A13TA Transistors-odd readings on DMM
Two of these are fitted in an ATX PSU used in a Dr.Dre Beatbox. The PSU isn't working, so, amongst other things, I decided to check the above components, which are in the primary circuit. On a cheap Chinese Tester they identify as NPN transistors having a hFE of 21, and Vf 614mV, which, to me seems reasonable enough, but on my M3800 DMM I get very odd readings, not like conventional Bipolar Power Transistors at all. I cannot find any data on these devices at all, ev3n if I put 2S in front of the numbers, but 2SC4242 transistors used in a similar ATX PSU (of which I've only seen a circuit diagram) have Vceo 400v, Ic7A, and are 40 watt TO220 devices, so I'd expect the (2S)A13TA to be similar. From what I can check, they appear to be OK, but I have in the past often had transistors check OK on testers only to fail when powered. Anyone have any further info. on these devices?
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