Hi,
I got this Alpine CVA-1005 for repair which has been to a couple of
technicians before me , all who've given up on it. Symptom , no signs
of life though it seems to draw 0.35 amps from my ps ) I open the hide
away unit and while tracing supply and acc lines ( i don't have a
service manual) i reach the first power switching transistor , a
2SB1417 ( Q 8027 on the pcb ). I notice that someone has messed around
in this region. Strange thing is, the base lead of the transistor ,
doesn't seem to be going anywhere , apart from to the 1.5 K ohm
resistor tied to supply and the emitter of the transistor. Obviously
the base would have to be connected to some device that would pull it
low , when on, for the transistor to be forward biased. I pulled out
the transistor and examined the copper trace and, zilch , no connection
whatsoever. So my guess is there's a wire missing and i need to know
between where and what.
If someone has the service manual or a working piece, i'd be greatly
obliged if they could look this up and inform me.
Emitter 12v (+B)
Collector 0v (output switched dc)
Base 12v (control)
I don't think buying a service manual would be a good idea as i rarely
get these units.
Thanx in advance,
Jango.