Damaged Silicon Identification - Inverter repair - SUCCESS !

[Dunk_c]

Hi
I have a blown component on an Aero-sharp inverter that I cannot identify. 

No luck finding a circuit diagram or service manual on line for HR-INV-X01-015

The inverter is not showing any fault indicators and the unit appears to be OK except that there is no Pout.  In the previous week there was a humming/rattling noise from inside the cabinet that ceased when I did a restart.


I think the smoked component maybe a MOSFET to control the output relays and would like to try repairing the board.  The underlying tracks are still all connected.

Hopefully someone can identify it?

Cheers

[fzabkar]

The bottom line is the part number.

This part appears to match the pinout, but it would be one of many possibilities:

https://www.infineon.com/dgdl/Infineon-IRF7103-DataSheet-v01_01-EN.pdf?fileId=5546d462533600a4015355f0f0141ac6

[gamalot]

The bottom line is the part number.

This part appears to match the pinout, but it would be one of many possibilities:

https://www.infineon.com/dgdl/Infineon-IRF7103-DataSheet-v01_01-EN.pdf?fileId=5546d462533600a4015355f0f0141ac6

[mengfei]

it looks like the PN starts with 7**3 but in the website there are a few combinations of those PN, you could get the highest spec or use the link below

If you know what you need
https://www.infineon.com/cms/en/design-support/finder-selection-tools/product-finder/mosfet-finder/?redirId=143927

[wraper]

You need to remove all carbonized PCB material, then bodge a new part on wires and fix it with neutral RTV silicone or UV solder resist. Carbonized FR-4 becomes electrically conductive, so you should never leave burned PCB material unless it's totally isolated to one trace only.

[Dunk_c]

Thanks
i did not know that.  I was going to apply conformal coating obver the damaged areas after masking off the solder pads and putting the new part in the same place but the carbonized PCB would have still been there.  Some more advice here would be good please.  Sounds like you might mean cutting the tracks back to clean PCB and using jumpers?

[Dunk_c]

Thanks the F7103 looks like a possibly the most likely match

[Dunk_c]

Thanks for the lead.  That may well be it 👍

[Dunk_c]

A quick search for a Dual N-Channel MOSFET, 3 A, 50 V, 8-Pin SOIC Infineon IRF7103PBF  shows that RS Components in Taiwan has them but not Australia.  I still have to look at the spec sheet for the highest rated version but in the meantime can anyone suggest a source?
Thanks

[gamalot]

You can buy IRF7103TRPBF, they are packaged in a tape reel instead of a tube.

[Dunk_c]

Thanks Everyone
Element14 Australia had IRF7103TRPBF in stock same day dispatch.

[Dunk_c]

One more thing …

I forgot to photograph PCB before removing the chip 😩

How do I ensure correct orientation of the IC on the PCB?  The datasheet has no typical circuit diagram but there appears to be a notch on the PCB screen print.

[gamalot]

In your pictures, the bottom left pin is the pin 1.

[ArdWar]

Pin 1 is bottom left in your photo. There's silkscreen visible, the traces also matches with the double drain pins.

Your MOSFET should have matching dot or bevel.

[Dunk_c]

Thanks for the confirmation 🙏🙏🙏🙏🙏🙏🙏

I reckon I have less that 50% chance of a successful repair but worth a go. 

Not worth buying a new (or second hand) isolated inverter for my old 1.5kw system.  Locked into a high feed in tariff with this old system until 2028, so won’t be upgrading until after that.

[Dunk_c]

Well, I think I got lucky!
Inverter back up and running and saved it from the skip!
First IC was installed with a solder bridge I could not remove.  When I removed that IC, solder had crept underneath also so luckily I replaced it.  Used a finer tip in the iron second go.
Also noticed a slight swollen 470uf 25V cap on the board (marked).  Removed it and it had failed (180uf).  Possibly this contributed to the MOSFET failure if it was supplying its regulated power.
Scavenged a replacement from a scrapped power supply.
Origin Energy can start paying me again !
Thanks for the support!
I will add this to the previous Miele induction cooker repair (power MOSFETs, diodes and capacitor), and call it a good 12 month!
😀