{"id":9912,"date":"2024-02-22T19:30:47","date_gmt":"2024-02-22T17:30:47","guid":{"rendered":"https:\/\/hex.ro\/wp\/?p=9912"},"modified":"2024-09-18T07:29:31","modified_gmt":"2024-09-18T05:29:31","slug":"mbo-alpha-82-pr-calculator","status":"publish","type":"post","link":"https:\/\/hex.ro\/wp\/blog\/mbo-alpha-82-pr-calculator\/","title":{"rendered":"MBO Alpha 82 PR Calculator"},"content":{"rendered":"

Introduction<\/h2>\n\n\n

The MBO Alpha 82 PR is a programmable 10 digit calculator, powered by two LR44 \/ AG13 batteries, based on the Sharp LI3301A CPU.<\/p>\n\n\n\n

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\"\"<\/a><\/figure>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
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Sharp LI3301A<\/figcaption><\/figure>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
\"\"<\/a><\/figure>\n\n\n\n
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MBO Alpha 82 PR<\/figcaption><\/figure>\n\n\n\n

The “=” key is a bit faded.<\/p>\n\n\n\n

As a small background story: I have an almost identical calculator and totally forgot about it for many years until I saw an identical one at a second hand shop! Bought the second one but forgot about it too until I found this one at a flea market. I bought it and figured I should start posting them so I don’t forget.<\/p>\n\n\n\n

This one needed two new batteries and a bit of cleaning.<\/p>\n\n\n\n

The calculator is branded “MBO Alpha 82 PR” and is build around the Sharp LI3301A CPU. Having a name, it helped me find the world of Sharp clones \ud83d\ude42 Surprisingly, nobody scanned the manual so far – I hope I will, but that original calculator is far away from me for now.<\/p>\n\n\n\n

But not all is lost. The Casio SRP-145N is based on the same CPU and its manual can be found online. It is more complex, but principles are the same.<\/p>\n\n\n\n

Coming back to this calculator, It is interesting that it cannot calculate the yx<\/sup><\/strong> values for negative numbers. For example, the combination 8 +\/-<\/strong> yx<\/sup><\/strong> 2 =<\/strong> (interpreted as 8, then followed by the +\/-<\/strong> button press to make it -8, followed by yx<\/sup><\/strong> button to rise to an arbitrary power, then followed by 2, to rise it to the power of two), produces error. This behavior is a “domain error”. Most likely, the calculator uses a combination of logarithm \/ exponential formulas to calculate arbitrary yx<\/sup><\/strong> numbers, but logarithm is not defined for negative x. Typing 8 +\/-<\/strong> x2<\/sup><\/strong> gives the right result since probably it just does a multiplication.<\/p>\n\n\n\n

ON\/C button is identical with C button. C button wakes it up from the Off state (just like the ON\/C button). Pressing 2nd<\/strong> ON\/C<\/strong> switches to STAT mode, just like 2nd<\/strong> C<\/strong> is supposed to do.<\/p>\n\n\n

Programming the Scientific Calculator<\/h2>\n\n\n

I figured I should post a small program. One idea I had was to program it to calculate the power delivered by an amplifier into a 8\u03a9 load, based on the Vpk<\/sub> captured on an oscilloscope.<\/p>\n\n\n\n

Formula linking Vpk<\/sub> to Vrms<\/sub> is detailed on RF Cafe website here: https:\/\/www.rfcafe.com\/references\/electrical\/sinewave-voltage-conversion.htm<\/a>. Assumptions are that the signal is a perfect sine wave and that the load is purely resistive, without parasitic inductance. As a clarification, the meaningful value is Vpk<\/sub> and not Vpk-pk<\/sub>. <\/p>\n\n\n\n

Power = Vrms<\/sub>2<\/sup> \/ R = Vpk<\/sub>2<\/sup> \/ (2R)<\/p>\n\n\n\n

K1 and K2 memory locations are useful for constants because pushing their respective button also triggers a multiplication with their memory value. <\/p>\n\n\n\n

Thus, let’s store the load resistance at K1<\/strong> memory location, this way we can switch between 4\u03a9, 8\u03a9 or 12\u03a9 load easily without changing the program.<\/p>\n\n\n\n

Button presses<\/td>Meaning<\/td><\/tr>
8 2nd K1<\/sub><\/td>Store 8 at location K1<\/td><\/tr>
2nd COMP<\/td>Switch to Learning mode (LRN is displayed)<\/td><\/tr>
2nd (<\/strong><\/td>Program will ask an input value – ((x)<\/strong> is displayed)<\/td><\/tr>
x2<\/sup><\/td>Program will rise the last value to power of two<\/td><\/tr>
\/ ( 2 K1<\/sub> ) =<\/td>Divide
Open left parenthesis
2
K1 – this also does multiplication, so it will multiply 2 with the K1 memory value
Close left parenthesis
Equals<\/td><\/tr>
2nd COMP<\/td>Exit learning mode<\/td><\/tr><\/tbody><\/table>
Small program for MBO Alpha 82 PR calculator<\/figcaption><\/figure>\n\n\n\n

Running the program is triggered by the COMP<\/strong> button. To confirm that you finished typing the input value, you have to press COMP<\/strong> again. Thus, to run the program with a Vpk<\/sub> = 1.414V you have to:<\/p>\n\n\n\n

COMP<\/strong> 1.414<\/strong> COMP<\/strong><\/p>\n\n\n\n

Value displayed is: 0.12496225 which is very close to the theoretical value of 0.125W of power that a 1Vrms<\/sub> = 1.414Vpk<\/sub> signal produces into an 8\u03a9 load.<\/p>\n\n\n\n

To switch to a 4\u03a9 load is easy: 4<\/strong> 2nd<\/strong> K1<\/sub><\/strong>. Then program can be ran again, and will produce: 0.2499245. It is faster in fact to just multiply the previous value with two (less buttons to press). But I hope it highlights the usefulness of K type memory locations.<\/p>\n","protected":false},"excerpt":{"rendered":"

Introduction The MBO Alpha 82 PR is a programmable 10 digit calculator, powered by two LR44 \/ AG13 batteries, based on the Sharp LI3301A CPU. The “=” key is a bit faded. As a small background story: I have an almost identical calculator and totally forgot about it for many years until I saw an […]<\/p>\n","protected":false},"author":1,"featured_media":9913,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[239,35],"tags":[225,224,223,95],"class_list":["post-9912","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-calculators","category-flea-markets","tag-calculators","tag-casio","tag-li3301a","tag-sharp"],"_links":{"self":[{"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/posts\/9912","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/comments?post=9912"}],"version-history":[{"count":7,"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/posts\/9912\/revisions"}],"predecessor-version":[{"id":9927,"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/posts\/9912\/revisions\/9927"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/media\/9913"}],"wp:attachment":[{"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/media?parent=9912"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/categories?post=9912"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hex.ro\/wp\/wp-json\/wp\/v2\/tags?post=9912"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}