hpr-knowledge-base/hpr_transcripts/hpr4182.txt

Episode: 4182
Title: HPR4182: Replacing backup batteries in my Kenwood TS940S HF Radio Part 1
Source: https://hub.hackerpublicradio.org/ccdn.php?filename=/eps/hpr4182/hpr4182.mp3
Transcribed: 2025-10-25 20:56:13

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This is Hacker Public Radio Episode 4182 for Tuesday the 13th of August 2024.
Today's show is entitled Replacing Backup Batteries in My Kenwood TS940SHF Radio Part
1.
It is part of the series Ham Radio.
It is hosted by Mr. X and is about 26 minutes long.
It carries an explicit flag.
The summary is, this is part 1 recording my experience of replacing backup button batteries
in my HF Ham Radio.
Hello and welcome to Hacker Public Radio days.
My name is Mr. X and welcome to this podcast.
As usual, I'd like to start by thanking the people at HPR for bringing this service to
us all.
She's learning valuable service on these here into troops.
Hacker Public Radio is a community-led podcast provided by the community for the community.
That means you can contribute too, so if you've got something you want to say, pick up
a microphone, your mobile phone, anything with the hand, and record something and send
in a short.
It's really, really quite easy.
You know, it's a lot of effort to time slam down the process and make it nice and easy.
So and then once you're sending in one, you might get hooked.
You know, for all sent in a short, there'd be more shows than not to do, they're always
shorter shows, so let me give it a go.
Maybe this episode was actually the main part of the audio was recorded back in December,
and I was having, I decided to do some work on my amateur radio set that I came with
TS940S, and it was the memory that holds up the clock, I think it was a clock failed,
and it was reporting incorrect time and whatnot, and that's kind of an indication that the
battered field turns out there was actually two batteries inside the radio, one for a clock,
and one that holds in the memories for the frequency memories for the PLL unit phase
lock loop unit, which controls the radio, but the concern was that when I started looking
into it, discovered that these were quite, they could feel like any button battery, it's
kind of a watch type button battery, they can leak, and I had no idea whether these
batteries are changed or not, or how old they were, so I see, this was a bit Christmas
time in 2023, I thought I'd have a go and delve into the radio and try and replace these
things, so it was even more involved than I thought it, I mean I watched a funny YouTube
video that gave some advice on that, so I thought I'd bring you along for the journey,
and I hope you kind of find it interesting, it took me a bit longer than I expected and
had issues and problems along the way, but I got there in the end, so, I'll leave it
at that and I hope you enjoy, and I'll take you back to December 2023, okay so I'm going
to have a go at replacing a couple of back-up batteries that have, well at least ones
failed on my beloved King with TS940S, I have my tools arranged, my solder and trusty
well, I've soldered and there is well, I found a video online which explains how to
do it, which obviously put a link to that in the show notes, so the first thing we do
is remove the SO239 connector, that's the antenna connector basically, and it's just
a screw thing, just unscrew it, remove that, I'll place that to a safe place, remove the
mains lead, which just pull out basically, it's a kettle plug, that's that out, and then
remove, I'll also remove the microphone, I've got a handheld King with microphone, just
unscrew the ring, and I hope it locates it and pull it out, move out of the way, I'm
sure health and safety now would say it's a two-person lift because it's a heck of a heavy
radio, so I'll have to be careful as to kind of two handles at the side, I'll actually
have only one handle, now I'll just put my fingers under the, underneath it actually,
oh quite, it was a tongue, I don't have to drop the thing because that would be disastrous,
place it on the bench, that was heavy, right, so the first thing we need to do is remove
the screws, so I'll just, I trust it, screw it over here, and I think it's going to be
a pretty niche episode because, how many people are going to have a Kindred TS940S from
1986 era, remember that time frame, it's an amateur 8CF radio basically, I've got a
built-in antenna tuning unit on it, a hundred watts output, although I never on it, a hundred
watts because it was an early transistorized PA stage on these videos and they're a bit
delicate and prone to failure, so the previous owner, the previous owner said to me that he
generally run it at 65 watts, I very rarely use it these days, especially on transmit, but
I have used it in the past, and it's still using the same original transistorized PA that
haven't failed, and I think that was a very wise move by the previous owner, that's a
two top panel screws removed, I'll just move the tube back panel screws, so that's basically
four screws on the top to the front, to the back, yeah so I think I've got a wise decision,
and it's probably the reason why the radio still is operating, and there's two screws at
the side, that's the one, and two, I know I remember this is, I think, you know that I wasn't
as radio many years ago when it developed a small fault and it turned out to be a bad
solder joint, I believe these videos kind of suffered from that era a lot, maybe also
to do with age, as well as I guess, but when they went through the flow soldering machine,
it was tend to produce dry joints, so a dry joint, you know, you basically, I don't know
the much distributed, but basically they, you end up with that kind of, the solder, doesn't
adhere to the lead of the leg of the component, and you can pull the leg out and leave a hole
in the middle of the solder where the component was, and so there's not direct contact to the
