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Help with transistor replacement

leo morane

Apr 27, 2015
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Hello, i'm trying to replace a burned transistor on my synth.
Original is a B731 E / D48. (here :http://imgur.com/WpmaRIm) I was following a tuto from a guy who's had the same problem, so i ordered the same transistor he used in replacement, but i just saw he used B744 instead of the original. It seems it's not exactly the same characteristics and voltages ?
So i was searching for B731 but i found these : http://imgur.com/jLQfBhm which are labeled as B731 E / D33. What does this last number mean ?

In short - can i replace a B731 with a B744 ? What does D48 , D33 mean ?

Thanks :)
 

davenn

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Sep 5, 2009
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In short - can i replace a B731 with a B744 ? What does D48 , D33 mean ?

most likely a manufacturing date code .... not important
the B731 ( 2SB731) is the important part

can i replace a B731 with a B744 ?

have you looked up a datasheet for the 2 transistors and compared their characteristics ?
do so, and that will tell you if you could use the B744 as a replacement


Dave
 

leo morane

Apr 27, 2015
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Apr 27, 2015
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Yep i've looked at the datasheets and the voltages values are : -70 / -60 / -6 for the SB774A, and original transistor is -60 / -50 / -6

I put below the original schematics section : it seems to me that the 744 is replacing the 731, but would love your advice :)
 

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HellasTechn

Apr 14, 2013
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dont really look that different. might work ok with the replacement also but if you can buy the original then why not ?
 
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