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I am led to believe that this transistor came out of a (bass) woofer - one one speaker, and only one transistor (not two).

This is the best photo I can get:

L70M09CV

The markings appear to read

L70M09CV
MCCO - 0031

Googling L70M09CV comes up with nothing related.

Any idea what it is, a datasheet, and/or a suitable alternative?


I don't have a photo of the PCB, as it belongs to a Thai friend, who speaks no English, and my Thai isn't fluent, so more details are either sketchy or non-existant. I may be able to get a photo of the PCB tomorrow.

FWIW, I get 0.6V across the collector-base and emitter-base junctions, when forward biased - when checking it and assuming it is an NPN transistor.

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It's most likely an L78M09 9V, 500mA linear voltage regulator. You may replace it by an 7809 or 78S09 if those are easier to purchase at your place.

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  • \$\begingroup\$ Ah, the second number is an 8 not 0... well spotted. Many thanks. I thought I might have been a regulator and did ask my friend if it was from the power supply part of the circuit but they said no... but then he said a lot of stuff that I didn't understand :-). \$\endgroup\$ – Greenonline Nov 22 '18 at 3:22
  • \$\begingroup\$ As an update - I ordered some 7809 regulators for my Thai friend off eBay, and after a short delay they arrived yesterday. He has replaced the regulator (along with a couple of dodgy electrolytic caps) and he told me today with a big grin that it works. Many thanks for the component identification, you really made someone's day :-) \$\endgroup\$ – Greenonline Dec 16 '18 at 17:34
  • \$\begingroup\$ You're welcome. \$\endgroup\$ – Janka Dec 16 '18 at 18:49

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