1970s Commodore Calculator Refinements

Nice Video. Looking at the calculator is like going back in time - Happy days !

Schon wieder nicht erster 🤣🤣🤣

GL-997R, the calculator that sits on my desk since 2 decades now. A bit newer than yours and less functions. But I love it, especially the green display.

500,000 years from now, our descendants will find this Commodore in the clutches of Jan Beta's bones and they'll ponder it's ceremonial significance.

I wonder if something like polywatch might be able to repair that display and take the scratches out.

From the 1970s calculator wars, that were about the first mass-produced electronic gadget. In order to raise profits in a linear fashion (or even just stay in business) the company has to produce exponentially more calculators over time. The business works like this to this day.

Great video Jan 👍 what’s in the red box in the background ?🤔

Hi,
it cannot be ruled out that that circuit can be used to generate a negative voltage. You could have checked what voltage is on the blue wire.

Bit of Peek polish (or similar) ought to get that mark polished out from the display lens, it's quite good at making scratches and scuffs disappear from shiny plastics like that... :D

With annoying cables like that that keep going back the that shape where it's been cabled tied, I soak the cable briefly in hot water from a kettle and then stretch it out until cool.

For the scratches on the display Brasso in the can works great. A little pinch of that would probably get rid of the scratches completely. Learned that one from tech moan. Used that method on a horribly scratched turntable lid and it eliminated all but the deepest ones

Hi Jan, I just finished a package for you today and will ship it tomorrow (hope your address is still the same). It contains a device frorm the same era. I won't tell you what it is, but i'm sure you will like it and I hope that you will make it the subject of another video.

Of course, another workaround for the case scratching the display would be to turn the calculator around in the case, either front-to-back or top-to-bottom.

Jetzt brauchst Du nur noch eine Commodore Schreibmaschine und die Sammlung ist komplett. Obwohl die Reparatur dann vielleicht nicht Deine Stärke wäre?😄

Awesome calculator.

I would have stuffed the guts of the modern power supply into the original power supply case.

Just a man and his Commodore calculator 😊❤

To remove marks and scratches on plastic screens Displex display polish is very good, if a bit on the expensive side. Here in the UK it’s around £8 on eBay / Amazon for a small tube but you don’t need to use very much of it.

You could of course easily mod this to power it via USB. Then you could power it with the computer or a USB docking station and keep it on the desk without using an extra mains socket. I know you want to keep it mostly original, but it's an option for these old mains powered calculators.

You can remove the marks on the display glass by using a polish creme used for car lights. Done that to some other modern calculators, works fine.

You should have used the old case of the old power supply and moved the board from the new to the old one. Changing the plug on a new power supply ruin the whole thing.

Turn the calculator the other way so the bottom is turned against you and it will not scratch the screen any more.

cbm? That can't be Commodore, because i got one without the Commodore logo.

Gotta love that LED display.

Years ago, I had a T.I. Calculator that had a very similar display and worked with both batteries or a power supply much like the one you have here. Wow, lots of memories. I got a lot of years worth of use from that calculator and it still works !!

At one time, many years ago, I had a Commodore 64 that I just loved ! One thing I found it very very useful for was it's ability to act as a very large calculator. I just turned it on and typed in whatever formula I was working on and I always got the correct answer. I also liked being able to change how many digits the answer could be changed to for accuracy.

I've also always used permanent marker for touch-up. Now I'm wondering if black nail polish would be better? Will have to give it a try next time I need to touch up a metal surface.

Good job with the felt pad and marker pen Jan. My OCD is now truly covered.

I bought some of those felt pads years ago - now and then I used to randomly stick them to my wife in her sleep for her to discover later on in the day, she loved it ... 😮‍💨 heheh.

Other workaround for scratching the display is to simply put the calculator in the pouch backwards.

You can hate me now! 😊

The AC⚡DC adapter, for those about to calc.

Your videos are always very interesting!

Your videos are always interesting.

No rude comments here. Thanks, Jan!

The year was 1976 and 1977 for me and my electronics class and this calculator was the best! In later years I too made a power supply for it. With 1.1 in both memories and the display it used a few hundred milliamps. With -8888888888.88 in both memories and the display it pulled a whopping 800 milliamps. Even in school the battery never lasted more than a couple hours even when it was new. I did not care. It is an awesome calculator.

What amazes me is how a calculator can add, subtract, multiply, divide and much more with 12 digit floating point numbers. Whoever programmed this is a genius.
🙂👍

love your work - interesting as always - maybe you can build an USB to 6V converter to use it while working on the pc or notebook
keep going

Michael

To get the display back into its shiny glory and remove the scratches left by the button, I recommend using masking tape (so as not to polish the rest of the case), some PolyWatch, and lots of patience.

This "step-up converter" is definitely needed to provide negative voltage - on the PCB close to the edges you find labelled voltage rails VSS (positive) and VGG (negative). The circuit looks like typical negative voltage generator designed around PNP-NPN transistors/two diodes/two capacitors judging by the components and PCB layout in my CBM. It would be great to reverse engineer and know the diagram for the learning - for me difficulty is the toroid transformer. There are 5 pins coming from it, all windings are connected, not sure what it does.

Your English is so perfect, you must have spent a very long time in an English speaking country. Love your videos 😊