Agilent E4400B Reverse Overload

[RCHRDM]

I am embarrassed to say that I accidentally sent RF into the signal generator at about 50 watts.  This is higher than the overload circuit can protect, I think.

The resistance across the output N-connector is zero or open.  It should be 50 Ohms, right (with power off)?

The signal generator still has a normal output as far as I can tell.

Does anyone know how to check this out and repair it?

I am looking through the service manual.

Richard

[nctnico]

But it is still working? If yes, consider yourself lucky and carry on.
I have a similar generator; AFAIK that has a relay inside which disconnects the output in case of reverse power (or overload).

[RCHRDM]

Thanks!  That's encouraging.

But shouldn't the RF output connector measure 50 Ohms (power off)?

Richard

[TheSteve]

I believe the output is AC coupled so you'll likely measure an open.

[RCHRDM]

SIGH OF RELIEF!

I tried testing the output with my oscilloscope with an output of 10 MHz and 10 mV.  Everything looks good!

I really appreciate your help.  That makes a bad evening turn into a good evening!

I will be more careful...

Ricahrd

[bob91343]

I recently did the same thing with my HP 8657B.  After resetting the reverse protector, the output was down about 20 dB although everything else worked.

I tracked it down to bad SPDT switch(es) in the frequency doubler.  Replaced those and now all is well again.  And learned a lesson on repairing SMT.

[RCHRDM]

Good work!  I have not worked on SMD stuff yet...

Richard