Restoring and Improving A Thorens TD-124 MKII - Page 60 - diyAudio
Go Back   Home > Forums > Source & Line > Analogue Source

Analogue Source Turntables, Tonearms, Cartridges, Phono Stages, Tuners, Tape Recorders, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 11th August 2012, 09:08 PM   #591
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Quote:
Originally Posted by kevinkr View Post
Hi missouricatman,
The bearing kit was purchased from jec965 on eBay, I've also used ones from analog depot when they were still available. As long as you make sure to impregnate them properly there should be no problem.

Yeah, I stopped obsessing over the belt tension issue as they loosen up pretty quickly in use, they will stretch something like a half inch or more with use.

I can imagine this is a much bigger issue for Europeans running these tables with the larger diameter 50Hz pulley than it is for those of us in the 60Hz world.

I have never been able to conclusively determine that there were different belts for 50Hz and 60hz installations, as has been alleged, but there are definitely two different belt part numbers over time, but I have never seen the earlier PN. Original Thorens belts from the 1960s are both more pliant and somewhat thinner than any modern belt I have encountered. (More IMHO than would be accounted for by stretch) See my measurements further back in the thread if you are curious.
Hi Kevinkr. Thanks for the info. Right now looks like the bearing that needs replacing first is the one for the stepped pulley. Until this morning, I hadn't pulled and cleaned the stepped pulley or the idler wheel, nor had I oiled the top motor bearing. With that done, the turntable comes up to speed in about one rev., but my cleaning introduced some noise from the stepped pulley. Inspection shows it to be wobbling just a hair. Until I get a new bearing, I'm thinking that instead of 20wt, a silicone grease may be the ticket. I suspect all that dark matter I swabbed out was actually helping to keep it quiet, since it was likely tighter before the cleaning.

As for spin-down, I'd say at 33 1/3 it's taking about 45 seconds to come to a stop. The main bearing's still oiled with Mobil 1 10-30 wt.

Other notes on overall condition. I've examined what I assume is the original belt by stretching it slightly and looking for any cracks. Looks just fine to me, so I just reversed it. I may order a replacement, but it seems to run just fine, so don't see a point just yet. The motor bushings may benefit from replacement, but if it's making any noise, it would take a stethoscope to tell. As for the motor mounts, they're intact and pliant, but there was enough rubber debris scattered about to suggest they should get swapped out too.

By the way, I've been pulling spectrograms using Audacity if anyone is interested. I'm sampling output with the tonearm at rest, of the run-in, about 3:00 minutes in, and the run-out. I've been capturing the waveform at maximum magnification and putting that next to the spectrogram.

I've been using an Ortofon I had installed when I bought a Technics SL-D2 new back in the 80s and while I doubt it's the best match, I'm pretty pleased with it. The stylus on that one is an OEM replacement with probably 20 hours on it at most.

Last edited by missouricatman; 11th August 2012 at 09:11 PM.
  Reply With Quote
Old 11th August 2012, 11:58 PM   #592
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Hi missouricatman,
There is an eBay seller based in Spain who sells replacement bearings for the later variant of the intermediate pulley used in the TD-124/II. These have only recently become available and he is the sole source I am aware of, probably a good idea to get some now. Your table must have a good many hours of use on it as I have never seen one with significant wear in the intermediate pulley bearing.

Yeah it's a good idea to replace the motor mounting bushings. I'm running geltec bushings from jec965 in my TD-124/II and they do seem to make a difference. I just acquired a set of natural rubber bushings for my other TD-124 and will be installing them shortly.

A spectrograph of the noise spectrum of your table should be of interest..
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 12th August 2012, 05:00 AM   #593
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Quote:
Originally Posted by kevinkr View Post
Hi missouricatman,
There is an eBay seller based in Spain who sells replacement bearings for the later variant of the intermediate pulley used in the TD-124/II. These have only recently become available and he is the sole source I am aware of, probably a good idea to get some now. Your table must have a good many hours of use on it as I have never seen one with significant wear in the intermediate pulley bearing.

Yeah it's a good idea to replace the motor mounting bushings. I'm running geltec bushings from jec965 in my TD-124/II and they do seem to make a difference. I just acquired a set of natural rubber bushings for my other TD-124 and will be installing them shortly.

A spectrograph of the noise spectrum of your table should be of interest..
Hi Kevinkr,

When I was cleaning the stepped pulley well, I flipped what I presume is a teflon disk that was in the bottom. At the time, I thought it a good thing to do, because I could see a depression in the middle. However, for all I know, I swapped a concave surface for a convex one, which obviously would not be a good thing! In the morning I'll put it back the way it was and see if that settles the thing down. Still, I don't see how that could result in a shimmy unless there is some slop in the bushing, so I'll see if I can track down the ebay seller you mentioned.

By the way, a little insight as to how you managed to press old bushings out and new ones in might be helpful as I move on to this next stage.

There is no doubt though that as changes are made, it takes some time for things to settle in. I was seeing some noise at max magnification in Audacity that after recording three sides, seems to have disappeared.

