Easy to check continuity on the switch with a VOM¡or maybe a wire got disconnected while you were fixing the fuse.
On Dec 7, 2023, at 1:06 PM, Thomas Key <takey89@...> wrote:
Thanks everyone for you response.? I cleaned the pot with alcohol and while I was inside found that the fuse holder had a loose wire.? Put everything back together and the erratic RPM problem is solved (pot or fuse?, but now the chuck won¡¯t turn clockwise. ?? Guess that means the forward/off/reverse switch is faulty.
Tom
Yes there are several ?¡°numbers¡± but which numbers mater?? If you have a generic 7x lathe then you can buy an exact replacement part from LMS. ? The 7X uses a pot that is slightly hard to find and LMS offers an easy solution.
But if this is from some different lathe, you have to remove the pot and inspect it. ? The brand or manufacturer does not matter, but all pots can be identified by measuring them with an ohm meter.? You need to find or (by measuring) a few things:
1) What is the resistance, in Ohms between the two outside terminals or pins?? Ignore the center pin for now. ? ?This will be something. Like 1000, 10,000 or 50,000 Ohms. ? it will be some kind of round number like that.? So round the measurement you get so that it has a few zeros on the end.
2) Some pots have a switch built-in and these will have more than three terminals, likely 5.? Does yours have the switch?? These switched pots are for a combined on/off speed control.? The stranded pots are speed-only controls.
3) the center tap will change as you rotate the knob.? Measure the resistance relative to one of the other three pins. ? The resistnce will be either (a) proportional ?to the amount you turn the knob. ? In other words, a halfway know angle gives half the resistance or (b) very non-linear.? The first is called a ¡°linear pot¡± the second is called ¡°audio taper¡± or ¡°log taper¡±,
As long as the replacement pot has all three characteristics matched, and can physically fit in the space you are good to go.
Different manufacturers will use different parts numbering codes to describe the pot.? Although for example, 25,000 Ohms is always written ¡°25K"
On Dec 6, 2023, at 8:04?AM, Thomas Key <
takey89@...> wrote:
??
Should numbers on backside or on side.
There are different brands but the numbers tells which one to buy.??
Dave?
--?
Bruce Johnson
The less a man knows about how sausages and laws are made, the easier it is to steal his vote and give him botulism.
