I couldn't wait any longer for a good sound decoder, so I purchased a ZIMO MX621 and installed it today Thanks to Peteski for the very helpful schematic regarding where to cut gaps into the KATO light board. The feature I like is the decoder fit in the boiler underneath the KATO board. I have completed all the soldering except I need to add the "reliability" wires. Here is a short video of the thing. Thanks for looking and I hope there is some inspiration here for others to do a "DIY".
Carl
/>
