SD90/SD80's take a replacement board decoder. Very easy installation.
Digitrax, TCS, and MRC make replacement board decoders for those engines.
Martin Myers
They should be:
http://www.tcsdcc.com/public_html/Customer_Content/Installation_Pictures/N_Scale/Kato/EMD%20SD90-43MAC/EMD%20SD90-43MAC.html
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Am looking at 2 N scale locos made in 2001 first issue I think. Seller is saying they are DCC ready. To me that means a drop in decoder. Any opinions out there? They are two SD90/43 mac"s