Homebrew PCBs

Hi J,

I'm no expert, but I've gutted many devices for parts which were 
equipped with PCB-mounted transformers. I've got a small cable box 
here that I'm using for an enclosure, and am going to clone the board 
dimensions and probably re-use the xformer. Most of the stuff I've 
gotten has been the type with the bottom exiting pins. On the cable 
box, for instance, they just go straight down into the board (looks 
like about a .04-.06" thick single-sided), and the pads are average to 
medium sizes, with the exception of the ground lines, which drop 
directly into a large surrounding copper pour area. The hole sizes, of 
course, will likely be a bit larger.

You sound as if you're dealing with the type with the top exit wires, 
instead of pins. I've seen those on boards too, and they just drop 
through wherever they go, like the rest of the parts. That was usually 
on cheaper small stuff like clock radios. I'm guessing the pin style 
ones are preferred, but may be more expensive(?). I've got some 
massive ones from amps and monitors, which are also thru-hole mounted, 
directly to the single sided board, maybe with heavier pins. I think 
all of them use the two "mount ears" coming off the sides, and have 
screws protruding through the board into the metal chassis.

I guess your only real concerns are heat, current (no extra thin 
traces), and proper electrical placement. The cable boxes and stuff 
usually have them mounted near the rear, close to some vents in the 
back or top of the chassis.

Good Luck,

George