I have a few Legacy diesels from 2006 to 2010 (e.g., 6-34513, 28307, 31772) that all use a 620-8265-200 6-Volt regulated fan driven smoke unit. That smoke unit uses a 691-FSMR-E00 PCB. Both parts are available from Lionel's Parts Department. Last year a couple of my smoke units stopped running the fan although they all continue to heat the resistor. So in November I ordered from Lionel 1 complete smoke unit and 2 PCBs. When I received them they all had the same problem: they heat the resistor but fail to run the fan, just like my "defective" boards do. When I tested the fan motor on the new 620-8265-200 smoke unit with a known good board in one of my diesels it worked fine, so I suspected something was wrong with all 3 PCBs. I am testing all these boards on 34513 and 31772 engines that have correctly operating smoke units. I emailed Lionel all the facts and asked if there was something I might try to check the fan circuit on the PCBs. After several weeks of no reply Lionel finally gave me an RA and I returned the boards and smoke unit just before Christmas. After a month of waiting I finally got them back last week. The paperwork from the Lionel tech says the 2 PCBs tested "good," and the test of the new smoke unit showed a "bad fan motor" which he "replaced." This is the exact opposite of what I tested. The fan motor on the new smoke unit I returned to Lionel operated perfectly fine, just not with the board mounted to that smoke unit. So it was no surprise that none of the items returned from Lionel run the fan!
Does anyone know a magic trick to get the fan motor running with these 691-FSMR-E00 PCBs? I now have 6 of these boards that all heat the resistor but don't run the fan. Any help greatly appreciated.