I have an old JR radio that needs a new internal lithium battery. I
opened the radio compartment to find a 3V button battery that is
basically soldered in to the printed circuit board. As I did not have
the proper replacement parts I had to send mine in for repairs. I'm
quite ticked off with JR's installation method. I'm curious whether
someone out there has figured out a way to replace this battery with a
battery housing (& a battery).
On 28 Dec 2006 19:37:44 -0800, I said, "Pick a card, any card" and
"ahdofu" instead replied:
Those batteries typically have a shelf life and useable life of
around 10 years. Ordinarily, that's more than enough time to get
100% use from it before you replace your equipment. Any other kind
of holder would not be reliable enough for backup memory. Standard
practice was to use a soldered connection for reliability. Today,
they use non-volatile RAM for storing things like programs and such.
Real time clocks still use a lithium battery which may or may not be
soldered in place.
I'm guessing that the repairs will cost around $50. This amount brings
into question whether it is worth repairing the radio. Unfortunately my
radio works just fine (at least it used to) and I just find it a waste
to toss a perfectly OK radio. My old sport watch never failed in use
and yet I could unscrew the battery cover and swap the battery with a
new one. For JR perhaps cost was a factor or perhaps it was the
reliability issue that you've mentioned but to me this is subpar
engineering. Thanks for your comments though.
Ray Haddad wrote:
What really ticks me off is that when the memory battery dies, or is
disconnected, the radio's computer drops its operating system. Not only do
you have to return it to get the battery replaced, but they also have to
reload the operating system. Even if one had a proper battery holder,
removing it without offering the system back up voltage in the interim would
lead to an R/C transmitter that doesn't know if it is a scanner/TV
set/microwave oven, etc.
Are you sure that the newer JR rigs use non volatile RAM? I wouldn't assume
so without some form of verification. Icom amateur radios did the same thing
for a while. We hams raised cane on them for this dufus form of engineering.
Happy New Year.
are you sure it holds the operating system? I would have thought that
would be in an EPROM of some description, as backing up a few bytes of
user changeable data is one thing,storing the OS that does not change is
Mine is an X388S which, I think, came after the X347. Following the
battery failure the radio was still functional except that all of my
programming had been erased. Now if the radio loses its functionality
all toghether then that is really a poor/cheap (I have more colorful
words) design. I grew curious following your question and checked the
XP9303 manual. There it says that all programming data is stored in
flash memory. It also appears that there is no internal battery to
replace either. If this is the case then it is good that JR has learned
from its design flaws.
Happy new year to all,
Ed Cregger wrote:
You know, now I remember that the 388 didn't use that battery to hold the
main OS of the radio. Thanks for jumping in there. I think the X-347 was the
last of those rigs.
I can live if just the channel memories are lost, although, these days,
there isn't any excuse for that either. Who knows, maybe today's radios do
not lose the channel memories.
I had a "discussion" with JR and later with R.Stephens about the backup
battery in early JR radios.
Was told but the JR tech that only they had the skill and technical know
how to change the battery.
Complained to the highest up and was told much the same, I said BS, then
he admitted that it was possible and that the processor had to be
restarted with a jumper to reload the default values. That the system
was programmed to lock up if there was a RAM error.
I asked what pin to what pin to jumper, was then told that the
information was secret and proprietary.
Send it in and pay your money boy we are the all powerful
50+ years of designing, prototyping, repairing RC systems.
I'll have you know that I have this simple stupidity thing down pat!
Another poster said that the X-347 was the last JR to use the system that I
mentioned previously. The next radio, the 388 and on up, did not use the
memory battery to hold the OS. It all came back to me when he mentioned the
Sounds like one would get a 3v (or whatever is used) source with a couple
of leads - and solder (or clip if possible) them to the board in parallel
with the JR battery to keeps things going while you remove the old one and
solder in the new one.
Doesn't seem too hard, but I haven't tried it
Hugh Prescott wrote:
"quietguy" wrote in
Yep, that's how it is done, unless you are forgetful like me and don't get
around to it in time. Now I have a JR X-347 in like brand new condition that
doesn't know it is a radio. Should I spend the money to bring it up to date?
I have an 8103, a brand new still in the box 9303, a DX-6 and a DX-7
Spektrum radios. Oh, what shall I do?
My legs are bad from diabetes, so my ability to walk is very limited.
Believe it or not, this is why I bought the Spektrum radios - so I wouldn't
have to walk to the frequency control board and back again after finishing
flying for the day. No other reasons. Well, maybe some curiosity.
Anyone want to buy a brand new, never flown 9303 on six meter PCM with four
standard servos? I'll let it go for $450 plus shipping (48 US contiguous
states only). IIRC, this saves the buy $200. It should be on 50 MHz channel
04. New the end of last summer. Never removed from the box. No, I won't go
lower in price. US Postal money order only.
As the "proud" owner of 2 JR radios - an X-347 and an X-388, the 347
at least being well over ten years old (nearer fifteen I think) but
still working well, this thread has rather spoilt my Christmas as it
seem that both sets are well overdue for self-destructing!!!!
However, having had too much homebrew last night and having blurred
vision and shaky hands as a result, this morning seemed the obvious
time to delve into the innards of my X-347. So having taken the back
off, undone every screw in sight, unplugged every connector I could
find, turned it upside down and shaken it, I was left with a workbench
of assorted bits and the odd screw and spring bouncing round the floor
- strewth, that's were the cunning devils hid the backup battery is
it, I have often wondered. Having stirred the pile of bits with my
finger and poked them a few times with a screwdriver I finally
realized, "Taking that apart perhaps wasn't a very sensible idea!!".
Having just re-assembled it without too many bits left over - just one
screw actually (said proudly) - and finally figuring out where the 6
little springs went, I took a deep breath and turned it on. There was
immediately a continuous warning buzz and a "backup error" message on
the screen. However, after a couple of seconds, the warning buzz
stopped and the display reverted to normal. It now appears that all my
personal model settings have been lost and the Tx has reverted to its
original factory settings, otherwise all seems fine.
Is this an indication that perhaps not all X-347 sets are the same and
if I were to replace the backup battery, I would not lose the
programming - or isn't life that simple??
One thing I would point out is that I live in the UK so mine is a
British radio - so could it be that UK sets are different and do not
lose the programming?
Actually, it very nearly does just that.
A few years ago, I played around with diesel powered models. Since
then, the silver finish on the front of the X-347 has gone all soft
and wrinkly (a bit like myself!!!).
I am not certain of the reason, but my best bet is that the ether
content of the diesel fuel acted as a solvent for the paint or
whatever the silver finish is. Certainly it got well covered in
diesel fuel. My other JR Tx (X-388) has only ever been used for glow
models and the silver finish is still fine.
I cannot figure out why some flyers at the field always have
immaculate trannies and mine usually look as though they have just
been dragged from the trash can, usually ending a day's flying covered
in oil and liberally dripping model fuel - and yes I do clean them
when I get home. 8^)