N
N_Cook
Guest
Was in a valve /tube amp HT line as a dropper carying about 250V , no
obvious heating of the body or surround of this 10K resistor and no obvious
burning of the resistor track, microscope view
http://home.graffiti.net/diverse:graffiti.net/MO_resistor.jpg
B is the original blue body colour, C is part of the ceramic coating that
got left after my scraping. My scraping was axial so not the cause of the
tapered loss of metal oxide in the spiral between * and *, actual break just
off pic and a slight trace of this loss on the spiral above *-*. What caused
this tapering loss ? electrochemical? manufacturing fault ? All other 1/3 W
resistors in the amp look the same manufacture so wonder if being in the HT
line is significant or could any/all of the other 1/3W resistors fail in
similar fashion
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
obvious heating of the body or surround of this 10K resistor and no obvious
burning of the resistor track, microscope view
http://home.graffiti.net/diverse:graffiti.net/MO_resistor.jpg
B is the original blue body colour, C is part of the ceramic coating that
got left after my scraping. My scraping was axial so not the cause of the
tapered loss of metal oxide in the spiral between * and *, actual break just
off pic and a slight trace of this loss on the spiral above *-*. What caused
this tapering loss ? electrochemical? manufacturing fault ? All other 1/3 W
resistors in the amp look the same manufacture so wonder if being in the HT
line is significant or could any/all of the other 1/3W resistors fail in
similar fashion
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/