*** M E M O R U M ***

Sounds like it. But you can still test the resistance of the +5V supply to 0V to see if you no longer (hopefully) have a short circuit.

Thanks for that info Mark, where should I put the meter to test this?

Charlie

I attempted to de-solder a leg of the zener diode ZD2. While I was heating the solder and applying light upward pressure on the diode it broke in half. Given how easily it came apart I think it was pretty much already broken.

Charlie

Hi Mark, no I haven't had a chance yet, hopefully this week.

Charlie

If I remove the nut and bolt from the TIP2955 and lift it upwards so it's completely clear of the heatsink and put the meter on the heatsink and the tab of the TIP2955 there is still a connection.

Charlie

Ok thanks Mark, going by your picture if I put my meter on the metal plate in the foreground and the tab there is a connection, is that the short?

Sorry for all the hand holding, I'm learning on the job as it were.

Charlie

Thanks again chaps, with the meter on the diode I'm getting 0.45-0.5v. I'm powering down after 10 seconds or so as the board starts to smell hot. My TIP2955 doesn't look anything like the one you pictured, there is no heatsink although these is some soldering iron damage. Here's a picture:- http://a...

I've gone over both sides of the board with a magnifying glass and there's loads of dodgy soldering all over the place, lots of burnt flux and signs of attempted repair.

Charlie

This area doesn't look very clever.

Hi Dave,

Thanks for your reply, sorry for the confusion, the fuse was blown when I received the machine.

I did remove the board completely, I don't think I've caused any shorts. Is a short the likely culprit with the fuse doing that?

Charlie

Here's the top of the board. http://thebigsky.smugmug.com/photos/i-hRXQc3w/0/XL/i-hRXQc3w-XL.jpg http://thebigsky.smugmug.com/photos/i-btxtTxz/0/XL/i-btxtTxz-XL.jpg http://thebigsky.smugmug.com/photos/i-qXFFdHD/0/XL/i-qXFFdHD-XL.jpg http://thebigsky.smugmug.com/photos/i-Jc7hmGM/0/XL/i-Jc7hmGM-XL.jpg