I bought a Pioneer PL-300 on Trademe. It had runaway speed.
Cleaning the speed adjusting potentiometers fixed that, but the strobe markings were ‘rocking’ back and forward, and I could hear the sound wavering when I played a record.
New potentiometers, and, even though they tested OK with my Mega tester, new electrolytic capacitors. Still wavering.
The motor rotor seemed to be higher on one side, which made me think something had been bent.
I bought a PL-200 motor on eBay, thinking they were interchangeable, from ratbagt (lots of useful turntable parts) for NZ$50 including shipping (which was actually more than the cost of the motor!). When it arrived today I realised the PL-200 and PL-300 motors are different, d’oh!
Good grief, what is my problem?
The 300 has quartz speed control, the 200 not. I couldn’t just swap them, so did the next best thing – started swapping the interchangeable components (there are a few). First, the rotor. Still wavering.
Next, I swapped the PA2005 IC from the PL200 motor – big one, heatsinked – to the PL300 motor.
No longer wavering. Great! Success!
Just a note – I don’t think it was just the refreshed solder joints which fixed the problem – I’d already done that and it had no effect.
I looked on eBay for a PA2005 IC after doing this – about NZ$18 with free shipping. However, the PA2004 IC which is also on the PL-200 board goes for NZ$67 including shipping, and I got a whole lot of other bits as well, so I’m not too upset.
Worked out well, then. All of the advice for fixing this ‘wavering’ that I’ve seen in forums has been things like cleaning and/or replacing pots, replacing electrolytics. These may be valid suggestions in some cases, but in mine it seemed to be the PA2005.
I say SEEMED! We’ll see how it goes. On a positve note, the platter no longer needs a bit of a push to get started, so the problem may be fixed.
I was looking at the plate with the coils and Hall elements mounted on it and thinking that it would be possible to swap that by desoldering the coil wires and Hall element leads from the pcb mounted on it, but that’s for down the track and ONLY if necessary.