neals@tekigm2.MEN.TEK.COM (Neal Sedell) (06/30/89)
Ok, how about this problem. I have two Radio S* PA amps, 30 or so Watts, cheap little things, that have both output trannys shorted. Clearly marked on the packages is "D 1046", which I assume to mean 2SD1046, but there seems to be no crossreference anywhere that lists the D or 2SD type. By anywhere I mean the Moto power tranny book and Radio S*'s own reference. They're almost certainly NPNs, and they drive an output xfrmr (I assume center-tapped since they're both NPNs) with a 40V or so power supply. They're in what looks like a TO 220 case on steroids ;-). Anybody got any ideas? A local little-league will surely appreciate it! -- # Neal Sedell (206) 253-5280 # aka neals@tekigm2.MEN.TEK.COM # Tektronix, Inc., Delivery C1-936 # PO Box 3500, Vancouver, WA 98668
zahid@neptune.AMD.COM (Zahid Ahsanullah) (07/01/89)
In article <5119@tekigm2.MEN.TEK.COM> neals@tekigm2.MEN.TEK.COM (Neal Sedell) writes: >Ok, how about this problem. I have two Radio S* PA amps, 30 or so Watts, >cheap little things, that have both output trannys shorted. Clearly >marked on the packages is "D 1046", which I assume to mean 2SD1046, but >there seems to be no crossreference anywhere that lists the D or 2SD type. >By anywhere I mean the Moto power tranny book and Radio S*'s own reference. >They're almost certainly NPNs, and they drive an output xfrmr (I assume >center-tapped since they're both NPNs) with a 40V or so power supply. >They're in what looks like a TO 220 case on steroids ;-). > >Anybody got any ideas? A local little-league will surely appreciate it! >-- ># Neal Sedell Neal, this is a Japanese silicon type beast manufactured by Matshushita Electronics. Try to get their manual. For fixing your problem, just plug in a 3 amp npn from Moto or such and you should be cruising. Remember, you gotta change 'em both and get the junctions right ar they'll pop again. If the change makes the transistors seem hotter than normal, play very carefully with the skeleton potentiometer situated near the power drivers. This is the feedback control for the thermal runaway circuit. Bring it to a point where it gets moderately warm and slightly above the point where the speakers start to crackle. Mostly none of this will ever be necessary, just replacing the transistor will be sufficient. On a second thought, don't mess with it. Just put in direct equivalents.