Hello all Got a question for you's ,got myself a clarke mig welder 130te, but the motor was not turning so I took it out and had a look ,there was a burn mark on the back of the board so I solder it . All well working but I can not slow the motor down it runs fast all the time please help
Evening, and welcome. Photos tell a thousand words. What did you solder up? Variable speed motor? Wire speed knob?
I think that when the speed control is maxed out like that, it is due to failure of a (errr...power transistor?) mounted on a heatsink. Do the burn marks on the board correspond with a component of that description? It should be a quid or two to replace.
There's a photo showing the component on this one below, and probably many other Clarke threads as the boards are all very similar: https://www.mig-welding.co.uk/forum/threads/wire-feed-issues-with-a-us-190en-welder.106162/page-2
Hello and welcome to the Forum. Are you sure that an actual copper track on the PCB had burnt through? Sometimes it's just a brown scorch mark, caused by a component on the other side of the board getting hot. This heat could be due to a short circuit failure in that component, or just some part that gets rather hot during normal operation - such as the white cement wire-wound resistor marked 5WJ 470R. From the pictures, it is not easy to locate the place where you soldered the wire and the corresponding pins of whatever is above that on the other side. Can you turn the board over and back and identify the solder pads on one side and the exact component(s) on the other side, then mark them e.g. with a black felt pen or Tipp-Ex ? As a111r wrote, when a wirefeed motor runs flat out it is often due to a short-circuit in the power transistor that drives it. I don't think there is a circuit diagram available for this Clarke PCB, but the component is probably the flat black one bolted to the black aluminium heatsink. Can you read the part number on that component?
