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Entry  Thu Oct 13 23:58:38 2011, Koji, Update, LSC, fixing REFL165  PA131612.jpgPA131618.jpg
    Reply  Sat Oct 15 16:42:08 2011, Koji, Update, LSC, Testing REFL165  REFL165_test_111014_KA.pdfREFL165_transimpedance2.pdf
       Reply  Sat Oct 15 17:06:20 2011, Koji, Update, LSC, Installation REFL165  
       Reply  Sun Oct 16 02:30:00 2011, rana, Update, Electronics, Testing REFL165  
    Reply  Wed Mar 1 17:25:28 2017, Steve, Update, LSC, MCREFL condition pictures IMG_3646.JPGmcRefl_1.jpgmcRefl_3.jpgmcRefl_5.jpg
       Reply  Fri Mar 17 14:49:09 2017, gautam, Update, LSC, MCREFL condition pictures IMG_7219.JPGMCREFL_X.pdfMCREFL_Y.pdf
Message ID: 5664     Entry time: Thu Oct 13 23:58:38 2011     Reply to this: 5671   12860
Author: Koji 
Type: Update 
Category: LSC 
Subject: fixing REFL165  

I already have reported in this entry that REFL165 shows too high DC output which does not depend on the light level on the diode.
Today I removed REFL165 from the table and inspected it.

The diode has been burnt as shown in the first picture (left).
The window is smoked, and the photo sensitive surface has been removed from its base. It moves in the can.

The burnt diode was replaced to the new one.
The new one shows ~30% better capacitance of ~50pF
and I had to increase the inductance from 14nH (i.e. 15nH//220nH) to 18nH.
After some struggles to increase/decrease the stray inductance by moving the SMD capacitors a little, the resonance is reasonably tuned to 166MHz.

The comprehensive test will be performed shortly.

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