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flat assembler > Heap > Batteries for the electronic calculator Citizen SDC-848.

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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
I have got an old (produced in Malaysia in 80's or 90's) but still functional electronic calculator, Citizen SDC-848. It is said to be powered from two sources: solar panel and battery but in fact it works well only in properly illuminated places.

I'd like to know what kind of batteries are used in this type of calculator. In the Internet I can find only incomplete or contradictory information. Some sources claim that this calculator was powered only from the solar panel despite of the description on the cover: "2 POWER".

Datasheet from an internet museum of calculators: http://mycalcdb.free.fr/main.php?l=0&id=6824
Post 06 Jun 2018, 11:04
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16051
Location: 112 Ocean Avenue, Amityville
Open it up and post a picture of the battery(s).
Post 06 Jun 2018, 11:25
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shoorick



Joined: 25 Feb 2005
Posts: 1603
Location: Ukraine
I think it should use one or two 1.5V button cells. these batteries have wide range of dimensions - it is better to take original battery to the shop to buy similar one. the problem could be the cost of new battery may appear comparable to the price of the new such calculator.
Post 06 Jun 2018, 12:47
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
Thanks for your replies revolution and shoorick.

I have opened it up for the first time and have taken the photo presented below:

Image

and yes, I am aware that the cost of the battery can be comparable with the cost of a new calculator. Wink
Post 06 Jun 2018, 17:03
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DimonSoft



Joined: 03 Mar 2010
Posts: 418
Location: Belarus
MHajduk wrote:
Thanks for your replies revolution and shoorick.

I have opened it up for the first time and have taken the photo presented below:

Image

and yes, I am aware that the cost of the battery can be comparable with the cost of a new calculator. Wink

The text written on the battery seems to give a lot of search results, even with Amazon pages. I wonder if this one is replaceable with the one used in desktops.
Post 06 Jun 2018, 19:11
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
I have made some searches too and found alternatives that are really cheap. However, to make the cost of delivery of the parcel lower than the cost of delivered items I have to combine it with sets of accumulators (for a digital camera etc.) that I'm going to order anyway. Smile
Post 06 Jun 2018, 19:28
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16051
Location: 112 Ocean Avenue, Amityville
It is difficult to know the scale but perhaps that is an LR44 size button cell.
Post 07 Jun 2018, 00:29
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
revolution wrote:
It is difficult to know the scale but perhaps that is an LR44 size button cell.
Some sources say that analogues for the battery presented above are G10 (AG10) and LR54, i.e. "GP 189/G10/LR54".

The same sources also give the information that analogues for LR44 are G13 and A76.

I'm not an expert in that matter and have got also another Citizen calculator SRP-45 (produced in Thailand in 90's) that needs two A76 batteries, so I most probably will buy two blisters containing pairs of LR54 and LR44 respectively. Smile
Post 07 Jun 2018, 09:07
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16051
Location: 112 Ocean Avenue, Amityville
BTW: When the battery holder was soldered in, they forgot to clean up the flux residue (that is the brown stuff around the solder pads). The flux can be quite acidic. You might want to consider cleaning it off before it eats through the board. Products of the type "contact cleaners" usually are good for clearing that stuff away.
Post 07 Jun 2018, 09:13
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
revolution wrote:
BTW: When the battery holder was soldered in, they forgot to clean up the flux residue (that is the brown stuff around the solder pads). The flux can be quite acidic. You might want to consider cleaning it off before it eats through the board. Products of the type "contact cleaners" usually are good for clearing that stuff away.
I guess that it is the rosin (colophony), am I right? I've heard somewhere that it could be dissolved by acetone or denatured alcohol.
Post 07 Jun 2018, 09:22
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
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Location: 112 Ocean Avenue, Amityville
Yes. If you have some rubbing alcohol, or IPA, or similar, then you can try that also.
Post 07 Jun 2018, 09:38
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
Here you have photos of the same battery with the scale added:

in centimeters

Image

in inches

Image
Post 07 Jun 2018, 09:55
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16051
Location: 112 Ocean Avenue, Amityville
11.6mm diameter is either LR44 or LR54. The LR44 is 5.4mm high. The LR54 is 3.1mm high.

You can also use SR instead of LR.
Post 07 Jun 2018, 10:22
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
revolution wrote:
11.6mm diameter is either LR44 or LR54. The LR44 is 5.4mm high. The LR54 is 3.1mm high.

You can also use SR instead of LR.
The height of the aforementioned battery seems to be about 3.1 mm, so it should be LR54 indeed. Thanks for the info.

Image

Detailed view:

Image
Post 07 Jun 2018, 10:57
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16051
Location: 112 Ocean Avenue, Amityville
I hope that vernier is not metal. Confused

Yeah, it appears as though you have LR54 or SR54.
Post 07 Jun 2018, 12:24
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16051
Location: 112 Ocean Avenue, Amityville
So talking about shorting out those batteries with metallic verniers. Another thing to be careful of when you install the new one is to make sure you don't touch it with your fingers. The oils in the skin can create a bridge across the terminals and drain the battery within a few months. Wear some clean gloves, or use some plastic tweezers, or both, when handling the batteries.
Post 07 Jun 2018, 12:40
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
revolution wrote:
So talking about shorting out those batteries with metallic verniers. Another thing to be careful of when you install the new one is to make sure you don't touch it with your fingers. The oils in the skin can create a bridge across the terminals and drain the battery within a few months. Wear some clean gloves, or use some plastic tweezers, or both, when handling the batteries.
Thanks for your important remarks. BTW, that battery was dead for sure but indeed having vernier calipers with isolated jaws would be reasonable. Do you have a more detailed information about such tools? The vernier I have got was made in DDR (East Germany) and is about 50 years old (or even more). Smile
Post 07 Jun 2018, 13:00
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revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 16051
Location: 112 Ocean Avenue, Amityville
You can get really cheap plastic vernier calipers. They aren't very accurate IME, but good enough for general usage if one isn't doing finely detailed work, and understands there are probably relatively big errors.
Post 07 Jun 2018, 13:13
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MHajduk



Joined: 30 Mar 2006
Posts: 5983
Location: Poland
revolution wrote:
You can get really cheap plastic vernier calipers. They aren't very accurate IME, but good enough for general usage if one isn't doing finely detailed work, and understands there are probably relatively big errors.
OK, I will make some reconnaissance and probably buy such a thing.
Post 07 Jun 2018, 13:30
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shoorick



Joined: 25 Feb 2005
Posts: 1603
Location: Ukraine
using metal caliper you can measure battery insulated with thin polyethilen, obviously it may be piece of packing bag or similar
Post 08 Jun 2018, 05:41
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