Uni-T UT61D diode id?

[frodef]

My somewhat trusty UT61D dmm has become rather unreliable (ohm-mode spurious beeping and/or no contact, "works again" if I turn it on and off, etc). Looking at the PCB I see a cracked diode, one of a pair, on the front side near the probe plugs. I want to replace the diode(s), but with what? The PCB silkscreen is labeled D6, and both SMDs are labeled "65" above "6i" in relatively big, clear lettering. Somehow I'm unable to identify either the diode itself of find a schematic. 

Any ideas what to replace one or both of these diodes with?

The diode pair is clearly visible here, center stage between the circular multi-switch and banana receptacles:

[wasedadoc]

Can you post a close-up photo of the diodes so we can see the markings?

Those are probably protection diodes.  If so, removing them should eliminate any spurious operation*.  If it does not you probably still have a problem slsewhere.

* Not recommended to continue using the meter until faulty diodes are replaced.

[gamalot]

https://pdf1.alldatasheet.com/datasheet-pdf/view/394658/EIC/STU656I.html

[frodef]

Thanks for the info. Here's a photo:

[frodef]

Thank you!

[frodef]

Not so easily sourced, that STU656i ...   

[fzabkar]

I would think that any 6V TVS diode would be a suitable replacement.

[floobydust]

STU656I is a 600W SMB TVS diode, 6.45-7.14V at 10mA. Oddball manufacturer. Other 61E's schematic use two 1N5342B (6V8 5W) in series protecting the low current shunt.
For a substitute I would consider SMBJ5.0A or SMBJ6.0A
If your diode cracked open circuit, it might have allowed the overload to get further and damage a shunt or other parts.

[oskimac]

My ut61b started acting strangely in the ohms reading, never stabilizing. So I opened it and the first thing I found was a very strong burning smell. Then I found the same two diodes broken. I just removed them and everything was fine (except the ESD and surge protection!). I was reading amps and forgot the settings and started measuring volts...that was the problem.