OM5P-AP radio failing... no lights

[PhilBot]

We had a harrowing practice last night. In the end we had two OM5P-AP radios that don't show any lights when they get plugged in.

We took our newly wired robot and tested it via USB. All ok.

When we switched to the new OM5P-AP radio things didn't go well.

We had configured two radios on our prototype robot without issues. NOTE: They both worked fine driving around, connected to a laptop wirelessly.


We switched the radio to the new robot and powered it up. All the lights came on and appeared to do a normal power sequence, but it wouldn't connect. Somewhat frustrated, we switched to the other radio and it connected an ran for a few minutes while they got familar with the production bot. After taking a defende, the radio dropped out.....

No problem... we assumed a loose connection was the issue. We jiggled the connector and things seemed a bit flakey, and then the lights went out and stayed out. Suspecting the barrel plug we tested the voltage and it was 12V.

We plugged the radio into the protobot and it was still dead. The first radio got plugged back in and it lit up, but still didn't connect.

So... diagnosis... radio had failed. Hmmmm.

We checked the power wiring, and there is only ONE thing connected to the Voltage regulator module... the radio. The cable is about 8" long. No real opportunity for problems.

We switched in a third radio.

This one connected,and ran for a while and then ALSO died in the same way. No lights any more when plugged in.

As a final test, we openned one of the dead radios and used a meter to probe the terminals on the power input connection. There was a solid 12V present.

The only thing we could think of was that we were getting spikes on the 12V line, but this seems very unlikely.

Anyone else have anything like this, or can think of a failure mechanism?

Phil.