John,

It's probably irrelevant by now, but 'What's this' is identifying the small torroid positioned between the big resistor and the heatsinks.

MichaelG.

VC

When you say that you have destroyed the "Whats this" do you mean the small transformer where you have placed the title or do you mean that you are looking to replace the entire board. It is possible to repair these boards for a very small outlay depending on whats damaged. If it was a simple overload/being worked too hard for too long then it might only be something like the SCRs or diodes that have failed.

Where abouts are you, roughly, as there are several people on this forum that have the knowledge to repair a board like this and may be prepared to take it on, trouble is Christmas is coming up which could put a spanner in the works. The other alternative is to contact the supplier to see if they hold stock of this board. I suspect companies like Warco, Chester, Amadeal and possibly Arceurotrade would have boards would be suitable but they are usually fairly costly items.

MW

Looks like everybody got their reply in before me 

Edited By Martin W on 14/12/2016 17:58:26

Ok, I missed the annotation on the photo……its the trigger transformer for the two thyristors that form part of the bridge network….removing it from the pcb is nigh on impossible as the holes for it are plated thru types….only way is to destroy it and remove each pin one at a time…..

Oh, and I missed Les's description too……

I best not try and go to any parties this Xmas….I may be too late   

Edited By John Rudd on 14/12/2016 18:05:43

I daresay that if the toroidal core can be saved, it may be possible to rewind it and solder the wire ends to the pins…..

But one has to ask, what has happened to lead to its demise?

What other unrevealed failures are there?

Google "ferrite ring transformer core" lots about, a few quid.

You will need lacquered copper wire of the same diameter and to wind on the same number of turns.

Someone might have a burnt out board they can take one off for you.

Neil

Hi Vic,
Before you remove what is left of the transformer make a note of which way the windings are wound on the toroid so you can get the phasing of the two windings correct. So note the direction (clockwise or anticlockwise) that the wire is wound round the toroid. This must be done for both windings. Also try to count the number of turns on each winding. (If there is enough of it left.) If you can measure the dimensions of the core and post that information one of us may have a core of about the same size. We would just have to hope the permeability is about the same.

Les.

I've been looking at some pictures I took of my X3 board. The transformer has 15 turns on the primary and also on the secondary. I estimate that the core is about 12mm dia. (By comparing it with the size of the TO220 SCR package..I have some cores removed from CFL lamps that may work. (They are about 10mm dia.) I have seen some toroidal inductors in the past used on mains input filters on switch mode power supplies that might work. I have also found this pulse transformer on ebay that would probably work provided a way could be found to mount it.

Les.

Edited By Les Jones 1 on 14/12/2016 22:45:34

This ebay item number 311617340418 is actually advertised as working with the mini lathe.>>

I hope this helps it really got me out of a hole, when I found I could use these.>>

Richard>>

The terminals marked A- and A+ go to the motor, P1,P2 and P3 go to the speed pot, L1 and L2 is the 240v ac input.

The P terminals, 2 is the pot wiper( middle tag) 1 is the left tag looking from the knob end, 3 is the remaining tag…

This info relates to the KB board or the chinese equivalent, NOT the Sieg boards.

Depending on whose mini mill it is, there may be another seperate board with a relay and some passive components. The AC and motor wiring goes via this board….

Hi VC,
You will need to say whose version of the mini mill you have before anyone knows if they have the same one as you. Failing that I would start as John suggested and connect the wires that are easy to identify. If your mill has a reversing switch then the wires from the motor will connect to that then two wires from the reversing switch will connect to A+ and A- (It will not do any harm if they are the wrong way round. The forward and reverse positions will just be transposed.) Some pictures of the wiring would help. If you put some markers on the end of the wires that would be a great help so we can say something like connect wire "A" to terminal. This will be easier than trying to describe which wire we are talking about.

Les.

Edited By Les Jones 1 on 08/01/2017 20:05:49