Oddball GEC Marconi military electronics  - Page 1
Forum section: electronics / general

author: adriansmith31
author_rank: Contributor
timestamp: December 07, 2020, 12:09:47 am
content: This is a very long shot but is there any ex GEC Marconi engineers here or anyone who worked on custom military electronics?I came across a rather interesting box called a GRF control panel which is ex UK Royal Air Force which looks like some video system control panel. It has led readouts for time into mission, frame sequence etc and keys relating to switching video inputs. Going by the keys it looks like this is something to do with the tornado jet. There's no information on the net unsurprisingly.Anyway it is full of CPLD and EPROM chips used as combinational logic. It all runs off 5v and communicates with a host system over RS232. This just appears to be a keyboard and display assembly but it's outputting a constant stream of data.I've been unable to make any sense from it and was hoping on the very slim chance someone has seen something similar who can give any information on the communication protocol it uses.I've an article on my blog with pictures and a link to a YouTube video of a teardown and example of the data stream plus EPROM dumps. It's here if anyone wants to take a lookhttps://www.adrian-smith31.co.uk/blog/2020/11/oddball-military-hardware-grf-control-panel/It's probably going to be used for parts but if something meaningful can be done with it via the serial port it would make an interesting project.

author: coppice
author_rank: Super Contributor
timestamp: December 07, 2020, 12:20:45 am
content: I think its for thermal image control. There is a button labelled FLIR, which usually means forward looking infra red. GEC-Marconi Avionics made a lot of airborne thermal imaging equipment. Its not production airborne equipment. You don't put all those parts in sockets and fly the unit - they fall out. I guess it might be socketed if it is production ground replay equipment.

author: coppercone2
author_rank: Super Contributor
timestamp: December 07, 2020, 02:03:39 am
content: I think turbulence could cause problems and cause a fail.Could be for calibrating or testing a system prior to installation or something. It's probobly difficult to install the thing that its connected to so they test it right before starting the work because it means there is a plane out of service being hooked up with imaging pods or something. You might need to drill some holes and rivet some things etc. There is a reason all those avionics upgrades and retrofits are super expensive and time consuming.Military = fly low in turbulence to avoid detection, rapidly change altitude, et. They don't plan the nice route like a commercial air liner all the time.What does RAD mean? Is that a radiation detector that they can aim at things to see the fall out after nuclear weapons? or something with radians? Radial?

author: LaserSteve
author_rank: Super Contributor
timestamp: December 07, 2020, 03:10:25 am
content: Ask on Military Aircrew forumn on PPRUNE.

author: adriansmith31
author_rank: Contributor
timestamp: December 07, 2020, 08:51:38 am
content: Yeah will try that. As for the unit there's also TV tab front and rear pilot and navigator audio etc. The tornado jet recorded to a VHS tape(s) capturing FLIR footage, video to the TV tab units, the HUD etc. I've seen the VHS recorder units on eBay which are made by teac. Think this unit is a keyboard and display for a video switching and mixing device for offloading footage from the tapes to another medium.I wondered how well a VHS recorder ruggedised or not would work in a jet at 500mph pulling 6g+ turns. 😂I know the tornado had an avionics upgrade at some point and mission footage was recorded to solid state and HDD recorders.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: December 08, 2020, 12:02:49 pm
content: I agree with @coppice, it's a ground based tactical ops video player or, maybe it's from a flight simulator rig? If it was flight qualified it would be grey and wrapped all over in locking wire. Any numbers on the back of the PCB/PEC? For those playing at home, found on ebay...A Tornado cockpit AVRS module:https://www.ebay.co.uk/itm/Tornado-Aircraft-AVRS-Video-Control-Panel-Part-No-J233ZZ30000-020-D1B/143834089097A TEAC VCR unit:https://www.ebay.co.uk/itm/Tornado-GR1-Aircraft-Video-Tape-Recorder-Unit-Aircraft-No-ZA322-1R1C-/133022287516And an older Computing Devices Inc VCR unit:https://www.ebay.co.uk/itm/Ex-RAF-Tornado-Video-Cassette-Recorder-Unit-From-Aircraft-No-ZE116-3R10B/132711313673

author: adriansmith31
author_rank: Contributor
timestamp: December 08, 2020, 02:43:40 pm
content: The only identification of the manufacturer is Tactus International who appear to be defunct. I haven't got round to posting on the PPRUNE forums yet but yeah it's the keyboard and display for a tactical ops video player.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: December 08, 2020, 04:00:54 pm
content: The PCB has the serial number 046-613-01. Meanwhile, that ebay seller has an older style video flight controller listed:https://www.ebay.co.uk/itm/Tornado-Aircraft-Video-Control-Panel-Part-No-046-016-01A-1R9B/133101514031The plate serial number is 046-016-01A (mod 1). Which suggests in GEC Avoinics speak, 046 was their project number for 'Tornado'. Possibly?

author: adriansmith31
author_rank: Contributor
timestamp: December 08, 2020, 05:18:10 pm
content: 046 could quite possibly mean the Tornado project. It mentioned on the listing of the item I bought it was from a Tornado jet but was only used on the ground. As someone mentioned the chips wouldn't be in sockets or would be fixed with zip ties through the socket and over the chip (yeah I've seen that in some kit) otherwise they would fall out. The 74 series logic isn't mil-spec (54 series) either which implies it's not a massively critical unit.I've run the data stream through various analyzing software but have turned up a blank. I have been able to control some of the 7 segment displays by sending a bracket followed by a hex code but there's no pattern to it.

