Help please

[Seyyah55]

Hello everyone,
I am repairing the endolight x300 endoscopy light source device.
 There is a component on the power board with do-213ab sheath black color and only blue band on it. There are two and they are connected in series. I think it is a diode or zener. as seen in the photo. how can I find out what this component is and its value?
 Thanks..

[Grandchuck]

Looks like a MELF rectifier.  Have you tested it as a diode?

[IanJ]

Single blue band = zener diode
Single black band = general purpose diode
Single green band = Schottky diode
Single yellow band = switching diode

See:
https://www.repaircompanion.com/diode_color_markings

Ian.

[boz]

Single blue band = zener diode
Single black band = general purpose diode
Single green band = Schottky diode
Single yellow band = switching diode

See:
https://www.repaircompanion.com/diode_color_markings

Ian.

In all my 40 years in the game I never knew that 

[wraper]

The question is what for? If they measure like diodes (in one direction), they're likely fine regardless of what they actually are. Then you could measure voltage on them in working circuit. I rarely bother wasting time on figuring out model/value of random components unlike many inexperienced repairers here. I only do so I suspect there is something wrong in particular part of circuit. If they seem fine on a first glance, I'd be looking somewhere else for issues and return back if did not find any suspects instead of trying figure out a model of every single component.

[Martin72]

There are two and they are connected in series. I think it is a diode or zener. as seen in the photo. how can I find out what this component is and its value?

Component tracer...
Alternative:
The ring usually symbolizes the cathode.
Connect a series resistor to a power supply unit, plus to the cathode and minus to the anode and slowly increase the voltage (0V..40V)
Measure the voltage directly at the component.
If it breaks down at some point and remains defined, it is a Zener diode.

[Seyyah55]

Yes, I did a test. one of them shows a short circuit in both directions. the other one shows a value like 0.1V and 125Ohm in both directions.

[wraper]

Yes, I did a test. one of them shows a short circuit in both directions. the other one shows a value like 0.1V and 125Ohm in both directions.

As I understand both test like this out of circuit? As they most likely zeners, you will not be able to figure out voltage rating unless there is another one somewhere that works. If no working part is present, the only thing you can do is reverse engineer the circuit to guesstimate actual rating.

[Seyyah55]

Yes, you're right, there is no working part and I couldn't determine the value either. I think reverse engineering is the most logical solution.

[Hamelec]

Single blue band = zener diode
Single black band = general purpose diode
Single green band = Schottky diode
Single yellow band = switching diode

See:
https://www.repaircompanion.com/diode_color_markings

Ian.

In all my 40 years in the game I never knew that 

yep, never heard..  but note the last line     : "RepairCompanion Beta 0.61. Built in Collaboration with Artificial Intelligence. Copyright © RepairCompanion 2023"