Presto 6n Motor speed problem

[piaptk]

Hi everyone... I have a Bodine motor on this new 6N that I got that is running about 8% slow (a 120 bpm plays back at approximately 130 bpm), and there is a little bit of wow and flutter.... I've tried multiple pucks (the flutter might be in that... as it gets better/worse depending on which one I use... waiting on a new one from Terry)... But I'm completely flumoxed by the speed issue. Everything is oiled up, and should be fine...

Is there any reason that the motor would run (somewhat) consistently slow? I've got a LOT of these machines and never had this problem...

[piaptk]

Could the motor run capacitor have failed? Would that cause the problem?

[tragwag]

I would look to the caps, I've had more issue with those than with the motors themselves.
I believe there are two caps in the motor circuitry?

let us know how it works out!

[piaptk]

Upon further testing, it's not running at a consistent percentage slow. Sometimes it will be on speed, sometimes 10% slow, sometimes 20% slow... REALLY frustrating.. would the motor be dying and running at inconsistent speeds, or would it just run or not?

[piaptk]

Have you found that a bad capacitor would cause something like this?

[rsimms3]

Probably already tried it, but have you adjusted the tension against the puck by moving the motor mount closer/farther away? I've found that depending on the amount of pressure on the puck, I can be over/under by quite a bit. Also, is the capstan the same size as the others? Possibly sanded down? Smaller capstan = slower speed.

[piaptk]

Yes, I've been very careful about adjusting the motor placement.. And that shouldn't change the speed from one cut to the next, if no puck pressure changed.... And, the capstan looks ok... don't know why anyone would sand it down, and that also wouldn't account for the variation in speed.

I talked to Conrey Electric Motor Repair in PDX, and they said that the motor run capacitor, could definitely be the culprit, so I will try changing that out... Does anyone have any other ideas?

[gold]

If the speed fluctuates then my first guess would be the capacitor. If the speed was consistently off then I wouldn't suspect the capacitor.

[markrob]

Hi,

I wonder if its just loaded up with old dried up lubricant. You might try flushing the motor bearings out with some sort of solvent and re-oil. Perhaps WD40 (which is not a lubricant). If you have access to a strobe light it would be interesting to see if the speed of the motor is exactly 1800 RPM and if it appears jumpy even with no load.

Mark

[tragwag]

Try the cleaning like mark said, but I had this exact problem with one of my motors, turned out to be the capacitor.
Basically, once it would get going (maybe 10 minutes of running or so) the motor would start warbling heavily, huge audible pitch swings.
Definitely sounds like the cap in your case as well.
As I'm sure you know, the harness wiring isn't too complicated, give a good look over that stuff and replace that cap.

[markrob]

Hi,

After posting I was wondering if there was a low cost strobe tach using a smart phone flash LED. It turns out there is:

https://play.google.com/store/apps/details?id=com.tp77.StrobeAd&hl=en

This is pretty cool. If you have an Android, its worth giving this a try (it free or low cost with no ads). It even has a mode to display in RPM. It worked well on my Samsung Avant (a cheapy cellphone). I haven't tested it for accuracy, but it does look promising.

Mark

[shawnborri]

Maybe I am crazy but any piece of equipment I get in, that is made before 1970, I usually at least replace any large electrolytic capacitors, without hesitation! Motor starting capacitors, filter caps any wax paper caps, like coupling caps.