Author Topic: No battery in a Panasonic KX-T61610?  (Read 4251 times)

Offline podor

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Re: No battery in a Panasonic KX-T61610?
« Reply #15 on: September 19, 2015, 09:21:58 PM »
It appears to be factory. I haven't had any memory issues yet, I just want to make sure I don't lose my program. It's pretty elaborate. Would it keep the battery charged if I installed the pigtail?

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Re: No battery in a Panasonic KX-T61610?
« Reply #16 on: September 19, 2015, 09:32:12 PM »
unbeldi, what about the voltage difference. The KX-A16 is a 2.4 volt NiCd rechargeable while the CR 2354 3v Lithium Ion battery.

Could there be a resistor in the PC circuit to compensate or is +0.6 volts not that big of a deal.
            John . . .

              

unbeldi

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Re: No battery in a Panasonic KX-T61610?
« Reply #17 on: September 19, 2015, 09:57:33 PM »
unbeldi, what about the voltage difference. The KX-A16 is a 2.4 volt NiCd rechargeable while the CR 2354 3v Lithium Ion battery.

Could there be a resistor in the PC circuit to compensate or is +0.6 volts not that big of a deal.

I was concerned about the voltage difference too before I saw the picture.  But they took out the large 2200 F capacitor as well. I can't tell from the picture exactly whether the circuit traces are still there or whether they redesigned the whole battery feed.
The CR2354 also has higher capacity (>500 mAh vs 110 mAh).

Offline podor

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Re: No battery in a Panasonic KX-T61610?
« Reply #18 on: September 19, 2015, 10:18:32 PM »
I'll just grab a replacement. No big deal. I'm not too worried about my $12 investment on the other battery. I've spent way more $ on the wrong part before. Thanks for everyone's help!

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Re: No battery in a Panasonic KX-T61610?
« Reply #19 on: September 19, 2015, 10:21:26 PM »
Comparing the two boards as best as I could given the photos do no quite match, it seems the CR 2354 has a much larger diameter than the capacitor that was removed and as such covers up components - the battery covers what is about in the yellow circle in the photo on the right.

Also, the CR 2354 is a thin battery and what I see is a CR 2354 in a yellow holder of sorts that is very thick. So, could it be a special battery holder which raises the thin CR 2354 up above the board components?

If so, is the battery holder for the CR 2354 a screw down bracket because if there are components under the battery, that would not allow it to be slid out sideways.

Curious issue.
            John . . .

              

unbeldi

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Re: No battery in a Panasonic KX-T61610?
« Reply #20 on: September 20, 2015, 10:38:28 AM »
Comparing the two boards as best as I could given the photos do no quite match, it seems the CR 2354 has a much larger diameter than the capacitor that was removed and as such covers up components - the battery covers what is about in the yellow circle in the photo on the right.

Also, the CR 2354 is a thin battery and what I see is a CR 2354 in a yellow holder of sorts that is very thick. So, could it be a special battery holder which raises the thin CR 2354 up above the board components?

If so, is the battery holder for the CR 2354 a screw down bracket because if there are components under the battery, that would not allow it to be slid out sideways.

Curious issue.


The battery doesn't have a holder, actually, I think.  The terminals are spot-welded on the top and bottom, and are designed to insert into holes on the PCB for soldering.  The yellow material is simply insulation shrink-wrap, just like the green plastic around the large cap next to it.  As for space, it could easily be elevated over and cover up the few small components surrounding the original wire points.   [added: However, the bracket could still be some kind of holder, I suppose, which simply clamps the cell between two metal contacts.

That big capacitor, btw, has a size of 1 farad, perhaps a supercap of the 1980s, and I have not figured out its function, I haven't actually even found it in the circuit diagrams, but I haven't been looking at that detail very much.  It may serve as backup power source in case the battery is exchanged during power off.

The static RAM that is powered by the battery when utility power is off has an operating voltage of 5 V, but for only holding data the voltage is permissible to go to 2 V, according to the data sheet.  So, while I haven't taken any measurements of the battery circuit, it may mean that the potential of the battery is not so important as long as it has a safety margin above 2 V.

Next time I open one of my units, I might take some measurements on the battery feed.  This discussion may have been very useful, because in case of failure I could replace the expensive original battery with a much cheaper, more readily available type, such as the one in this board.
« Last Edit: September 20, 2015, 10:46:41 AM by unbeldi »

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Re: No battery in a Panasonic KX-T61610?
« Reply #21 on: September 20, 2015, 11:55:44 AM »
The battery doesn't have a holder, actually, I think.  The terminals are spot-welded on the top and bottom, and are designed to insert into holes on the PCB for soldering.  The yellow material is simply insulation shrink-wrap, just like the green plastic around the large cap next to it.  As for space, it could easily be elevated over and cover up the few small components surrounding the original wire points.   [added: However, the bracket could still be some kind of holder, I suppose, which simply clamps the cell between two metal contacts.

podor,

Could you take a photo of the battery from the top down, similar to unbeldi's full board original image (I can crop it for a comparison) and a close-up of the battery from the other side showing how the holder wraps down around the battery and attaches to the board?