I'll pull some more spectrograms in the morning and will post them.
  Reply With Quote
Old 12th August 2012, 04:01 PM   #594
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Hi missouricatman,
I've never pressed out the bearings for the intermediate pulley, but I would imagine that you would remove the thrust screw and nut and using a custom machined piece of drill rod press them out. IMO you would machine the drill rod so that it has a step on it and the narrowed diameter would be enough to go through 2 X the length of the existing bushing so that it captures the second one on the way out. Press out from the bottom since that end is threaded..

I've attached a picture of the tool I use to replace the main bushings. There are a pair of nylon bushings still on it from the main bearing I posted about in a previous post.. This tool was turned from G10 and has a step. It is designed to allow bearings to be pushed out or extracted as required - the longer part is split and there is a wedge that can be inserted to force the tool to grip the bearing if this proves to be necessary - it has not been necessary so far.
Attached Images
File Type: jpg tool.jpg (110.8 KB, 336 views)
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 13th August 2012, 03:39 AM   #595
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Default Thorens TD 124 MK II vs Dual 1219

OK, this is hardly a fair comparison, given I've already rebuilt the Dual 1219, plus it's running a Shure V15 MKIII with the JICO SAS stylus, but it does give some idea of why the Thorens needs all the bushings replaced. The attached image shows at maximum magnification of amplitude, a snippet of the lead in on a disk I'd first recorded on the Thorens, then on the Dual. To keep things honest, the rumble filter was off for this test run. The Thorens is on top.
Attached Images
File Type: jpg Thorens And Dual lead in.jpg (96.1 KB, 320 views)
  Reply With Quote
Old 13th August 2012, 04:24 AM   #596
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
I'd start with the motor overhaul and bushings, and give the intermediate pulley and motor pulley running surfaces a good cleaning with a light pass with scotchbrite followed by 1000 grit sand paper for a wet polish. It may well be that the intermediate pulley bushings need to be replaced, but yours would be the first I have heard of that required this - but it is quite possible, and replacing them can't hurt. (If you can see wobble either the shaft is slightly bent or the bearings are really bad) My TD-124/II came to me from the original owner and had very few hours of use - a couple of hundred at most.

The 124 also benefits from being directly coupled to a heavy, lossy plinth. In terms of rumble if everything is working correctly about 1 in 10 records will have a residual rumble level close to that of the TD-124/II and most will be much worse. Prior to this set up I never had anything this quiet. (Of course I did not have the resolution either, Schick and Meister Silver are pretty hard to beat IMVLE.. )
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 13th August 2012, 01:28 PM   #597
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Morning krvinkr,
Yes, I considered that the stepped pulley shaft may have gotten bent, that the bearings aren't the issue. Next time I get into it, I'll be trying to isolate the cause. I'm pretty sure whichever is the problem, it's also the reason I'm getting a little noise from the pulley. It really sounds as though at some point the pulley is just lightly scraping something as it rotates. The noise wavers with the rotation. Now if it's bent, coming up with a safe way to true it up might be a bit of a challenge.

Since each drive train element can impact others, I also suspect that whatever is making the stepped pulley wobble is probably also the reason I see a small height deviation in the idler wheel. It travels up and down the stepped pulley a hair.

While I may take on replacing bushings in steps, there are enough that need to be done that I may track down a machine shop here in Kansas City. As you pointed out, creating a tool to press the old bushings out requires milling a rod, unless I managed to come across the right tool ready to go. If it involves machining, I won't be able to do that on my own, so might as well try to find a place all set up to press bushings out properly. If I had all the measurements, getting custom bushings milled would probably be possible too, although whether I could get it done more cheaply than I could buy them is questionable. My guess is the type of machine shop I need to work with rebuilds industrial motors and we've got several of those around here.

As for polishing various spindles, I'm pretty well set up. I think the finest grit I've got is 3000 wet or dry.

I didn't quite get your comment on rumble on the TD 124/II. Did you mean to say that all things being equal, the Dual 1219 should have more rumble than the TD 124/II once its rebuilt?
  Reply With Quote
Old 13th August 2012, 03:07 PM   #598
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Hi missouricatman,
Hopefully it isn't a case of bent spindle on the intermediate pulley.. One of the unfortunate issues with this design is that the intermediate pulley will ring slightly if there is anything on the running surfaces, a good clean and some talc on the belt will do wonders. The eddy current brake generates a significant amount of noise as well, but you should not hear any scraping sounds.

Something to bear in mind - if you are hearing scraping it is likely that the intermediate pulley height is no longer correct due to wear in the thrust pad at the bottom of the bearing well - you can replace this part if necessary, but in either case a slight adjustment of the thrust bearing height should be performed.

