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Shop Fox Mini Lathe Circuit Board

tj107us

Apr 23, 2011
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Hey guys, I have a Shop Fox lathe that has failed. To give you an idea of how it went down... I was using it pretty hard (probably past it's duty cycle) anyway I had it at full speed and then it slowed way down (like i had a large load on it) and then I turned it off. I took the circuit board cover off and turned it back on to see if i can smell anything getting hot!! I then shut it off cause it didnt want to burn it up and as soon as I turn it off, I saw a blue flash close to the transformer. So i'm thinking the transformer blew. How to you test a transformer to see if it is any good. It a FT2813-110-16DP transformer with 2 legs for input and 3 legs for out put. I ohmed out the input legs and it ohmed to 606 ohms, but dont know how many ohms it needs to be.

thanks for any help,
tj
 

john monks

Mar 9, 2012
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Your stuck.
I hope you know how to do this safely.
What I would do is place a 100 watt light bulb or an electric heater in series with the line cord and turn on the lathe. Then I would start probing around with a voltmeter.
I don't know the specifications of the transformer but if the light bulb does not light up and the output of the transformer is somewhere between 5 to 100 volts I would assume it is OK.

If I didn't know what I was doing I would get another lathe.
 
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CocaCola

Apr 7, 2012
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If I didn't know what I was doing I would get another lathe.

I don't know anyone that would toss an entire lathe out because of a failure like this, it's almost certainly cost effective to swap the failed part, as most all of them are very modular in design and made in the same factory in China so parts are plentiful...

What model is the lathe, most don't have transformers and if they do only a small one on the control board...

** Edit OK it's one of the small transformers as I suspect, it's only $10 to replace...

https://littlemachineshop.com/products/product_view.php?view=classic&ProductID=2857

BUT I would suggest you look a little further, there might be further damage that caused it to fail...
 
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CocaCola

Apr 7, 2012
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I'm assuming now that it's this transformer on the speed control board?

If so you might get lucky just replacing it with the one I linked, or you might need to replace the entire control board... FYI the fact that they sell just the transformer part of the control board is a good indication that it's prone to fail on it's own and not be a true fault or failure of the entire board... China is good at designing things like this with a weak link that fails on it's own...

Electronics and thus this control board is the one part of the mini mills and lathes that vary from company to company even though the machines are all made by the same factory in China... So even though you could almost certainly replace it with one from another companies machine, it might be best to get the exact replacement to avoid hassle...

So you might want to contact http://www.woodstockint.com directly about their replacement if you do a complete boards swap...
 

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tj107us

Apr 23, 2011
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ok thank yall for the info. So do you think that if i replace the transformer i "Might" be good to go? Cause i dont want to buy a new one and then it brun up too! Which we have had this lathe for 5 or 6 years now and have used the heck out of it.
 

CocaCola

Apr 7, 2012
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If it was me I would look over the entire board and if I saw no obvious signs of other damage, yes I would just replace the transformer and give it a go... If it burns up I'm out $10 and I know that I have to invest the full amount in the new control board...
 

tj107us

Apr 23, 2011
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Ok i ordered the transformer last night, i will let you know what happens when i receive it.
 

tj107us

Apr 23, 2011
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well i got the transformer and installed it, and nothing still wont work!! So now im testing the caps. None are leaking or bloated but heard that they still can be bad. Is this statement true?
 

KJ6EAD

Aug 13, 2011
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Yes, but it's likely a drive component failed.
 

KJ6EAD

Aug 13, 2011
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I don't know; I've never seen your circuit board.
 

tj107us

Apr 23, 2011
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can you test a bridge rectifier while still in the board?
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Yes, but depending on the circuit you may get completely confusing readings.

A well lit (not flash) and focussed image of both sides of the board, allowing us to read component values and board markings would be very useful at this point.

I realise you've been asked this before, so I'll just add my voice to the choir.
 

tj107us

Apr 23, 2011
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Hey i finally got it to upload the pics, sorry guys for taking so long to upload them. The rectifier is the black thing besides the transformer.
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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An image of the other side would be useful, but I would recommend removing the bridge rectifier to test it.

You could measure pairs of pins for an indication of diode action, but the results may be difficult to interpret, and surrounding circuitry may mask some problems anyway.

Take it out and if you have a diode test function try it both ways around from each ~ (call them ~1 and ~2) to both the + and - pin. That will be 8 measurements.

Give us a list looking like this perhaps:

~pin +/-pin red_on_~ black_on_~
~1 + 0.670 OL
~1 - OL 0.675
~2 + 0.001 0.001
~2 - OL 0.672

In this case the problem would be a shorted diode between ~2 and +, but that's not a prediction :)
 
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