Chinese lathe upgrades.

Aaron_W said:
The 7x and 8x lathes have electronic speed controls that have a reputation for being fussy.

There are groups specific to these lathes that may help with some of the trouble shooting. I know we have people that own these lathes, but there doesn't seem to be much active discussion of them.

It may be worth making a post specific to the issue you are having which may get the attention from some of the mini-lathe owners.


There is a groups io group for the mini lathes that is pretty active. I believe there are also some mini lathe groups on Facebook.

https://groups.io/g/7x12MiniLathe


It is not uncommon that new owners have to do a fair bit of work to get these small lathes working well, but many are quite pleased with them once they have worked out the bugs.
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Its VM 210 or MX 750 lathe I have..
 
PaulsM said:
Its VM 210 or MX 750 lathe I have..
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Yeah, the group title is 7x12 but in reality they cover quite a variety of these lathes from the Harbor Freight 7x10 to the various 8x16 and 8x20 lathes as they all have similar issues and solutions. Problems with the control board in the speed control seems to be a common problem.

I don't even have one of these lathes and I joined the io group because small lathes share the common problem of being small machines, so there is some common user information useful regardless of brand.
 
PaulsM said:
If it gives max reading, why whould it short out?
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I have seen bent wipers, mangled resistor strip. I have seen the resistor strip come free and crumple like a ways protector. I have seen small pieces of metal and solder floating around in them.

sometimes its just easy to put a new one in from a hopefully better manufacture;
 
PaulsM said:
Now it wants to start, motor spins maybe a few revs and motherboard shorts to case of lathe.
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what do you mean the mother board shorts to the case?
are you tripping the machines fuses when you attach the mother board or are you tripping your service panel breaker/fuse. Its time for some pictures if you can ..... or even some you tube vids. Join in the mini lathe "how to fix" club. Im actually going to look at older mini lathe next week
I think its a enco ?

1675897271541.png

I found this if it helps any
 
mac1911 said:
what do you mean the mother board shorts to the case?
are you tripping the machines fuses when you attach the mother board or are you tripping your service panel breaker/fuse. Its time for some pictures if you can ..... or even some you tube vids. Join in the mini lathe "how to fix" club. Im actually going to look at older mini lathe next week
I think its a enco ?

View attachment 436795

I found this if it helps any
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What I mean by that is that boards radiator - aluminium is shorting to ground. So, boards aluminium is attached to cover which is attached to machine case and those are shorting. I measured DC motor resistance, it is 4 ohms. I guess it is good.
 
PaulsM said:
What I mean by that is that boards radiator - aluminium is shorting to ground. So, boards aluminium is attached to cover which is attached to machine case and those are shorting. I measured DC motor resistance, it is 4 ohms. I guess it is good.
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Is it possible what ever is attached to the heat sink is shorted to the heat sink? Maybe for testing insulate the heat sink from the case
Make sure all your grounds are clean and tight, sand paint down to bare metal where any grounds contact. I can bet a $1 or $2 that any ground on that machine is fighting through paint oil and crud.
Im doubtful they made any effort to keep paint out of the threads or attempt to clean them after painting.

You have any local electronics places or school that might help?

Im still looking for a circuit board diagram so I can get a better Idea how the circuit board works/flows

I might even replace the control panel fuse with a circuit breaker until you get it sorted.
 
I disconnected DC motor and turned it (board/machine) on, it doesnt short. DC motor resistance 4 ohms..didnt check how much multimeter wires take.
 
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PaulsM said:
I disconnected DC motor and turned it (board/machine) on, it doesnt short. DC motor resistance 4 ohms..didnt check how much multimeter wires take.
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Time to hunt down that short
Wires go through or under bed ways? Check all your contacts.
To and from that motor

Did you check the voltage output from the circuit board to the motor.

What voltage is the motor?
 
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Q
PaulsM said:
Hello. :)
My first post here.
I am ordering MX 750 lathe from China and I would like to understand what parts/standards are there.
It comes with simple tailstock, I would like to buy with bearings and tool holder/toolpost, do not know how it is called, but as far as I understand it gives ability to change tools easily. What else should I look for? :)
Thank you
View attachment 433709
View attachment 433711

View attachment 433710
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uick change tool post....
 
At this point I just wrote my seller from Chine and let him decide. This is not the first time I ordered something from them, so will wait and see how their warranty works.
 
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