[mailto:london-hack-space@googlegroups.com] On Behalf Of Eugene Nadyrshin
Sent: 20 October 2012 21:18
To: london-hack-space@googlegroups.com
Subject: Re: [london-hack-space] Re: mini lathe status?

Thanks for taking a look Adrian.

The filter PCB had an insulating sheet (similar to the one in the control
box) on it, but it was loose so it must have fallen out. And yeah the
plastic box for it s shattered, it may be worth making a new one, just to
keep it safe!

I've checked the pot itself and it worked fine, there is something wrong
with the control board I believe. But as there has been little interest in
fixing the control board we'll have to take a look at replacing it.
I'll look into it once I'm at the space next.

Cheers
Mentar

On 20/10/12 19:55, Adrian Godwin wrote:
> I had a look at this today, couldn't get any life out of it at all.

> Plug fuse had blown and some tracks on a filter pcb in the rear box.
> This had happened because it had been plugged in with the filter pcb
> wandering around freely in the rear box and had shorted against the
> mounting screws. It can't easily be put back as the plastic insulating
> casing is all smashed up.

> I repaired the pcb and added some insulating material : however, this
> isn't a permanent repair and will need more attention. I also repaired
> the speed control knob and fuseholder, which were falling off.

> This then got back to the state Mentar describes : on switching on,
> the motor starts at low / medium speed and there is almost no control
> of speed with the pot. It's possible that the pot is damaged / burnt
> out, perhaps more likely that the motor control is faulty. I don't
> think a motor fault is very likely, but it's possible.

> However, the speed controller is reasonably complicated.
> Reverse-engineering it enough to repair it is a long job.

> It's probably worth checking the pot more thoroughly, then
> investigating the cost of replacing the motor control board.

> It may be the same board in the small mil : testing with this could be
> a way to eliminate the motor as a cause.

> -adrian

> On Wed, Oct 10, 2012 at 2:14 AM, Eugene Nadyrshin <menta...@gmail.com>
wrote:
>> Right, the brushes have been replaced with the help of Charlie. Motor
>> running well without load but when connected to the drive belt spins
>> very slowly. And it's almost like there is some sort of current
>> limiting. Need someone with knowledge of control electronics to take a
look. Any takers?

>> Thanks
>> Mentar

>> On 03/10/12 11:35, Eugene Nadyrshin wrote:

>> I believe these are the similar to:

>> http://www.amazon.co.uk/Replacement-10PCS-Motor-Carbon-Brushes/dp/B00
>> 524TF00/ref=sr_1_fkmr0_1?ie=UTF8&qid=1349257435&sr=8-1-fkmr0

>> might need to sand them down a bit, should be easy (famous last
>> words)

>> I've ordered a set! ETA 9th of October

>> Cheers
>> Eugene

>> On 03/10/12 10:31, Nigel Worsley wrote:

>> it's the C1-X1-BRUSHES  we need. They had them then, but now they're
>> out of stock.

>> No, the lathe is a C2 not a C1. It looks like the brushes are the
>> same as the C3:
>> http://www.littlemachineshop.com/products/product_view.php?ProductID=
>> 1686&category=5

>> If the measurements on that page match the old ones then order the C3
>> brushes (which are also out of stock).

>> As for the uneven brush wear, bear in mind that this is a DC motor.  
>> One brush will be an anode and the other a cathode, when arcing the
>> erosion behaviour will be very different. And with a cheap Chinese
>> motor I would expect arcing to be the norm.

>> Nigle

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