A boring post on a boring topic

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30. August 2022 by Peter

I am rewiring. It’s not very exciting and it is very time-consuming…

At this point my cockpit is 9 years old and parts of it has been untouched since. This includes the MIP.

Those who have followed my build for many years might recall most of my interfacing has been based on OpenCockpits MasterCards. Some might even recall that I always have had issues with the stability of these cards. To get more stability I have been switching away from MasterCards over the last years.

I switch to CP-Flight EFIS earlier this year which freed up Pokeys interface card. I had an additional Pokeys and a Phidgets LED card laying around. Enough for the MIP.

But new interface boards require new wiring. That is why I am having an appointment with my old friend Mr. Solder Iron.

For some strange reason my OpenCockpits MasterCards only supplied 3.5v to the LEDs. When wiring LEDs 9 years ago I figured out two LED in a serial connection easily could share those 3.5v.

Everyone recommends wiring LEDs in parallel connection with a resistor. But I never found the need with MasterCards. Now I have the need. When using Phidgets LED card the LEDs needs to be directly connected to the interface board as it regulates the voltage. If using dual LEDs they must be wired in parallel connection with no resistor.

Tn order to use the setup with a Phidgets card I have to rewire all my annunciators from serial connections to parallel connections.

It is a very boring task and a bit time-consuming as rewiring not really adds good energy.

Lesson learned: When wiring LEDs for annunciators do it in a parallel connection.
If you need to lower the voltage with a resistor it might be worth considering how you – at a later point – easily can bypass the resistor.

Back of six-packs

First up has been my glare wings. The home made six pack was a mess. No tidy wiring. So that was a complete gutting of all wires and a new wiring. I am using DB15 plugs for the LEDs and DB9 for switches.


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About BuildaBoeing

My name is Peter and I live in Denmark.
I am building the cockpit of a Boeing 737 in my basement using my limited skills and inspiration from fellow builders.
I post my progress on this blog and hope it can be an inspiration to others.

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