Was hoping this would work out too. Tried to fix the bearing damage, no dice. Nice table otherwise.
Vintage Turntables: Time to Throw in the Towel?
- Thread starter cmnparlance
- Start date
Thunderbox
Super Member
Shame.
cmnparlance
Active Member
I checked a couple years ago and the motor had indeed been replaced with the good one, so my issue, as you say, is not the common Dual motor thing.If I understand OP right the issue with the Dual 601 is a 0.2% wow reading that seems a bit to high for this deck. If it were to be the common Dual 601/SM840 motor issue it would be more like a real runaway speed problem caused by a flaw that does not handle US 60hz current well. A lot of 601:s in the states had the SM840 motors replaced to SM860-2 motors under warranty. These does not have that speed issue.
It would be interesting to know what motor OP:s 601 is equipped with.
To me it seems as if the wow issue here is caused by something else. And since this is a motor that locks speed to the line freq there is not much that can go wrong in terms of electronics. Here troubleshooting can start with the usual culprits:
- Belt (as mentioned these Duals are a bit picky and it seems as if belts from Thakker in Germany works best)
- Cleaning of the pulley and inner platter to avoid slippage
- Lubrication of the motor top and bottom bearing (a dissassembly is required to get to bottom but top bearing can be reached with a fine dropper tool of some sort)
- Cleaning and lubrication of the platter bearing. Dual recommends renotac oil that can be hard to find. Chainsaw oil or other lubricant with adhesive properties can work as replacement.
- The vario-pulley for the drive belt to be checked for functionality. This handles the pitch control by a mechanism that changes its diameter. With age it can get stuck. Should not cause wow though, but how knows what the little gremlins inside a TT are up to...
I still thing the 601 is the coolest/best TT in the lineup. But that´s just my humble opinion
I think my next step will be to get a new belt, although as I think I mentioned earlier in this thread, I already bought one a few years back and it didn't fix the issue. I've heard Thakker is the way to go but last time I checked they weren't shipping to the US, so that may not be a possibility. Are there any other belt companies you'd recommend?
I will also lubricate the platter bearing and check the pulley. Thanks!
cmnparlance
Active Member
Thank you. For the JVC, I did read through that thread and others have suggested replacing that switch as well. I'm wondering though, would that likely be causing the speed to waver and not quite lock in? My issue isn't that the 45 or 33 only is off, or that the pitch is WAY off (that actually was the problem a while back but I cleaned the fine tune speed pot and 33/45 selector switch with DeOxit and it made it a lot better).
The problem is that I can't get the strobe dots to sit totally still. They are always moving slightly and sometimes jerk more suddenly one way or the other. We're only talking millimeters here, but it's noticeable if you watch the strobe for a few seconds.
cmnparlance
Active Member
That does make me feel better, thanks. Is there any way you could post or send me a video of what your strobe looks like in action?
cmnparlance
Active Member
Update: today I opened up both the Technics and the JVC. My plan was to lube and clean with DeOxit anything I could and hope it made a difference.
With the Technics, I first put some sewing machine oil on the spindle. Problem is, there's no "well" and so I basically just had to put a few drops where the base of the spindle meets the metal piece around it. Hopefully, some of the oil made its way to where it was supposed to go. Next I opened up the bottom of the table and cleaned the fine speed control pot and the 33/45 switch. I'm never really sure if I'm spraying DeOxit in the right place, since these components are all so small and it's hard to see what's going on unless you were to take literally everything apart. Anyway, I worked those controls many times. Not really knowing what else to do, I put some lithium grease on some of the plastic gears where they touch each other, and where the plastic meets the metal pieces. I also played around with the speed control adjustments that you can control with a screwdriver from under the platter to see if it made a difference.
All the instructions in the SL-D202 service manual (which looks almost identical to my SL-D212) involved unscrewing many screws and removing plates and circuit boards. I started to remove some screws but I didn't really want to get into that without knowing what I was going to do next, and was worried that I wouldn't be able to put it back together again correctly. Anyway, I tested out the table again and it's exactly the same in terms of the strobe issue. With the JVC, I basically did the same thing, lubing the center spindle, speed control pots, grease on some plastic parts, etc. Again, no difference in the speed/wow issues.