author: Syntax Error
author_rank: Frequent Contributor
timestamp: December 08, 2020, 06:12:15 pm
content: I noticed in your image how neatly bound together the cables on the D-Plug are. Someone was meticulous with lacing chord! I understand, possibly from a Dave Youtube video, cable ties are a big no-no in avionics. Tthe edges of plastic ties can chafe the cable insulation through the mechanical vibrations of flight. Lacing chord is kind to cables. For an avionics manufacturer, doing things this way would be just another day on the assembly line.

author: coppice
author_rank: Super Contributor
timestamp: December 08, 2020, 06:51:45 pm
content: Quote from: Syntax Error on December 08, 2020, 06:12:15 pmThat is not an especially good lacing job. Super neat lacing is a core skill for wiremen in defence work. The best wiremen can tie them faster than most people can apply cable ties, so there is no cost overhead in using them, and they take less space.

author: adriansmith31
author_rank: Contributor
timestamp: December 08, 2020, 06:55:48 pm
content: I tore down a interface unit LRU that was filled with cards plugged into a backplane which was entirely wire wrapped. The workmanship of it was fantastic. Was a shame to pull it apart. It's here if anyone is interestedhttps://www.adrian-smith31.co.uk/blog/2020/09/panavia-tornado-avionics-lru-teardown/#more-934

author: coppice
author_rank: Super Contributor
timestamp: December 08, 2020, 08:29:10 pm
content: Quote from: adriansmith31 on December 08, 2020, 06:55:48 pmI'm surprised that has a wire wrapped backplane. I'm also surprised by the edge connectors they used. Most things used DIN 41612 connectors at that time, and thick many layer backplanes were the norm for flight use. The rest of the construction is pretty standard. PCBs with a thick tinned copper heat ladder. The heat ladder then pressed against a cold wall. No air flow over the PCBs. These boards all have conformal coatings, but that was uncommon with cold wall cooling. Its absolutely essential if air can flow over the boards, as there can be a lot of salt corrosion when flying over the sea without it. I can't see the back of any of the boards, but I expect there is a teflon strip down the edges, so the card slides smoothly into its slot. That was banned later on, as teflon was removed from flight systems as a hazard in fires, and was only permitted where it was essential for its RF performance. Teflon doesn't burn, but if you get it hot enough in breaks down into fluorine compounds which are no fun on an aircraft in trouble. Those big 106 pin connectors on the back were used in many Avionics LRUs. There are a number of versions of the plastic shells in those connectors, offering options of thicker pins, coaxial feed-throughs and so on. The pins look a bit vulnerable at first sight, but they are very robust and reliable in practice. The ones in that box seem to be wire-wrapped. I'm used to crimped ones.

author: adriansmith31
author_rank: Contributor
timestamp: December 08, 2020, 09:34:13 pm
content: 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.

author: coppercone2
author_rank: Super Contributor
timestamp: December 08, 2020, 09:37:56 pm
content: so did anyone figure out what RAD means ? maybe to draw a radius on the picture to measure a circle?

author: coppice
author_rank: Super Contributor
timestamp: December 08, 2020, 09:57:03 pm
content: Quote from: adriansmith31 on December 08, 2020, 09:34:13 pmThe 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.

author: adriansmith31
author_rank: Contributor
timestamp: December 08, 2020, 10:03:42 pm
content: Quote from: coppercone2 on December 08, 2020, 09:37:56 pmI 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

author: adriansmith31
author_rank: Contributor
timestamp: December 08, 2020, 10:07:48 pm
content: Quote from: coppice on December 08, 2020, 09:57:03 pmI 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.

author: coppice
author_rank: Super Contributor
timestamp: December 08, 2020, 10:17:34 pm
content: Quote from: adriansmith31 on December 08, 2020, 10:07:48 pmConnectors 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.

author: cdev
author_rank: Super Contributor
timestamp: December 09, 2020, 01:07:49 am
content: 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

author: aargee
author_rank: Frequent Contributor
timestamp: December 09, 2020, 09:46:56 pm
content: I would venture a ground based piece of gear given the construction used.I agree with the simulator suggestion, particularly in the simulation control area. I have seen something similar from last century simulators.

author: MadTux
author_rank: Frequent Contributor
timestamp: December 09, 2020, 11:21:13 pm
content: I would strip that thing for parts, not much use for such a panel.74 logic, EPROMs, EPM7096 CPLD, opamps, DC/DC converters.... are always useful for repair or DIY projects and cost quite some money if bought new on ebay.

author: adriansmith31
author_rank: Contributor
timestamp: December 10, 2020, 12:56:48 am
content: I think I will do just that. I could make use of those parts for several projects and the case would be useful. I haven't managed to make any sense of the data protocol but programming up an Arduino to look for a particular character when a key is pressed is easy enough. It's figuring out how to control the lights and led displays. It's beginning to look like it's more trouble than it's worth but I might persevere with it a bit more. I have a strong feeling ill be taken off furlough in the new year so that will leave me with little time to mess around at home with electronics projects.

author: coppercone2
author_rank: Super Contributor
timestamp: December 10, 2020, 04:15:58 am
content: Quote from: adriansmith31 on December 08, 2020, 10:03:42 pmthat does seem like a useful thing to review during a debriefing