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Warco 250WM Lathe - Speed readout problem

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SeagoMac08/04/2019 20:35:13
1 forum posts

I had a problem where on pressing the start button the motor would not run however there was power as the speed display showed '0.0' see video below.

I tested the motor and it ran on an applied DC voltage. In the end I narrowed it down to the 'Start/Stop' switch. Terminals 13 & 14 were not making a connection when the start button was pressed. I ordered a new switch from Warco and fitted it. The motor now runs and I get a variable speed using the pot on the front. However I have now lost the speed output on the LED display!

I know that it is not the variable speed control board as I got Warco to send me a new one and swapping that out made no difference.

Anyone had similar problems?

Mick B109/04/2019 09:36:19
1552 forum posts
83 photos

Very occasionally mine reads (IIRC) 000.0.

It generally goes away when I switch off the power and on again. Once I had to wipe the pulley at the back end of the spindle where the thing wot triggers the sensor is, and maybe I wiped the sensor thing too.

Pete Hatchett17/05/2019 11:08:41
1 forum posts

Hi, I had the same problem which seemed to be caused by grease on the magnet which generates the speed "pulse". This is on the rear of the spindle pulley. Wiped it clean, now fine.

SillyOldDuffer17/05/2019 12:50:48
5631 forum posts
1157 photos

Most likely messing about testing the motor and fitting a new switch has dislodged a wire. I have a WM280 which may be similar inside.

First, as suggested by others, check and clean the sensor (silver object with red led and black wire) mounted on the change-gear end of the spindle:


Your sensor may look different, but the wire is a giveaway. Note where the wire enters the headstock in case cleaning grease / swarf, doesn't fix the problem. The sensor is actuated by a small block magnet stuck to the splndle, at least one, maybe 2. It's unlikely but make sure the magnet hasn't fallen off.

Behind the front panel you should find the tachometer power supply, on mine it's part of the mains filter, green board mounted on the floor of the headstock.


As the display is working, the problem is unlikely to be due to a power supply problem. Note however the large black cable bundled together and plugged into the rear of the tachometer/display mounted on the aluminium front panel (bottom right of photo): this is the sensor input. Make sure it's plugged in properly.

Another view of the tachometer board, on mine the red/black pair are low voltage DC power, and the green/white pair are the sensor input.


The wiring of my lathe isn't arranged as a tight loom fixed firmly inside the headstock, rather the various parts are wired point to point and tidied up by gathering with a few nylon cable ties. This simple arrangement makes the lathe vulnerable to dislodged connections due to pulling on wires elsewhere on the machine, for example when your switch was investigated. In the worst case, a board could be damaged by pulling a plug hard in the wrong direction, but considerable force would be needed.   It's all simple enough to replace if need be.

Hope that helps,


Edited By SillyOldDuffer on 17/05/2019 12:54:38

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