Main components
CABINET SAFETY THERMOSTAT F2
Safety thermostat F2, located nearby the heating element and fan motor on the top left side on the rear of the cooking cabinet. It’s main safety of the appliance and it lets supply the safety contactor C6.
It switch in case the temperature exceed 375°C for some seconds and can be reset by customer.
If thermostat switch leave the unit to cool down with the door opened for some few minutes and only than remove the protection (see picture) on the back and press the reset pin of this thermostat.
Consider that the thermostat can switch also in case of negative temperatures; in winter time or after long stoking time check it during installation.
Warning: If thermostat switch several times is recommended to replace it.
SAFETY CONTACTOR C6
All LAINOX units are equipped with a safety contactor named C6 in case any protection open (cabinet thermostat, fuses, …) this contactor open deactivating all components.
Display stays always on to visualize error messages
MONITOR FUSES EML EMN
Just on side of the contactor you can find the two high voltage monitor fuses which protect the unit against improper use or defect on door microswitches and avoid microwaves can be activated with door opened.
In case of failure of those fuses check door and if needed the left interlock group
POWER SUPPLYER
Oracle has an electronic power supplier instead of the classic transformer; this allow to avoid inserting the rectifier on the main board and save energy when in stand-by.
Output voltage of the power supply is 15VDC 3A
MAGNETRON THERMAL SAFETIES SWITCHES
The magnetron generates a lot of heat and is installed in order to achieve the maximum air flow for cooling down. To prevent overheat anyway each magnetron has a thermal cut-off protection.
The thermal cut-off open if magnetron become too hot (135°C) and close back when cooled down.
Main reasons for intervention:
‐reflected microwaves goes back to the magnetron mainly because of cooking without a load.
‐unproper unadeguate air cooling flow
CABINET PROBE SC
Cabinet prove SC is a K thermocouple and is located on the top lefs side of the cooking cabinet near by the safety thermostat, the fan and heating elements.
It will measure the cabinet temperature and will manage through the control board the behavior of the heating element.
The spare part is LAR19201250, similar to the standard LAINOX temperature probe but with a shorter cable to avoid interferences with HV lines
DOOR SWITCH B3
Door switch is managing the behavior of the oven from the point of view of cooking and heating.
When B3 is closed and unit is switched in High Speed Oven the appliance is constantly heated up to keep the preheating temperature.
If B3 is open (door is opened) the power supply to the heating element and the fan motor are switched off.
B3 manage also the acknowledge about the cooking start but the power to the magnetron is managed by the safety door switches located on bottom and activated by the right and left door hinges
INTERLOCK SWITCHES B1 B2 AND BM
It’s mandatory on microwaves oven to avoid microwaves leakages and for this the door is equipped by a set of safeties switched activated by door hinges.
On the right side of the unit you can find the B1 microswitch that manage the phase line to the magnetrons.
On the left side you can find the B2 and BM microswitches which manage the neutral line and grant that a fault on any microswitch will cause the burn out of HV fuses EML EMN.
In case of any door adjustment or replacing will be mandatory an adjustment of those micro.
HV Transformer
Frequency related
HV transformer 50Hz LA19200820
HV transformer 60Hz LA75187320
There are 2 HV transformers one per each magnetron
The high voltage transformer, powered by the Power board, transform the standard power voltage up to 2000Vac.
Warning: dangerous voltages on the unit only expert technicians can operate.
Warning: on the HV protection box are marked the colours for the HV transformer cables which are reversed to let them work in opposite phase
Transformer is connected to the capacitor and to the magnetron with HV cables; in case of damages only replace HV cables do not try to rebuild lost connections.
HV Capacitor
Frequency related
HV Capacitor 50Hz LA19200530
HV Capacitor 60Hz LA19200660
The High Voltage capacitor is supplied together with his discharging diode and resistors
Before to act on the HV area disconnect the unit from the power and discharge the HV Capacitors
Keep separated the electrical connections between the circuit of the 2 magnetrons
To check the capacitors you must disconnect them and test with appropriate multimeter.
Magnetron
As just described the magnetrons are electronic resonance cavities and generate a characteristic frequency, 2,450GHz, they are connected to the cavity by a wave guide with drive the microwaves on the cooking chamber
Magnetron is a microwaves generator and operate as a thermionic valve; means there an activation time of about 10 seconds.
The magnetron need a proper air-cooling flow
WAVEGUIDES SHIELDS
Microwaves are injected in the cabinet trough a window on the side of the cabinet, one per side. The window is covered by a microwaves transparent material which must seal the cabinet avoiding grease and dirty reach the waveguide and magnetron
In according to the prescribed maintenance or in case of damages replace the window shield.
Warning: apply only the same shield type as per original version
Warning: grease and dearty can be ignited by microwaves and damage shields.
Left interlock B2 + BM
adjustment
A) Open the door and closing back search for the click of the microswitch; if click come just before complete closing or doesn’t come after closing proceed with adjustment
B) Loose lightly the screws 1
C) With door closed search for the click screwing/unscrewing the bolt 2
D) Fix the screws 1
E) Check again the adjustment after heating the cabinet at high temperature
F) Verify microwaves leakages (less than 5mW/cm2)
Left safety microswitch grant that when the door is properly closed the circuit to power the magnetrons is closed
It’s activated by the left door hinge when the door is closed. One of the micro is the power switch the second one is the monitor that will cause a short on the power line if first one fault.
Warning: The interlock must be adjusted in case of door/hinge replacement.
Right interlock B1
adjustment
A) Open the door and closing back search for the click of the microswitch; if come just before complete closing or doesn’t come after closing
B) Loose lightly the screws 1
C) With door closed search for the click screwing/unscrewing the bolt 2
D) Fix the screws 1
E) Check again the adjustment after heating the cabinet at high temperature
F) Verify microwaves leakages (less than 5mW/cm2)
Right safety microswitch grant that when the door is properly closed the circuit to power the magnetrons is closed.
It’s activated by the right door hinge when the door is closed.
Warning: The interlock must be adjusted in case of door/hinge replacement.