The Museum of HP Calculators

HP Forum Archive 09

[ Return to Index | Top of Index ]

Re: Nothing much
Message #1 Posted by Les Bell (Sydney) on 27 Aug 2002, 11:17 a.m.

Steve Borowsky wrote:

"This is good to know, but i'd have to know more about the specific models to tell whether they would have been a good or a bad influence on the acceptance of RPN. The NS models for example were so crappy, comaparatively, that they may have had a negative influence".

I remember the old Sinclair Scientific, from around 1974 or so. I used to build the earlier Sinclair calcs from kits, and then typically sell them that evening to the first person who saw me use one in the bar where I worked during student vacations. So when the Scientific came out, for GBP14.95 in kit form, of course, I had to have one!

Trouble was, after I built it, it wouldn't work. I had no schematics, of course, but probing around with a scope, all I could see was DC everywhere - there was no clock running. I remember walking back to the university Hall of Residence where I lived, and despondently fishing the calc out of my parka pocket, only to discover it now worked - for a few minutes.

A little experimenting revealed that the calc would work for a few minutes after being cooled down in the icebox of the fridge next to my room - so for a few days, I used it like that to do Bode/Nyquist calculations: grab the calc from the freezer, work the numbers like crazy until it stopped, and then back into the icebox!

Eventually, a phone call to Sinclair revealed that TI had supplied a faulty batch of chips, and they would rework the calc if I sent it back, which I did.

However, the Sinclair's implementation of RPN (three level stack, from memory) was fatally flawed by the absence of an X<->Y key, so that intermediate results had to be written down. Nonetheless, it beat the *crap* out of using a slide rule, so I persevered, until the bar job during the following Easter break provided the funds to buy an HP-45.

Blessed relief!

Best,

--- Les Bell, CISSP [http://www.lesbell.com.au]

      
Re: Nothing much
Message #2 Posted by Steve Borowsky on 27 Aug 2002, 7:10 p.m.,
in response to message #1 by Les Bell (Sydney)

Les Bell wrote:

<<A little experimenting revealed that the calc would work for a few minutes after being cooled down in the icebox of the fridge next to my room - so for a few days, I used it like that to do Bode/Nyquist calculations: grab the calc from the freezer, work the numbers like crazy until it stopped, and then back into the icebox!

Eventually, a phone call to Sinclair revealed that TI had supplied a faulty batch of chips, and they would rework the calc if I sent it back, which I did.

However, the Sinclair's implementation of RPN (three level stack, from memory) was fatally flawed by the absence of an X<->Y key, so that intermediate results had to be written down. Nonetheless, it beat the *crap* out of using a slide rule, so I persevered, until the bar job during the following Easter break provided the funds to buy an HP-45.

Blessed relief!>>

'Cool' story, Les! It's difficult to appreciate today how valuable a few trig keys were back then. The NS RPN wasn't much better; a three level stack, though at least one model, the 'Scientist' had an X<>Y key. In fact, that model virtually reproduced the HP35 keyboard. The top level wasn't perpetuated when the stack dropped though so the neat trick of filling the stack with the same number and using it as a constant couldn't be done. Interesting that the Sinclair used TI chips. I guess they didn't sell only AOS.

I think a lot of people came to RPN not for it's own sake, but simply because HP's were the best calculators out there and everyone knew it. The advantages only became apparent later. Machines like the Sinclair and NS models didn't have enough going for them in the quality department to carry people from the initial purchase desision on to proselytizing conviction, as we see in the case of HP.

            
Re: Nothing much
Message #3 Posted by Masao Kinoshita on 28 Aug 2002, 9:18 p.m.,
in response to message #2 by Steve Borowsky

<<Machines like the Sinclair and NS models didn't have enough going for them in the quality department to carry people from the initial purchase desision on to proselytizing conviction, as we see in the case of HP.>>

I used to own one of those neat Sinclair RPN scientifics. They looked cool and were small enough to put inside your jeans pocket. I remember also having to key in pi (3.14159 was printed on the calculator). I even built one of their algebraic scientifics from a kit, but by that time it was only for fun.

I had bought an HP 25 and the Sinclairs were no match. I was still saving up for an HP 65, so when HP introduced their HP 67 in 1976, I could afford one. :-) But not the HP 01, which came shortly after. :-(

Masao Kinoshita PPC 8585, CHHU 123, HPCC 1031

                  
Re: Nothing much
Message #4 Posted by Masao Kinoshita on 29 Aug 2002, 12:34 p.m.,
in response to message #3 by Masao Kinoshita

Now that this little beauty is on my mind, I googled around and found this web page: http://www.vintagecalculators.com/html/scientific.html

Back before buying an HP 25, I did use my fatherís HP 21 quite a bit; but the Sinclair RPN was mine.

Thread-wise, I really donít know if the Sinclair RPN helped or hurt RPN-ing in the long run. It certainly helped in that the HP Classics were so expense back then, but unless you were comfortable using scientific notation and keying in constants, this little machine might have put some people off a bit. I also remember comparing the speed at which the HPís and the Sinclair RPN performed trig transcendentals. Letís just say that the Sinclair took a lot lot longer.


[ Return to Index | Top of Index ]

Go back to the main exhibit hall