[QuadList] Ampex VR1200 power supply question

[Chill315 at aol.com]

Lee
 
There are a couple of things to check.  
 
First are the air filters clean below the power supplies?  Very  important 
for cooling.
 
Second, are all the fans turning?  Pull the filters and use a small  mirror 
to check.  These have a tendency to stop or get so sluggish.   Or you can 
pull all three supplies and see if they are turning.  The first  method is 
easier other than for us old folks having to get down on the  floor.
 
Third, are the shunt resistors strapped correctly.  If you have added  or 
removed any accessories, this can cause a problem.  So if you have  
disconnected the Editor, Erase amplifier, or other items, follow the procedure  in 
the manual.
 
Lastly, check the capacitors in the supply, signal system, and Intersync to 
 see if you have an issue there.  There might be a load on the +12 volt 
side  that is drawing more current.
 
Chris Hill
WA8IGN
 
 
 
 
In a message dated 6/28/2011 3:05:20 P.M. Eastern Daylight Time,  
lasvegastvengineer at yahoo.com writes:

I have been working on a VR1200 and noticed that the +12V power  supply 
transistors run noticeably hotter than the -12, 24 and 135  transistors. 
 
Is this normal for a 1200? 
 
Thanks 
Lee  


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