[Amps] Clipperton-L question

[Larry]

One day when I switched from CW to SSB mode on my Clipperton-L it blew the fuse with a good bang. The switch picks between a tap and one side of the power transformer secondary – tap being for CW. I forget but for SSB I think the power supply supplies 2500V(+/-) and somewhere around 2000V(+/-) for CW. Nothing obviously wrong  that I could see with just the covers off. I replaced the fuse and as soon as I turned the amp on it blew the fuse again. I searched the web to see if someone had seen this problem before and had written about it but I didn’t find anything.  I have had the amp since it was new (1984?) but I put a Harbach power supply board in it about 2 years ago. As a long shot I thought I might ask here if anyone had seen a similar problem before I try to troubleshoot this. 


73, Larry  W6NWS