"30W" wrote in message
...
Thanks for the quick reply I have no way of telling what role the
transistor is playing. There are 5 transistors screwed into the back
metal plate for a heatsink. There is one small one and 2 medium size
ones and 2bigger ones. The medium ones are the bad ones. There is no
marking on the board to identify it as NPN or PNP, all that is on the
board are the usual BCE. You have any idea if its a power or small
signal?

The size of the body of the transistor is a good guide. Look for TO-3 TO-220
and you'll find pictures of various sizes.
http://www.mospec.com.tw/package.htm

N