From shott at stanford.edu  Thu Feb 26 12:53:48 2009
From: shott at stanford.edu (John Shott)
Date: Thu, 26 Feb 2009 12:53:48 -0800
Subject: Replacement power supply ....
Message-ID: <49A7015C.8070409@stanford.edu>

Drytek2 Community:

We are in the process of replacing the problematic Drytek RF power 
supply with a more supportable ENI supply.  At the moment, this supply 
is sitting adjacent to the Drytek on the floor but we hope to have it 
more or less in place of the normal power supply by the end of this 
afternoon.

There are two or three minor changes in the way that the system will 
operate:

1. When the instructions say to turn on and off the circuit breaker on 
the Drytek RF supply .... you should turn on and off the circuit breaker 
on the ENI supply.

2. The LED readout of forward and reverse RF power will now read zero 
(unless it is reporting an error condition).  There is now a little 
remote readout box that has both forward and reverse readouts and, 
unlike the old Drytek, this will now read both forward and reverse power 
with a resolution of 1 W instead of 25 W.

3. If reverse RF power exceeds about 50 W, you will see a yellow LED 
light up.  If this happens, the forward power will also be reduced to 
protect the supply.  As a result, it is important that you run a dummy 
run in advance of running real wafers to make sure that you are very 
close to the match point.

Note: although it will soon be "buttoned up" there is currently an open 
interface box sitting on top of the ENI supply.  While you should not 
disturb this, there are no lethal voltages in that box .... nothing more 
than 15 VDC, in fact.

Note: we've compared the readout on the analog power meter with the Bird 
meter and with the digital readout.  They all agree within a few watts, 
so I believe that previous readings of 500 W (which, of course, have not 
been achievable for some time ....) on the Drytek readout should closely 
match the power observed on the ENI when it reads 500 W.

Let me know if you have any problems, questions, or concerns.

Thanks,

John