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Biggtank 18th February 2013 04:20 AM

Hello..I am repairing a Memphis 16-MCA3004 amplifier..I have found two smd's that are defective,but can't cross-reference their markings. One is marked 3B horizontal with J vertical,and the other is marked C3 horizontal ,with 2C vertical.Any help will be greatly appreciated:)

kds9591 18th February 2013 04:34 AM

SMD CodeBook
Here's one link to a SMD CodeBook. There are others on the web if you do a search.

The SMD Code Book

Perry Babin 18th February 2013 07:47 AM

What is the circuit board designation for these?

Biggtank 18th February 2013 05:31 PM

Perry..they are the power fet driver transistors...on the vertical board Q708,and Q709

Perry Babin 18th February 2013 09:39 PM

Are you sure that both have a Q prefix?

The C3 is likely a diode and would have a D prefix.

Biggtank 18th February 2013 11:01 PM

Correct Perry c3 does have a d prefix....

Biggtank 18th February 2013 11:04 PM

Thanks Perry,for the help..I also found this very helpful site.
Marking smd

Perry Babin 18th February 2013 11:17 PM

The diodes likely survived. I'd use MMBTA56s as replacements for the transistors.

Biggtank 19th February 2013 05:03 AM

Actually..the diodes are functioning properly...the transistors are what failed...

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