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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Alpine CVA-1005
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. |
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