Hello everyone,
I have been given a DIY project of a pre and power Amp from around 1972 which 'never worked'. I got this without schematics but that is no huge problem as I have almost reversed engineered it. Basically it appears that it uses 108 transistors paired with 503 and the final stage uses 3055 and 2955 transistors.
I am not sure what the transistors marked 503 are (i believe they are PNP) can anyone clarify this?
I also have at least one which is open circuit anyway so does anyone know is there a modern equivalent?
thanks
Daz
I have been given a DIY project of a pre and power Amp from around 1972 which 'never worked'. I got this without schematics but that is no huge problem as I have almost reversed engineered it. Basically it appears that it uses 108 transistors paired with 503 and the final stage uses 3055 and 2955 transistors.
I am not sure what the transistors marked 503 are (i believe they are PNP) can anyone clarify this?
I also have at least one which is open circuit anyway so does anyone know is there a modern equivalent?
thanks
Daz
I think that '108' stands for BC108, I've seen these small signal transistors in old audio equipment quite often.
http://www.ortodoxism.ro/datasheets/siemens/BC109B.pdf
'503' may stand for 2N503 but I have never seen these.
http://www.datasheetarchive.com/semiconductors/specsheet.php?specsheet=119447
http://www.ortodoxism.ro/datasheets/siemens/BC109B.pdf
'503' may stand for 2N503 but I have never seen these.
http://www.datasheetarchive.com/semiconductors/specsheet.php?specsheet=119447
thanks for the replies guys,
the 3055 and 2955 have MJE marked on them,, I have found datasheets on MJE3055 and 2955 (NPN and PNP transistors) they are similar to TO220 package type, although they appear slightly bigger and there is a slug where the heatsink tab is (I am not sure when jedec packges where defined). I have made the assumption that the 108 are BC108. anyway the 108 and 503 are similar to the TO92 package type (just a bit squarer looking down)
cheers
Daz
the 3055 and 2955 have MJE marked on them,, I have found datasheets on MJE3055 and 2955 (NPN and PNP transistors) they are similar to TO220 package type, although they appear slightly bigger and there is a slug where the heatsink tab is (I am not sure when jedec packges where defined). I have made the assumption that the 108 are BC108. anyway the 108 and 503 are similar to the TO92 package type (just a bit squarer looking down)
cheers
Daz
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