Anyone recognise these pluggable PCBs? - Page 1
Forum section: electronics / general

author: austfox
author_rank: Regular Contributor
timestamp: August 03, 2022, 05:09:49 am
content: I scored a few boxes of these pluggable PCBs a while ago. They are all doubled-sided, but populated only on the top side.I've similar boards used in mainframes. Anyone recognise these ones, and from which computer?I'm also thinking they might from industrial automated machines or traffic signalling equipment?

author: SeanB
author_rank: Super Contributor
timestamp: August 03, 2022, 11:39:11 am
content: I will take a guess teaching logic systems, pluggable boards, into a common socket, all brought out so you can teach logic, and then wire them together with jumpers to make complete demo systems to show how the logic works. Would explain all being 40 pins, and all having common power and ground connections, along with almost all parts being brought out to the edge connector, instead of being connected into more complex logic, except for the LED decoder, which has CMOS inverting buffers to drive them. CD4009, obsolete a really long time, and made by Harris as well, the second source of RCA original CMOS. Normally you would see a CD4049 there, capable of 50mA source or sink, and faster edges, because it has a cascaded inverter and then a big buffer stage, but instead you have the slow single stage pair of inverting gates.

author: Gyro
author_rank: Super Contributor
timestamp: August 03, 2022, 11:46:00 am
content: They do look like some sort of modular logic system - probably educational, possibly very light industrial, but definitely not traffic signalling.DEC (Digital Equipment Corporation) used to have the 'Flip Chip' range of logic boards, which they offered for industrial use but also used in-house for building their early computers and peripherals...https://en.wikipedia.org/wiki/Flip-Chip_module, but those look more 'mickey mouse' -large board area for their functionality andnot very mechanically robust (ICs socketed), hence the educational / prototyping thought.

author: SmallCog
author_rank: Frequent Contributor
timestamp: August 04, 2022, 03:27:24 am
content: Never seen them before but they look like a possible competitor to the pluggable stuff we used in schoolI reckon the description of the boards being printed on them and the socketed IC's are signs they were intended for use in education (easy to ID for students and easy to fix for staff)

author: austfox
author_rank: Regular Contributor
timestamp: August 04, 2022, 04:55:34 am
content: Makes sense that they are for educational purposes, especially since the components are so sparse and spaced out.Thanks for all the replies.

author: pcprogrammer
author_rank: Super Contributor
timestamp: August 04, 2022, 07:17:56 am
content: Love the rivet style viasWonder what happened to the LED driver board, where it seems to be missing a bit

author: austfox
author_rank: Regular Contributor
timestamp: August 04, 2022, 07:51:32 am
content: Quote from: pcprogrammer on August 04, 2022, 07:17:56 amIt's a nice clean cut, with an appropriate bodge wire on the underside to make up for the severed track!

author: AndyBeez
author_rank: Frequent Contributor
timestamp: August 04, 2022, 08:40:40 am
content: Certainly a modular system made from robust fiberglass PCBs. A range of date codes and component styles suggests these were bricked and fixed over a couple of decades. The ground returns look standarised on the back. The pcb traces are an example of hand positioned sticky tape masking. The rivets are unique.btw, before any Pi bunny suggests otherwise, these are not parts from Steve Wozniaks prototype Apple computer, and therefore not worth a fortune at Sotherbys... or are they?

author: pcprogrammer
author_rank: Super Contributor
timestamp: August 04, 2022, 09:27:46 am
content: Quote from: AndyBeez on August 04, 2022, 08:40:40 amMaybe some of his earlier workA bit of a shame the cut on the LED driver is clean and not like the Apple 1 board that is up for sale nowhttps://www.eevblog.com/forum/vintage-computing/apple1-prototype/msg4336981/#top

author: austfox
author_rank: Regular Contributor
timestamp: August 04, 2022, 12:03:45 pm
content: Quote from: pcprogrammer on August 04, 2022, 09:27:46 amThe IC sockets look awfully similar to those in the prototype, including some with the white 'feet' that I've never seen before.I have about 100 of these boards... I could be sitting on a small fortune! 😊