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SWPM Training

PostPosted: 22 Jul 2017, 14:55
by Electron
Dear all

I wish to be a better mechanic and was wondering if there is any training theory notes that can help me use the SWPM more effectively, accurately and efficiently.

I am still fairly young in my career, but as a result of aircraft reliability, and working on the line, I rarely get to repair electrical wiring and/or equipment.

I will build myself some test leads too, at some time in my career and I'm sure this will help me. If I were to build myself some test leads, what would be the best way to go about it? What would you recommend?

Re: SWPM Training

PostPosted: 23 Jul 2017, 08:09
by sjap
For test leads we just use LONG wires (kept on a small drum / spindle) and some multimeter connections with different adapters for the different pins/socket sizes.
This way you can measure from any plug to any plug anywere on the plane. (so use LONG wires, 1,5 x length of the airplane).
But of course only if you know exactly from which pin to which pin you are measuring with the WDM with you all the time.

And use it only for analog signals. Digital stuff etc will not work this way.
Good luck

Re: SWPM Training

PostPosted: 24 Jul 2017, 05:32
by Dunny
Databus cables are just copper wires.

Whilst you cant test for voltages, you can test for continuity, shorts to ground, insulation resistance etc like you can on a standard copper wire.

......unless your databus cable is a fibre optic

Re: SWPM Training

PostPosted: 25 Jul 2017, 14:51
by Electron
Thanks sjap and dunny, that helps.

Most of my senior colleagues have a set of test leads using old or left over bms wire and pins/sockets. They've crimped pins or sockets on one end, and alligator clips on the other. They are very neat and excellent for wiring checks at the equipment racks and other connectors around the place.

I only dislike the reel idea because it isn't handy and very cumbersome. We had/have the reel solution, but this was wholly rejected by all the B2's for the aforementioned reasons.

I have managed to narrow down a number of usable wire from the SWPM to make my test leads. It'll be just a general spec wire, single conductor, anywhere between 20 to 24 gauge.

What stands to be the hardest bit is finding different sized sockets and pins. To the WDM I shall go. I will try to find some connectors that have 20 gauge single conductor unshielded wires (almost impossible, I know) and pick out some sockets and pins of different sizes.

Re: SWPM Training

PostPosted: 25 Jul 2017, 18:21
by Dunny
I happened on a rather interesting trouble shooting guide for wiring faults, not sure how to post it here though ?

Hey, SJAP how do we upload stuff here, or do we have to send it to you directly ? I've a mountain of 787 stuff that you might find of use as well

Re: SWPM Training

PostPosted: 25 Jul 2017, 18:28
by Dunny
instead of using a large reel of cable, use the airframe as a return path, through a resistor of a known value. For instance a 47 Ohm, you can then differentiate between continuity and a short to ground