EEVblog #638 - Apollo Saturn V LVDC Testing

[Richard Crowley]

It appears that a major limitation on integration levels were those "huge" thick-film resistors on the bottom of the (presumably?) ceramic substrates.  Clearly there was adequate space available on the top for the "flip-chip" transistor and diode dice.

Interesting that modern CPU chips with 1.4 billion transistors and LGA "packages" are in many ways similar to that 50-year old technology. The LGA "package" is simply a small epoxy-glass PC board with printed pads on the bottom ("land-grid array") and on the top, matching the "pads" on the inverted die. Much simpler than when we used to do individual bond wires to each pin along the edge.

[KK]

Hardening against cosmic radiation was a requirement for the systems on Apollo. Might have had some influence on the pcb coatings and component spacing.

[bobwidlar]

Hardening against cosmic radiation was a requirement for the systems on Apollo. Might have had some influence on the pcb coatings and component spacing.

I'm not sure, but definitely PCB coating and packaging of the ICs required radiation protection. Even airplane circuits requires these kind of protection in a lower level of course.

[VK3DRB]

In the mid 1980's, I was a specialist on a machine that the architecture was spawned from the computer used in Apollo 11 - the Series/1. The Series/1 was used in a wide variety of applications in Australia. For example I worked on machines that:

- Monitored the conductivity of flesh of sheep used in experiments (the place stunk)
- Counting soiled laundry from hospitals (the place stunk worse than the sheep)
- Interfaced an array of 3101 VDU's to the System/7 for Telecom's Directory Assistance
- Interfacing the major banks to the overnight money market (Tandem operation for ultra reliability)

As for DTL, my first job out of uni was working on a machine that used DTL boards at IBM. They were used in the IBM 129 Card Punch. The cards were very similar to that Dave has been testing, but by 1971 the IC's were encapsulated in aluminium covers. It was amazing the low level logic used in that machine. As I recall, the 129 had no microprocessor, but had 80 columns of memory for verifying punch cards and a digital display - it was electronic poetry in motion. Here is a peek as to the innards of the 129 (check out the DTL board and the ratsnest of wirewraps): http://sturgeon.css.psu.edu/~mloewen/Oldtech/Keypunch/IBM129.html

I was very lucky to have been trained at IBM to debug much older equipment than what was used in Apollo, like the IBM 557 Alphabetic Interpreter - an immensely complex electro-mechanical programmable machine that was full of relays, commutators, motors, cams and selenium rectifiers. Quite challenging to debug. On such equipment, memory was achieved with valves (vacuum tubes) that had on-board resistors and capacitors INSIDE the valve. These were integrated circuits long before the semiconductor IC was invented. http://www.columbia.edu/cu/computinghistory/557.html

The oldest machine I ever had to fix was made in 1922 called the 011 electric hand punch made by the Computing-Tabulating-Recording Company (CTR) which became IBM in 1924. I only saw on once but it was a privilege to fix that for a customers. http://www.columbia.edu/cu/computinghistory/011.html

For newbies who don't know about what these machines were used for, check this out...

[dgtl]

1) It looked from the video like some of the metal contacts had left impressions on the bottom epoxy. Thus, the metal contacts are probably put on before the chip is covered with the epoxy. Finally the ready-made chip is soldered to the board.
2) Are the top and bottom sides electrically connected on the chip? Maybe the metal contacts connect the tracks at the top and bottom sides and when the chip is removed from board with the contacts ripped off from it, the connection may be broken and thus the resistors should be probed on the bottom side and diodes-transistors at the top side?

[BMac]

OK Dave now you have a working Saturn V Rocket diode, you need to feature it in a project!

BMac

[EEVblog]

OK Dave now you have a working Saturn V Rocket diode, you need to feature it in a project!

I would if you could reliably connect to the thing...