The Power Supply (PS) of a DIRC Wiener CRate (WCR) is located on the back of the crate. It is cooled by the three (unfortunately non-bypassable through epics, design feature) fans which are located on the back of the fan tray.
The first failure of a DIRC PS occured on Tuesday 09/27/05 (owl shift) after almost 6 years of running w/o problem. We lost connection with the WCR in sector #9 (white epics channels) and couldn't communicate again with it. Therefore, an access with the opening of the backward east door was requested which was unfortunately delayed by one day for lack of manpower. While we were waiting for the acess, we investigated the problem and a power supply failure was among the 4 favoured hypothesis:
Although the change of a PS is not technically difficult, one should be very cautious when doing this for two main reasons:
To remove the PS from the WCR, one just needs to unscrew the two black screws located at the top-left and at the bottom-left -- see all 4 pictures for details. One should also be cautious not to damage the connections which are visible on the crate below the PS. They are normally protected but one needs to be smooth when moving carefully the PS in and out.
Before doing this, it is worth checking the PS fuse one can access by opening the black disk located close to the power cable connection. The 20 Amp fuse can be tested using a meter and Ray Rodriguez is keeping new spares in one of his cabinets.
Web Page created by Nicolas Arnaud