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Fri Sep 8 00:32:20 2017, awade, Summary, FSS, Schematic block diagram FSS loops
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Thu Sep 14 21:54:26 2017, awade, Summary, FSS, FSS modifications: series resistance (R1 and R2) to monitor points on servo board D040105
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Mon Sep 18 00:46:08 2017, rana, Summary, FSS, FSS modifications: series resistance (R1 and R2) to monitor points on servo board D040105
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Mon Sep 18 13:34:13 2017, awade, Summary, FSS, FSS modifications: series resistance (R1 and R2) to monitor points on servo board D040105
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Tue Oct 10 00:49:34 2017, awade, Craig, Summary, FSS, Replacing U3 on north path (2010:005) FSS servo board.  
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Mon Oct 2 12:30:15 2017, rana, Summary, FSS, LISO & mfil
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Wed Oct 18 11:19:15 2017, awade, Summary, FSS, Comparing south TF to LISO model  
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Wed Oct 18 15:42:59 2017, awade, Summary, FSS, Comparing south TF to LISO model
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Mon Oct 23 15:05:44 2017, awade, Summary, FSS, Comparing south TF to LISO model  
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Wed Oct 25 23:15:51 2017, awade, Craig, Summary, FSS, Comparing south and north TF to LISO model  
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Message ID: 1925
Entry time: Mon Sep 18 00:46:08 2017
In reply to: 1918
Reply to this: 1926
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Author: |
rana |
Type: |
Summary |
Category: |
FSS |
Subject: |
FSS modifications: series resistance (R1 and R2) to monitor points on servo board D040105 |
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Ugh - no, plugging in the network analyzer should not change the gain of the servo. This seems quite bad. Lets discuss and fix.
In addition to Frank's fixes, Tara also did some patches with advice from Koji. We should make sure you have the right version of schematic.
Quote: |
I switched the R1 and R2 50 Ω (on D040105-C) out for something higher again, this time 470 Ω. I could only find 470 Ω in the EE workshop (which is close enough to the design value of 453 Ω).
Now plugging 50 Ω loads into the OUT1 and OUT1 common monitor points lowers the common path OLG by 7.8 dB and 10.8 dB respectively. This still seems like a big change to me but I'm not sure if I should increase series resistance any higher.
Let me know if this is dumb and I'll change it back.
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In any case, once you have R1 and R2 at 450-500 Ohms, the circuit should not change behavior just by adding 50 Ohms onto EXC or OUT2. You should be able to do the TF without OUT1. |