CRABTREE@kuhub.cc.ukans.edu (12/29/89)
Hi. My Mac Plus has a fried transistor on the power board. Everything else on the board checks out except one transistor next to the large heat sink toward the top of the board. Do any of you technical types have the specs for the transistors, etc on the board? If I could buy a $2 part instead of the extreme penalty that Apple charges for a board, my life would be much better. If anyone has any info that might help, I would appreciate it if they would forward it to me, or at least clue me as to how I could find it. Thanks in advance. Paul Crabtree@ukanvax.bitnet
gordon@cs.washington.edu (Gordon Davisson) (12/30/89)
In article <20495@kuhub.cc.ukans.edu> CRABTREE@kuhub.cc.ukans.edu writes: >Hi. My Mac Plus has a fried transistor on the power board. Everything else >on the board checks out except one transistor next to the large heat sink >toward the top of the board. Do any of you technical types have the specs >for the transistors, etc on the board? If I could buy a $2 part instead of >the extreme penalty that Apple charges for a board, my life would be much >better. If anyone has any info that might help, I would appreciate it if >they would forward it to me, or at least clue me as to how I could find it. I assume you're talking about the one labeled Q3? If so, it's a standard BU406 bipolar power transistor, and you should be able to find them at any reasonably serious electronic supply store (i.e. not Radio Shack). By the way, the most common cause of Q3 failure seems to be shorts in the flyback. Have you checked to make sure your flyback's 2 windings are still isolated? -- Gordon Davisson Westwind Computing (206) 632-8141 4518 University Way NE, Suite 313, Seattle WA 98105