Neff induction hob repair

[Seadog]

Judging by the copper pad beneath in the picture, a solder bridge has vapourised.

 

[RaceDiagnostics]

It's blank, I suspect a short elsewhere caused this to blow. Could be a fuseable link.

 

[Seadog]

It's most likely a MOSFET that has gone s/c.

 

[bourbon]

I'm watching this thread carefully, Understanding it? no chance. But watching to see if I can learn stuff.

 

[RaceDiagnostics]

Here is a simplified circuit.

 

[RaceDiagnostics]

It looks like the bridge rectifier and two of the igbts are short circuit, no easy way to tell if there is more damage.

My meter shows .2 ohm for a short circuit.

AC input to the regulator, dead short.

Diode drop, 0v.

Igbt 1, dead short.

Igbt 2, dead short.

The igbts are NLA but there is a replacement, I'll order 2 and a new bridge rectifier as they are all cheap from Mouser. Worth rolling the dice rather then shelling out £300. The fused PCB is on the Neutral line and I'll fix that with a couple of blobs of solder.

 

[brightspark]

bin it

 

[RaceDiagnostics]

Haha, to late, bits now ordered.

 

[123hotchef]

Has anyone tried this?

Yesterday there was a bang from the hob and the cooker circuit tripped. After resetting 3 of the rings showed a P1 code. Googling says replace the control board for these rings, the board costs about £300.

View attachment 410366

In a bit further.

View attachment 410367

My concern is there is zero sign of damage on the board and £300 is a bit of a gamble on maybe getting it fixed.

It's 9 years old so perhaps should just replace it.

9 years i say bin it mate, I binned ours earlier this year after only 6 years it gave up working

 

[Anguz]

there are a lot of spares/repair on the bay.... seem to fetch reasonable money for scrap as well

 

[Chippie]

The mosfets that went bang, how are they driven? if there's a driver chip, it too may have met its end... to blow both mosfets, potentially thay have been turned on simultaneously?

When you power it up after repair, put a 100 watt light bulb in series with the supply.. limits the current and and a repeat performance...

 

[RaceDiagnostics]

These are the pre drivers.

Opto isolators so hopefully the damage will not have gone further upstream.

 

[badabec]

Close up.

View attachment 410381

From one of my favourite films, that's not Griswold's cat is it?

 

[RaceDiagnostics]

All four of the optoisolator pre drivers buzzed out the same so I'm assuming they are ok.

 

[Erie Fred]

Awful lot of electronics with exposed hi-power coils right at waist level.....might
want to stand a bit farther away.

 

[KemppiFrog]

Witchcraft I tell you! Put it all in the chair and drown it!

After cooling down, I find this all quite interesting. But I might stick to gas..

 

[KemppiFrog]

Awful lot of electronics with exposed hi-power coils right at waist level.....might
want to stand a bit farther away.

Reminds me of stories from the Marconi works in Essex way back. Their sailing club had a fleet of our dinghys, so we knew a few of the guys.
Anyway, blokes with 'plans' for the w/end would stand in front of one of the test units with the covers off for a couple of minutes. Saved on contreceptives.....

 

[Red'n'Black]

It looks like the bridge rectifier and two of the igbts are short circuit, no easy way to tell if there is more damage.

My meter shows .2 ohm for a short circuit.


View attachment 410403

AC input to the regulator, dead short.

View attachment 410405

Diode drop, 0v.

View attachment 410404


Igbt 1, dead short.

View attachment 410409

Igbt 2, dead short.

View attachment 410410

The igbts are NLA but there is a replacement, I'll order 2 and a new bridge rectifier as they are all cheap from Mouser. Worth rolling the dice rather then shelling out £300. The fused PCB is on the Neutral line and I'll fix that with a couple of blobs of solder.

Is there any sign of moisture anywhere?

Ours is an AEG, no permanent failures so far but if you put anything in front of the oven vent the whole under-hob area fills up with condensation and it goes into fault mode.

When I get a minute I'll open it up and see if a duct has come loose, or if it's worth conformally coating the PCB. Performance of induction hobs is great but they still seem a bit fragile to me.

 

[Seadog]

Reminds me of stories from the Marconi works in Essex way back. Their sailing club had a fleet of our dinghys, so we knew a few of the guys.
Anyway, blokes with 'plans' for the w/end would stand in front of one of the test units with the covers off for a couple of minutes. Saved on contreceptives.....

Were you at the Chelmsford works?

 

[KemppiFrog]

Were you at the Chelmsford works?

No, this was back in the 50s, while I was at school. Told a bit later... But yes, must have been Chelmsford.