11
H4-72-02-03
For internal use only
Q701 / Q702 (for adjusting resistance on a 9-V measuring
instrument)
DB701 (for diode adjusting on a 9-V measuring instrument)
5.3.2
Carrying out a check due to a short circuit
• Function of the cooling fan!
• Microwave oven has been installed in accordance with installation instructions!
• The ventilation slits are not blocked and air can enter!
5.4
Checking the safety switch
The safety switch ensures that no microwaves are generated when the door of the oven is open.
Main switch
•
Cuts off the supply of 230V alternating current for converter switching.
Short-circuit switch
•
If the main switch fails when the circuit is closed (short circuit) and the user then opens the door,
the monitoring switch will trigger a short circuit on the 230Vpower unit. The short circuit will acti-
vate the 10 A safety fuse and the short-circuited switching contacts will be fused together.
Signalling switch
•
Reports the position of the door (open/closed) to the control module.
Checking the switch
1. Remove all of the leads from the three switches.
2. Check each switch for transmission with the door open and closed.
Normal
Fault
Forwards
Back
Forwards
Back
E-C
> 1k
Ω
> 1k
Ω
approx. 0
Ω
approx.
0
Ω
E-G
> 1k
Ω
> 1k
Ω
approx. 0
Ω
approx.
0
Ω
G-C
> 1k
Ω
> 1k
Ω
approx. 0
Ω
approx. 0
Ω
Forwards
Back
+ –
Reading
∞
~ ~
∞
∞
Door open
Door closed
Main switch
∞
Ω
open
0
Ω
closed
Signalling switch
∞
Ω
open
0
Ω
closed
Short-circuit switch
∞
Ω
open
∞
Ω
open
