Smd identification help

sagor

Joined Mar 10, 2019
490
Top one is likely a Zener diode. Many "WN" devices are, and the Z81 on the board solkscreen indicates Zener diode as well. However, cannot find any reference to Zener voltage.
Bottom is also labelled Z82, likely a zener as well, and likely a different voltage (a guess)

EDIT: found one reference that says WN is a 22V Zener, WY is a 2.0V zener. Strange values...
http://www.s-manuals.com/pdf/datasheet/b/z/bzt52c2v0-bzt52c51_r37-2_diodes.pdf
D5 and EN may be the date codes
 

sagor

Joined Mar 10, 2019
490
@neet, Lets get back to basic questions. Why are you looking at these diodes in the first place? They do not look blown. While they are in circuit, no multi-meter reading will be significant, you can't tell if they are good or not with a simple meter diode test. With power on, you can measure the voltage across the Zener, see what the voltages are. They should be fairly constant. Then, what are the rest of the reasons why you are looking at this section of the board, what is not working?
 

bob2

Joined Jun 15, 2019
213
While they are in circuit, no multi-meter reading will be significant, you can't tell if they are good or not with a simple meter diode test.
A digital multimeter in diode test mode should be able to check them in-circuit normally. I even did comparison tests with the LCR Pro1 Plus tweezers, no difference.
 
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