[aprssig] Kenwood TR-7730 backup battery?

Steve Noskowicz noskosteve at yahoo.com
Sat Apr 20 18:23:16 CDT 2013



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
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> > >> Click to tune. Click to capture Radio freq.
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> > >>
> > >>
> > >> --- 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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