Citizen SRP-45 programmable scientific pocket calculator from 1991

[jebem]

This one was acquired in a lot of several machines.

It sports a nice in metal face plate.



Pi constant displayed to 10-digits



Forensic test in Degrees mode (other featured options are Grad and Rad).
9 sin cos tan Inv tan Inv cos Inv sin
result displayed as = 9.00001562



Hyperbolic and Inverse functions waiting to be selected.



This is a low profile machine.
It suffered some abuse from previous owners when opening the case using brute force approach.



Label in the back cover:

Citizen
LCD Display Calculator
type: SRP-45
T.M. Licenced by Citizen Watch
Co. Ltd. Tokyo, Japan
Japan CBM Corporation
Made in Taiwan Fabrique à Taiwan

[jebem]

The SoC processor from Sharp model LI3301A Japan was once popular among the calculator manufactures and this LSI has a date code of 9109 B.
This calculator was made after 1991 week 09.




Battery electrolytes leakage marks are visible in the battery terminals.

A single legacy 200Kohm 1/8Watt pass through resistor is used here.
Edit:
Now, a brief look into the usual Russian sites is enough to find what can be done with this resistor... overclocking the machine (with battery consumption increase) can be the solution for the slowness of this LI3301A SoC processor.

The PCB references includes this "SR-35P" label.



Easy machine to dismantle when maintenance is required.
Extra care is needed to open the case when replacing the battery cells, though.
The plastic case locking pieces are very tight and can break easily.

[Eddie W. Shore]

This calculator looks similar to the Radio Shack EC-4036 I just bought. Thank you for this thread because now I think I know at the [A ->A] and [B ->B] keys are. Looks like store is the second function and recall is the primary function (outside of stats).

I notice that many calculators find it popular to make Statistics mode the second function of the [ON/C], I find that strange. I have a solar scientific calculator (Staples 27952, it has hole punches designed to fit in a three ring binder) with this setup. On the Staples, I can't access the Stat mode when pressing [2ndf] [ON/C], instead the calculator clears.

[jebem]

(01-03-2017 03:09 AM)Eddie W. Shore Wrote:  This calculator looks similar to the Radio Shack EC-4036 I just bought. Thank you for this thread because now I think I know at the [A ->A] and [B ->B] keys are. Looks like store is the second function and recall is the primary function (outside of stats).

Hi, Eddie, thank you for your comments.

Yes, on my Citizen SRP-45 these keys are constant memories.
If there is a non zero displayed value (register X), then when recalling one of these constant memories it will multiply the displayed value by the constant value.

I have run again the forensic test to extract all the available digits.
9 sin cos tan Inv tan Inv cos Inv sin - 9 * 1000000
and got the combined result of: 9.0000156204, the same as reported for your machine.

I do not have the Radio Shack EC-4036, but based on the forensics result from the site above, it looks like it uses the same Sharp LI3301A processor. So it could present the same features as many other calculator brands using this processor.

(01-03-2017 03:09 AM)Eddie W. Shore Wrote:  I notice that many calculators find it popular to make Statistics mode the second function of the [ON/C], I find that strange. I have a solar scientific calculator (Staples 27952, it has hole punches designed to fit in a three ring binder) with this setup. On the Staples, I can't access the Stat mode when pressing [2ndf] [ON/C], instead the calculator clears.

Just guessing here, but probably all the machines sharing the same Sharp LI3301A processor (assuming the same firmware was burned into it, that is) will have the STAT function mapped to the 2ndF ON key combination, and an extra dedicated key to power off the machine.

Still it is a strange place to invoke functions. The ON key should be used to manage power duties only.

I have others machines like the Citizen SR-35N, the Canon F-400 or the Deli DL-1704, that also uses that STAT / ON combination and a dedicated power off key, despite showing different forensics results. So this key arrangement is not exclusive of the Sharp LI3301A processor.

Our local Staples store do not sell the Staples brand and I have none of their calculators. Your Staples 27952 can have a fault, assuming the calculator advertising is correct.

[Eddie W. Shore]

(01-03-2017 09:51 AM)jebem Wrote:  Hi, Eddie, thank you for your comments.

Yes, on my Citizen SRP-45 these keys are constant memories.
If there is a non zero displayed value (register X), then when recalling one of these constant memories it will multiply the displayed value by the constant value.

This is unusual! Not only the with the automatic multiplication but on the EC-4036 the way the keys are labeled ( [A >A], [B >B] ), I would have not been able to figure this out without your post.

(01-03-2017 09:51 AM)jebem Wrote:  I have run again the forensic test to extract all the available digits.
9 sin cos tan Inv tan Inv cos Inv sin - 9 * 1000000
and got the combined result of: 9.0000156204, the same as reported for your machine.

I do not have the Radio Shack EC-4036, but based on the forensics result from the site above, it looks like it uses the same Sharp LI3301A processor. So it could present the same features as many other calculator brands using this processor.

I get the same forensic value you have. Is the Citizen a bit slow, like the calculator has to process for a micro-second before returning answer? My Radio Shack is like that.

(01-03-2017 09:51 AM)jebem Wrote:  Our local Staples store do not sell the Staples brand and I have none of their calculators. Your Staples 27952 can have a fault, assuming the calculator advertising is correct.

I will have to try another 27952. The Staples calculator was only $7.99.

Eddie

[jebem]

(01-08-2017 10:08 PM)Eddie W. Shore Wrote:  I get the same forensic value you have. Is the Citizen a bit slow, like the calculator has to process for a micro-second before returning answer? My Radio Shack is like that.

Yes, it is on the slow side as well.