Thanks.
            John . . .

              

Offline podor

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Re: No battery in a Panasonic KX-T61610?
« Reply #22 on: September 20, 2015, 03:51:36 PM »
Sure. I'll take some more detailed pictures when I replace the battery. It's back in service for the time being.

Is the battery used when the power switch is off, or is it just for power failure? Sometimes, for my wife's sake, it's easier to switch it off when the kids get a little carried away ringing each other.

I was also wondering if the circuit diagrams are published. I would like to be able to troubleshoot in the future.

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Re: No battery in a Panasonic KX-T61610?
« Reply #23 on: September 20, 2015, 04:25:30 PM »
From what I've read, I think the battery saves the memory when the unit has a power failure or it is unplugged. One of the way other members boot it back to factory setting is to unplug the unit and disconnect the battery for some period of time allowing caps to discharge and the memory to go blank, forcing the unit back to factory settings on the next power up, all programming lost.

Good question about turning off the power switch vs totally unplugging the unit. unbeldi should be able to answer that question after looking at the schematics in the power circuit.
            John . . .

              

unbeldi

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Re: No battery in a Panasonic KX-T61610?
« Reply #24 on: September 20, 2015, 07:03:30 PM »
From what I've read, I think the battery saves the memory when the unit has a power failure or it is unplugged. One of the way other members boot it back to factory setting is to unplug the unit and disconnect the battery for some period of time allowing caps to discharge and the memory to go blank, forcing the unit back to factory settings on the next power up, all programming lost.

Good question about turning off the power switch vs totally unplugging the unit. unbeldi should be able to answer that question after looking at the schematics in the power circuit.

As I mentioned earlier, the battery powers the static RAM, which stores the configuration and probably other things.  It does not matter whether the power is turned off, or has failed, or the unit is unplugged.  You want to save the configuration in any case.



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Re: No battery in a Panasonic KX-T61610?
« Reply #25 on: September 20, 2015, 09:16:51 PM »
As I mentioned earlier, the battery powers the static RAM, which stores the configuration and probably other things.  It does not matter whether the power is turned off, or has failed, or the unit is unplugged.  You want to save the configuration in any case.

I think what he, or I, was asking is if the unit is plugged into the wall and its power switch turned off, will the RAM continue to be preserved by the power cord still plugged into the wall or does the battery start holding the RAM memory as soon as the switch is turned off?

In other words, if a 616 does not have a battery, or the battery is dead, will turning the 616 power switch off kill the RAM memory or will the memory be maintained somehow by the line cord plugged into a hot outlet?
            John . . .

              

Offline twocvbloke

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Re: No battery in a Panasonic KX-T61610?
« Reply #26 on: September 20, 2015, 10:22:55 PM »
When the power is off, it's off, as the main switch is cutting off mains power to the transformer, the battery is there to hold the settings in volatile memory (I.E. cut power and it loses data), just like in a computer, you have a BIOS battery to retain the settings while the computer is powered off... :)

The supercap that's next to the battery connection I would presume is in-circuit with the battery and holds the settings for a few minutes in the event of a duff battery and intermittent power disruptions, or for retaining the settings while changing the battery with the unit powered off, I've observed this with my 308, which lacks a battery, where turning it off for a couple of minutes and back on again, the system has retained it's settings, but after 10 minutes or so, it's lost them and is back to defaults...

Offline podor

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Re: No battery in a Panasonic KX-T61610?
« Reply #27 on: September 21, 2015, 07:41:12 PM »
Well, Batteries Plus didn't have the battery, but I've got one coming. To be continued.......

Offline podor

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Re: No battery in a Panasonic KX-T61610?
« Reply #28 on: September 25, 2015, 09:05:27 PM »
I got the battery today and pulled everything apart again. The battery is permanently mounted. I can barely see underneath with a mirror. It looks like the bottom tab is soldered on to the battery and directly to the board. The top tab looks like it is soldered also, with a bit coming out of the 4 holes in the center. It's then soldered into two points on the board. There are no components underneath the battery as far as I can see. I'm just going to leave it alone. I've wasted enough time and money just so I don't have to reprogram if we loose power, which doesn't really happen that often anyway.

unbeldi

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Re: No battery in a Panasonic KX-T61610?
« Reply #29 on: September 25, 2015, 09:48:07 PM »
Thanks for the update.   Wise decision.

I suspected that the bracket is spot welded to the battery, this is pretty common actually. It was probably installed in the factory or a Panasonic dealer/service center.  I will compare with the new picture, thanks.

So I take it you have never powered it down since you configured it?