From xzhuan1 at snf.stanford.edu Wed Dec 3 22:19:02 2008 From: xzhuan1 at snf.stanford.edu (xzhuan1 at snf.stanford.edu) Date: Wed, 3 Dec 2008 22:19:02 -0800 Subject: Problem drytek2 SNF 2008-12-03 22:19:00: high reflection power and no forward power Message-ID: please fix this problem, thanks!!! From eenriquez at snf.stanford.edu Thu Dec 4 08:32:06 2008 From: eenriquez at snf.stanford.edu (eenriquez at snf.stanford.edu) Date: Thu, 4 Dec 2008 08:32:06 -0800 Subject: Comment drytek2 SNF 2008-12-04 08:32:05: Update high reflected power Message-ID: Best tune point for O2 recipes is with the Coil near the fully counter-clockwise position and the Cap near the fully clockwise position. Ran with O2 at 500 W Forward and 40W reflected for 4 minutes with no problems. Power dropped from 525 W to 500 W as it warmed up. From ahazeghi at snf.stanford.edu Fri Dec 5 14:39:00 2008 From: ahazeghi at snf.stanford.edu (ahazeghi at snf.stanford.edu) Date: Fri, 5 Dec 2008 14:39:00 -0800 Subject: Problem drytek2 SNF 2008-12-05 14:38:59: power inconsistent! Message-ID: power surged raised to 500W during run after being set to 400W for test run and running for 5 minutes. From lindaw at snf.stanford.edu Sat Dec 6 11:16:03 2008 From: lindaw at snf.stanford.edu (lindaw at snf.stanford.edu) Date: Sat, 6 Dec 2008 11:16:03 -0800 Subject: Comment drytek2 SNF 2008-12-06 11:16:03: Process 2 RF level knob has little if any effect Message-ID: The process 2 RF level knob has little to no effect on the actual process power. From shott at snf.stanford.edu Sat Dec 6 17:00:33 2008 From: shott at snf.stanford.edu (shott at snf.stanford.edu) Date: Sat, 6 Dec 2008 17:00:33 -0800 Subject: Shutdown drytek2 SNF 2008-12-06 17:00:33: Shutting down for RF checks ... Message-ID: A series of earlier measurements lead me to believe that the problems that keep the RF supply from putting out more than 400-500W lie in the front end (the oscillator, the first power stage, and the level control). I'd like to remove that briefly to bench test it. I have replacement components of the main transistors and capacitors that, I think, may be the most likely culprits. Hopefully I'll kno more later tonight, John From shott at snf.stanford.edu Sat Dec 6 21:54:14 2008 From: shott at snf.stanford.edu (shott at snf.stanford.edu) Date: Sat, 6 Dec 2008 21:54:14 -0800 Subject: Comment drytek2 SNF 2008-12-06 21:54:13: RF Problems .... Message-ID: I took out the oscillator and first gain-stage module this evening to see if I could identify why it seems to produce less power than it should. Unfortunately, I didn't get very far ... When I was studying the circuit, I realized that while it is similar to what we have in our schematics, it is not identical. For example, the feedback of the op amp shows that it should be a 1 MOhm resistor in parallel with a 1 uf capacitor. What is in our circuit is a 330 kohm resistor and no capacitor. When I reassembled things, however, I found that I had no RF power. It's likely that I've done something stupid .... but I can't figure it out at the moment. John From shott at snf.stanford.edu Mon Dec 8 08:16:48 2008 From: shott at snf.stanford.edu (shott at snf.stanford.edu) Date: Mon, 8 Dec 2008 08:16:48 -0800 Subject: Shutdown drytek2 SNF 2008-12-06 17:00:33: Shutting down for RF checks ... Message-ID: 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 From shott at snf.stanford.edu Sun Dec 14 08:24:13 2008 From: shott at snf.stanford.edu (shott at snf.stanford.edu) Date: Sun, 14 Dec 2008 08:24:13 -0800 Subject: Shutdown drytek2 SNF 2008-12-14 08:24:13: Shutting down for 2 hours for capacitor replacement ... Message-ID: From shott at snf.stanford.edu Sun Dec 14 08:53:36 2008 From: shott at snf.stanford.edu (shott at snf.stanford.edu) Date: Sun, 14 Dec 2008 08:53:36 -0800 Subject: Shutdown drytek2 SNF 2008-12-14 08:24:13: Shutting down for 2 hours for capacitor replacement ... Message-ID: Didn't do anything ... sidetracked by AG4100 water flow issues. John