Help me indentify components

[CrazyTiger]

Hi,

I got a Anritsu 331D which is failing self-test (intergrator fail). I see no RF level or sweep happening. Taking things apart i found the input section is defective, likely fried from high rf power injection.



The amplifer, what I believe is NBB400 is dead, this can be easily replaced, but I am stuck with two component that have turned open, and sadly no marking on them. My only option is now is to compare it with another board which i dont have or by some miracle someone have the circuit diagram. Can someone help me out here.

My Guess (i might be wrong:)
Blue chip, is a 50 ohm resistor.
The SOT23 marking (RS2) maybe a detector diode, it makes sense, since the output of amplifier is fed into test port, and there is not other circuitary to monitor the output power
But the black chip, i have no idea what it could be

[gamalot]

The one in SOT23 package with the RS2 mark may be SMP1340-005LF. The one in QFN package with the S218 mark may be AS218-321LF. They all come from the same company - Skyworks.

https://datasheet.octopart.com/SMP1340-040LF-Skyworks-Solutions-datasheet-38206149.pdf

https://www.richardsonrfpd.com/docs/rfpd/AS218-321.pdf

[CrazyTiger]

Replaced the Qorvo NBB400 amplier and tried a 50 ohm resistor on the open resistor (blue 0603 chip resistor).I  also removed the other unknown chip. Unit passed selftest and i see its measuring swr correctly.  .
Its a good progress
Still i am wondering the value of the other chip would be.