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testing transistors
Posted: Tue Jul 08, 2003 4:44 pm
by mikezx
Does anyone know of a quick and easy way to test transistors with a multimeter? I am rebuilding an old amp, it's a BGW 750C, and there are 6 Motorola SJ7407A transistors and 6 RCA 6803394 transistors per channel (2 channels). I'm assuming that these are FET's but I haven't been able to find anything on them. Thanks for the help!!
Re: testing transistors
Posted: Tue Jul 08, 2003 6:29 pm
by russlk
You need a diode checker or analog meter. The FET will measure open circuit gate to source and gate to drain. The drain to source will measure open and source to drain will show a diode. If those check out, it is probably good but for a definitive check, put 10 volts on the gate and see if it draws current.<p>If a BJT shows diode from base to collector and base to emitter and is open in reverse, 9 times out of 10 it is good.