I acquired this Ferguson TX90 TV/Monitor some time ago and it's been working perfectly, until a day or two ago. When switched on, there is a loud HUM which cannot be turned down with the volume control. There is also a large dark band (HUM BAR) rolling down the screen. Checking the suppliy rais for ripples was not the answer. Upon checking the output from the 12V regulator, revealed it was no longer regulating, but giving out 16V. Replacement restored normal operation.

The service manual for this was not available from any of the normal sources, but the chassis was written up in the September 1992 editon of TELEVISION magazine by NICK BEER. THis helped a lot. I also found more information about it in the 1986/87 edition of RADIO & TELEVISION SERVICING. I scanned in the pages and printed them out which also helped. You can download the file here: Download 20PC1150-020