Anybody know a thing or two about repairing Defy stoves

**adrianh** · 13-Jul-21, 01:37 PM

We have a Defy 735 Thermofan stove. All 4 plates turn on full with no temperature control. I tried to replace one of the controllers with a standard MP101 controller but it doesn't work correctly at all then. The plate turns on very late and turns off quickly again with the MP101 - I was told that the old Defy controller is no longer manufactured.

Do the plates have thermocouples inside them? Could those thermocouple be blown?

**Justloadit** · 13-Jul-21, 01:49 PM

Thermocouples do not blow. They are made of two wires of dissimilar materials, which cause a small variable current to flow with temperature.
This is the reason that one would like to know the temperature of the point that the thermocouple connects into the controller, so that the ambient temperature is then subtracted from the measured temperature.

Try this company, they usually have most spares in stock - Tecsareco

**adrianh** · 13-Jul-21, 04:55 PM

Originally Posted by Justloadit

Thermocouples do not blow. They are made of two wires of dissimilar materials, which cause a small variable current to flow with temperature.
This is the reason that one would like to know the temperature of the point that the thermocouple connects into the controller, so that the ambient temperature is then subtracted from the measured temperature.

Try this company, they usually have most spares in stock - Tecsareco

Thanks. Maybe the word "blow" was inappropriate - I should have used "become defective"

**adrianh** · 13-Jul-21, 05:08 PM

I still don't understand how the plate temperature controller works - It doesn't seem to sense the temperature of the plate - Is some sort of crude PWM system?

**Justloadit** · 13-Jul-21, 05:34 PM

Originally Posted by adrianh

I still don't understand how the plate temperature controller works - It doesn't seem to sense the temperature of the plate - Is some sort of crude PWM system?

It is possible that they measure the internal resistance of the element, and then can deduce the temperature of the plate and use a triac switching time within in each mains half cycle to control the temperature.

**Justloadit** · 13-Jul-21, 05:43 PM

Have you done a Google search on your stove model?
Usually there are good videos on how to fix things on it.

I do remember in the old days, that they used a bi-metal switch to control the element. When you adjusted the control knob, you basically adjusted the spring, and the expansion and contraction of the bi-metal heating due to the current flowing through it would control the element.

It may be the contacts are welded due to years of use.

**adrianh** · 13-Jul-21, 06:18 PM

I've done a lot of research into the issue. The controllers that was fitted to the stove when it was made are no longer available. I got replacements from a local shop but they don't work correctly - I think they gave me the wrong controllers. I am going to go to Defy tomorrow and see if I can find replacements from them.

**Derlyn** · 14-Jul-21, 08:43 AM

Solid plates are manufactured to be connected to 6 heat switches. Spiral plates use simmerstat controllers.

You can adapt solid plates for use with simmerstat controllers by bridging terminals 1 and 2 on the plate together and also terminals 3 and 4 together.

Terminal 1 or 2 is connected to load terminal on controller and 3 or 4 to neutral.

Of course, if the stove has spiral plates then this mod is not necessary.

Peace out .. Derek

**Blurock** · 14-Jul-21, 11:38 AM

DEFY used to be a proud South African company with reliable and affordable products.
We are unable to find a roller latch for the stove's oven door.
The 610 fridge is a poor comparison to previous models that we have had.
Flimsy and inferior materials inside and door seals cannot be replaced - you have to buy a new door.
The inside of the fridge is starting to rust and nothing can be done about it. (Just out of guarantee)

I have since established that the company was taken over by a Turkish group. Obviously not concerned about quality, just profits.

**adrianh** · 14-Jul-21, 07:21 PM

The stove is a 20 year old Ceran top model 735. The machine has lasted well and considering that it would cost R13k to replace I really prefer to repair it.

Modern White goods are the ULTIMATE OBSOLESCENT JUNK - We always buy Defy machines because we believe that spares are readily available (I am questioning this wisdom now) but anyway, each consecutive machine is 100x more junky than the last.