Marconi F3049-02 : Joystick Controller

[doubletopParticipant @doubletop]

Michael

What you describe is very much military style construction, the description of the pink wiring gives me a flashback to some avionics systems I have worked on in that era.

I understand your reluctance to pull it apart. After testing with a meter your curiosity may get the better of you. Unlike consumer products the cost of manufacture made it a necessity to design them to be maintained. There will be a way of investigating its internals without compromising it too much.

Pete

 

Edited By Doubletop on 24/08/2018 08:34:24

[BazyleParticipant @bazyle]

The pink PTFE or ETFE wire was standard. Coloured wires not allowed because someone using it might be colour blind and get it wrong.

An interesting catalogue with way more products in the multioctave ECM TWT range than when I was getting parts from them. It also mentions the Lincoln site is still actively designing the ferrite devices which was where the semiconductor parts were also designed. If the part had an F number it might have come from Lincoln even though not involving ferrites.
Actually it was my job application to EEV at Chelmsford that stared my career in electronics though the job I got was elsewhere as they operated a group recruitment system.

[doubletopParticipant @doubletop]

Posted by Bazyle on 24/08/2018 09:13:50:

The pink PTFE or ETFE wire was standard. Coloured wires not allowed because someone using it might be colour blind and get it wrong.

As a bit of an aside; up to the late 60’s all avionics cabling was colour coded.

I was an RAF avionics apprentice in the mid 60’s, one of the guys in our entry had managed to get through the entry tests despite being colour blind. When we were doing training on systems he’d ask us to help him identify anything with colours cables, resistors etc. We thought nothing of it and would help him out. This went on for three years and at the end, as he was one of the brightest guys, he got selected for a commission as an engineering officer. He went for medical and they then discovered that he was colour blind. Rock and a hard place for the RAF, one of their top guys and they couldn’t use him. He got packed off to uni at their expense and then civvy street.

Pete

[SillyOldDufferModerator @sillyoldduffer]

Posted by Michael Gilligan on 24/08/2018 07:31:27:

Posted by Doubletop on 24/08/2018 06:07:11:

I may be way off the mark here but the absence of a nato stock number (NSN) would indicate that it wasn't a military item. By 1977 anything that moved or could be removed would have had an NSN.

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Not off the mark at all

… all the leads to the D connector are pink …

MichaelG.

The pink colour convention is connected to the Modification Number. If during service an equipment was changed by design or repair, a different colour wire was used to make it easy for the next guy to see what was altered. Anything not pink is a change, and the absence of a colour means a modification hasn't been done.

Made a lot of sense when electronic equipment required constant maintenance and kit was upgraded through life, perhaps several times. During the 1970's the switch to printed circuits and replaceable modules reduced the value of wire colours : it was cheaper and safer to swap modules to match serial numbers rather than have blokes poke at it with a soldering iron.

More likely to find pink wires in military equipment because commerce often preferred to colour code wires by function – makes it a lot easier to trace wires, and understand what's what. It's not the law – I've seen pink wiring in commercial equipment and mixed colours in military.

Michael's joystick is probably a rare item, perhaps sold briefly and in limited numbers as part of a larger outfit, like a radar console. Identifying the main unit might be more fruitful

Dave

[Michael GilliganParticipant @michaelgilligan61133]

Posted by SillyOldDuffer on 24/08/2018 09:53:13:

The pink colour convention is connected to the Modification Number. If during service an equipment was changed by design or repair, a different colour wire was used to make it easy for the next guy to see what was altered. Anything not pink is a change, and the absence of a colour means a modification hasn't been done.

[ … ]

Michael's joystick is probably a rare item, perhaps sold briefly and in limited numbers as part of a larger outfit, like a radar console. Identifying the main unit might be more fruitful

Dave

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Thanks for the info about pink wires, Dave … I didn't know that.

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If you look back at my earlier notes, you will find references to 'marconiradarhistory'

Regarding identification of the 'larger unit' … Here is, I believe, the most relevant page: **LINK**

http://marconiradarhistory.pbworks.com/w/page/54058331/Display%20and%20Data%20Handling

MichaelG.

[Michael GilliganParticipant @michaelgilligan61133]

For info.

For Scale: The top plate is 4.25" diameter, and the box is a 3" square extrusion.

The stick has large angular travel, so [for Pete] it's unlikely to be strain-gauge based.

No idea what the rubber bungs are for; there's a matching set on the opposite face.

MichaelG.

[Alan VosParticipant @alanvos39612]

Posted by Michael Gilligan on 23/08/2018 20:38:55:

It's a digression, Alan … but you may like this: **LINK**

Interesting. I don't recall the particular add-on, but you can't remember everything. Connected via the user port, so digital, not analogue.

To get back to the original question, which pins are wired? That may offer somebody a clue.

Most people of my era first came across a trackball on the 'Missile Command' arcade game. Unlike a computer mouse, you can perch a trackball on top of whatever junk is on your desk and it still works perfectly

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Alan Vos on 24/08/2018 21:37:17:

To get back to the original question, which pins are wired? That may offer somebody a clue.

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All nine pins, plus a separate connection to an earth tag

… all in pink wire, with tiny Hellermann sleeves over the solder joints.

A proper job, but a tricky guessing game !

MichaelG.

Edited By Michael Gilligan on 24/08/2018 22:00:32

[Ian PParticipant @ianp]

Posted by Alan Vos on 24/08/2018 21:37:17:

Posted by Michael Gilligan on 23/08/2018 20:38:55:

It's a digression, Alan … but you may like this: **LINK**

Interesting. I don't recall the particular add-on, but you can't remember everything. Connected via the user port, so digital, not analogue.

