Recently had a client request the addition of a DCC mobile decoder to a TYCO engine with a pancake motor. My first reaction was that seems wrong. However the more I thought about it, the more I warmed up to the idea.
If the power truck operates well, then what is the problem? On initial check out, the stall current at 12 volts is under 1 amp. So no stopper there.
The long term reliability of the motor might be in question, but that is not a DCC issue.
The pick up points may be a concern. Each truck picks power on one side. Thus the engine can lose power in turnouts or dirty track. With todays keep alive capacitors, that problem can be minimized. The client is not interested in sound, just wants a mobile decoder. That actually may work fine.
My DCC system is old and had not been used since the move to Florida. It is an early NCE pro. It seems to work to program the decoder, but it is not working to run the unit on DCC power.
At the end of the day, the command station on this old unit was dead. So I could not verify that the DCC module worked
The engine ran on DC with the decoder in place. The performance has declined fairly dramatically. The starting voltage is considerably higher & the 12 volt velocity is 20 smph. less.
The mobile decoder initially installed was from Soundtrax. I have see this in other decoders. I tried a second Sountrex decoder and saw the same result.
This indicates a substantial power loss, most likely from the bridge rectifier. The BR voltage loss is at least 1.5 volts, but in some modules it looks to be as high as 3 volts. This is the case here. My experience showes that TCS decoders have a BR loss that is closer to the 1.5 volts. So I replaced the Soundtrex with a TCS module and everything improved.
Because my DCC system failed, I sent the engine back to the client in this condition. Because I could not verify the module worked, I refunded his money. I am sure the engine runs fine.
it was a fun project. It would have been nice to have a verification set of results. Next time.
