peter-h
Line Up and Wait
I have rewritten my original writeup here after taking apart the last failed servo, plus some which others have sent me, having found some much worse issues in there than I had thought previously.
These servos can drop into instability in the output MOSFETs, causing heavy RF radiation which gets conducted into the rest of the aircraft wiring. This condition seems to be caused by the current limit circuit (which has no frequency compensation) which can be activated momentarily with a partially worn motor, but is much more likely to be triggered if the latest SB11 mod is implemented.
The standard of analog circuit design in these things is absolutely appalling.
I think Honeywell were probably right to give up on the GA avionics business, when they did. Best to quit while you are still losing.
These servos can drop into instability in the output MOSFETs, causing heavy RF radiation which gets conducted into the rest of the aircraft wiring. This condition seems to be caused by the current limit circuit (which has no frequency compensation) which can be activated momentarily with a partially worn motor, but is much more likely to be triggered if the latest SB11 mod is implemented.
The standard of analog circuit design in these things is absolutely appalling.
I think Honeywell were probably right to give up on the GA avionics business, when they did. Best to quit while you are still losing.
