[Test-Equipment] TEK 494AP Gain problems

[Fuqua, Bill L]

 Looks like I am narrowing it down.
My 110 MHz output is constant in amplitude but not the 10 MHz.
Must be in the variable resolution block. 
Bill 
________________________________________
From: test-equipment-bounces at mailman.qth.net [test-equipment-bounces at mailman.qth.net] on behalf of Fuqua, Bill L [wlfuqu00 at uky.edu]
Sent: Wednesday, December 11, 2013 9:04 PM
To: Test-Equipment at mailman.qth.net
Subject: [Test-Equipment] TEK 494AP Gain problems

  I have a Tektronix 494AP who's bain changes as it warms up as much as 8db. It will finally, after a long period of time, stabilize where it should be. However, it is not related to a display board problem or filters. I have looked at the 10MHz output and the IF output changes the same amount. It is the same regardless of resolution bandwidth.
  So it has to be something between the RF input and the 10MHz output. Has anyone encountered this problem before and found the problem?
I noticed some notes regarding the problems on the display board but this is not the cause since the 10MHz IF is before this board.
  Thanks
73
Bill wa4lav
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