PROBLEMS AND MAYBE A SOLUTION FOR THE MEMORY BATTERY ON A TS570D

[N0NZG]

TS570D memory battery problems.

I have a TS570D that loves to eat memory backup batteries like a lot of others.  The CR2032 battery doesn’t seam to last more that a few months. Has anyone had any luck with mounting an external back up battery for this rig? My plan was to solder 2 wires onto the internal holder for the lithium battery ( CR2032 coin cell). Then extend those wire to the back panel were I could put two lithium AA batteries in a holder Velcro-ed to the back panel. The hope here is that I can get at least a year out of the larger batteries and it will just take a few seconds to swap them out.  If anyone has any info on this being done before, that would help a lot.
Any comments or suggestions on this idea? 

73, Jeremy Engbrock

[KA5IPF]

There is a Kenwood technical service bulletin that covers a modification to correct the battery issue. Once applied the batteries last years.

Look for Kenwood ATB-0027

Clif

[KA4POL]

You can find the procedure under http://www.hampedia.net/kenwood/ts-570dg-back-up-battery-current-drain.php

[SWMAN]

I bought my 570 new 13 years ago and never had a problem with the battery at all.
  73 Jim. W5JJG

[KA4POL]

Kenwood incorporated the change some time into production. So it is very likely you got a modified unit.

[N0NZG]

I saw the mod, but I am not to keen on soldering smt devices into the radio to do the mod. I was hoping someone else thought an external battey might be a quick and dirty fix.

[KE3WD]

Supplying more current is never a good way to resolve a problem in any circuit that should not draw that kind of current in normal operation. 

Consider a failure mode that could take out more expensive components, such as your memory, just because there was enough current available to do so. 


73

[KA4POL]

The external battery, even a rechargeable one, certainly could come to mind. This could introduce additional risks as just mentioned.
There is certainly a Yahoo group for this rig. They are more specialized on that radio and can give advice.

[KE3WD]

And don't suffer an irrational fear of Surface Mount repairs. 

Replacing two pin SMT devices is actually EASIER than replacing their equivalent thru-hole devices. 


73

[SWMAN]

I have always heard and understood that a device will only draw as much current as it actually needs as long as the voltage supplied is correct. Like if you put a super large battery in your car it will be ok and draw only the current needed to start and operate the car. Or having a flashlight that runs on 2 AAA batteries at 3 volts and you instead manage to put 2 D batteries in it at 3 volts it will be ok and last longer for lighting. I have some small blinking LEDs that are suppose to run at 3 volts from 2 AAA batteries. I instead wired the with 2 D batteries wich has almost 5 times the current as the AAAs do and have never had a problem with them at all. they just last about 10 times longer. Someone please correct me if I am wrong. But higher current batteries have always worked for me. Oh yah, what about my 12 volt scanner with 8 AA batteries in it, I connect to the car battery that has probably 100 times the current and no problems ? Please let me and the guy with the 570 mod in his mind about my thoughts. Thanks and 73   Jim W5JJG

[KA5IPF]

True, on drawing current, BUT. In the case of the 570 it's not shutting down correctly which is leaving the processor running and that is what kills the batteries. The mod alters the shutdown so that the processor correctly "goes to sleep" and doesn't draw excess current. Will the processor not shutting down correctly hurt it, I don't know, but it can't help.

Why not just fix it correctly or have it fixed correctly?

Clif

[KE3WD]

I have always heard and understood that a device will only draw as much current as it actually needs as long as the voltage supplied is correct...

That is true, but please do consider the situation where a circuit fault occurs. 

How about a simple short somewhere along that DC line? 

That could happen due to a failed solid state junction, perhaps a diode, perhaps a transistor, could happen if a capacitor shorts, or might just be due to a conductive bit of flotsam and jetsam getting in there on the board and crossing the right two points. 

If there is enough Current available it will be there to perhaps burn circuit board traces away, or depending upon where a short to ground may occur, such as in a solid state junction, the excessive current available could get costly in terms of component failures that would not happen with the designed supply, which in this case is apparently a simple memory cell. 

Now, since this is an Internet Forum, I fully expect somebody to come along and state that they used XXXX capacity external battery and swears up and down that it works.  Well, it may work, but they just haven't had a fault that could cause the aforementioned problems. 

Don't "fix" it --  REPAIR it.  There's a Service Bulletin for this one, issued by the mfr.   The same guy who doesn't follow it and incorporates this added battery scheme is likely the same one who will post bad reviews about the mfr and product when it fails.  Don't be like that guy. 


73

[N0NZG]

Thanks for the input. I am getting a quote on the repair.

Jeremy N0NZG

[N0NZG]

Well I hate to disappoint y’all, but…. I got snowed out of work and had some time to kill so I opened up the TS-570D and soldered some 20ga red and black zip cord onto the battery socket inside the rig and then routed it out to the rear panel were I neatly velcroed a dual AA battery holder.  The end result , I am very happy with my choice to replace the short lived Lithium battery with 2 AA cells and the rig works great. The old Lithium cells would last about 3 to 6 months and I suspect the AA cells will last over a year. Best of all next time I have to replace the memory backup battery, I won’t have to risk a trip inside the cover to get the job done.

[SWMAN]

Good going Jeremy, I really thought that way would work. It will only draw as much current as it actually needs as I mentioned here last week. I think it will last longer than a year also. Good job! 73 Jim W5JJG