RCA Cosmac Microtutor - 256 bytes of RAM

Spotted - not by me - at the recent VCF East, photo posted on discord (link?) by gloriouscow

I think it’s a two-chip version of the COSMAC microprocessor that’s on the expansion card.

Video (German language) of the Microtutor II

The Microtutor is possibly from 76 or otherwise from 77, shortly before the ELF.


Related, TELMAC: Telmac 1800 - Wikipedia

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Sadly, that Discord link doesn’t work unless you’re already a member of that particular Discord.

The manual for the Microtutor is somewhat snarky in tone, though:

A. Turning it ON
Figure 1 shows what MICROTUTOR looks like in case you don’t have one. If you do have one, plug the memory card into the first socket (M). plug the COSMAC microprocessor into the middle socket (P). The component (bumpy) side of these cards should face the rear. Don’t apply power until the M and P cards are in unless you enjoy replacing integrated circuits. Likewise, never remove a card unless the power is off.

Plug the power pack cord into the back of MICROTUTOR to turn it on. Pull the cord plug out to turn it off. If the red display lights don’t come on when you plug in the power you are the proud owner of what is technically known as a lemon.

Wow - I agree, although I might call it playfully witty. I find it very surprising phrasing in a 1970s corporate product. Perhaps I misjudge the culture in RCA at the time!

Search on “Bob Widlar National Semiconductor ad” to get an idea of how snarky things were back then!
Oh, and if anyone can point me to an actual magazine that carried it, very much appreciate. I only remember seeing it as a photocopy, so I don’t believe it was ever really published.

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An amusing rabbit hole - thanks!

More COSMAC goodness in photos from VCF East in this carousel embedded in a Hackaday writeup

COSMAC Elves on the Shelves

First described in a series of Popular Electronics articles in the back-half of the 1970s, the Elf was a simple homebrew computer based on the RCA 1802 Complementary Symmetry Monolithic Array Computer (COSMAC) chip. In the boilerplate configuration, it used a pair of LED hexadecimal displays for output and eight toggle switches for input. There was no ROM — programs were entered directly into memory using the toggle switches as God intended.

Different kit versions of the computer were sold over the years, and the community has produced countless spin-offs of the basic concept right up to the present day. For their exhibit RCA COSMAC 1802 Computers, Josh Bensadon and Walter Miraglia had a wide collection of these DIY machines on display, as well as a few commercial devices that used the 1802 such as the RCA Studio II.

Aha! So that’s where they went the other weekend. They’ve been building all sorts of 1802-based things recently, including some that used RCA’s rarer video and sound chips.

They have a Discord for this kind of 1802 goings-on: COSMAC CDP1802
(link expires in a week, sorry)

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