tt varying speed problem and tonearm/cartridge setup

[mlb1515]

I don't by any means consider myself an expert in turntables, but I must say I'm a fan of vinyl and have been for my whole life. Two things:
1. I finally re-hooked up my turntable after it was out of commission for three years. It's a Pioneer PL-400 (not high-end by any means, but decent). It worked well w/out issue three years ago when I used again.

Now, however, it'll run at the normal 33 1/3 speed, then, for no apparent reason and at varying intervals, it'll slow for about a half-second then pick back up to normal speed. The only perceptible thing I can see is that there are three small red lights that are always on when the turntable's spinning. When it slows for this half-second, those three lights almost move like they're attached to the turntable. (I'm sure no one has this exact model, but if they did, they'd know exactly what I'm talking about. If you don't, I'm sure you're in the dark).

Any ideas?

2. I'm COMPLETELY confused w/ the counterbalance and the anti-skate and everything else. I feel like I get it up through balancing it so the cartridge/needle is balanced w/ the counterbalance on the other end. Then I get completely lost when it comes to spinning the dial in front and lining up the counterweight in back. Any suggestions for how to REALLY do this right? Anyone know of a video I can watch of someone doing this? I figure if I can't figure this out (and I'm a relatively intelligent guy), millions of people must have their turntable setup completely wrong as well. Help.

[royphil345]

Your table is a quartz-locked direct-drive. The thing most likely causing your speed stability problem is a dirty / slightly corroded switch. Probably the speed selection switch... Could be the quartz-lock switch if there is one... or the pitch control if there is one... power switch... The cure is to pick up a can of contact cleaner and shoot a little inside the switches, turn the switches on and off a few times while they're wet. May require taking the turntable apart to make sure the contact cleaner hits the right spot and gets inside the switches. I noticed Home Depot sells contact cleaner in their small electronics section. It's sometimes not easy to find outside of electronics supply stores. Could also be a failing electronic part inside or a PC board mounted potentiometer that's dirty. 90% of the time it's just a dirty switch or pitch control causing speed problems on a direct-drive though...

Main center bearing may need a few drops of oil if it feels tight. Could be worn-out. If there's any play in the center bearing, that could cause speed issues on a quartz-locked table. Not sure what sort of sensor is used on that table for the quartz-lock system to sense and adjust the platter's speed... I think it may be optical on that model if I remember correctly... Check the underside of the platter (lifts off) to make sure any shiny silver parts are shiny and any flat black painted parts are still flat black. Gently clean any part in the base that looks like it may be the speed sensor.


Balancing the tonearm is pretty easy. Just turn the heavy part of the counterweight until your tonearm just barely floats above the surface of the record. Keep the anti-skate turned all the way down while doing this.

The stylus pressure is now 0 grams. While making sure the heavy part of the weight does NOT turn... adjust the part of the counterweight with the calibrated markings to 0.

Now... as you turn the heavy part of the weight... the calibrated part will accurately display the stylus pressure. Where you set it depends on the recommended stylus pressure range for the cartridge. It can be tweaked a little by ear from there.

The anti-skate setting should be set to about the same value as your stylus pressure. Maybe a little more when using an elliptical stylus, or slightly less when using a spherical stylus. Can also be tweaked by ear from there...

Hope that's enough to get you going. Welcome to Audio Review!!! Let me know if you're still having problems... or even if everything works out great... :)

[mlb1515]

Wow... thanks for all your excellent advice. I think I finally get the tonearm balancing thing now.

And as for the cleaning of the turntable, that'll be my weekend project. The only part I'm a little confused about (which I thought I knew, but maybe I don't) is that you mentioned it's a direct drive unit. I thought if the turntable spins when you move the tonearm over and you're not able to stop the record w/ the needle on it, then you have a belt-driven turntable. And that's the case w/ the one I'm using.

But, as I say, you obviously have much more knowledge about this than me. I will clean everything up this weekend and see if that helps. And thanks for the tip on where to find the cleaner -- I'd've been searching everywhere for it.

Thanks again. I'll let you know what happens.

[nobody]

Belt or direct drive doesn't determine how the table is used like that. It just tells how the platter is spun. With direct drive, the motor turns the player directly where with a belt drive a belt is wrapped around the motor and around the platter thus spinning the platter when the motor turns. The could make a belt drive that shut off whenever or a direct drive that requires a button to start.

And, just an FYI...here's a link to a web site where you can download a maunual for your table: <a href="http://www.vinylengine.com/library.php?make=Pioneer">Pioneer Manuals @ Vinyl Engine</a>

[mlb1515]

Man, thanks a TON. I'd been looking for a manual for my turntable online and was unsuccessful. This is excellent.

And thanks for the clarification of direct drive vs. belt-driven. I'm learning more all the time.

[hifitommy]

like you describe usually requires some repair. the prob is in the speed control electronics. i had my kenwood kd500 repaired for about $125 and its now fine.

if you can make yours come around for reeeely cheeeeep then good. but be prepared for some expense.

[mlb1515]

so... maybe problem solved.

Took apart the table as far as I could, but I couldn't seem to figure out how to get to the real inside of it. Still, I took off the actual platter that resides under that rubber mat. Minor minor dust I cleaned out. Put it all back on and... so far... so good (let's hope it stays). Didn't use contact cleaner or anything. I'm not sure maybe if it was simply a case of the metal platter not being on correctly and "catching" at certain points? Don't know if it's on its way out? Don't know if it'll rear its ugly head again? Confusing. Let's just hope it stays the way it is.

The only thing now is that for some reason, the automatic return tone arm doesn't return. It just stays at the end of the record until I hit the "return" button. Odd. Does this ruin the record or the stylus at all to just have this sit like that? I'm fine w/ this "problem" if the speed stays consistent.

[royphil345]

Hope it keeps working for you... May be that you charged up some some old capacitors a bit...

Could be something wrong with the auto mechanism. There is usually an adjustment screw somewhere to adjust how far the arm has to travel before triggering the auto lift. Will it trigger if you lift the needle and move it over the label a bit? If so, it probably just needs adjustment.

You can use the turntable as a manual. It's not wise to leave the needle in the end groove for long though. Some are harder on the stylus than others...