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.

Reply via email to