I think my problem with all this is that unless there's a video or instructions showing exactly what to do and where for my specific table, I don't feel confident doing much. There are lots of videos out there with people servicing tables, and I got some hints from them, but things often look very different from table to table, and the service manuals haven't really been much help either. Even the names for the components seem to often be different between companies and on various videos and manuals, posts and threads on here, etc.
Thank you all for your ideas and guidance, but I'm not really sure what else I can do at this point.
With the Technics, I first put some sewing machine oil on the spindle. Problem is, there's no "well" and so I basically just had to put a few drops where the base of the spindle meets the metal piece around it. Hopefully, some of the oil made its way to where it was supposed to go. Next I opened up the bottom of the table and cleaned the fine speed control pot and the 33/45 switch. I'm never really sure if I'm spraying DeOxit in the right place, since these components are all so small and it's hard to see what's going on unless you were to take literally everything apart. Anyway, I worked those controls many times. Not really knowing what else to do, I put some lithium grease on some of the plastic gears where they touch each other, and where the plastic meets the metal pieces. I also played around with the speed control adjustments that you can control with a screwdriver from under the platter to see if it made a difference.
All the instructions in the SL-D202 service manual (which looks almost identical to my SL-D212) involved unscrewing many screws and removing plates and circuit boards. I started to remove some screws but I didn't really want to get into that without knowing what I was going to do next, and was worried that I wouldn't be able to put it back together again correctly. Anyway, I tested out the table again and it's exactly the same in terms of the strobe issue. With the JVC, I basically did the same thing, lubing the center spindle, speed control pots, grease on some plastic parts, etc. Again, no difference in the speed/wow issues.
I think my problem with all this is that unless there's a video or instructions showing exactly what to do and where for my specific table, I don't feel confident doing much. There are lots of videos out there with people servicing tables, and I got some hints from them, but things often look very different from table to table, and the service manuals haven't really been much help either. Even the names for the components seem to often be different between companies and on various videos and manuals, posts and threads on here, etc.
Thank you all for your ideas and guidance, but I'm not really sure what else I can do at this point.
cmnparlance
Active Member
Also, what exactly does recapping the PS on the Technics entail?
krisjay
Super Member
I'd wager a few dollars if you bought an AT LP140 XP, threw on an AT VM95ML, added, a decent mat, played one of your favorite albums, you'd never look back. Sure you could spend far more money, and I have, but I have rarely been as satisfied in just listening to records as I have been with the 140. Just one man's opinion.
cmnparlance
Active Member
An updated to my update: I've been spinning the Technics, and it now looks like the W/F issue is worse than it was before I opened the deck up. The strobe is more noticeably dancing around and when I use the RPM app (I know, not totally accurate), the W/F reading now comes in around .3 - .35%, whereas before it was around .1%.
Now I feel like even more of an idiot, because this was exactly what I was afraid of--opening it up and making something worse.
adnick
Addicted Member
Your comments causes me to wonder about what you’re hearing vs what some app is displaying?
This table is audibly worse than it was?
You could hear issues with excellent recordings and those issues became even more pronounced?
These questions assumes there is a known good table and recording at hand for a direct listening comparison?
VR
Andy
T68
Super Member
Unfortunately I have no good knowledge of good vendors of belts for Duals in the US.
Hopefully the stop for shipping to the US is temporary and will open up again when the pandemic situation is better.
BillWojo
Addicted Member
@cmnparlance, back in post 75 I directed you to the manual with schematics for the JVC. Both of the variable resistors that you cleaned go directly to that switch so if the speed wanders on both speeds than it's a good chance replacing it will fix your problem. It's not expensive to replace and switch contacts do get dirty and those microswitches are hard to clean so just put a new one on.
I even gave you a link where you could purchase on for not much money.
BillWojo
I even gave you a link where you could purchase on for not much money.
BillWojo
You try using the Turntabulator app? It’s free and will tell you your exact speed. It could be your strobe is off and the speed is correct.
That or the power supply board may need to be recapped, I don’t know that table but I’m sure someone on the site has been able to fix one.
Download the app and check your speed, this will give you a little more info and may show your at the correct speed.
cmnparlance
Active Member
Hi, thank you again. Is Encompass the site, or do you have a source that's cheaper?
cmnparlance
Active Member
So, I actually just happened to download Turntabulator earlier tonight, although I paid $2 for it! Is there a free version? Anyway, 2 bucks isn't much if the thing does what it's supposed to do.
