EEVblog #658 - Mailbag

Mailbag Monday.
Dave opens his mail

Spoilers:

Commodore GL987R Calculator Teardown and VFD probing.

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[Afrotechmods]

The knife cracks me up every time. Also loved the Commodore calculator.

[SimonB]

We had one of those Commodore calculators in the mid 70s.  When my stepfather brought it home, we were all absolutely fascinated and played with it every evening for a few weeks.

[alexzirnea]

Aussies' knife:) On every mailbag video I feel like Christmas, when I was a small child. Greets from Romania!

[TakeTurnsGaming]

I'm not an electrical engineer but I like watching some of your videos (fun to learn random information about other industries/hobbies) but these mailbag ones are the best lol. 

[Philbytronic]

I used to have a Commodore calculator just like that. It was my very first calculator. I was thankful for the fact that it had a rechargeable battery.

[FranLab]

That Compucorp has the Burroughs Panaplex gas plasma display in it - Can't wait to see you fire that one up Dave!  Geeeear!

[tubical]

AS for your compucorp 322 calc, not only a teardown, at least i want you to make this thing working again. Showing us your mighty repair-ing skills and make this beauty working again....PLEASE Dave....hear me....this unit just deserves that...!! It´s just crying out loud....REPAIR Me....You´re the Guy....so don´t miss this upportunity....:) :) :)

[RandyLott]

Speaking of spoons. I remember when you somehow cut your finger on a spoon and wore a bandage a few years back. This is much safer, haha!

[PCReboot]

Thanks for all the videos chap! I have almost no idea what your talking about most times but I love taking things apart :)

[richfiles]

I have one Monroe version and another Compucorp version of that series calculator. I have a fully functional Monroe 344 Statistician model with dual program banks. The other one's broken. Also in storage, so I forgot the model. I've read they were very susceptible to static discharge.

You are going to LOVE that tear down. If I recall, there are 4 layers of PC boards. It has a Power PCB, a Memory PCB, a Processor PCB, and an IO PCB. It was very modular, and they used a crazy interconnect to bus the boards together.

The display is a 16 digit Panaplex neon gas display. It glows orange, like a nixie tube, but uses segmented digits. I do believe it displays 10+2 digits, with inline (-) symbols.

The 2ND FUNC key is very unusual on these models. You press it AFTER performing the desired function. The calculator actually calculates for BOTH function's result, and the key toggles which result is displayed, and is used for the next operation. This leads to an unfortunate bug, however, where if you perform a calculation that is valid on one function, but would generate an error on the other, it will error out the calculator. Oddly enough, you could press the RESET key and clear the error, but you could STILL press 2ND FUNC to swap the other (valid) result in!

And yes... This thing is an absolute BEAST! I love it!

Still not as heavy as my SCM Cogito 240-SR or my Friden EC-132... Of course, this one IS portable, what with it's QUAD "D" type batteries! XD

[AFLJSue]

Good stuff Dave but you really need to make Mailbag Monday longer. :)
Take Care
Sue

[MrBuck]

Yeah a quick open and peek is OK for mailbag Monday but a complete teardown should be left for Tuesday plus I would like to see a longer mailbag video

[michaeltuckey]

Can't wait to see inside that compucorp!

[EdEditz]

I look forward to that tare-down Tuesday for that little computer at the end there. Looks awesome!

[michaelhawthorne]

Wow, just getting into that and it Some great stuff to look forward to, keeping my eyes open for the videos.
Can' wait

[llloyd]

EEVblog Just a suggestion, Dave, more mail opening and less teardowns for the Mailbag, leave the teardowns for Tuesday. :D Also longer videos, I don't mind an hour long video. :D 

[BenChilds]

Loved the warranty void sticker at 18:23

[TheCode-X]

The cap on the Commodore calc is for clearing the EPROM

(I know all of you knows it, but i've been studying and i had to say it)

[agilemm]

As someone who used to sell Calulators back in the Day, the Commodore was one of the LAST of the CBM calculators, after the GL series they just started to sell little LCD credit card sized ones.  I used one of the GL series for a couple of years.  Before that there was the US 3 US 4  up to US14 desk top, most with Plasma displays, and several pocket ones with individual VFD, One tube (valve) per digit. they sold a few LED units also.
One interesting experiment is to try using a VFD as a triode.
Commodore also MADE filling cabinents at one time, put mostly here in Canada only.  I have yet to find a commodore Typewriter., I did see a commodore Adding Machine once, but did not get to touch it.

[pyroslavx]

The thing at 15:00 is a magnetron core of a mini flux capacitor. no Jigawatts needed.