Not relevant to Michaels question really, but I think the 'user port' on the BBC micro had analogue and digital inputs.

Ian P

[Alan VosParticipant @alanvos39612]

Posted by Ian P on 24/08/2018 22:02:59:

Not relevant to Michaels question really, but I think the 'user port' on the BBC micro had analogue and digital inputs.

Nope. User port is digital. There is a separate analogue port. I still have one, with the documentation.

[Ian PParticipant @ianp]

The fact that all 9 pins are wired does not really help identify the method it uses to communicate, other than to say that the most, maybe all, of RS232 equipment I have seen never had 'all' pins connected. Its unlikely that a joystick would need all RS232 lines anyway.

Whether this product was industrial or just commercial, it was made to aerospace type of standards and as such was surely designed to be serviceable or MOD-ifiable. I would suggest that it should be possible to access its innards without doing and damage and it would be the best way of finding out how it works.

Ian P

[Ian PParticipant @ianp]

Posted by Alan Vos on 24/08/2018 22:13:08:

Posted by Ian P on 24/08/2018 22:02:59:

Not relevant to Michaels question really, but I think the 'user port' on the BBC micro had analogue and digital inputs.

Nope. User port is digital. There is a separate analogue port. I still have one, with the documentation.

Oops! my error.

I still have a model B but no longer have the analogue joystick I made for it which I now realise did not connect to the user port (I had a RTC on that).

Ian

[doubletopParticipant @doubletop]

Posted by Michael Gilligan on 24/08/2018 12:32:16:

For info.

For Scale: The top plate is 4.25" diameter, and the box is a 3" square extrusion.

The stick has large angular travel, so [for Pete] it's unlikely to be strain-gauge based.

No idea what the rubber bungs are for; there's a matching set on the opposite face.

MichaelG.

Far too robust and agricultural for an avionics system. Civilian, ground or naval radar maybe? An interesting read here. **LINK**

and maybe try theses guys

**LINK**

 

Dave's thoery of the reason for pink cables was interesting. On all the system mods I installed I can't remember ever using different coloured wires to define the mod. There would have been too many other things that could be replaced that couldn't be defined by the colour. If you wanted to know about a mod you checked the mod record plate and obtained a copy of the mod instruction and read it.

The discussion about BBC, Atari type computers is also incorrect. The only similarity would be the use of a 9pin D connector. This is clearly a milspec item and the design process would have started well before 1977 so pre-dates home computers by many years. If you are really lucky it could be one of the protocols around at the time, but I'd suggest unlikely. The good news will be that once you find out what it is one of todays  micro controllers could be pressed into converting the protocol to whatever you want it to be.

Pete

Edited By Doubletop on 24/08/2018 23:20:00

[Frances IoMParticipant @francesiom58905]

is it a servo controller fed by 2 signals in phase quadrature feeding two coils, the joystick moving 2 pickup coils arranged in quadrature – many aeroindicators used similar servo mechanisms

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Doubletop on 24/08/2018 23:01:21:

Far too robust and agricultural for an avionics system. Civilian or Naval radar maybe an interesting read here. **LINK**

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Thanks for your continuing interest, Pete … but that ^^^ is where we came in.

MichaelG.

[doubletopParticipant @doubletop]

Posted by Michael Gilligan on 24/08/2018 23:16:58:

Posted by Doubletop on 24/08/2018 23:01:21:

Far too robust and agricultural for an avionics system. Civilian or Naval radar maybe an interesting read here. **LINK**

.

Thanks for your continuing interest, Pete … but that ^^^ is where we came in.

MichaelG.

Yes I thought I recognised it but yesterday I found a page on that website that went through the chronology of Marconi radar systems. Find one that is around the right period and you may be on to something. Then maybe go to the Bawdsey mob and ask them. Or just send them an email with your photos and see if they recognise it.

Pete

[Alan VosParticipant @alanvos39612]

Posted by Ian P on 24/08/2018 22:16:01:

Oops! my error.

I still have a model B but no longer have the analogue joystick I made for it which I now realise did not connect to the user port (I had a RTC on that).

You win. I bought mine. Horrible things. **LINK**. The tiny joysticks were probably fine buit into a desk. As this is (usually) a mechanical engineering forum, I don't need to detail why the handheld style was horrible to use.

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Doubletop on 24/08/2018 23:24:10:

Then maybe go to the Bawdsey mob and ask them. Or just send them an email with your photos and see if they recognise it.

.

Too far for me to travel … but I have eMailed this morning.

MichaelG.

[andrew mulcockParticipant @andrewmulcock29621]

Its a log time ago, but I worked at Marconi Specalsed Components in Billericay, sat next to the guy that made these.

If I remember, they had two 'pots; / variable resistors in them, one for X one for Y, I thought they also had a button on top,

They were designed at the time that nuclear bombs were though survivable, Very rugged, designed to be used by Milterary personel "under conditions stress", when excess force might be applied. …

A quick go with a ohm meter should get you which pins are which.

[Michael GilliganParticipant @michaelgilligan61133]

Thanks for the note, Andrew … and welcome aboard the forum.

My understanding is [was] that mine is a 'contactless' version that uses something more exotic than simple pots, but I may be wrong … I have so far resisted the temptation to open it up.

MichaelG.

[andrew mulcockParticipant @andrewmulcock29621]

Did you ever get to try out a DVM on this ?

I was cleaning out the attic last month

came across a few of the encoder wheels from the tracker ball

made me remember this post,

[Michael GilliganParticipant @michaelgilligan61133]

‘fraid not, Andrew … to my shame, it’s been tucked away in a cupboard since then.

We have massive reorganisation in progress at the moment, so I won’t even be able to take your hint

In a few months time, I may introduce it to the oscilloscope

MichaelG.

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