I have an old B&O Beomaster 4000 which I wish to restore. One channel works, the other channel keeps blowing one of the output Darlington transistors after a few days of working perfectly. The stage is directly-coupled and all the relevant transistors check out 100%, as do the bias voltages. But the @#$%^ thing keeps blowing MJ2501 transistors, although not the complementary MJ3001.
As I am now down to my LAST MJ2501 transistor, I am going to replace all semiconductor devices in the channel, as well as the output electrolytic. But now the fun starts... Mantech do not list any of the transistors here other than the MPSA13. Does anybody know of a source for obtaining the following transistors?
MPSA13
BC262B
BC312
BC261B
AA143 (diodes)
And I am definitely open to any ideas on how to prevent the amplifier from blowing any more transistors, the MJ2501 are not too cheap either
I like valves ... <sigh!> ... they are *so* much more understanding than transistors.
-F_D
As I am now down to my LAST MJ2501 transistor, I am going to replace all semiconductor devices in the channel, as well as the output electrolytic. But now the fun starts... Mantech do not list any of the transistors here other than the MPSA13. Does anybody know of a source for obtaining the following transistors?
MPSA13
BC262B
BC312
BC261B
AA143 (diodes)
And I am definitely open to any ideas on how to prevent the amplifier from blowing any more transistors, the MJ2501 are not too cheap either
I like valves ... <sigh!> ... they are *so* much more understanding than transistors.
-F_D
