error codes say door communication failure & door not sensing limit within spec time. Any suggestions? No hand held device, no flash drive.

How old is the job? A year or so ago TKE had a bunch of HD door motors with bad brushes which would cause a stall and the doors would go offline making you believe the door board was bad, and the trouble didn't show up for months. The brush shunt was so short the actual brush barely made contact with the motor armature. or-
Check the encoder wiring at the motor and at the board (LD-03). Does the door respond to "manual open and close" button inputs? WatchDog LED not lit? Any change if you Reset the card?

no response to buttons, wd is lit, no change with reset. this one does fall into that age group. was told of a way to check, short the leads together and try to turn by hand, should have resistance but be smooth. using that way motor felt right.

Regarding the brush issue, removing the brush and visually inpecting them you can easily see the short shunts and the restricted spring, and if they are short, the armature contact end will be dull and a little rough in appearance. I've not heard of the test you performed, but that doesn't mean it's not a good way to check. Any voltage at the motor wire terminals when forcing a direction via the MDO/MDC buttons?

performed tests from ldo-03 manual. all test points tested good, steady voltage of 15vac at motor but no change from buttons. when trying to use uit only get awaiting response.

WD is lit... is "VBUS" LED lit?
If you have 115VAC at CON 11 pins 1&2 and the VBUS is not lit- time for a new card.
Check to be sure the door motor leads are secure in their terminals. There is also a fuse on the card (of which I'm sure you checked already). And again- the brushes are good correct? I only ask again because I didn't see you address the physical condition, but did perform a test between them.

Thanks forr trying to help elmcannic. Yes both WD and VBUS are lit,checked fuse on bd, both good. I'm having a guy go check leads and brush condition (he said he checked them, but he's not describing it very good. time to recheck). Let me say the whole problem seems to have started after main transformer at street blew.

also has checked encoder, it's good

Communication has 0 to do with the brushes. CAN com is to the UDC card only, regardless of brush, motor, or encoder conditions. Check for 60 Ohms across CCH and CCL with power off. Assuming this is TAC 32 hydro, CWIL card could have blown pico fuse, CPUA Could be shot, IOD could be shot. Personally I am leaning on IOD.

I believe the CAN comm from UDC is on Con 3. Worth verifying that it is wired properly down to CWIL card in COP as well. The CCH/CCL is very very easy to corrupt with induced voltages. Look in COP and make sure things are neatly separated, may need to do the same in the door operator, have had the 3 phase AC motors corrupt door communication as well.

If it's still kicking you without mercy, PM me. I'll get you my number so we can chat.

PM sent, thanks Silly

Now regardless of communication, the MDO/MDC should still work, no?

thanks all, my first thiughts were right. door bd bad and needed settings from missing flash drive. power problem from blown transformer

Very good.

Yes Elm, unless the micro switch is bad on the board, MDO and MDC typically work even with bad comm. the exceptions for this are, software, and board issues unrelated to power (encoder, dcl, dol, etc.)

For everything I have ever thought I had nailed down to a single problem... Let's just say there is a reason I now carry multiple solutions, lol. These are just the most common for me being a NI adjuster, some may not translate well to the service world, because at the very least you all know, it used to work right.