"Michael Black" <
et...@ncf.ca> wrote in message
news:alpine.LNX.2.02.1...@darkstar.example.org...
All valid observations, but any kind of older boombox will likely have a
straightforward linear supply utilising a power transformer. The primary of
such is almost invariably connected straight across the power socket, and so
can be read on a meter set to ohms. The OP said that he had a reading of
infinity across the AC ...
Whilst there might be a separate fuse, this is often not the case,
protection being afforded by a thermal fuse buried in the primary. The on /
off switch is also never in the primary circuit. This is always either a
mechanical switch in the main low voltage supply rail, or a tactile switch
read by the system control micro, which then outputs a control signal to
turn on sleeping parts of the power supply.
If the unit uses a 'figure 8' AC socket, this is the first place to look. It
is extremely common for these to go bad jointed, often on just about every
pin. This can give the symptoms described, because not only is it the AC
input socket, it also has a switch that 'rolls over' when the plug is
inserted. This switch controls where the DC to run the set comes from i.e.
either from the secondary side of the AC power supply, or from the
batteries.
Arfa