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Replace Encoder - 3520c

D

Daniel Henry

Joined
Aug 10, 2021
Messages
194
Likes
139
Location
Benton, AR
I will greatly appreciate some sound advice. According to customer service at JPW the encoder on my 3520c died. For the record the digital display went blank. While I was on hold for a few minutes with JPW, the tech was knowledge and polite. Today I received a new encoder.
Has anyone replaced this little black box? Are there any secrets? Thanks for your consideration.
 
If you go online you can look up the manual for the model you have and you should be able to find a parts break down that will show you where the sensor/encoder is located. Before you change it out try to reposition the sensor incase it is just to far away from the magnet that it is reading.
 
I don't have experience replacing the speed sensor, but I've spent more time inside the headstock of a 3520a and 3520B. It's very hard place to work. Take your time and be patient.
 
Dean Center said:
I don't have experience replacing the speed sensor, but I've spent more time inside the headstock of a 3520a and 3520B. It's very hard place to work. Take your time and be patient.
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I can attest to the fact that your advice is SOUND. It is not a task for those that are faint of heart, easily frustrated, or have hands the size of a gorilla.
 
Tim, you obviously have experience inside that headstock. My misfortune, I had to be that 13 year old you described and my hands are complaining this morning. I hope no one on this forum finds it necessary to perform this task (replace the encoder aka speed controller) but if you do give me a call. The procedure is far too tedious to describe herein.
 
Daniel - I was trying to track you down after your note in the chat at Coffee hour yesterday. I looked up the manual and the exploded parts diagram. Does not look that difficult. Seems to be a tin box in place that the moveable control fits into? Like Don I would suggest checking alignment. There should be a magnet in a collar on the spindle shaft too. If that came out there would be no impulse to the sensor which is likely a FET transistor. Doing more research it could be a magnetic pickup? By the part number it looks like the same sensor is used on the Jet 1640. Checked 1640 manual and it is. Maybe there are discussion threads on that? Item 16 is the encoder. I have a Oneway 2436 and they do not believe in digital tachs but I bought a kit from Amazon and made one for it.

C0EF6A38-97C0-4ED5-82FC-BD4D422A13F3.jpeg
 
Mike, thank you for responding to my note in the Coffee Hour Chat. The item PM calls the encoder is item 23. Item 16 is an extreme small circuit board with a red LED light in it. Removing the motor is the first order of business. The encoder has a total of 20 wires extending from it. There is no adjustment nor alignment possible The replacement part was covered under warranty. I had looked at the schematic but when I saw the new encoder with wires and pin connectors it was shocking. For the record item 16 has a 3 pin connector that joins a matching pin connector that is part of item 23. IMHO the schematic drawing is a bit lacking.
 
Mike - it is not as complex a job as it is a physically difficult one. The space inside the headstock must have designers that formerly work for Ford, chevy or Chrysler.....and if you have looked under the hood of a current generation car - you know that a human hand has no chance at "fixing" anything in there anymore. Powermatic must have thought that was a good idea too..... :cool:
 
Tim Tucker said:
Mike - it is not as complex a job as it is a physically difficult one. The space inside the headstock must have designers that formerly work for Ford, chevy or Chrysler.....and if you have looked under the hood of a current generation car - you know that a human hand has no chance at "fixing" anything in there anymore. Powermatic must have thought that was a good idea too..... :cool:
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Based on actual experience, "I concur."
 
Daniel Henry said:
Mike, thank you for responding to my note in the Coffee Hour Chat. The item PM calls the encoder is item 23. Item 16 is an extreme small circuit board with a red LED light in it. Removing the motor is the first order of business. The encoder has a total of 20 wires extending from it. There is no adjustment nor alignment possible The replacement part was covered under warranty. I had looked at the schematic but when I saw the new encoder with wires and pin connectors it was shocking. For the record item 16 has a 3 pin connector that joins a matching pin connector that is part of item 23. IMHO the schematic drawing is a bit lacking.
Click to expand...
The encoder is a device used to provide position and speed feed back as in a CNC machine such that a cutting tool can be moved at a constant feed rate to an exact position, but of course a woodturning lathe has no need of positioning accuracy so there is no need to have the more complex sensor.
 
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