73, Steve, K9DCI
> >>
> >>
> >> --- On Sat, 4/20/13, Greg D<ko6th.greg at gmail.com>
> >> wrote:
> >>
> >>
> >>> Thanks for the link to the schematic;
> >>> Google wasn't quite so friendly to
> >>> me this time.  I had found the operating
> manual, and
> >>> the battery part
> >>> number, but no details like voltage or pinout.
> >>>
> >>> I see the mod you are referring to.  The
> battery
> >>> appears to get charged
> >>> from the mains, through a diode and
> resistor.  1.2v x
> >>> 6, it says, so
> >>> 7.2v.  That's pretty high for a memory
> backup
> >> battery,
> >>> no?
> >>>
> >>> I'm guessing the box to the left is probably
> the 3-pin
> >>> connector, though
> >>> it looks to have spots for 4 pins.  One
> pin for
> >> ground,
> >>> one to the mains
> >>> for charging, and one out to the
> circuitry.  So, the
> >>> charge limiting and
> >>> such was originally in the battery
> product?  Odd. 
> >>> But if so, then the
> >>> big question is the black smudge above. 
> What is
> >>> it?  What is it covering?
> >>>
> >>> If I follow what appears to be the output wire,
> it
> >> looks
> >>> like it goes to
> >>> some sort of adjustable voltage
> regulator.  Again,
> >>> odd.  Why have an
> >>> adjustable regulator for a processor memory
> backup? 
> >>> There's another mod
> >>> there ("4k", presumably a resistor), so it's
> probably
> >>> related to the
> >>> other battery mod.
> >>>
> >>> The final odd thing is that I don't see where
> that the
> >>> backup battery
> >>> supply would be replaced with mains power in
> the
> >> original
> >>> design, if as
> >>> I have it, the battery is removed.  That
> regulator
> >>> circuit isn't
> >>> diode-driven by mains, for example. 
> Unless it's
> >> under
> >>> that smudge.
> >>>
> >>> Still searching...
> >>>
> >>> Thanks for the help,
> >>>
> >>> Greg  KO6TH
> >>>
> >>>
> >>>
> >>> Steve Noskowicz wrote:
> >>>> The link in the upper left of the page
> below has
> >> a
> >>> slightly better schematic.  It is in the
> upper right
> >> of
> >>> the schematic right at the power input, but
> someone
> >> added a
> >>> mod and the otiginal is obscured. 
> However, it
> >> appears
> >>> you may be able to ohm it out.
> >>>> One pin is ground and it may be that the
> other
> >> three
> >>> are plus, but it's hard to tell.  A better
> schenatic
> >>> will tell.
> >>>> http://elektronicsstock.blogspot.com/search/label/TR%207730#!/2011/04/schema-kenwood-tr-7730.html
> >>>>
> >>>>
> >>>> 73, Steve, K9DCI  USN (Vet)  MOT
> (Ret)
> >>> Ham (Yet)
> >>>> --- On Sat, 4/20/13, Steve Noskowicz<noskosteve at yahoo.com>
> >>> wrote:
> >>>>> From: Steve Noskowicz<noskosteve at yahoo.com>
> >>>>> Subject: Re: [aprssig] Kenwood TR-7730
> backup
> >>> battery?
> >>>>> To: "TAPR APRS Mailing List"<aprssig at tapr.org>
> >>>>> Date: Saturday, April 20, 2013, 10:43
> AM
> >>>>>
> >>>>>
> >>>>> Mods.dk probably has it.
> >>>>> Also...
> >>>>> Please remember that Google is your
> friend:
> >>>>>
> >>>>>      try Google "kenwood
> tr-7730 service
> >>> manual"
> >>>>> BUT BE CAREFUL.  On some sites the
> big,
> >>> obvious
> >>>>> "DOWNLOAD" buttion is for something
> else.
> >> The
> >>> real
> >>>>> download is in "fine print" somewhere
> else:
> >>>>> e.g. this operator's manual:  http://elektrotanya.com/kenwood_tr-7730_sm.pdf/download.html
> >>>>>
> >>>>> Poor resolution Schematic:
> >>>>> http://elektronicsstock.blogspot.com/2011/04/schema-kenwood-tr-7730.html#!/2011/04/schema-kenwood-tr-7730.html
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> 73, Steve, K9DCI  USN (Vet) 
> MOT
> >>> (Ret)  Ham
> >>>>> (Yet)
> >>>>>
> >>>>> Up to date APRS Beginner Guide -
> updated
> >> Oct-2011
> >>>>>      http://K9DCI.home.comcast.net
> >>>>>        Click 'APRS
> Beginner INFO'
> >>> under Contact
> >>>>> Manage Radio Memories with an Excel
> >> Spreadsheet !
> >>>>> Click to tune. Click to capture Radio
> freq.
> >>>>> All Memories on one page. Cut, Copy,
> Paste,
> >> Print
> >>> 'em,
> >>>>> etc...
> >>>>> For:
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> >>>>> A version for the D7 is in the works.
> >>>>>
> >>>>> More Details, Features and Downloads
> at:
> >>>>>      http://k9dci.home.comcast.net/
> >>>>>
> >>>>>
> >>>>> --- On Fri, 4/19/13, Greg D<ko6th.greg at gmail.com>
> >>>>> wrote:
> >>>>>
> >>>>>> From: Greg D<ko6th.greg at gmail.com>
> >>>>>> Subject: [aprssig] Kenwood TR-7730
> backup
> >>> battery?
> >>>>>> To: "TAPR APRS Mailing List"<aprssig at tapr.org>
> >>>>>> Date: Friday, April 19, 2013, 10:54
> PM
> >>>>>> Hi folks,
> >>>>>>
> >>>>>> My packet station and iGate runs on
> an old
> >> but
> >>> quite
> >>>>>> serviceable Kenwood TR-7730. 
> The rig
> >> has
> >>> a connector
> >>>>>> in the back for a backup battery,
> but none
> >> is
> >>> present,
> >>>>> so
> >>>>>> any momentary glitch in power send
> it back
> >> to
> >>>>>> defaults.  I have not been
> able to find
> >> a
> >>> battery,
> >>>>> nor
> >>>>>> the pin-out and specs to fashion
> one of
> >> my
> >>> own.
> >>>>>> There appear to be 3 pins in a
> triangle
> >>> formation.
> >>>>>> Anybody know what the spec is?
> >>>>>>
> >>>>>> Thanks,
> >>>>>>
> >>>>>> Greg  KO6TH
> >>>>>>
> >>>>>>
> >>>
> _______________________________________________
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> >>>>>>
> >> _______________________________________________
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> >>>>>
> >>>>
> _______________________________________________
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