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| Mini Lathe Electrikery....... |
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| Stilldrillin:
Hi Chaps! My Chester 7 x 12 has very occasionally flashed, from the motor area..... But, kept on running. :scratch: Fitted new brushes..... No difference! Yesterday, waiting for instructions. Speed control off. Direction switch, forward. It took off at top revs, in reverse! :bugeye: Stopped it, using the direction switch. Tried it again. It produced a beautiful flash from the motor area, and died...... :zap: Today, I've stripped and cleaned out the motor. Replaced the blown plug fuse. No joy....... :scratch: Working in from the plug, is this plastic box. It is inside the motor enclosure...... Guess this is the culprit...... It is mounted on this face, protected only by a sheet of mica (or similar). Power reaches the l/h connetor block. But not the r/h one. (There's power in the middle, I inadvertently touched the pcb)! :palm: Guess it's a transformer? Anyone any ideas or guidance? Where do I get another? Thanks in advance....... :thumbup: David D |
| Bluechip:
It's the supression board. Some capacitors, resistors and a choke ( the copper wirey bit ) Parts a commonly available, repaired several. Give the values off the parts ... Dave BC Another shufti ... Don't look like any of the components are shot, probably just visited blast fire and destruction on the PCB traces. You can, at a push, run without it. :thumbup: Wait !! Don't !! It looks like the line trace is burnt. Maybe you have a short on the controller board :( Can you see anywhere where it has shorted through the insulator sheet ??? |
| Bluechip:
Dave SD Where is that connected ?? On the machine mains input ( usual ). Or between the controller and the motor ??? ( can't imagine this on a DC motor, not with those mains colours ?? but, Chinky device, who knows ) Dave BC |
| Stilldrillin:
Dave. Mains input J1. Out, to machine J2..... I'll see if I can find any blast damage...... David D |
| Bluechip:
Dave Looks like the line trace has carried a lot of current out to the rest of the machine circuitry ... which is why it's got that incinerated look. I would suspect that's just a symptom, the real cause lies further on, ie, maybe a MOSFET blown or summat ?? You say the motor revved up then snuffed it ?? Well, the motor does what the controller wants. If a MOSFET goes short, it will dump current into the motor unrestricted. The motor will zoom away .. Until a fuse goes pop or some other protection device trips .. That line trace appears to have acted as a fuse, and failed. :( Don't think that's the real problem though. Dave BC |
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