Re: Fried Ch0 S11 port #hardware


Reinier Gerritsen
 

There is a 10 uF series capacitor at both inputs, so DC is blocked. But when connecting your device under test, the DC transient may still kill your analyzer. The capacitor charge current path is through the internal protection diodes in the input switch (port 1). Port 2 is much better protected for DC transients since it has 14 dB of resistive attenuation.
I had a bunch of broken units, they came back to life when I replaced the input switch U551. It is a MXD8641 which is sold on Aliexpress, 50 pcs for a few dollar.
How much DC did you apply?

Reinier


Op 29-11-2020 om 23:54 schreef GM7TFP:

Hi all

I toasted the S11 port of my SAA2 v2.2 the other day with an un-scheduled DC input event. Bought a new one to replace it already (and a few Nooelec DC blocks!..ahh, hindsight), but I'm wondering if I can put the brick to any useful RF measurement purpose still with just S21 operational? If not, I'll salvage the screen, battery and SMA connectors for other use. Any suggestions?

db


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