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12767 Steam Clean And Wheel Grind Shop

Wheel Grinder Circuit Repair

The Floodlight  Tower and Control Panel lights were out on the Wheel Grind section.  Inspection revealed  a melted Lamp Adapter inside the control panel.  The circuit board appeared to have a damaged bipolar transistor, capacitor and the 16V lamp adapter .

Electronics component identification required a consultation with my electronics engineer (my son Brad).  The following components were replaced.

Damaged Transistor Upgraded Bipolar Transistor
Bipolar Transistor

The reference numbers refer to the connection positions in red on the circuit board photos with the schematic pdf.
Capacitor The damaged capacitor between the motor leads was a 0.1uF Ceramic-Disk Capacitor 50WVDS maximum (High K dielectric).

Radio Shack part #272-0135 Pkg. of 2

Yes, Radio Shack stores are still open as of June 2016.
See melted adapter circled in red.  The socket with red and white leads was undamaged.
Melted Lamp Adapter
Upgraded to 18V / CLEAR LAMP

Adapter with 16V Lamp Installed
16V Lamp with Adapter
Lionel Illustration and Part # for Floodlight  Tower Lamps


See Brad's circuit schematic and component connection photos.

Parts List of Circuit Board Components Replaced

Q2 (TO-92 case) Bipolar Transistor - BJT NPN/40V/1.5A
    Fairchild Semiconductor #SS8050BBU  or   Radio Shack part #276-2009
C4  0.1uF Ceramic-Disk Capacitor 50WVDS maximum (High K dielectric).
    Radio Shack part #272-0135 Pkg. of 2

Lamp1  Lionel #620-5100-300 LAMP / 18V / CLEAR / W/ADAPTER  (The higher voltage may prevent a future melt.)
    (Lionel lists an original 12V 70MA lamp for the control panel.)

Parts List of Possible Circuit Board Components to Replace

Q1  (TO-220 case NPN silicon)) original # 99227 TIP31A
     Central Semiconductor part #TIP31 Bipolar Transistor - BJT NPN Gen Purp Power
     Radio Shack part #276-2017 (not replaced)

D1  Zener Diode 12V 1W ZENER 5%  Fairchild Semiconductor # 1N4742ATR (not replaced)

Motor and Flint for Spark Generation

Lionel Replacement Flint is Part #610-2767-111.  The replacement motor is listed as unavailable.

A possible motor replacement is Mabuchi FK-280 Motor - 10 to 15 VDC - Model Train Motor


Grinder Motor Measurements in Inches
Motor Nylon End Motor in Place


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