HarrisonM300

The lo voltage light on my Harrison M300 stopped working I thought it was just a bulb but a new bulb didn’t solve the issue The seems to be no power at the pins in the bulb holder ,does anybody know if there is a fuse in the transformer for the light

The Harrison M250 circuit diagram does not show a fuse in the light circuit. This does not really help, but I would be surprised if the Company changed "philosophies" between models.... but then again, it may have been modified by a previous owner!

You will need to track the wiring back. Conductors break in places where the cable is being flexed alot - like where the cable goes into the light fitting, or back into the machine. A good wiggle at these points may "shed light" upon the problem - if the light switch is "on," and the switch is not physically broken. The M250 diagram does not show a switch, but it could be an integral part of the light fitting on the M300. The light fitting itself may have failed, but I am sure you have already checked that.

With the machine disconnected from the mains, it would be worth checking the continuity of the conductors from the transformer to the pins in the lamp holder. (Check from the terminal of the lampholder, not just the pins )

If the lampholder is intact (Springs in the pins not broken ) at the same time, check the secondary of then transformer for continuity.

If this OK, check the primary winding for continuity.

If all is OK so far, check continuity of the power supply leads to the transformer.

HTH

Howard

On one I used at work there was a MEM Lo Vo light attached which has two fuses one on the supply to the transformer and another on the supply to the lamp. They were both inside the housing for the transformer at the back of the headstock.

David

Thanks to all who replied but I have sorted the problem to gain access to the transformer I had to move the lathe forward from the wall I moved it a small amount and with limited access I found 2 fuses but these were ok after a bit more movement and better access I found 2 more fuses ,these were on the 2 wires that go up to the lamp and one of these was blown these are 20mmx5 glass fuses fortunately I had a fuse so after replacing it the lamp worked but it was a bit of a hassle to get the lathe levered back into position but I really couldn’t manage without a machine light

Thanks. David