Garland GI-MO/DU 7000, Service Manual

Page: 13 / 20

Part # 4526029 (02/22/11) Page 13
Measure Activity Comment
M41 • Measure the resistance of coil temperature sensor resistor
at 25º Celsius (77º F) resistor will read 1kOhm
at 180º Celsius (356ºF) resistor will read 3,5kOhm
• Resistor is higher on a higher temperature (PTC-resistor)
• Replace sensor with a value less than 900Ohm
• For a test: Short-out the sensor with a 1kOhm fi xed RESISTER
Disconnect sensing element
M50 • Measure operational control or main power control switch with
potentiometer: Potentiometer is 10kOhm and linear
• On level “0”: resistor = 0 Ohm
• On maximum level resistance= 10kOhm
• Resistor is proportional (linear) to swing angle
Disconnect operational control
(Poti)
M60 • Measure temperature inside the case
• Admissible ambient temperature: 0°C/32ºF to appr. 70°C/158ºF
• Check point is on the CPU-circuit board
M100 • Check connection cable for serial operational control and
CPU-circuit board
M101 • Change serial operational control
M200 • Check mains cable, perhaps one phase missing
• Check the building fuses
M220 • Disconnect ST2 on CPU-circuit board and measure resistance
between brown and blue,
Measured value: 200Ohm < R < 2kOhm
• Replace rectifi er circuit board
M240 • Use suitable pan material
• Test with a pan with a diameter of 24cm (4.75”)
M241 • Disconnect mains power supply
• Visually inspect : blackened cables, components or strip
conductors?
• Transistor module: measure internal diodes (UF = 0.4V)
• Rectifi er: measure internal diodes (UF = 0.5V)
• Control trafo: measure electric voltage
• Check power supply CPU-print +24V
CPU-circuit board ST1/1 and ST1/4 (24V +/- 1V)
M251 • Check power switch on operational control