Oven not quite getting hot enough after repair, and occasionally cutting out.

I’ve measured the sensor at about 1055ohms @ about 16 degrees room temperature. That seems pretty close to spec? The sensor doesn’t appear to be bent or touching the metal, so I don’t know if this is the cause of the under-heating.

As for the heater element+light going off at random I’m not much further on. When they are off the controller doesn’t seem to care, and all the front panel is alive, just that the temperature falls (as you’d expect.) Slamming the door in the right way usually fixes it, though it can go off again a short time later.
The shared connection between light and element is the neutral wire which passes through what I believe is the thermal cut-out (see image below) on the way back to the power block on the mains supply side. I’m trying to work out if the thermal cut-out is sensitive to vibration, but it doesn’t seem to be when cold at least. Could it be the problem when hot? I’ve temporarily by-passed it and will (carefully!) determine if the problem has gone away over the next couple of baking sessions.
[IMG2=JSON]{“data-align”:”none”,”data-size”:”full”,”height”:”185″,”width”:”200″,”src”:”http://invisibules.org/wp-content/uploads/2022/01/IMG_20220102_1119417071.jpg”}[/IMG2](I found this part online for about £40, which seems expensive given that other makes have them for under a tenner, eg: https://www.ebay.co.uk/itm/142870009152 — would it be reasonable to use one of these instead?)

Happy new year!

Thanks Dave. I’ve temporarily by-passed the temp limiter and will (carefully!) determine if the problem has gone away over the next couple of baking sessions.

The fact that slamming the door ‘wakes it up’ suggests bad connection, bad solder joint, or sticking relay to me.

I don’t think it’s a relay: Slamming the door can also turn it off (and, why would it have gone off in the first place?) But I will check later, thanks for the tip. When I fixed the relay before I just moved an identical but unused relay from elsewhere on the board. The rating is the same. Also, that relay controls only the element, not the lamp.
Bad wiring/soldering is more likely. I started investigating the wires, but whatever it is has to be common to the element and the lamp (and, I think the grill, but I haven’t checked) and nothing else. Which is why I focussed on the thermal limiter. But you are right, there could be other common paths.
The thermal limiter says “Type 261/PB” which seems to indicate the basic shape and function — normally closed and with a reset button?
Then 16/3 250~ which I think is the current/voltage rating? And then T175K which I suspect is the temperature of cut-out in … Farenheit — about 80 celcius?
What is the 12nc number?
cheers

[IMG2=JSON]{“data-align”:”none”,”data-size”:”full”,”height”:”83″,”width”:”800″,”src”:”http://invisibules.org/wp-content/uploads/2022/01/IMG_20220102_121105069-scaled.jpg”}[/IMG2]
Presumably one of those barcodes is the 12nc, and one is the serial?
Anyway, it doesn’t matter now, because even with the thermal cut-out bypassed the bad behaviour remains — so it’s not that. (You’ll be happy to know that the ginger biscuits turned out very well, even though I had to shake them several times to keep the oven on 🙂 When it’s cool I will open it up again and do some more searching.

[I had another thought about the low temperature. I’ve realised that when the oven runs some air is constantly expelled through the door — so I think this would explain the low temperature? (And, not to mention sending my electricity bill soaring… and why it’s so hard to keep steam inside for baking.) I could replace the seal.]

Thanks again.