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dave dave is offline
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Default Ashdown MAG 300 amp, 2004

On 07/30/2013 07:00 AM, N_Cook wrote:
Both 6.3amp fuses blown, 2 diodes of the bridge rectifier s/c. Internal
failure of this bridge, dodgey looking splodge logo, presumably Fronter
logo and 8amp rating, marked
AC BP8-04
or something else to change as well?
Main caps look ok and ESR (for what its worth in such cases) ok
The 2 failed diodes are
-ve to AC
+ve to other AC
Suspiciously 2 solder points look like crazed PbF solder but all is SnPb,
melted and reformed? the 2 points are at the -ve terminal and the AC
terminal of the other failed diode. Output devices DVM-D cold test as
expected. No heated traces or even obvious gaseous eruptions from the
bridge or anything out of the normal. No reported preceeding noises
prior to failure.


DVM-D cold test? Amps can become radio transmitters and fry themselves
without any audible indication, other than maybe some "rizzing" on the
violins. Are the output devices shorted?