MGL Avionics User Forum

Hi,

Started up my trike today and received the following error on my Stratomaster Enigma EFIS, "RDAC1 failed" . All the usual engine sensor readings were replaced by this message. I did some research and I see that the RDAC is the engine management unit for the EFIS. Would anyone have a simple fault finding procedure for this unit? I will start with checking the main connection from the RDAC to the Stratomaster enigma EFIS and for any possible shorts anywhere. I have yet to return to the airfield and look for the RDAC unit, I assume it will be somewhere near the engine. I will update in the next few days when I get a chance to see what's going on Thanks

Hi,
Done some more research and my RDAC is a 'RDAC-VD' which is now superseded by the RDAC-XF. I have checked the Blue,red and braid wiring between the
RDAC and Enigma EFIS and there are no apparent breaks or poor connections. Is it possible the RDAC is cactus? Does anyone have any suggestions on how to determine if the RDAC is non functioning. Has anyone upgraded their RDAC to the newer version and is it pretty much plug and play. Looking at the manual for the RDAC-XF it appears that I would have to wire a RS232 plug to except the red, blue and braid line that connects the enigma and RDAC.
Thanks for any assistance
Richard
TANARG 912S
Stratomaster enigma

On the back of your Enigma is a three-screw terminal block. There's +12V, Signal and Gnd. Remove the RDAC's red and braid wire and temporarily jumper them to a power and ground to see if the failure indication remains or not. If not, then individually return the power and ground back to its normal spot on the EFIS and see which one causes the fault. In either case, the Enigma should be repaired to ensure safe operation.

If that test yields no successful results, the RDAC can be upgraded to the XF. You should give the new RDAC its own power and ground (ground to engine block!!) and tie the braid to the OPT- at the RDAC connector and the blue wire to OPT+

Adam

The RDAC VD takes its power supply ground NOT from the Enigma (via the braid of the cable) but from its REF GND terminal that is supposed to have a wire going straight to your engine block. Check that connection - ohm meter is a quick way to do that.
The RDAC has a little LED that will flash if it has power and it running (the flashing is done by the processor itself as part of its routine program execution - so if you see the flash the RDAC is running).

If the RDAC is running then check the cable going to the back of the Enigma. It supplies the 12V (the LED is flashing so we know all good here). The blue wire and the cable braid form an optically isolated data connection - check both with an ohm meter.