HP 8560E problem: need calibration or repair?

[tektech]

I have a HP 8560E that was working fine when it was put on the shelf a couple of years ago but when I dusted it off last week the signal amplitude from the cal out was showing down about 40dbm. I setup the tracking generator sweeping the full range and it was down across the range.I checked the cal out with my 8594E and it was off a couple of dbm and it was down the same 40dbm using the cal out of the 8594E into the 8560E. I did try the internal cal and it did not change anything,

 I've never worked on a SA, just used them so I don't know if calibration could fix this of if I should start digging through the circuits.

Any hints appreciated.

[tektech]

I found the sections in the service manual on testing the input attenuator and other front end modules so I'm going to step through those.