Changing Controller Hardware

 A full set of spare controllers, power supplies and cables can be found in the WHT detector lab.

Suspected hardware faults should be addressed by COMPLETE CHANGE of controller.

There should normally not be any need to swap controller boards during the night. Doing so is likely to cause more problems than it solves. When changing controller hardware it is important that the observing system be shut down, the controller is powered off (but with the mains plug in-place) the cryostat disconnected from the controller and the CCD connector dust cap replaced.

When disconnecting the CCD connector make sure you are earthed to the telescope structure with an anti-static bracelet.

Spare Controllers : there are four types of SDSU controllers:

1. TEK/SITe controllers, fully interchangeable.
2. EEV/MITMarconi controllers, fully interchangeable. Used for any single chip EEV or MIT camera.
3. EEV/MIT MOSAIC controllers, interchangeable. Used for the MIT mosaic and the 2EEV cameras.
4. INGRID controller. Dedicated.

Anti-static boxes : these provide anti-static protection for the CCDs. If a controller should need replacing then this box will have to be disconnected from the controller at the controller end not from the cryostat end by undoing the wing-nut holding the box in place. It should then be carefully re-connected to the replacement controller. Anti-static precautions must be taken.

Spare Power Supplies

All the CCD cameras use the same power supplies, however, the Aux.port detector uses a power supply rack with a slightly modified shutter card. If you suspect a power supply failure at the aux.port you will need to remove the shutter card from the old PSU rack and fit it to the replacement.

INGRID uses a different type of power supply that has a rectangular rather than circular connector. There is one spare INGRID PSU.

Spare Cables

There are also spare CCD to SDSU cables. These have a circular military connector at one end and a mixed D connector at the other (shortly to be replaced with a static protection module). They are all labelled clearly. All single chip EEV cameras use the same cable. The two SITe cameras use different CCD cables which are not interchangeable. The TEK CCD cable comes in two types, one for those cameras that use either output amplifier A or B, another for those that use C and D. Currently all cameras use either amp A or B.

Test Boxes

There is a shutter test box kept in the detector lab that can be used to diagnose shutter or shutter cable faults. It can be attached to the shutter interface card (mounted in the PSU rack).