Scan Pause and Bright Zipper or Band in Images caused by TWIN GRAD SWITCH BOX.

MRIQ Gradient Switch Related Errors Pause Scans and Resultant Images Contain a Bright Zipper or Band Artifact Scans suddenly pause then the system lights the Start Scan button for the customer to restart the scan. If this is done the images show a big zipper-like artifact that looks like a partially collapsed gradient. This is seen on many different scans not unique to one PSD. The problem may occur several times a day, and it may skip some days altogether, then reappear again another day. See the Attachment for copies of the errors and an example image. Scans suddenly pause then the system lights the Start Scan button for the customer to restart the scan. If this is done the images show a big zipper-like artifact that looks like a partially collapsed gradient. This is seen on many different scans not unique to one PSD. The problem may occur several times a day, and it may skip some days altogether, then reappear again another day. See the Attachment for copies of the errors and an example image. This system is a 1.5T Excite II TwinSpeed running 11.0 M4 software with Service Pack 1 loaded. Scans suddenly pause then the system lights the Start Scan button for the customer to restart the scan. If this is done the images show a big zipper-like artifact that looks like a partially collapsed gradient. This is seen on many different scans not unique to one PSD. The problem may occur several times a day, and it may skip some days altogether, then reappear again another day. There are several error messages logged which seem to point to the GSC (Gradient Switch Controller). Below are copied the error messages logged at the time of one of these scan pauses and a typical image. The fix was to replace the "TWIN GRAD SWITCH BOX" part number 2253466 in the TAC cabinet. This module contains the GSC. Reference SPR # MRIhc16978. Mon Sep 25 10:12:27 2006 2244648 WHMR1 NSP SCP:GP 668 The GSC reported a problem with the Whole switch on the Y axis. If the problem persists, please call a service engineer. Mon Sep 25 10:12:28 2006 2244655 WHMR1 NSP SCP:GP 1307 The GP received an ALARM message from the GSC. Subsequent error messages should reveal the cause of the alarm. Mon Sep 25 10:12:35 2006 2244598 WHMR1 NSP SCP:GP 1069 The gradient system on the Y axis recovered successfully. There are no faults at the present time. Mon Sep 25 10:12:35 2006 2244598 WHMR1 NSP SCP:GP 1069 The gradient system on the Z axis recovered successfully. There are no faults at the present time. Mon Sep 25 10:12:35 2006 2244598 2 WHMR1 NSP SCP:GP 1069 The gradient system on the X axis recovered successfully. There are no faults at the present time. Author Paul Lyman SME John Schumacher