Subject: TOHM (modified) power supplies
Ioanni.Katsavounidis@lngs.infn.it
Date: Thu Sep 16 1999 - 11:24:30 EDT
Ciao a tutti,
Here is the situation regarding the TOHM CAMAC power supplies:
- Massimo modified the negative voltages regulator card on the power
supply that is currently on SM4 Attico TOHMs (uvax:2, br:2, cr:4)
and it is working OK now. I remind you that this crate failed yesterday
when we tried to restart full MACRO after Wed. maintenance/calibration.
Due to failure of the spare power supplies, also, we had to exlclude
uVAX#2 from ACQ till this morning.
- I fixed the power supply that failed yesterday by changing the 2N3771
transistor on the -12V line (that was the line that failed yesterday).
This is the power supply that is now on "Bbuono's shelf" with no cover
- I also fixed the power supply that Massimo had removed at some point
from the detector due to a higher +12V indication. This was due to
a broken 2N3771 transistor on the +12V line (Q9) that was measuring
0.5V diode drop between Collector and Emmiter. This power supply is
on the calibration uVAX chain (br:2, cr:1) and should be considered
as a good working spare.
- Note that all 3 power supplies in question are 1500 Kinetic Systems
models. In testing them, a load of ~3.5A on the -12V and ~5.5A on the
+12V lines was used - they passed OK.
- In addition, there is one more 1502 Kinetic Systems model spare TOHM
CAMAC power supply on "Bbuono's shelf".
A presto,
Ioannis
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