[Test-Equipment] Tek 7613 with 7L13 plug-in help

[Greg Miller, K2GTM]

Hi all,

Does anyone have any experience repairing the 7L13 Spectrum Analyzer 
plug-in from Tektronix?  I am working on one with a 7613 storage scope.  
It seems the scope's power supply is dragged down by the plug-in when 
it's installed (the 7613 power lamp is dim).  I've run the scope without 
the plug-in and it seems much happier (the power light is full 
brilliance, etc.) 

This is what happens when the plug-in is installed:
-  No reference level or center frequency LED readout on the plug-in.
-  There is a dot about one major division up from the bottom of the 
screen which can be slightly controlled by the vertical position control 
on the plug-in.
-  There is no horizontal sweep.
-  There is no on-screen readout.

Instead of wasting time digging, if anyone has any suggestions or knows 
of any common problems with the 7L13 I would GREATLY appreciate it!  I 
have the manuals for both the scope and plug-in.

Thanks!
- Greg