Induction Hob

[Onoff]

Daughter switched the induction hob on last right and the dedicated 32A RCBO tripped.

I reset the RCBO but the hob is dead. Pressing the power on button and nothing though the mains supply is there.

Whipped it out and started to take it apart. Mains comes in and splits to two induction plates either side:

Control PCB does the same, appears to control two + two:

First thing I've found, 20A fuse one side has blown:

Any pointers?

 

[Seadog]

Rectifier, power semiconductors (IGBTs)

 

[angellonewolf]

Not that I know what I'm doing as never played with one

But I'd be tempted to remove both plates (screwed to board mark thr up first so you know pos negative)

Replace fuse and see if it blows again if it works and does not blow replace each plate in turn (REMBERING TO TURN POWRR OFF BEFORE DOING ANY THING AT ALL AND BE AWARE THE POWER STILL MY RESIDE AFTER POWER TURNED OFF AS WELL)

if your luck one plate has blown and triped the fuse and removing the faulty one will start it working again

 

[Onoff]

PCB has no obvious scorching:

 

[Onoff]

12V fan is good on a 9V battery.

 

[Onoff]

What should I be looking at resistance wise on an induction hob ring? AI suggests 50 - 300 ohms.

 

[angellonewolf]

Google im sure would be your friend on this but I'm assuming very high or very low would be bad

 

[Onoff]

Testing with my trusty old multimeter:

These two matched IGBTs (?):

Testing in circuit, with the meter set on continuity:

Left one:

B to C - nothing
C to E - continuity

Right one:

B to C - continuity
C to E - continuity

Mean anything?

 

[angellonewolf]

I'm a bit out of touch with circuits but I think they need to be disconnected from any components before testing to get good readings

Have you tryed replace fuse and removing the plates from the board ?

 

[RaceDiagnostics]

Here is a simplified circuit.

Here is a simplified circuit.

 

[Onoff]

I'm a bit out of touch with circuits but I think they need to be disconnected from any components before testing to get good readings

Have you tryed replace fuse and removing the plates from the board ?

Half a plan to just disconnect that side from the mains and control and try it. Oddly the side that appears to have gone is the side we rarely use.

Never really done much transistor testing but I'm sure you can test them in circuit somehow...

 

[RaceDiagnostics]

Here is how I tested mine. I had multiple igbt and rectifier shorts. Once replaced it worked perfectly.


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.

 

[Onoff]

Here is how I tested mine. I had multiple igbt and rectifier shorts. Once replaced it worked perfectly.


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.

Thanks. Looking at my post 8 do you think I have a dead short on one of them?

 

[Onoff]

Damn! Saying that, main number the same but others following are slightly different:

 

[Onoff]

Would these be any good. Again, main number the same:

Pardon our interruption...

 

[RaceDiagnostics]

Thanks. Looking at my post 8 do you think I have a dead short on one of them?

Disconnect the load from the PCB and check the actual resistance between the pins, what ohms values did you read?

Also check the rectifier. Since the parts are cheap you can replace them all

I bought my replacement parts from digikey.

 

[Onoff]

Since the parts are cheap you can replace them all

You mean all 4 circled?

 

[RaceDiagnostics]

You mean all 4 circled?

View attachment 502474

Yes.

 

[RaceDiagnostics]

I've got a few spares for the regulator. Let me know your address and I'll stick one one the post

 

[Onoff]

I've got a few spares for the regulator. Let me know your address and I'll stick one one the post

View attachment 502482

Thanks. PM sent.

I'm finding the main GW number for those others but the numbers underneath differ. Critical? Wonder if it's like the old BC109 vs BC109C...