Strobe Light Problem on Lionel GP-20

was your train has it been upgraded, if you're not sure you might try a tmcc reset, it might make the strobe light work and headlight issue! make sure the strobe light is plugged in all the way!

Alan

I believe there is a trick the HO'ers do, that since their motor run off of DC, with a diode in series with a light bulb, or an LED with a protection diode, you can tap off the connections to the DC can motor to light forward or reverse light. Not sure what happens when the motor receives PWM.

If it was kitbashed as you said, was the original flashing bulb a grain of wheat (or rice) bulb that was replaced with an LED?  If so, and the LED wires were just spliced to the wires to the non-LED bulbs, the electronic circuitry doesn't detect that the LED bulb is there.  The explanation is a bit simple, but I'm no tech guru.  I had that issue with the flashing bulb when I replaced one with an LED.  The gurus on the forum pointed that out, and said I needed to install a triac.  Perhaps you could do a search on that.  It was easy to buy and install, and it worked.

@FortyFivePalms posted:

Hello Folks,

I acquired a kitbashed Lionel GP-20 with TMCC and sounds.

I managed to get everything working except two things: (1) Headlights forward/reverse - The rear light lights up and the front light goes out in reverse, but both lights stay on when going forward, is this normal? If not, can it be fixed? This may be due to needing to set the correct Feature Code into the TMCC radio receiver when setting the TMCC ID. Feature code is what determines how the outputs for lights and smoke outputs work- with smoke sometimes being used for strobe- easily an explanation of why you have problems.

(2) Strobe light on top of cab does not work. Could it be a bad bulb? I removed the wires from the circuit and applied 9 volts but it still did not light up, and also I read across the leads to the bulb with my VOM and it shows dead open. This would seem to indicate a bad bulb; if so, where can I get one? Haven't been able to find any replacements on the Web.

This is just likely a standard grain of wheat (the size of the bulb) rated for 14-18V typically given TMCC operation at 18V. It may have burned out because of using the wrong feature code used- set to smoke output rather than strobe.

Example https://www.lionelsupport.com/...EAR-GRAIN-OF-WHEAT_3

Thanks!

You didn't mention what electronics are used, R2LC modular or other?

Standard reset code sheet- you need this if you own TMCC engines

https://ogrforum.ogaugerr.com/...%20Reset%20Codes.pdf

Below is a chart of reset codes specific to Lionel Command Controlled locomotives. These reset codes are to be used when resetting the engine's ID number. If in
doubt, check the instruction manual that came with your engine for the correct.

Reset Code to use.
The feature code tells the command receiver which features are present in the engine. For example, if the engine has a smoke unit or strobe light, a back up light, or a single headlight, cab light, etc.

To use these codes, you must follow these steps:
• With the engine on the track and the PROG/RUN switch in the program position.
Turn the track power on to 18 volts.
• On the Cab-1 hand held remote press ENG + # # + SET + ENG + # # + AUX1 +
Program Code (see below)
• Take the engine off the track and slide the switch back to run, leave it sit for
about 30 seconds.
• Place the engine back on the track, address the appropriate engine number and
you’re ready to run.

PROGRAM CODES
Insert these numbers in the space for "Program Code" in the Cab-1 sequence
above.
0 Steam engines with Signal Sounds
1 Diesel engines with Signal Sounds
2 Diesel engine with cab light and signal sounds, all Legacy diesel engines
4 Steam engine with smoke, Pioneer Zephyr, M10000
5 Diesel engine with strobe light, GP-7, GP-9, GP-20, Crew Talk Cabooses,
S1 Electric, Missle Launch Engines
6 Diesel engine with cab light , PB-1 with Railsounds, FT's, F3's w/ Pullmor
Motors, Veranda Turbine, Station Sounds Passenger Cars
8 All Diesel engines with smoke, Scale GG-1, BB-1, BB-3 Electrics
34 6-2800 Series Hudson and Pacifics, Small K-4's, Shays
36 Alco PA-1 (from 1997, Santa Fe & NYC)
60 SD-40 UP 6-18273
74 All engines with Wireless Tether including American Flyer Mikado. Note:
For J1-e Sante Fe Warhorse Hudsons see below.
75 Soo Line SD60 (6-18232)
76 Acela
740 J-1e NYC Hudson, Santa Fe J-1e Hudson (Warhorse set - both engine
and tender must be on the track)
750 Conrail Dash-8, 1999 (6-18240), 1999 Centennial SD-40 (6-18585)
760 BNSF Dash-9 (6-18235)