There are no electronics on the motherboard to fail. Assuming there is no break in the wiring, it sounds like the smoke triac on the r2lc has died. According to Lionel's site, the r2lc in that engine has C08 code. The r4lc-c08 from err is a perfect match. You do not need to change the id number in the r2lc but you do need to make sure to program the board for a steam engine so the smoke unit will function properly (It should be code 4). If you are pulling the board from a steam engine, then just plug it in. No programming needed.
As a side note, I would also try and reprogram your original r2lc board. Sometimes they loose their programming and a full reset using the below procedure will fix it.
INSTRUCTIONS TO RESTORE TMCC FUNCTIONS (R2LC/LCRU 2 CIRCUIT BOARDS) RESTORE SOUND / LIGHT/ MOTION / SMOKE OPERATION
STEP 1: Move switch on locomotive from run to program.
STEP 2: Turn on Command Base.
STEP 3: Place locomotive on track, then turn on power to track.
STEP 4: Press “ENG” then input locomotive ID#. Press “SET”.
STEP 5: Press ”ENG” then input locomotive ID# again.
STEP 6: Press “AUX 1”, then input the reprogramming code number that corresponds to your locomotive. (See the chart below).
STEP 7: Turn off power to track, wait ten seconds.
STEP 8: Remove locomotive from track, move switch from program to run.
STEP 9: Place locomotive back on track. Turn power on to track.
STEP 10: Press “ENG” and ID#, then operate as normal.
** REPROGRAMMING CODES **
1 Diesel with Signal Sounds, all Legacy Steam Engines
2 Diesel with Cab Light and Signal Sounds, all Legacy Diesel Engines
4 Steam with Smoke / Pioneer Zephyr, M10,000
5 Diesel with Strobe Light –GP-7, GP-9, GP-20 / CrewTalk cabooses, S1 Electric, Missile Launch engines(For flashing red light)
6 Diesel with Cab Light / PB-1’s, FT's, PULLMOR motored F-3’s, Veranda Turbine,StationSounds passenger cars, Missile Launch engines(For steady red light)
8 All Diesels with Smoke / Scale GG-1’s/BB-1 & BB-3 Electric346-2800 Series Hudson and Pacifics, Small K-4’s, Shay’s
36 Alco Pa's (New in 97), 6-18192 WP, 6-38101/8103 Texas Specials, and 6-38106 NYC F3’s60SD-40 UP 6-18273
74 All Engines with Wireless Tether including American Flyer Mikados. NOTE! For J1E and Santa Fe Warhorse Hudsons see below.
75 Soo Line SD-60 (6-18232)
76 Acela
740 J1E Hudson (6-18056) & SF Warhorse Hudson (6-18062) NOTE! Both loco and tender must be on the track.
750 Conrail Dash 8 (6-18240), 1999 Centennial SD-40 (6-18585)
760 BNSF Dash-9 (6-18235)
