Wanting to get others opinions if the following symptoms indicate a failing TIU.
Background: I have a Rev L TIU with the latest software. I am driving all 4 channels using two Z4000. One channel for each of 3 loops and 1 for yard. I do not have any external TVS hooked up. I also have Legacy on all the tracks. I have both remotes and WIFI. I have been running this setup for about 3 years with flawless operation (except occasional operator errors 
). I have made no changes to the layout except adding some buildings and accessories; these are all driven with a separate transformer. I have multiple PS2 and PS3 engines. As a general rule I only run 1 engine on each loop at a time and I have the yard off until I want to run one of those engines.
Symptoms: Over the past couple of weeks when I start up an engine I get a flash on remote "Engine Not On Track", then engine starts up. I can operate the engine for a period of time but sometimes the horn will blow when I push button but won't turn off; this happens with bell as well. On occasion, an engine will lose all of its lights and I will have to do a feature reset. This happens with many of my engines and at multiple places on the track. I would say the PS2 engines seem more likely to show these symptoms, but I have not tested all of them.
Actions Taken so far: I first did a thorough cleaning of track. Any engine that experienced an issue I removed and cleaned wheels and pickup rollers. I have a TIU port tester that I checked all of the channels. Three channels show red and green light flash, one channel only red flash. I can't swear to the calibration accuracy since I don't own a scope. I have not opened up the TIU to see if this has the TVS mod; I plan to do this after the holidays when I can borrow a spare rev L TIU from my brother.
In the meantime, I was wondering if there are other simple actions I can take until I can substitute the TIU? I want to keep the layout running for visitors during the holidays.
Ken
