ST MFU C104 diode info.

[Kendog]

Help please!

I'm unable to find any info on this diode from an old Siemens Siplus 24RCL PLC controller.  Pictures attached.

The diode shorted closed.  I'm assuming because, someone hooked up the supply backwards!

The only marks I've found are "ST MFU C104" on the top and "MRC" on the bottom.

Dimensions closely resemble the ST SM30T28AY found on the data sheet at this site: https://www.st.com/content/ccc/resource/technical/document/datasheet/90/0c/ab/be/9d/d1/49/bd/DM00035136.pdf/files/DM00035136.pdf/jcr:content/translations/en.DM00035136.pdf 

 I would greatly appreciate any help/ info on this.  So, I can find replacements.

Thank you,

Kendog

 

[Peter BENSCH]

Welcome @Kendog, to the community!

The marking MFU stands for a customer-specific TVS that was discontinued a long time ago and whose data is only available to the customer at the time.

A possible replacement (without 100% guarantee) could be the SM15T39A.

Hope that helps?

Good luck!
/Peter

[Kendog]

Thank you for your response!  I really appreciate it.

Yeah. This Siemens I/O controller is from our Skoda light rail vehicles, manufactured over 20 years ago!  It controls the opening and closing of the passenger doors.  

I'll order some of these to test.

Thanks again Peter!