No there is nothing on it? sitting there nothing on the output trying to output anything in the ohms range ell zippo passes self calibration and diagnostics and ohms zero. Also same error in 2 wire comp and 4 wire comp. Reset all the boards already and blew the dust out of it.
I was trying to calibrate either a Fluke 85 or 77 on Friday and this error came up.
In the 5520A Service Manual dated April 1999, Rev 1 12/02; section 4 page 4-11 there is a listing for error code 1504 that states: Input V or A limit exceeded. Either the Meter hooked up to it has more that the compliance voltage or something was blown in the Ohms input section where normal compliance voltage is seen as too much. Good luck with that. If you dont' have a copy of the Service Manual send me a private message and I'll forward one to you.
John Treekiller