Mill X Feed Boo Boo Mea Culpa!

R35 would normally be connected across Q4, subject to Les's schematic being correct,  which is the fault light latch....closer examination of the board will tell if it has been 'blown away' or just not fitted....

And just to clear up any misunderstanding on the board and X3 mills....this is not the same board fitted to later X3 mills with the brushless motor....

Edited By John Rudd on 22/11/2016 09:46:47

Hi John,
I was wondering about the same thing but I think the component numbers are different to those used on the X3 board. You can see that the components around the fault circuit in the schematic are placed close together on the X3 board. (The picture of the etch side of the X3 board was taken by placing the board on a flat bed scanner.) It would be nice if the missing R34 acted as a fuse and prevented too many other components to be destroyed. I think I will add your comment about the difference between the X3 and SX3 to my website.

Les.

Hi

The fact that none of the lamps lit when Martin applied power to the unit implies that there was no mains getting to the unit, one item Les wanted Martin to check. Looking at the pictures Martin posted there 'appears' to be no damaged components or tracks, unless R35 has vanished into oblivion. While I realise that it is a low power device I was wondering if the 22V zener might have afforded any protection to the components downstream before the fuse blew. Looking at the pictures it doesn't look as if it suffered catastrophic failure as could happen with a mains short, though a fast acting fuse may limit the visible damage. I am fully aware that the physical appearance of a component does not always reflect its functionality, some failures can be spectacularly obvious and need no checking.

If the zener diode is intact then I would assume that downstream components would stand a fair chance of survival and there might be some hope of resurrecting the board.

Just musing.

Martin W

Hi Martin (W),
I think you are probably correct that the zener Z1 will have provided protection to the rest of the circuit. I had looked at the wrong "K" terminals on the circuit. (I had looked at K1 and K2) and was thinking that there was no simple path for the fault current to get to the negative rail. The fact that it was K3 and K4 means that the zenner would have probably shunted the fault current to the negative rail and probably going short circuit in the process. Providing the fuse went open circuit before the zener was blown open circuit there hopefully will not be too much damage. I have been in touch with Martin K via email and he has confirmed that there continuity between the mains plug and the power input pins on the board. He only used a buzzer type tester as he does not have a multimeter. So the power light not lighting remains a mystery.

Les.

Have you plugged another appliance or tool like a mains powered drill into the same power socket to see if there is power there?

There is also the possibility although a small one that the limit switches have been damaged or the direction switch .

If the power light is not lighting up you either have no power , lamp is blown , the fuse is blown or not making contact inside the holder so i would look at that first by checking continuity between the mains plug active (hot) pin and the connector that the power lamp connects to the active (hot) line , if your buzzer sounds when you check this it means the lamp is dead but if it does not sound check either side of the fuse as i have seen fuse holders do some strange things !

Then check the neutral line the same way but leave out the fuse check as it is on the live side only but do check the neutral side of the lamp for continuity as a broken circuit here will stop the lamp lighting also .

Hi All,

Someone has kindly offered to take a look at the whole unit for meto see exactly how much damage I have caused.

Doubltless we will see the resuklts of the post mortem here later on.

My grateful thanks to all who have tried to help me with this, very much appreciated.

Regards,

Martin

Hi All,

Unit arrived this pm from oop north and is back in working order complete with a now fucntioning power on light!

Cannot express my appreciation enough to John Rudd for doing this for me.

Perhaps he may be along to explain what was wrong with it but I am one happy bunny!

Now where was that soldering iron.......?

Happy Xmas All!

Martin