If you still have the problem this old trick may come in handy.
A trick from the old days with IVC & Ampex 1” was to use a brand new 20 Dollar bill to lightly burnish the surface of the head. Being careful to pass horizontally over the head not up and down. Any new bill will work, but it always looked more professional to the client using a crisp new $20. It must be a new bill for 2 reasons. First the new bill has not been contaminated by a lot of handling. Second the longer the bill is in circulation it looses the surface texture that works to burnish the surface of the head. If you use the tip of your finger with slight pressure you will feel the tip of the head thru the paper. Gently move back and forth across the head. Short quick passes, very gentle pressure. You will need to do it a few times, using a new part of the paper every time you do it. As you wipe the bill across the head it will pick up the clog and after removing the contaminant the burnishing action will take care of any high spots on the surface that may have been causing it to clog. In most cases it should remove any stubborn clog, and then you should wipe the head and drum with the alcohol to remove any residue left behind. Hope it helps.
Bob Fiori
Croma-Video Inc,
Collegeville, PA 19426
Mac Pro, 3GHz, Dual Quad Core, 8gb Ram