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Entry  Wed Dec 4 19:00:37 2019, Noisemon board modified, DailyProgress, , Noisemon board modifications 
    Reply  Thu Dec 5 12:37:58 2019, Noisemon board modified, DailyProgress, , Noisemon board modifications ModificationComparison.pdf
       Reply  Thu Dec 5 20:42:55 2019, Duo, DailyProgress, Electronics, Noisemon board modifications NoDrive.pdf10HzSine.pdfTF.pdf
Message ID: 1836     Entry time: Thu Dec 5 12:37:58 2019     In reply to: 1835     Reply to this: 1837
Author: Noisemon board modified 
Type: DailyProgress 
Category:  
Subject: Noisemon board modifications 

The modification is successful. The attachment shows the result after the board runs for 12 hours. We modified channel 1 and 2 so we see FM0 and FM1 channels are still decent. We only split C2 but not R2 for channel 3 and 4 so FM2 and FM3 are bad.

Quote:

According to previous post 1834, we think the noisemon problem is very likely caused by C2 charging. Hence we did the following modifications on a noisemon board:

1. Split R2 into two 400 Ohm resistors, with grounding between them.

2. Split C2 into two 3.3uF capacitors, with grounding between them.

We hope these modifications will provide a path for the bias current to go to ground, instead of charging up C2.

 

Attachment 1: ModificationComparison.pdf  35 kB  | Hide | Hide all
ModificationComparison.pdf
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