Shutdown drytek2 SNF 2008-12-06 17:00:33: Shutting down for RF checks ...

shott at snf.stanford.edu shott at snf.stanford.edu
Mon Dec 8 08:16:48 PST 2008


The drytek2 supply is back and operational at about the level that is was before I shut it down to look at the oscillator and front end.
In other words, after all of my fussing, I fear that I didn't really fix anything ..... and, in fact at one point feared that I had broken the equipment man's Hippocratic Oath "First, do no harm ...".  
I still think that the problem is in the front end ... but I can't quite pinpoint the cause.  But, the troubling things that I observe are:
1. The oscillator section puts out something like 400 mW of power (90 mA RMS current) into a 50 ohm load .... when I think taht it should put out about 1W or more.  Note: 90 mA RMS = 250 mA P-P.  Across a 50ohm load that is about 12.5 V P-P.
Also, under load, the 40 V supply (which sends most of its powere to the following amplifier stage starts at about 45V under no load .... and drops to about 34V DC and 2 volts of ripple under full power draw  .... that seems excessive too.
The actual second stage is, I think functioning properly ... with in imput drive of about 100 mA RMS, it is putting out about 500 mA RMS .... which is a power gain of 25 which is about what it should be.
Sorry for the windy clear of this shutdown .... I guess I need to add more words to make up for my failure to resolve the problem.  Sigh ....
John




More information about the drytek2-pcs mailing list