Products > Vintage Computing

Misc. SSI computer boards

(1/2) > >>

D Straney:
Just thought I'd show off some interesting old computer boards I've ended up with, from non-integrated-CPU systems with mostly SSI logic ICs.  There's already the Univac CP-901 flight computer board, and a Honeywell 316 industrial computer core-memory-related board (helpfully identified by PA0PBZ), but now there's also...

Sperry-Univac 7165534-02 from AN/UYK-7

I'm pretty sure this is from the 32-bit AN/UYK-7 computer, which was the US Navy's standard shipboard computer for roughly 15 years through the 70's and part of the 80's.  The reason I'm confident in the source is because shows a similar board (IMG_1873.JPG, bottom-right corner) with a directly adjacent part number (7165535 vs. 7165534) and identical construction, which it identifies as being from the AN/UYK-7.

As for what this board actually does...

...I'm not totally sure.  The array of magnetics in the middle suggests either ferrite core memory or transformers for driving or receiving external signals of some kind.  However, having a group of 3 transistors on one side, and a group of 6 transistors on the other side, with 18 cores total, strongly implies that they're electrically arranged in a 6 x 3 matrix, which leans heavily towards the "core memory" theory.  I did manage to find two (1, 2) technical descriptions from Bitsavers, but there's no direct clues there.  Besides the 32-bit word size, this would be an impractically low-density way of implementing the main memory, so this could be some kind of auxiliary storage.  It explicitly mentions that the "control memory" is provided by ICs, so it can't be a register:

--- Quote --- ...memory used during the execution of instructions and input or output transfers, to capture, maintain, and provide status information when needed; and to provide various controlling  addresses and data as dictated by the operating programs.
...Eighty-two integrated-circuit random-access registers of appropriate size serve as the central processor control memory. The various registers are grouped into stacks according to their use, addressing, and relative size.
--- End quote ---
However, the address length is also 18 bits, so this is probably storing something related to addressing.

There's another one of these available if anyone else is interested.

D Straney:
Marconi-Elliott 6743-00191B03 Navigation Computer Board

From looking up the part number (equiv. NSN 5998-00-480-6599), the applications info I found on this was "FSC APPLICATION DATA:AIRBORNE INERTIAL NAVIGATIONAL SYSTEMS" and that it's from an A-7E aircraft.  According to that article, it has a fancy projected map display from the navigation computer (one of the first systems of that kind supposedly), tied into the inertial navigation system, which also could update its absolute location (both as an initial reference, and to correct for drift over time) from multiple external sources of position info.  So it sounds like this could be either part of the listed "AN/ASN-90(V) Inertial reference system" (if it has its own digital logic), or the "AN/ASN-91(V) navigation/weapon delivery computer".

The particular board is marked "Clock & Checkout", and has a 6 Mhz crystal, so at a minimum it generates clocks for the rest of the logic.  Because of the timeframe (the date codes are 1972-1973, and the NSN record was created in 1970) I wasn't able to find any info on the ICs, as they have specialized possibly-custom part numbers, but the info on the board lists its contents as "RESISTOR 63,CAPACITOR 31,PANEL 1,TERMINAL POST 2,DIODE 13,TRANSISTOR 9,RETAINER 5,FLIP FLOP 13,AMPLIFIER 6".  I'm guessing the many chips at the bottom edge are the flip-flops, which probably divide the clock signal and split it up into multiple phases for different parts of the computer, similar to the way that old integrated CPUs like the 8086 require multi-phase clocks to schedule instruction decoding / memory bus access / etc. separately.

There's also a mystery diode(?) down there:

Some of the gold chips with the Teledyne logo at the top edge are probably the "amplifiers" listed in the board contents.  There's also some discrete transistors there, mounted upside-down in heatsinking clips.  I'm not sure what the purpose of the analog section is: would expect a little bit of circuitry next to the crystal to be the oscillator circuit that's tuned by the crystal, but no idea what the rest of it would be for.  I'm also not sure what the "checkout" function of the board refers to, so it could be related to that.

One feature mentioned in the AN/UYK-7 technical description was how it would generate an interrupt if the power input failed, at which point it would have 250 ┬Ás to "clean up" and put things in a safe state; another useful feature in a "high-reliability" or "high-availability" computer would be generating a backup clock source if the crystal failed to start.  So it's possible that some of the analog circuitry here is a combination of power rail monitoring, to inform the stored program if something isn't working right for diagnostic purposes, and also as a clock supervisor circuit, possibly with a backup RC oscillator (like many microcontrollers), or maybe even also implements a hardware watchdog timer.  Any extra info appreciated.

In computers of that era it was common to have "margining" controls on the operator console. The operator could dial the power supply and the clock frequency up or down 10 or 20 % from the nominal value for testing. If no errors occur at extreme operation points it increases confidence that there are no latent faults.

D Straney:
Ahh good to know, that makes sense both for the "checkout" label, and the concentration of analog parts!

Alex Eisenhut:
Whoah  ^-^


[0] Message Index

[#] Next page

There was an error while thanking
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod