Narco just overhauled my DME 890 unit. They did a fine job and it came with a 6 month warranty. It was expensive, though. About $560. The turn-around time was about 3 weeks.
Our 172H has two Narco 12Ds, both of which started getting intermittent TX problems. Our local shop sent one back to Narco and it came back fixed with an $1130 bill. No joke! But it's fixed.
I yanked the second one out myself and sent it to Bevan-Rabelle in Kansas and it came back costing less than $200 to fix. They found a number of bad solder joints, a broken trace on the tx board which they fixed, cleaned it and realigned it, bench tested it hot and cold and sent it back. I'm not sure if it's really fixed, but I'm also starting to suspect a bad wiring harness is really the culprit this time. I was very happy with the service and turnaround time so would certainly recommend giving them a call. Look them up on Google.
