I’ll type up the notes for this over the next few days.
I’m on Steve-Time… W4HKL.
Remove the plastic cover on the battery.
This is the side we’ll pry up first.
The polarity is as follows:
Top battery lead : Negative
Bottom lead: Positive. You might want to pencil this in on the board somewhere to remind yourself later.
Let’s get this show on the road…
Use your fingers and the screwdriver… get it up far enough to get some angle cutters in.
Press the lower insulating pad back down if you can.
Yes, the bottom of the battery is the positive side.
I wondered why the TM-331 would retain memories most of the time yet sometimes lose them.
0.15 Volts… it should be around 3.0 Volts.
Time to prep the batter holder, etc.
This is more like it… and more likely to retain memory.
Making sure the battery will be insulated from everything.
Don’t tin these leads or you won’t be able to wind them around the battery holder terminals. After winding, I bend the pins down a little to reduce the footprint of the holder. This will have to fit inside the radio…
Soldered…
I tinned the ends here before crimping them inside the old battery tabs coming from the board.
Soldering to the crimped ends lends a lot more mechanical strength to the connection as well as a good electrical connection…
After you’ve heated the crimp… and also flowed a little more solder on the end of the tinned ends of the wire and up into the crimp… test your voltage on the board. It should be 3+ volts.
Now tape it all up.
Battery too…
Note that I bent the wire well away from the solder joint in order to get the cord going in the right direction.
Congratulations! You’re 10-20 minutes from being finished…
Work backward… and be careful. Don’t get in a hurry.
Routing the cables back into the RF section of the radio.
Don’t forget this green wire loop.
Again, I was lucky – the buttons were staying in place. If you’re are “squirrelly,” you may have to keep the faceplate tilted and bring the radio up to meet it.
Press all the button pads… make sure none are in a bind before proceeding.
You can tell if one’s stuck, etc..
Click… click…
Now for this little SOB… all I can say is take your time, work a little from one side and then the other…
and hold your mouth right.
Time to power up, enter a frequency, and give it a whirl.
Powering down, cutting off the power supply, and then seeing if the memory is retained.
Success!
- W4HKL
1 comment:
Very well done. I've done similar with my TM-231 and I am about to to the same with my TM-241. There is just enough space to place the battery and holder in a small plastic enclosure in the radio. I have mine along with the optional tone board in a tic-tac mint box. A small sheet of Kapton insulates them.
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