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Repair of a HP8753C searching for schematics

Question asked by maikhermanns on Feb 22, 2007
Latest reply on Aug 13, 2007 by JohnMiles
Hello altogether,

At first something about me, at the moment I´m still studying Microwave and RF engineering and going to write my diploma thesis in a couple of months.

I´m a (glad) owner of a HP8753C NWA and have problems with  the signal source. 
The output power is not levelled at all, in the lower frequency range (about 10MHz)  it decreases below ca. -30dBm and the PLL circuit fails. With increasing frequency the output power increases, too. (from -30dBm @ 25MHz to -4dBm @ 3GHz)
If the source is used in CW mode the power level menu(-10..+20dBm)has no influence on the output power.
I have the field service manual from the HP Website (500pages), but it contains no detailed schematics. I'm afraid that I have a problem with the source board and that I will need them to fix it. Is there any possibility to get these schematics? (I just want to get this unit running for my personal use (HAm..hobby) and Im afraid for the next years a collection of the circuit diagrams will be necessary..)

best regards