[aprssig] RE: [Kenwood_TH-D7] TH-D7 Power up problem

Herb Gerhardt hgerhardt at wavecable.com
Mon Jan 1 17:26:22 CST 2007

Since I did not get any responses to my original post, I finally got around
to opening up this radio to see if it was anything obvious.  I could not see
anything obvious and to take the bottom PC board off, I would have to
unsolder some shielding.  Am not willing to go that far at the moment unless
our county DEM authorizes it first.

>From what I have figured out so far is that the problem appears to be part
of the disconnect tab inside the external power connector.  It appears this
disconnect remains in the disconnected position with an external power
connector connected or not.  Connecting external power to the external power
connector does put 12 volts to the normal battery tabs on the back of the
radio.  This is the normal charging voltage for the battery, so it appears
that I would need to replace the external power connector.

Has anyone ever had this connector fail?  Has anyone ever replaced it?
Where did you purchase the replacement connector?  How difficult of a job is
it to replace this power connector?  Has anyone ever sent their radio to
Kenwood to have this connector replaced?  If so, what did they charge for
the repairs.

I am looking for answers to these questions so that I can better discuss the
next COA with my local DEM.



> -----Original Message-----
> From: Kenwood_TH-D7 at yahoogroups.com
> [mailto:Kenwood_TH-D7 at yahoogroups.com]On Behalf Of Herb Gerhardt
> Sent: Tuesday, November 21, 2006 5:01 PM
> To: Kenwood_TH-D7 at yahoogroups.com
> Cc: SAR_APRS at yahoogroups.com; TAPR APRS Mailing List
> Subject: RE: [Kenwood_TH-D7] TH-D7 Power up problem
> Our county recently tried to use their TH-D7 SAR tracker I set up for them
> several years ago and they could not make it work.  I did my darnedest to
> try to talk them through all the possible problems.  I did not
> succeed.  So,
> I now have the entire tracker here at my house for troubleshooting.
> Here is what I discovered so far:
> 1.    Even with a good fully charged battery attached, it will
> not power up.
> I bent the radio contacts out some more but that did not help.
> 2.    With 12+ V attached to the external plug, I can read
> voltage (11.6 V,
> which is normal since a diode is involved) on the normal battery
> connection
> terminals.
> 3.    The external battery pack cable that I made for them years
> ago, causes
> intermittent connection to the radio.  It does the same when
> connected to my
> radio.  I built a new cable using the power connectors I bought
> from Mouser
> and those are also too loose and work intermittently.  This
> looseness/intermittent connection was experienced on both the county's SAR
> TH-D7 and my personal TH-D7 radio.
> 4.    I supplied external power to the normal radio battery
> terminals on the
> SAR TH-D7 and it will NOT power up.  Applying the same power to
> the battery
> terminals on my radio makes mine work just fine.
> So, it appears that there is a problem between the normal battery
> terminals
> on the back of the DEM radio to the circuit board inside the radio.  Joy,
> joy......  I have never seen or heard of such a problem.  Is there anyone
> that has seen this problem before?  If so, what did you do to fix it?
> My late elk hunting season starts tomorrow, so this radio problem
> will have
> to wait till after my hunting season.  Any inputs in the mean
> time would be
> appreciated.
> The unfortunate part of this problem is that this is the first time that
> they really tried to use this TH-D7 tracker during an actual search.  Sure
> would have been nice if it had worked.  I have been trying for
> years to get
> them to use this tracker during an actual search and now when they finally
> tried it, it would not work.  It worked just fine about a year ago when I
> checked it out.  As far as I know, no one has used it since then.
> Herb, KB7UVC
> Mason County ARES/RACES ex-President & APRS Coordinator
> Mason County ComVan:  http://map.findu.com/KB7UVC-1
> Mason County Relay Truck:  http://map.findu.com/KB7UVC-2
> Mason County EOC:  http://map.findu.com/KB7UVC-3
> Mason County Foot Tracker:  http://map.findu.com/KB7UVC-6

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