Replacing the BF871 with the MJE340

[dvranizan]

hey guys! i found an old TV in the dumpster and have gotten it working like new except for some burned out transistors on the c-board!

Unfortunatly i cannot find any BF871's to replace them, and due to my ignorance cannot find a good replacement. After reading the forums for awhile i have seen various posts about using the MJE340 as a replacement! However, nothing requarding a television! Is it still a viable option?

Thank you for all your help!
David

 

[Eva]

There is no guarantee at all for this replacement to work. Both transistors may have the same Vceo rating but there are lots of differences like capacitances, charge storage and Ft

Try to get BF471, it's the same transistor as BF871 but in TO-126 package

 

[dvranizan]

Thank you for the reply!

Unfortunatly it seems the BF471 is just as hard to find. silly phillips keeps discontinuing!

Anyways, this may be an incredibally dumb question, and im sorry if it is... you can ban me from the forums or whatever. but im in EET 101 right now, so im just learning... ;D

What are the dangers of trying the MJE340? Can i destroy the board, or will it just not work.

I still cannot believe my luck @ finding this TV, and the only problem is a burnt out transistor!!! Thank you for your guys help and saving me from destroying the whole thing!!!!!

Thanks again!
David

 

[pinkmouse]

Sorry, but we have an absolute rule here at diyAudio, that we do not allow discussions of TV repairs, due to the extreme risks of personal harm in working on the very high voltages involved in CRTs, so I am closing this thread down.