AP74 dropping off of DSAB bus?????

[Brantel]

Is there any reason why the AP74 would drop off the DSAB bus when a battery charger is connected to the main aircraft battery?

This is the same AP74 that is at 5.1.1 instead of 5.2 for the rest of my system because I cannot get the firmware to update on the AP74, see the prior thread for this issue.

Is this AP74 bad and does it need to be replaced?

No other units have any issue...

 

[dynonsupport]

Depends on the charger. I guess if it's really noisy it could cause some issues with the power supply in the AP74 (which is different than the supplies in the EFIS/EMS so they might act different). But assuming your voltage is above 10V, it should basically be fine. This happening makes me wonder about the chance that maybe your DSAB wiring has an issue. DSAB can sometimes work with only one wire connected, but it will be really sensitive to changes in the electrical system in this case. Might be worth checking.

Oh, and next time give us more than 90 minutes to answer a question at 6am out time.

 

[Brantel]

Charger is a normal smart charger specifically made for the Odysee battery.

Is the AP74 power supply the same as the HS34?  I ask because the HS34 exhibits no issues.

DSAB wiring is confirmed good and the leads are all ran as twisted pairs.

If it is the charger causing the problem, I am not worried much because I won't be flying with it connected (as long as the alternator does not replicate the issue) but so far, this is two strikes against this AP74 and I want to make sure any real issues are resolved now before I really need the unit to be working.

Oh, lighten up! I was just giving you a hard time for answering other questions and leaving mine unanswered.    I know your busy!

 

 

[Brantel]

Dynon support,

To take this troubleshooting a step further, I powered up the system last night without any charger or any non-plane system connected.

After about 2 minutes of powered up state, the AP74 dropped off the bus.  Its lights all came on  brite and the EFIS and EMS announced the DSAB issue. Nothing else but the Dynon system was powered up.

So this eliminates the charger as the issue.

I did have some success with getting the firmware updated and I will talk about that on the other thread.  

I am convinced that there was something wrong with the load that was installed on the AP74 from the factory.  More about that on the other thread.

I did tripple check the wiring on the DSAB bus.  I ohmed each pin to each pin and checked that all units A & B were consistent.  The wires are all twisted together as pairs.   No noise sources were online at the time of the failure.

After one power down and restart, the AP74 stayed online and never dropped off again on its own.

So for now since I did change the firmware, I will try a cold system startup tommorrow night and see if the AP74 drops out again.  If it does, this thing is comming back to you if it does not, all will be well.