solder when you can tap it, and sometimes the component makes connection sometimes it doesn't,
so yeah, it turned out to be a dry joint as they call it, so that's what kind of a dry joint,
as I'm sure, I'll be looking up and back at Peter and Pat Link, and I'll show you
another member, so that's the top cover off, and it's a pretty complicated looking radio,
in fact, I'll take a picture of that actually, okay, so I had to pause the recording, because
it seems I can't take a photograph in record at the same time, that's interesting, anyway,
so I've taken a picture of the radio, it's rather dusty, and the, so there's two batteries
in this radio, I've already taken a picture of, so there's one battery, I should say,
used to, there's a clock, it's used for timing, clock, and alarm, and it also shows
slope filter, SSB slope filters, and what, there's various bits and pieces it shows,
I don't use it very much, it's not that important, but I was recently listening to a
Tick Monepisode, and he had an old piece of high-fi, and it was destroyed, because I battered
and corroded inside it, and the high-fi was immaculate, and there would be use basically,
but when it, when he received it, it was destroyed due to this corroded battery corrosion,
so mindful that that could happen here, if I just ignore it, even though I don't actually use
the display, in addition, although there's as battery for the timer, there's also another battery,
I believe, under the speaker on the left-hand side, so the, the timer's on the right-hand side,
and the speaker's on the left-hand side, on the left-hand side, underneath that there's a,
a battery, which is used to store the PLL phase locked loop circuitry, powered up basically,
for tuning and whatnot, so you need that battery operational too, so that could fail in the
near future. Now, I'm lucky to believe, oh, now I need to actually remove, I didn't realise,
I'm going to have to remove the bottom case, because I believe there's three screws
on the front panels, that you need to, or maybe two, you need to loosen,
and I thought, well, two, I think maybe we'll remove two and loosen a third one, and that allows you
to civil the front panel down, so yes, I'm going to have to take the bottom cover off, okay,
so I'll probably need to put the white chop some of this out, obviously, there's a front cover,
top cover, all right, I'll place that back on again,
okay, that'll start back on, that'll start one on, right,
what does that say? It's a heavy beast, okay, it's like, I think we have to do a bit of editing to this,
recording, as I see, need some more safety, put these screws, I don't have much room here,
much space, right, that's a screws for the top, just place them there,
so safe, and no, so there's two side screws, I feel a bit, for the bottom panel,
on the left hand side, I'm moving the first one, I'm moving the second one,
and the two on the right hand side, okay, look a bit of light on in here to get better visibility,
all right, I do want it to side, how many other screws, yes, as, okay, it looks like there's
a four screws on the base, try removing those two at the front, actually, I wonder if I can
tap this on this, I'll leave it on its side, I think, one, just loosen them two at the front ones,
two for the rear, do another pair of hands actually, next one, that's all the way out, three,
and, oops, four, okay, a lot come out, not sure, maybe, okay, make sure it's not going to fall over,
okay, let's get another light, we did fall over, all right, so,
so, so those were the side ones, okay,
and then back and front, okay, that's fine,
all right, place the rear on its top, try to remove this cover, oh yeah, that comes away quite
easily, I think by looking at it, it's not so bad, it's just trying to sound confident,
yeah, as there's that screw, there's another screw, there's a screw on the base,
there's that kind of well, okay, doesn't feel like anything's loosened underneath it, so I'm guessing
that screw needs to come out on the base, one single screw, how strange, okay, so, place that there then,
so, yes, base, so, the base has two, four, six, eight, nine screws, and the top has two, four, six, eight screws,
all right, now it's coming off, yeah, so it's quite easy to remove the base,
okay, oh wow, that looks complicated, yeah, I'm going to get a picture of that, I'm to pause the
recording as before, wow, yeah, I'll definitely show you a picture of that, okay, now, I believe,
I don't know, I need to take the other cover off now, oh yeah, now I see the three screws, there's
two screws beside each other, and a third one allows you to swivel the front panel down,
and then that makes it easy to remove the battery for the timer unit, and that's the one that's
actually failed, but the other batch is probably going to be quite close to failing as well, I would
imagine, so I will see how time goes and how much I get done today and how much I want you to,
if I get it all done today, whether I need to stop and make it a two-day affair, all right, so,
I'll try to, I'll try to hold this, goodness, I think I need to move this further, over that way,
that's it, and then, I said man, handling, you know, handling, this is quite tricky because of the
weight of the thing, all right, catch my fingers, all right, all right, I'm exhausted, right now,
I'll just pull this over the front of the desk, it's happening, the video makes it look so easy,
it's a, okay, I'll take the top cover off, right, now we're cooking by gas, as they say,
so I need to remove, I need to loosen, no, I need to remove these two screws at the side, and
loosen, oh, and the third screw, he also did say to remove a connector from the timer board,
to see which connector that was, I'll take a picture of the three screws anyway to start with,
okay, so I've re-watched the video, and there's a connector on a timer board,
and it goes to a cable form, which I'm just going to change my glasses here, because I need to
