Also check the contacts on the bandswitch. I have that amp and have a similar problem with 160 operation, apparently from burning out one of the contacts on the switch. It would be a bear to change out, even if you could find a replacement, so I just don't run that amp on 160 any more.
Good luck with it. Vy 73, Don W4ZYT On Thu, Dec 17, 2015 at 8:30 PM, Tom W8JI <[email protected]> wrote: > Just came off 20M, amp working fine. Went to 160 plate and load controls >> have no control, no output. Plate current climbs high with any added drive >> (45-50W) and blew both 10amp fuses.Off comes the cover.jimk2hn >> _________________ >> > > It might be something else, but I would bet the contact on the 160 > padding capacitor is burned off. This is what the anti-corona washer > reduced. Heath did not use that washer. > > It arcs there when the loading cap is too far closed (too much grid > current) for the amount of drive on higher bands, or if the antenna should > become grossly mismatched when at high power on bands other than 160. The > worse band for arcing the 160 padding contact is when on 80 meters. > > > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband > -- Don Lynch MD W4ZYT - EI2IM, 5Z4ZK Virginia Beach, Virginia ARRL - IRTS - ARSK - Virginia DXCC - PVRC FOC 1700 - RNARS 4473 - FISTS 3381 - CWOPS 55 [email protected] == Donald F. Lynch, Jr., MD, FACS Emeritus Professor of Urology Eastern Virginia School of Medicine Norfolk, Virginia, USA _________________ Topband Reflector Archives - http://www.contesting.com/_topband
