Tweco 151 with SL100SV - Manual (Page 84)

SERVICE 5-16 Manual 0-4691
5
11. Faulty ON/OFF switch
Measure for 28 VAC on the Main PC Board between J18-5 to J18-6.
a. If voltage is not present replace the ON/OFF Switch.
12. Faulty Main PC Board
Measure for 12 vdc on Main PC Board from TP4 to TP1.
a. If voltage is not present, replace the Main PC Board.
D. AC and TEMP indicators ON, fans do not run
1. Air flow through unit is restricted
a. Provide adequate air flow
2. Exceeded Duty Cycle of Power Supply
a. Deactivate torch and wait for fan to cool unit. Refer to Specifications Section for proper duty Cycle for this unit.
3. Faulty Fan(s)
Measure for 230 VAC (±) on the Main PC Board from J15-1 to J15-2, and from J15-5 to J15-6.
• If voltage at J15-1 to J15-2 is correct, replace lower Fan (M1).
• If voltage at J15-5 to J15-6 is correct, replace upper Fan (M2).
4. Faulty Temperature Sensor / Switch
a. Check IGBT Heatsink Temp Sensor (TS1). Disconnect wire connector P29 from terminal J29 on Main PC
Board. Check connector pins 1 and 2 for 10K ohm (±25%) (at ambient temperature). If resistance is not 10K
ohm (±25%), replace TS1.
b. Check Inductor Temp Switch (TS2). Disconnect wire connector P32 from terminal J32 on Main PC Board.
Check connector pins 1 and 2 for at least 12K ohms. If resistance is less than 12K ohms, replace output
inductor (L1). If temp switch is open, replace Main PC Board.
E. No gas flow; AC indicator ON; TEMP , GAS and DC indicators OFF
1. RUN / RAPID AUTO RESTART / SET switch in RUN position
a. Change switch to SET position.
2. Gas supply not connected to unit
a. Connect to gas supply.
3. Gas supply not turned on
a. Turn gas supply on.
4. Faulty RUN / RAPID AUTO RESTART / SET switch
a. Check continuity.
5. Faulty Gas Solenoid circuit
a. Test Gas Solenoid circuit per Subsection 5.08-E; repair as necessary.
6. Faulty Logic Board
a. Replace logic board.