Space aliens. Without more details it is hard to say from what planet.
39 responses Add your response
First, is it idler drive, belt drive or direct drive? If idler, perhaps the idler wheel needs resurfacing, if belt the belt could be slipping. You can put the belt in a bag with talcum powder and shake it up and reuse the belt. If it still slips, get a new belt from the manufacturer. If it’s direct drive, the speed controller circuitry could be defective.
On a deck with a synchronous motor (Elite Rock) a new phasing capacitor resulted in the pulley just quivering back and forth, until the deck was turned by hand when it kept going. After a while it would start on its own in the right direction but with momentary misses, which went after a few days. Was the new capacitor forming up after being unused for too long? No idea but the speed glitches never came back in ten years.
On a deck with a brushed DC motor and a feed forward power supply (Artemis SA-1) it was a symptom of the sintered motor bearing running out of oil. Getting some more in required removing the pulley but the adhesive had gone soft so it could be eased off and 100μl of oil (I used Nye Lubricants 181B but the designer recommended liquid bearing, however they wouldn’t supply that outside the US) run down the shaft to soak into the bearing, I did this 25μl at a time rather than all at once. When I replaced the bearing with a bit of loctite 648 retainer to hold it in place I made sure there was enough gap to get a micro syringe needle into to top up the oil in future.
There isn’t one answer to this one.
If it is a table with no fixed speed controller, it could have been a surge or power change in the system temporarily. in other words, if a large load came on-line in your area, the frequency would changes for a very short time so that additional generation can catch up with the load.
So, if you have a 60 hz system, it is fluctuating between say 59.5 hz and 60.7 hz. (just an example). So, most people use a stroboscope disc and a regular incandescent bulb and adjust the turntable speed for exactly the correct speed. But, this only works if the system frequency does not change and it always changes. Electrical system controllers and auto transformers adjust voltages to compensate for system load changes.
So, you could have experienced a system surge in your area for a short moment.
If you have a speed controller, that is different. A speed controller takes the 60 Hz frequency (USA) and voltage and converts it to DC, the converts it back to a fixed line voltage and a fixed unchanging 60 Hz, making your turntable speed always fixed regardless of changes in system frequency from the wall.
Unless one has a speed controller, internal or external, the turntable speed is subject to changes based on the electrical system changes based on loading.
Of course, this is assuming that nothing went wrong with your system.
I hope this helps.
For fun, get an inexpensive (a few dollars) stroboscope disc and a incandescent bulb and check the turntable speed.
Now after a full day of denial the military has released evidence of multiple sightings by pilots and radar. What was originally denied to even be happening is now openly discussed as being due to space aliens. Unfortunately too late, as we can see from the lack of replies the OP has been abducted. If only he had known to unleash the yodeling. https://youtu.be/aTe0MjAZvMU?t=49
Depending on time of day and prevailing weather conditions driving load against the power grid, it might have been a fluctuation in available current in the power grid feeding electric service to your home. It happens on a weekly basis for our power grid. The various fans that help our ancient HVAC system move air in our home will slow then speed up at various times through the day, much too subtle to cause the lights to dim. Once the load stabilizes after 10pm or so all things plugged in are much happier.
I actually went to play a record today, and I had to press the (electronic) buttons multiple times before it did its function. There was no speed swell, though.I put myself through engineering school fixing problems like this. Its very common on older turntables. The speed selector switch can have corrosion, as well as whatever controls might exist for setting the speed on both 33 and 45.