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Speed indicator

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Mike 9015/01/2020 20:35:10
23 forum posts
4 photos

Ive been using my new Chester DB7 lathe is today, modifying arcs wedge 000 tool post, and the speed indicator seems to have packed up working, not good considering it’s the first time I’ve really used it, it’s not a disaster though as I can still judge the approximate speed, but it’s still a bit of a nuisance all the same, I did not get time to have a look at what could be wrong, I’m hoping it’s an easy fix, but if anybody can suggest what could be wrong it would be appreciated.

Harry Wilkes15/01/2020 20:55:38
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794 forum posts
60 photos

Mike if it's new contact Chester they have to fix it or did you mean 'new to you' ?

H

SillyOldDuffer15/01/2020 21:50:51
5138 forum posts
1074 photos

Have a look at the detector : it will be mounted pointing art the spindle under the gear cover. Photo is of my WM280, but yours should be similar. Black wire at top connected to sensor on the L bracket: my sensor has a red LED, but I don't think that's universal.

tachodetector.jpg

Potential faults: sensor loose on bracket, misaligned, not close enough to the magnets on the spindle, or plastered in grease. Maybe the magnets have come off - unlikely.

The other easy-fix possibility is at the other end of the cable where it plugs into the tachometer circuit behind the front-panel : it may have come loose in transit. Make sure the plug is inserted properly.

If it's not obvious and a new lathe speak to the supplier.

Dave

Steviegtr15/01/2020 22:07:03
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481 forum posts
126 photos

Total Ditto on the above. They are pretty reliable.

JasonB16/01/2020 07:05:15
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Moderator
17086 forum posts
1839 photos
1 articles

It may also be a disc reading type that is mounted inside the head between the two bearings and accessed by removing the front cover which is what my Warco 280 has.

Mike 9016/01/2020 16:33:25
23 forum posts
4 photos

Had a quick look today and took the front oh my Chester it is a disc type JasonB, checked the small plugs for security

but all seem ok, by the way it is a new machine Harry, today the speed indicator flickered a bit, but still not working, cable From the sender is routed to the back of the machine, through a hole but I will have to unbolt and move the DB7 to get the back off, to have look, in the mean time I have sent an EMail to Chester and waiting for an answer,

SillyOldDuffer16/01/2020 17:50:32
5138 forum posts
1074 photos

Whoops, I didn't read the exam question properly! If the display is completely dead check the power plugs, sockets and wiring rather than the sensor. Mine is fed low voltage from a regulator on the mains filter board. It's fairly obvious how it works - follow the wires and make sure they're OK at both ends.

While Chinese Hobby lathes aren't as badly made as some believe, they certainly aren't perfect either! Mildly slapdash assembly results in minor faults. A plug not pushed fully home might come loose in transit, and this is made more likely because some wiring is able to flop around rather than everything being rigidly secured in a loom. Untidy rather than dangerous in my experience, but a flapping wire might be enough to dislodge a connector when the machine is transported. The flicker suggests power is nearly getting through, could well be a loose connection.

Dave

Mike 9017/01/2020 17:07:36
23 forum posts
4 photos

Had a good look at my DB7VS today checked all the connections and all seem ok still waiting for reply from Chester

but any suggestions would be welcome see the photos

Mike 9026/01/2020 14:00:36
23 forum posts
4 photos

I managed to fix my DB7 today after Mark at Chester machine tools had sent a replacement PCB Board, and speed display, although it turned out it wasn’t a fault with the speed control board, I replaced it anyway just in case, Mark then sent me the new controller board, which I fitted, and is now working perfectly, many thanks to mark for his help, what I have noticed is now the new board has been fitted ,when the potentiometer is turned all the way anti clockwise, the motor is turned off, and the display reads 000, which I think is how it should have been in the first place the old one didn’t do this but used to turn the motor at a very slow speed, anyway I am pleased it’s been sorted, perhaps now I can enjoy the hobby again.

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