RPM display on PM3520B

[Chris Durkee]

I'm a newbie, fair amount of furniture building but never turned before.
First - this forum is amazing! I've learned alot in the last few months.
Now my question - I just purchased a PM3520B. Everything seems to work perfectly, but the RPM display never changes from "0" regardless of speed of spindle. High or low range - no difference. Speed control seems to work fine from dead stop to full RPM, but no change in RPM display. I'm going to call Powermatic's tech support first thing Monday morning, but I'm hoping someone in the forum has a suggestion or insight on this.

thanks, I'm so anxious to start turning I can't stand it.

Chris

 

[Mike Peace]

Check this thread. It is likely a simple matter of the part that triggers the sensor for RPMs has a loose set screw and slid out of position.
check this thread http://www.sawmillcreek.org/showthread.php?181847-Potentiometer-not-reading-right-rpm-on-3520

 

[Chris Durkee]

Thanks

Mike - you're right on the money! I just removed the RPM display and checking the sensor position. It looked ok, but I tried moving all the way to the right, and it reads just fine now.

Thanks so much for your quick response - now I can start to play with my new toy.

best wishes,
Chris

 

[Chris Durkee]

Display stopped working again

Mike, the RPM display worked for about 1/2 hour, then went back to "0". I'll call tech support on Monday and see what they say, and share what I learn. I may just have to tinker with the position of the sensor and the locking collar on the spindle and see if I can't get to work.

Thanks again for your help.

Chris

 

[Chris Durkee]

Tech support's recommendation

I just talked with PM tech support - they recommended that the sensor (on back of RPM readout box) be positioned as close to the locking collar (part 64 in manual) as possible without touching it - about 1/16". Allignment of collar and sensor is not as critical. I'll give that a try and post the result.
Chris

 

[Chris Durkee]

problem solved

amazing how critical the gap between the RPM sensor and locking collar is. I inserted a shim (business card) between the RPM display box and the bracket that holds the sensor, and that was enough! RPM displays ok. Final gap between sensor and locking collar is closer than 1/16", though - it's probably around 1/32". 😀
Chris

 

[Steve Worcester]

time to get out the feeler gauges, remember those?

 

[Chris Durkee]

problem resolved

Ok, now it's really solved. The digital display worked intermitantly, then finally quit. Powermatic sent me a new display box - what great factory support. They said the gap between the locking collar and the rpm sensor doesn't need to be as precise as I had thought. The new digital display works perfectly. Back to making (learning to make) shavings.
Chris