I tested the speed on the Technics on the "Quick" mode and it came in 33.32. Not too bad...then I did the "Exact" mode, which does a much longer test sample, and it clocked in at 33.4. OK. But the problem is, it doesn't tell wow/flutter, does it? I'm more concerned with that than absolute speed, since I can alway fine tune the speed a little faster or a little slower. My problem is that I can't get the dots to sit still--at their most stable point, they lurch back and forth a bit.
I had a Luxman 289 that would do that, my advice, let it be. If your at 33.32 & 33.4 that’s pretty dang good.
As for the strobe being off, have you tried cleaning & lubing the motor bearing? I know it sounds simple but if it’s the original lube it may have thickened up and could be causing a slight drag.
I pulled apart my KD-550 motor, cleaned it and added some new 100% synthetic lube (liquid bearings) is the brand I use. Amazing stuff for tables.
I don’t know the motor in your table but take care of all the small things prior to any soldering. A single drop of lube in the arm bearings will also greatly improve the arm.
See if you can find a way to get a drop or 2 of lube in the actual motor. If you open it up snap a pix and post it, we may be able to assist.
stratokaster
Mental toss flycoon
The yellow/red RPM app for iPhone is garbage. I get not only different W&F readings every time I use it, it also shows different speeds as well. For example - I start my turntable and get 33.37 RPM. I stop it and start again and get 33.32 RPM. Needless to say, the turntable speed (as checked with KAB strobe) stays the same.
Another point is that iOS is not a real time OS, there are a lot of system processes running in the background. Any delays in processing the accelerometer data will likely manifest themselves as increased W&F within the app. I'm not a fan of VPI and Rega turntables but there's no way they have W&F of up to 0.5% as many entries in their database suggest.
Another point is that iOS is not a real time OS, there are a lot of system processes running in the background. Any delays in processing the accelerometer data will likely manifest themselves as increased W&F within the app. I'm not a fan of VPI and Rega turntables but there's no way they have W&F of up to 0.5% as many entries in their database suggest.
cmnparlance
Active Member
I had a Luxman 289 that would do that, my advice, let it be. If your at 33.32 & 33.4 that’s pretty dang good.
As for the strobe being off, have you tried cleaning & lubing the motor bearing? I know it sounds simple but if it’s the original lube it may have thickened up and could be causing a slight drag.
View attachment 2094899
I pulled apart my KD-550 motor, cleaned it and added some new 100% synthetic lube (liquid bearings) is the brand I use. Amazing stuff for tables.
I don’t know the motor in your table but take care of all the small things prior to any soldering. A single drop of lube in the arm bearings will also greatly improve the arm.
See if you can find a way to get a drop or 2 of lube in the actual motor. If you open it up snap a pix and post it, we may be able to assist.
I may open it up and try to get to the actual motor. As I mentioned in another post, there are several plates and boards that need to be removed to get to the motor (I think?) and I am afraid I'll mess something up or not put it back correctly when I am reassembling everything...maybe I'll open the bottom and take a pic and see if anyone on here can guide me.
I did put 2 drops of lube in the spindle, from the top (under the platter), is that theoretically the same thing as lubing the motor bearing--i.e., is the oil supposed to seep down into the motor? I'll post a pic of where I did that as well.
cmnparlance
Active Member
That's interesting about the RPM app and how processing delays in the iPhone may affect the W/F readings.
After cleaning and lubing (assuming I actually did either of those things correctly...) the other day, my readings with the RPM app were worse than ever (<.3, as I said), but after running the table for a while, the measurements went back down to around .1 or .15--more or less back to what they were before I opened the table up (I know the RPM app isn't super precise, but it seems like if it's giving consistently poor readings, something must be up--right?).
What's weird though is that the strobe dots DO seem to be bouncing around more than they were a few days ago, which is disconcerting. OTOH, the user manual for the Technics SL-D202 (very similar to my D212) notes that the strobe may move around a bit because of mains power fluctuations, but that this doesn't mean that wow is actually occurring. OK.
I know I've seen turntables with rock-solid strobe dots--is that just because higher-end decks have strobe systems that aren't subject to the electrical fluctuations?
Is it fair to say that strobe performance can be affected by several factors other than actual speed stability--such as power fluctuations, imperfections in the platter or the geometry of various parts that fit together, etc.? That's what I'm sort of realizing.
BUT I also printed out a strobe disc and the dots on there appear to jump around a bit too...