Service manual

Page 27 Microcook HD Ovens 32Z3385 Issue 5
The operation of this PCB is best tested when the oven is in operation. You will need to have a
pen and paper to hand in order to set up the Nozzle temperature.
(see Adjusting the nozzle temperature below for further details).
Initial Status of PCB Monitor LEDs
When the oven is turned on, the status of the LEDs on the PCB are as follows:
D1 Fan OK Off
D4 Motor On Off
D6 Sensor Error Off
D7 Full / Half On
If any of the LEDs are not as above check all connections to the PCB.
Adjusting the nozzle temperature
Setting the nozzle temperature should be carried out prior to all microwave tests, or should be
carried out on an oven which has been turned off for at least one hour. If this is not possible, or
if the oven does not function in Turbo mode, proceed to the next section.
1. Place a water load of at least 500ml in a suitable heatproof container into the cavity.
2. Measure the voltage between the Set Temp pin and GND pin with a multimeter set to
read at least 10Vdc. Adjust VR1 clockwise until the reading exceeds 7.5V.
3. Program the TA Oven for 3 minutes in Turbo mode on pad 0.
4. Measure the voltage between the T+ pin and GND pin.
This should indicate the ambient temperature.
5. With the meter still attached, press pad 0. When the oven time display indicates 2:48,
note the voltage reading. This should be between 2.0V and 7.5V. Press the Cancel Pad.
6. Measure the voltage between the Set Temp pin and GND pin, and adjust VR1 until the
meter reads the same as the reading obtained above.
7. Press Pad 0 again , and verify that the Half / Full LED (D7) switches on and off during
the cooking cycle.
Note : The above setting up procedure must be carried out on a cold oven , as the
oven will not cook correctly if carried out on a warm oven.
Do not carry out this procedure on a warm oven.
Operation of LEDs during Turbo cooking
On completion of the above procedure, a functional test of the PCB should be made and
operation of the LEDs observed.
1. Place a water load of at least 500ml in a suitable heatproof container into the cavity.
2. Program the TA oven for 3 minutes in Turbo mode on pad 9.
3. Press pad 9. The oven should begin to cook and the Motor On LED should light.
4. After about 1-2 seconds, the Fan Ok LED should light .This allows the heater element
to work.
5. Within 10 – 20 seconds, the Full / Half LED should go out. This should switch on and
off during the cooking cycle.
6. When the time display shows 0:10 the heater element should switch off, which should
result in a change of pitch in the noise from the fan. This completes the operational
test.
TA 1725 and TA 1925: PCB board operation during oven use