Hello,
I have got a broken smd component, but I can't find out what it is and what the specs are.
It come's from a Vaiilant 370 thermostat.
On the package it has this info: EF 41 B and some logo. In another thermostat there is the same component, but with the info: EF 06 and the same logo on it.

Can anybody help me find out what it is, so I can replace it.

 

It's a diode of some kind, but I think it could be a schottky, a normal silicon diode, a zener.
Maybe a photo of the board it was removed from would give more clues.

 

I mada a photo from the board and a schematic, so far I can.
The component is making a short, so the thermostat didn't boot anymore. I removed it and now it boots. But it doesn't communicate. E-bus.
I guess it has something to do with filtering the communication signal out.

 

There is a good database of SM component markings at
www.marsport.org.uk/smd/mainframe.htm

and they indicate that it is an MMSZ4715 36V SOD123 zener diode.

The data sheet is here,
http://www.onsemi.com/pub_link/Collateral/MMSZ4678T1-D.PDF

The logo looks like the onsemi one.

Hope that helps.

Nik

 

I started trying out some in hole components.
The thermostat works when I put an zener diode in place. Info on the zener is 5v1 83c.
Can someone confirm that this is a good replacement?

 

I started trying out some in hole components.
The thermostat works when I put an zener diode in place. Info on the zener is 5v1 83c.
Can someone confirm that this is a good replacement?

I forgot to mention that the powersupply of the thermostat is 24V dc.
But it can work from 9 to 24V dc