The second UP FEF #844 I purchased with a factory installed TCS K6D4 decoder. Unfortunately, the UP FEF has issues at very slow speeds.
TCS has offered to reprogram these K6D4 decoders if they are returned to the TCS factory. Due to the large train show in Springfield Massachusetts on January 25 and 26th, any decoders sent back to TCS will not be returned to users until late February to early March 2015 as I was told when I called TCS yesterday.
If by chance, you decide to order a new TCS K6D4 decoder on their website, you will receive the original version of this decoder and not the new re-programmed decoder. According to TCS, they haven't completely figured out the fix for the K6D4 decoder. I was also told not to change any of the CV's on the original K6D4 decoder. You, as a consumer cannot fix this decoder.
In any event, I decided to hard wire a decoder to the original light board of the UP FEF. When I received the factory installed TCS K6D4 decoder in the UP FEF, Kobo didn't include the original light board of the locomotive which was removed when they installed the TCS K6D4 decoder in the locomotive..
I then decided to order an original light board from the Kato parts department and I should receive it in the next few days. The cost of the light board is $5 plus shipping.
Meanwhile in late December of 2014, a member of RW forum published a diagram for hard wiring a decoder to the light board. It is listed below. If you carefully follow the diagrams you'll be able to hard wire a decoder in this locomotive. I'll be using a small Zimo N scale MX621 miniature Lok decoder which is tiny and should fit in a space behind the original light board. I'll be soldering the wiring to this light board on my work bench and then install the finished product into the UP FEF.
John Columbo of the RW and TB forums recommended using this decoder in the UP FEF as it has outstanding motor functions and performs well with the UP FEF's new coreless motor. It's small size allows you to easily slip the decoder in place in the locomotive with no adjustments to the locomotive frame.
In this FEF I'll be installing a Soundtraxx Heavy Steam decoder made for the UP FEF in the tender with several Zimo cube speakers. This is what is called a "two decoder" approach. Only the sound functions of the Soundtraxx decoder will be used .
I've used this "two decoder" approach in all of my previous Soundtraxx decoder installations. In those installations I used a Lenz mini silver decoder for motor functions as the Soundtraxx decoders' motor functions are poor at best. The Soundtraxx decoder was used for sound functions only. It's an added cost, but the "two decoder" approach is worth the added cost and effort.
