Thread: Ashdown MAG 300
View Single Post
  #1   Report Post  
Posted to sci.electronics.repair
n cook n cook is offline
external usenet poster
 
Posts: 1,220
Default Ashdown MAG 300

Blows mains fuses. Ashdown supplied replacement fuses to the owner, better
than FOAD I suppose. Survives long enough for the meter lamp to come on half
a second. Nothing found obviously suspect in ps or pa probing around cold
and inspection. Not looked at prea yet. Will power up on variac tomorrow
with lower rated fuses and prea disconnected initially. Bad internal AC
supply fuse holder contacts , arcing burn marks on the fuse barrels. Both
are 5 amp rating but neither blown or showing stress on the fusewire. The
mains primary of the torroid measures 6 ohm which seems reasonable for 300W
amp and no other filter items . Anyone ever found bad ac rail fuse contacts
leading to mains fuse rupture ? perhaps inductive back?/forward? emf kicks,
surely not.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/