MCDU results

[brianwilliamson]

As always these are observations that I have concluded and without laboratory test gear it is hard to be exact.
The RFI is severe enough to lock up the computer at times and this situation would vary at times as to what was connected etc. I could notice jitter in the trim wheel pot. as soon as I put power to the MCDU without even turning it on.
I can see situations where the RFI maybe limited but still cause problems in a cockpit.

Filtering between power supplies and the unit concerned can work in both directions, that is perhaps the power supply is producing RF or perhaps the unit is producing RF. Often the filtering in a good power supply can supress RFI from the unit, providing the power lead is not overly long or has a ferrite choke near the unit.
So there are many situations to be aware of and it is very easy to pick the wrong source as I have found out on many occasions.

Results of MCDU testing:
In situ in cockpit: First sign was black screen, when in operation
Removed complete Console for testing.
Seemed to indicate it was the power supplies which were plugpacks from FDS.
Changed to a seperate power supply seemed to cure the problem with no other connections.
Replaced back in the cockpit.
The trim wheel which is run with DC_Motor from OpenCockpits, would crash.(was not connected in earlier test) On same power supply as MCDU.
Removed console out again.
Checked various power supply connections.
If the Power supply was connected to the MCDU and the DC_Motor , it would crash regardless of which power supply.
Put a seperate power supply (computer P/S) only to the MCDU's.
This P/S was an earthed one as well, as well had to put ferrite chokes on the DC leads at the MCDU's. Seems to have fixed problem.
It would appear from all my tests that it indicates RFI from the MCDU's, possibly the screens.

Main thing now is to treat any problems with any program on the Sim, with suspicion if there are any unusual happenings that we sometimes  blame on the software for not being up to par.

Regards...................Brian W.