Anritsu MS2651B SMD component identification

[jkf1000]

I am working through the repairs of my MS2651B spectrum analyzer, I have now got the display working 100% and fitted a new front end mixer which now displays signals on the screen but I am showing several fails during self calibration. In log mode (default) the signal line is sat at just under the top line of the screen which indicates a failed level test. In linear mode (not ideal) the noise floor drops to near the bottom of the screen and signals are displayed correctly and the analyzer is usable.

One of the many self cal fails is the 10db IF amp and many of the other fails follow on from the IF stage so my best guess is that the IF amp is affecting the expected levels further down the chain including the LOG detector. My problem is that many of the components seem to be marked with in house codes and many hours of searching have not turned up any usable part numbers. From what I can work out from the component layouts and matching it to the block diagram, the suspect component is marked as RF62, but I just cannot identify what the actual part number is. I have included a few pictures of the board to try and help with the identification.

Any help or suggestions greatly appreciated.. Karl

[BFX]

May be 2SC3357 NPN HF transistor. 

[jkf1000]

Thankyou for your suggestion, I Just looked at the datasheets for the 2sc3357 you suggest and its certainly seem a likely replacement. If anything it appears to be rather over specified having an FT of 6.5Ghz and a dissipation of 1.2watt. The IF stage is only 10.7Mhz but still within the operational range of your suggested device.. Karl