All posts by Todd's Time

Problem definition for adding test points to a instrument face

I built  complicated test box, shown in this video, by wiring point to point by hand.  It is sold. It was time consuming to hand wire difficult circuits.

We are now building S/N 2, using circuit boards.  The wires will be very simple, and the complicated interconnect logic will be on  7 circuit boards. I am a novice at designing PCB’s.

We have had some successes that lead us to these steps:

Every item is set out on an EXACT 3/5″ x 3/4″ inch grid.  That harmonizes the artwork for the face, with the layout of the PCB. This is a success.

The PCB’s are EXACTLY 5/8 ”  below the face. That sets the correct depth for the switch solder tails to attach to the board. here is the drawing we used to arrive at that.  2 boards soldered. That is a success.

The LED’s are resolved by a LED capsule, that pushes through the face, and plugs into a 2 pin female header.  These are Dailite 559.  We will solder up the first example this week. May be a success.

The PCB’s MUST be removable……  Occasionally……. With some reasonably small amount of effort.  that means devises should “front release” and not require extensive labor to de-solder, re-solder.


Here is the heart of the problem:

We need dozens test points, that SOLDER to the 7 PCBs. Pin-Jack, or Banana.  The front bezel should unscrew and allow the face to lift off.  No such test points exist.

here is the current workaround:  A soldered test point that “leans” against a half of a solder pad.

populated pc board

Advantage: for removal, you can desolder and free the tail of the test point toward the large circle.

Disadvantage: every test point must be desoldered to remove the board. This is ~10 test points per board.  Next product will have 100’s of test points per board.

2 questions:

1. Using  this setup, or similar, is there a method to attach a test point to the pcb, AND secure it to the front panel so that it is removable?

2. Have i missed some vastly easier way to do the entire design?

Which Flap Slat WDM is effective for which G100?



WDM Effectivity toc-chaptoc-27_chptoc


Astra S/N 080 WDM 2 – flap                     3 – slat
Astra S/N 087 WDM 2 – flap                     4 – slat


Astra S/N 124 WDM 1 – flap                      1- slat
Astra S/N 130 WDM 1 – flap                      1 – slat


27-50-00 figure 2 page 1, mark off jumper center RH

27-80-003 f 3 1  0f 3  label bypass switch wire differences, notes change

27-80 f3  3 of 3 missing wire upper rh on early a/c


Falcon 10 pops ANN CB when LAMP TEST button is pushed

Turned out that the Smoke detector in the baggage hatch had a wire broken free, touching the plug shell.



Disconnecting either pilot or copilot ANN COUPLER on the zero  door will clear the fault.   No FD annunciators test in any condition.

R and R 1 pc card in the copilot ann box, now Pilot fms ann test good, copilot dark.  Now AUX bus must be on to get it to pop.  Pilot side still ANN good.



Harness labels:

NTE5256A zener in the ann couplers

falcon 10 ann coupler