put this evick in a detail here, and there's a, there's a kind of plastic thing which wraps around
the cabling to keep it all together, and it's basically secure it, and it's open, it's made of plastic,
and it looks like it'd be lovely and flexible, but it's rock solid, perhaps because of the
age of the radio, so that would suggest to me that this front panel has probably probably been
down before, and for some reason, and whoever did that didn't bother putting the cable harness
clip thing around the cabling, so that's interesting, also notice that the little board,
the cables attached to it, doesn't, is missing a screw, so something's obviously been in here
before at some point, apart from myself as, I don't remember missing a screw or losing a screw
in like that, so, but I think it was the other side of the board, I would have been touching
up all the soldering on the other side of the board, not the top side, right, so three screws,
so does this fit, I think so, first screws coming out okay, that's a good fit this would
give up, and okay, that's very tight, have I got a smaller and better fitting
than this I wonder, that's a bit better, but it's deeper into the head, I don't want to go
chewing a hell of a screw, I must admit being slightly nervous because I would hate to destroy
this video, but it should be quite a low risk thing this, and I'll just take the other screw,
let's grab this side, that's three screws moved, four screws moved,
okay, I'll put these to the side, these over here,
I guess this vintage of radio was much easier to work on than modern
radios are all surface mounted things, and probably all glued together and you can't get into them
very easily, but not as simple as an old transistor, I fully transesterized or a valve 3D of course,
although they are probably a bit more lethal, but if you're the voltage is working one,
it's all unplugged anyway, so we're fine, so I can't really see that screw very well, I have to
zoom, this will only fit, just a tiny bit, so that's a third screw on one side loosened a tiny bit,
and the third screw on this side loosened a little bit right now, according to the
chapter in the video, and I must think I'm very much for you to help because I would have
not broken something, I don't know, I still do, I suppose, oh yes, it's tipping,
it actually looks like there's plenty room on my radio for me to tip this down, I think,
without unclipping anything, without clipping that plug, and I wonder if that's precisely why
that clip was removed previously, because whoever repaired the battery, it replaced the battery last
time, and I'm guessing that's what happened, removed that clip, I would make perfect,
I might not go all the way down, actually, I might stuff to unclip, I think I'm going to take
a photograph of this so you can appreciate what I'm talking about,
okay, so in the photograph, the left hand side is the connector that was advised to remove,
and to the right you can actually see the button battery, which you need to unsolder,
which has got an orange rim round around about it, but on that connector you can see, if you
follow the cable harness from that, it heads towards a, I can have brown board,
and there's a black plastic thing, one of the better word, cable tithe type thing,
something above it, and it's completely rigid, there's no flicks putty to it at all, but I'm
I'm sure, I remind you at one point it used to be, this is actually metal, I'm not sure I'm
scared to, because I'll break it, so I'll just leave it be, actually, I don't know whether it's
maybe supposed to be solid like that, or not, I don't know, maybe it is, so it's maybe on
do with age, I can hear all the wires, creaking and groaning as I, and connectors, and oh,
oh yeah, that's not, that isn't going to reach, it's quite right, that's going to be too tight,
so I will have to remove that connector after all, so, how do I do that?
Oh my, oh dear, this is where I snapped something and it all goes horribly wrong,
can I unclap it from the other side, no, that's not really good, because it's going to other
wires as well, or can I, could I unclap it from that side, I wonder, would that release everything,
might do, suggested unclaping it from the socket bulb I've, I'm a bit worried that I'm going to
break something, so I'll slide the deal back up again and kind of remove it from the,
yes, there we go, I've removed it from the board, the brown board at the top, and pull the
deal back over the edge, and yes, that's going to work, I think that might be a little safer,
oh, there's some things, all right, so there's another cable, which is,
I've got to be mindful of things being tight as you bend things down, bend the front panel,
there's a kind of blue and white connector, which goes to the transformer by a look of it,
and that, getting a tad tight, I don't know, maybe I can move it further, to be fair, a bit nervous,
but this, there's any tension in there, I don't know, I think we're okay, I think that's okay,
well, so I think now I could unsolder this, can I move that over a bit, touch, yes,
right, I think what I need to do now is get my, I think I better take another photograph this,
it looks a bit, a bit, a bit, a bit scary now, and I've got my solder now and set up, and
and we can hopefully desolder the problem, problematic battery.
Okay, I think that's a good place to stop, where I have a radio with the front fascia
rotated down, ready to replace the back at battery for the clock. If you want to find out if
eventual repair is successful, you need to carry on listening to my further episodes, if you've
got any comments on this episode, or want to send me a line, you can, you can contact me at
MrX, at hpr at googlemail.com, that's mx80hpr, the at symbol googlemail.com, so until next time, thank you,
and goodbye.
Today's show is released on their creative comments, attribution, 4.0 international license.