DK MSD200 plasma meter diodes problem

[mata_haze]

Hello everybody,
the above meter just packed up for the second time, but now I am pretty sure where the problem is a couple of diodes in the PSU section of the plasma are completely cooked and I will try to replace them before I send it back to Denmark to get fixed.

I am not familiar with SMD packaging and I am not sure which diodes they are, can anybody pin point me to the right direction?
the diodes in question are marked D330 and D331 (picture is taken from a working unit!)
one has a "3" on it the other a "7" ...
thank you,
Mattia.

 

[mata_haze]

ok I checked the non working unit better and a couple of diodes in the place of the 2 marked are "37G" and the others are colour coded...here is a pic

am I correct thinking that it could be a 1n4937G diode in a do-41 package?
what about the colored ones?

 

[sodderboy]

Looks like two different versions of board, where they were already starting to use the 37's in part of the circuit.

Do you have the schematic?  It is important to ID why they are frying.  You could put a larger diode or rig a heatsink over them, but if there is something else causing them to heat you want to address it directly.

I work on components like that with a tweezer soldering iron using good liquid flux and a notched BBQ skewer to hold the component.
Mike

 

[mata_haze]

Looks like two different versions of board, where they were already starting to use the 37's in part of the circuit.

Do you have the schematic?  It is important to ID why they are frying.  You could put a larger diode or rig a heatsink over them, but if there is something else causing them to heat you want to address it directly.

I work on components like that with a tweezer soldering iron using good liquid flux and a notched BBQ skewer to hold the component.
Mike

HI Mike,
thank you for the suggestions, I have managed to get old of a DK tech who told me components are RGL34J Diodes and BYD77G but no schematics ....
I guess I have to replace the parts and then see what happens...

Mattia.