23-07-2021, 08:38 AM
Got it on the bench today. The mode stirrer is more subtle than I thought. Some of the air from the cooling fan flows through the holes towards the bottom left of one of the photos. In normal use this is in the roof of the oven cavity. The central probe is part of the magnetron.
The other photo shows the mode stirrer. The fixed vanes at the top (they are below the holes when in use) guide the air to the plastic blades on the rotating part. The metal part isn't visible in normal use. It's above the plastic housing. A simple turbine. I don't quite see how the microwaves pass via the mode stirrer to the oven cavity but I'll accept that Philips did their design properly. The holes in the stirrer seem to have been chosen very carefully.
I can't see any way to verify that the mode stirrer actually turns in normal use. From memory the fan runs even with the door open so I could feel the air supply. The central pivot can rotate but probably won't as its friction against the plastic housing is geater than the metal part against the pivot.
I suppose it's neon bulbs in a few places in the oven, along with a glass of water to provide some load for the magnetron. All of which I could have done without dismantling. If the bulbs flash then the mode stirrer is working.
The other photo shows the mode stirrer. The fixed vanes at the top (they are below the holes when in use) guide the air to the plastic blades on the rotating part. The metal part isn't visible in normal use. It's above the plastic housing. A simple turbine. I don't quite see how the microwaves pass via the mode stirrer to the oven cavity but I'll accept that Philips did their design properly. The holes in the stirrer seem to have been chosen very carefully.
I can't see any way to verify that the mode stirrer actually turns in normal use. From memory the fan runs even with the door open so I could feel the air supply. The central pivot can rotate but probably won't as its friction against the plastic housing is geater than the metal part against the pivot.
I suppose it's neon bulbs in a few places in the oven, along with a glass of water to provide some load for the magnetron. All of which I could have done without dismantling. If the bulbs flash then the mode stirrer is working.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
