General > General Technical Chat
Oddball GEC Marconi military electronics
coppice:
--- Quote from: adriansmith31 on December 08, 2020, 09:34:13 pm ---That thing dated from 1976 I believe and had at least one card replaced circa 1982. I don't remember seeing any teflon coatings but the boards slid in and out smoothly. Definitely no airflow over the boards and I imagine it would have got rather warm in there with the power supply module at the front.
I was very surprised myself to see wire wrapped connections in something that is subject to a lot of vibration, heat and cold stress.
--- End quote ---
The airflow through the hollow walls is usually quite fast. Properly constructed, with the chips pressed down on the ladder, and the ladder pressed tight against the cold wall with those springs, the whole thing can stay pretty cool.
Good quality wire wrapped edge connectors were fine. The problem in 1976 would have been IC DIL sockets. That was before the turned pin DIL sockets appeared. The wire wrap DIL sockets in 1976 would wear away the legs of the ICs with vibration.
adriansmith31:
--- Quote from: coppercone2 on December 08, 2020, 09:37:56 pm ---so did anyone figure out what RAD means ? maybe to draw a radius on the picture to measure a circle?
--- End quote ---
I think it is short for Radar as that was sent to the TV Tab displays presumably as a video signal that was able to be recorded on to the VCR
adriansmith31:
--- Quote from: coppice on December 08, 2020, 09:57:03 pm ---
--- Quote from: adriansmith31 on December 08, 2020, 09:34:13 pm ---That thing dated from 1976 I believe and had at least one card replaced circa 1982. I don't remember seeing any teflon coatings but the boards slid in and out smoothly. Definitely no airflow over the boards and I imagine it would have got rather warm in there with the power supply module at the front.
I was very surprised myself to see wire wrapped connections in something that is subject to a lot of vibration, heat and cold stress.
--- End quote ---
The airflow through the hollow walls is usually quite fast. Properly constructed, with the chips pressed down on the ladder, and the ladder pressed tight against the cold wall with those springs, the whole thing can stay pretty cool.
Good quality wire wrapped edge connectors were fine. The problem in 1976 would have been IC DIL sockets. That was before the turned pin DIL sockets appeared. The wire wrap DIL sockets in 1976 would wear away the legs of the ICs with vibration.
--- End quote ---
I think I read on a forum somewhere those avionics boxes were very unreliable but I'm unable to find it now. I don't think they were referring to that particular unit but the old 1970's equipment needed regular replacement. The box I got was marked as serviceable but it had clearly suffered damage at some point.
coppice:
--- Quote from: adriansmith31 on December 08, 2020, 10:07:48 pm ---
--- Quote from: coppice on December 08, 2020, 09:57:03 pm ---
--- Quote from: adriansmith31 on December 08, 2020, 09:34:13 pm ---That thing dated from 1976 I believe and had at least one card replaced circa 1982. I don't remember seeing any teflon coatings but the boards slid in and out smoothly. Definitely no airflow over the boards and I imagine it would have got rather warm in there with the power supply module at the front.
I was very surprised myself to see wire wrapped connections in something that is subject to a lot of vibration, heat and cold stress.
--- End quote ---
The airflow through the hollow walls is usually quite fast. Properly constructed, with the chips pressed down on the ladder, and the ladder pressed tight against the cold wall with those springs, the whole thing can stay pretty cool.
Good quality wire wrapped edge connectors were fine. The problem in 1976 would have been IC DIL sockets. That was before the turned pin DIL sockets appeared. The wire wrap DIL sockets in 1976 would wear away the legs of the ICs with vibration.
--- End quote ---
I think I read on a forum somewhere those avionics boxes were very unreliable but I'm unable to find it now. I don't think they were referring to that particular unit but the old 1970's equipment needed regular replacement. The box I got was marked as serviceable but it had clearly suffered damage at some point.
--- End quote ---
Connectors are the bane of electronics reliability. Most old electronics is a lot less reliable than modern electronics as there were so many connections. Ever increasing levels of integration have massively improved reliability. Take those 106 way connectors on the back of your box. There are two on that box. Many boxes had 5, 6, or more. That's a lot of connections which might fail. These days a box like that would probably have just a few pins on the back, far less PCB edge pins and be WWWAAAAAYYYYY more reliable, even if built with consumer grade parts.
cdev:
Recently (April 27) there were a (set of) video captures purporting to be from aircraft that were tracking a UFO from above that was released by the US DOD. Have any of you more knowledgeable folk seen it and if you have any thoughts about it- what we are seeing in it? Or do you think this is bogus, or whatever? Decades ago I helped some friends of friends put a database of UFO sightings from all around the world on the web and all I can say is, they were internally consistent. Which had I not worked with them I wouldn't have expected.
This is what I am talking about.
https://www.cnn.com/2020/04/27/politics/pentagon-ufo-videos/index.html
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