nibor

Full part number is 2sc3420. You should be able to find loads of inexpensive suitable replacements. Data sheet to get you started http://www.jbprojects.net/projects/wifirobot/c3420.pdf I would replace all the transistors.

25/26 years :( I thought it was much less but Google shows the last set I got was from 1986 (8620). I loved the early space and technic stuff, it was what I always wanted for birthdays and Christmas. Last week I bought 8110 and 8043 after a good quarter century away. First time building studless, in some ways it seams easier as there are so many more pieces to choose from but that gives you more options to work the imagination............. I'm going to start by remote controlling the Unimog and then have a go at building a cherry picker. Feels good to be back :)