On 2021-Feb-12, at 6:08 AM, Paul Koning via cctalk wrote: >> On Feb 12, 2021, at 7:50 AM, Jules Richardson via cctalk >> <cctalk@classiccmp.org> wrote: >> >> Hopefully the following link works, but someone over on one of the Facebook >> vintage groups has this oddball terminal from 1973 that they've been looking >> for any information on: >> >> https://drive.google.com/drive/folders/1-2uEFbi3OKBYr06y6yHnygDiLMtw2Qkj >> >> ... it's somewhat unconventional in that half the CRT is hidden from view >> within the machine, i.e. it only actually displays the top half of the >> display to the user - I've no idea if that's because it had a specific >> application where space was limited, or if it was simply that memory at the >> time was horribly expensive and so it was designed to only use a few lines >> (I know some vendors did that, although I think they typically presented the >> whole CRT and at least had the option of RAM upgrade to more lines). >> >> The blower assembly seems a little on the homebrew side, but on the other >> hand the PCBs and case construction make it seem like a professional product. >> >> The owner says the only label anywhere on the thing is the one on the CRT >> saying "Mfd in Japan for Conrac", but that's presumably just the CRT itself >> and not the entire machine. > > I remember Conrac as a well known CRT maker from that time. I think they > were used in PLATO III terminals (mid 1960s). > >> I don't believe there's anything resembling a microprocessor in the system, >> it's all just TTL logic (the large white ceramic IC is an ACIA). >> >> Oh, I believe the owner's in Canada, so it may be it was made there and >> never exported to other parts of the world. >> >> Jules > > The photos are not particularly helpful; they show parts of the device but > not close enough to tell the details, while much of the case is not shown. > Is there any manufacturer label or serial number tag on the case? > > One of those boards is full of rather sloppy ECO wires, which makes it feel > like a home made job, but the rest look like decent quality commercial > pieces. And yes, the blower is rather curious, it's hard to see how a device > like this might dissipate enough power to need that kind of air mover.
Between google and the browser I'm using, the photos didn't display properly, so I downloaded them (upper right corner), which unzipped to high-res versions. From those: The board with the white ECOs is the memory, it has 5 1402's (256*4 shift register), 3 of them from Intel and 2 replacements from MIL (Microsystems International Limited) which is the only place Canada appears to come into it. Not clear how they would be organised for the screen . The main board has a Fairchild 3258 64*7*5 character generator, along with the 1602 UART/ACIA. The blower is probably targeting the pass transistors for the linear power supply, to avoid requiring a giant heat sink. Most/many terminals from that period had a large heat sink for the pass trans. I don't think the CRT is half-hidden, rather just a high-aspect-ratio CRT (very wide rel to height). Interesting that aside from the Intel/MIL memory chips, a couple of specialised clock drivers for those, and a couple of other chips, it's entirely Fairchild 9xxx series stuff. In terms of design & construction it looks pretty typical for its period; nonetheless a cool unit to be working on.
