Quite by accident, I discovered the cause of a bogus "station status - major failure" LED indication on one of my MTR2000 stations. A major failure is present when the Station Status LED comes on as steady red after bootup. According to the Installation and Operation Manual 6881096E20, a steady red indication has four possible causes:
1. RX or TX synthesizer out of lock 2. PA failure 3. RF power cutback greater than 10 dB 4. Self-test failure Well, I found a fifth cause that escaped the Motorola Infrastructure Depot repair technicians: Optional module mismatch. One of my spare MTR2000 repeaters was equipped with the CLN1206 Auxiliary I/O Board, and I had pulled it out to use at another location. Months later, when I tried to put the spare unit into service, I got the dreaded major failure indication. I had a spare Station Control Module, but installing it made no difference. Since the station was still under warranty, I shipped it back to the depot for repair. The depot duplicated the anomaly, and replaced the power supply. The repair technician also noted that the station was programmed to have the Auxiliary I/O Board installed, but since it was missing, he programmed the SCM to show no optional boards installed. He then performed a full diagnostic check with no problems. I suspect that he assumed that the power supply was defective, and did not make the connection to the programming mismatch. The depot technicians use a different CPS than users like me have. Several months later, I was prepping the same station for installation at another site, and I had plugged a spare Auxiliary I/O Board into the optional cage before powering it up. Once again, I got the same steady red LED indication after bootup. While contemplating my choices, since the warranty had expired, I again tried swapping the Station Control Module, with no effect. Then, I tried pulling the Auxiliary I/O Board and re-booting. Bingo! Further experimentation revealed that a major failure LED indication will occur if an Auxiliary I/O Board is installed in the station when the programming says that slot is vacant, or if that module is missing when the station programming says it is installed. It is likely that a similar anomaly will occur when other optional modules are concerned, but I have not tested that hypothesis. Live and learn! 73, Eric Lemmon WB6FLY
