[dsg-svt] [New Logentry] HTSB4 Bad

[beng at jlab.org]

Logentry Text:
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Yuri reported that none of the humidity sensors were working and also inquired about the length of the HTSB pigtail lengths; namely HTSB4 (serial # 3) has one cable out of the bundle (of 4 cables) that is noticeably shorter than the others (it wasn't like this prior to R3 removal).

Since all the sensor boards are powered by a separate 5 V supply that's where I started.

- I first found that there was no voltage on the other side of the circuit breaker so that was replaced with a spare from Mindy (still no sensors worked due to no voltage).
- I got the same model power supply, also from Mindy, and replaced it (still no sensors worked due to no voltage).
- Measuring the resistance between the 5 V barrier blocks and ground was less than an ohm.
- Disconnecting HTSB4 at the pigtail allowed all the other remaining sensors to work.

So that board is the one that is causing the dead short.

At some point we need to see if we can isolate the short between H1 and H2 on that board, in the meantime the board will remain disconnected.

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This is a plain text email for clients that cannot display HTML.  The full logentry can be found online at https://logbooks.jlab.org/entry/3433730
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