Hmm. More cleaning may be.
Turntable Problem
- Thread starter geode
- Start date
Hmm. More cleaning may be.
nashvillebill
Super Member
No, if it's a .047 mfd 1000V it ISN'T an electrolytic. It's a ceramic disc. Failure rates on those are relatively low but it's still possible, but they don't have the old-age failure mode of an electrolytic. It's too low to be a motor run capacitor, imho. Even if it was shot, the motor should still turn, if you spin it to get it going with your fingers.
HOWEVER, the very first post indictated the motor had frozen up to the point it wouldn't turn, and it took lots of WD-40 to get it to turn freely. That certainly means motor bearings are shot, if they're ball bearings. (Even bronze bushings wouldn't be in great shape but they can be cleaned up somewhat, albeit with greatly increased clearances). Still, even with lousy ball bearings, the motor would likely spin though it would be unusable.
What were the resistance readings across the different windings? And are you sure the coils are connected properly (in parallel), since it's a split-coil motor? The two "positives" should be connected together and the two "negatives" should be together.
I actually posted some pics of the table here
http://www.audiokarma.org/forums/showthread.php?t=169893
It looks like an electrolytic. I will take the readings again. Thanks.
nashvillebill
Super Member
The link isn't opening for me. But that value is common for ceramic disc, yet unheard of for an electrolytic.
edit: It *could* also be a polyester film, I found one in the Mouser catalog, a Cornell-Dubilier DME series for less than a buck, but it 's most likely a ceramic...I don't think older polyesters were rated that high but I could be wrong. I've not seen ANY single electrolytics rated that high in audio gear.
edited again: Can you post a pic of the cap and the motor leads?
edit: It *could* also be a polyester film, I found one in the Mouser catalog, a Cornell-Dubilier DME series for less than a buck, but it 's most likely a ceramic...I don't think older polyesters were rated that high but I could be wrong. I've not seen ANY single electrolytics rated that high in audio gear.
edited again: Can you post a pic of the cap and the motor leads?
nashvillebill
Super Member
Okay, it took a while to sort through the various service manuals...but go to Vinyl Engine's web site www.vinylengine.com
Register and download (free) the service manual for the PL-117D. This is a simple motor, 4 lead (split coil) motor design. I believe it resembles your model, well at least the motor part. Scroll down to the schematics. They don't tell us what the capacitor value is--only their part number, but notice carefully: on the picture of the wiring, there are 3 suffixes shown. K model has one capacitor, this must be a 110V model since the windings are in parallel. H model has 2 capacitors. Its a 220 volt motor since the two windings are in series. Q model has NO capacitor.
This is why I say the motor will run without one. The cap is there to reduce a slight transient that occurs when the switch is made or broken. It's not critical.
If you're running on 110V, make sure its wired like the K version, unless you have a selector switch, then make sure it's like Q.
Register and download (free) the service manual for the PL-117D. This is a simple motor, 4 lead (split coil) motor design. I believe it resembles your model, well at least the motor part. Scroll down to the schematics. They don't tell us what the capacitor value is--only their part number, but notice carefully: on the picture of the wiring, there are 3 suffixes shown. K model has one capacitor, this must be a 110V model since the windings are in parallel. H model has 2 capacitors. Its a 220 volt motor since the two windings are in series. Q model has NO capacitor.
This is why I say the motor will run without one. The cap is there to reduce a slight transient that occurs when the switch is made or broken. It's not critical.
If you're running on 110V, make sure its wired like the K version, unless you have a selector switch, then make sure it's like Q.
nashvillebill
Super Member
Oh, and looking at the schematic: If your motor has green, red, brown, and black leads: With all the wires desoldered, your ohmeter should show continuity between the Green wire and the Brown (or Black, i'm too tired to sort it out) but not between the green and other wires. The Red wire should show continuity between it and the black wire only. I may be backwards, it may be green-black and red-brown, I'm tired and this involves thinking to go through their picture. One way or the other, there should be two and only two readings that show continuity, no more, no less. Green-brown is one reading and red-black the second--or if my thinking is backwards, green-black and red-brown...
Yahoo...I got it to turn and played a side of an LP on it. I took the motor back apart and relubed the bearings and this time I tightened the case enclosing the motor in small increments while spinning the capstan. I guess I had tightened it too much. It works 
Does it sound great...well I wouldn't say that, but it doesn't sound bad either. I know the table needs to be setup. I also have a Grado Black that is almost new just sitting there. There is some rumble when the idler wheel is turning the platter. The speed has a little variance in it. But it appears to be 100% functional. I also got the capacitor in the mail today. I can't say THANK YOU enough to all the AK'ers that offered advice and help on troubleshooting this. It seems this table will again see its glory days. So, I guess I need to lightly sand the idler wheel and use some rubber rejuvenation formula on it. Deoxit everything. Then install the new capacitor. Again, THANKs to All of You.
Does it sound great...well I wouldn't say that, but it doesn't sound bad either. I know the table needs to be setup. I also have a Grado Black that is almost new just sitting there. There is some rumble when the idler wheel is turning the platter. The speed has a little variance in it. But it appears to be 100% functional. I also got the capacitor in the mail today. I can't say THANK YOU enough to all the AK'ers that offered advice and help on troubleshooting this. It seems this table will again see its glory days. So, I guess I need to lightly sand the idler wheel and use some rubber rejuvenation formula on it. Deoxit everything. Then install the new capacitor. Again, THANKs to All of You.
nashvillebil...here is the picture. Also, It's working...Yahoo.
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I think you nailed it. Took it back apart and relubed. Slowly tightened the nuts while spinning the capstan and voila it works. Thanks a lot. NOw I need to work opn the other small issues.
nashvillebill
Super Member
Glad to hear it's turning!
outlawmws
On the Run
Did you take a look at the capacitor.
Fred
Do you think the 40 year old capacitor could be the cause of the speed variation. It isn't really bad, but it is noticeable. I'm just wondering since you said the motor would turn just not very well. Thanks.
nashvillebill
Super Member
I can't open the picture, all I see is the thumbnail with the message.
The speed variation is likely caused by the rubber idler wheel and/or some friction still in the motor. If the rubber idler wheel looks the least bit suspect, send it to Terry's Rubber Idler rebuild (Google it)and he'll rebuild it as good as new. Although I haven't used him--yet--several posters on this forum seem pleased with his work.
Again, if the motor hookup resembles this schematic, this cap's contribution to the motor is essentially nil. It's across the switch. It's not across the motor leads and it's not a run or start capacitor. It's not causing speed variation, IMHO of course. When the switch is made, the motor is running..but the switch has "shorted" (bypassed) the cap so the cap is not even in the circuit. When the switch is open, the cap is there...but the motor's not running then!! The cap is to absorb the inductance from opening and closing the switch.
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Thanks a lot for ALL of your helpful responses. I've got it closed up now and have been listening to it for a couple of LPs. I did change out the original cart with a pretty new Grado Black I had laying around. This table sounds pretty darn good. I think you are correct with the schematic, I think it is connected that way but I'll need to open her back up and check for sure. The speed variation appears to have lessened significantly with some play time. The idler wheel still has a rumble though. Again, Thanks a lot you have been most helpful.
Nashvillebil...you hit this one square-on. The schematic matches identically the way this table is wired. So, even though I have a new cap I guess I'll just leave the old cap in the table. I never plan on using it at 220V. So, I'm guessing this old cap poses no risk to the table. Thanks again for all of your help.