Many thanks to the many people who responded with very useful troubleshooting advice for my problem with the INOVA 28 Channel shim system. After opening it up and replacing 1 dead and 1 dying fan in the unit, I checked all of the power supply voltages. The 5 V supply for the CPU was only 4.6 volts, and the 5V OK and CPU OK status lights on the power supply board were off. It appears that the 5V regulator on this board is likely bad (cooked when the fan failed?), as the voltage going into the regulator seems OK. The schematic I have lists this as a LT1003CK three terminal 5V 5A regulator, but the actual unit is a bit different, with an LM338K adjustable regulator, and they are not directly interchangeable. My schematics would therefore seem a bit out of date. Would anyone have a schematic for this board with the LM 338K regulator? The board part number is 992156-02B, and the schematic should be number 87-195-821 G.
Thanks Again!
Kirk
Kirk Marat, Ph. D. NMR Facility Manager
Dept. of Chemistry, University of Manitoba
Winnipeg, Manitoba
R3T 2N2, Canada
Ph: (204) 474-6259 FAX: (204) 474-7608
Received on Thu Nov 01 2012 - 11:19:14 MST