Next check the idler, many of them may wobble a few thousandths in normal operation and as long as it does not hit the next step down on the pulley and is not extreme it does not seem to cause a significant performance issue.
Verify that the idler runs near the middle of the step on several speeds, and note that this height can be adjusted - there is a lock screw on the speed cam follower that sets the height, shims can also be used. Normally a very small tweak is all that is needed. I've only had to do this on one table that like yours had an issue with the intermediate pulley due to a missing thrust pad. (Had to make one)

Mirko sells a very nice replacement idler wheel - I have one as a spare against the day I need to replace one of mine, but I suspect at some point I may change to it as I suspect it may be even quieter than the really nice vintage one I am currently running.

I think your best course of action is to find someone to make the tools and do the bushing replacements yourself, it's not too hard, and several on line machine shops can probably also make the required tools. The Spanish made bushings sold on eBay are extremely inexpensive even with shipping (which is very quick from Spain) so I can't imagine you'll find them cheaper in the quantities you need.

I can't say for sure whether or not the TD-124/II has less rumble than a Dual 1219, but given their respective locations in the food chain it should be the case.. What I can say is that the TD-124/II in proper working order has much less rumble than most cutters used to cut records. I do have a number of records that were cut on heavily tweaked and upgraded cutters with rather low rumble, and I hear no rumble at all on these recordings. (My Onken style bass modules start to nose dive around 35Hz) It is an extremely quiet machine - mine however had very little use in its original life - I'm making up for that now at the rate of about 15 - 20 hrs a week.
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote
Old 13th August 2012, 05:44 PM   #599
diyAudio Member
 
missouricatman's Avatar
 
Join Date: Jun 2012
Location: Kansas City, MO
Hi kevinkr,
When I was working on the Thorens this weekend, I did tweak the height adjustment screw for the stepped pulley, in part to be certain I was spot-on with the idler wheel on all speeds, but more to investigate the scraping sound and mild shimmy. I did it while the turntable was running (re-oiled afterward), so I could hear in real time any changes while raising and lowering the stepped pulley. While I did get it quieted down a fair amount, I'm pretty sure that was the result of flipping the teflon thrust pad back so the base of the stepped pulley spindle was back in the tiny impression I assumed was a wear spot.

In any event, as a result of making that adjustment, I know it's not hitting the top of the bushing, nor is the bottom of the idler wheel hitting the top of the next step. What I failed to do, however was to simply check at idle to see if I had any play in the bushing.

As for the idler wheel, I haven't really checked that for play either. You mentioned normal operation may allow for a few thousandths of an inch. I'd say I've got a tad more than that going on. It's not walking a lot, but it is walking more than I suspect it should, although I'm basing that on how the Dual 1249 idler wheel behaves with its platter off. The Thorens idler wheel is larger, of course, so anything that's transmitted to to the outer edge will be more apparent, but doubt it's just that.

I don't think I mentioned what I'm using downstream of the turntables. I picked up a Sansui AU 719 for $99 at a local thrift store. I'm sure there are better amps, but outside of studios I did some work with back in the 70's, I sure haven't had access to them. I've yet to have it gone through (setting bias is within my knowledge base, but past that I'd be gambling), simply because I'm so happy with the upgrade I don't much like the idea of being without it.
  Reply With Quote
Old 3rd September 2012, 01:24 AM   #600
kevinkr is offline kevinkr  United States
diyAudio Moderator
 
kevinkr's Avatar
 
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Default Early TD124 Refurb Part II

Rebuilt the motor today and happy to report the table now runs on speed and has been doing so for several hours now. The table after reassembly just refused to run at full speed, it was just slightly slow no matter what I did - even disabling the eddy current brake didn't help. The problem was evident on all speeds - pointing to the motor.

This is a tight budget project for an acquaintance so where possible parts are being cleaned up and reused.

The last picture shows the victim apart and the rivets retaining the bearing housings have been drilled out.

The first and second picture show the original felts in soak cycle 3 of 5 in lacquer thinner, and when clean and dry. The felts looked and felt pretty good after their soak in lacquer thinner, they were pretty hard from the oil gummy oil prior to soaking. I dried them thoroughly before impregnating them with fresh oil

The third picture shows filthy oil oozing out of the bearings in my dedicated workshop oven after being heated to 300 degrees F (149 degrees C), this was followed by a quick soak in lacquer thinner. Once clean they were soaked in hot oil in the oven for 10 minutes and then allowed to cool.

The fourth picture shows the upper bearing housing sans large felt, but otherwise ready to be reinstalled.

Fifth picture is the lower housing , six with lower housing completed, and seven is the motor reassembled. Make sure the bearings are aligned properly prior to tightening things down and check for freedom of rotation and noise (powered on the bench) prior to installation if possible.

The next to last is the victim being run in. So far running on speed for a couple of hours.
Attached Images
File Type: jpg soaking_felts.jpg (241.2 KB, 272 views)
File Type: jpg clean_felts.jpg (115.6 KB, 260 views)
File Type: jpg dirty_bearings.jpg (182.1 KB, 257 views)
File Type: jpg bearing_assy.jpg (126.9 KB, 89 views)
File Type: jpg lower_bearing_assy.jpg (208.7 KB, 77 views)
File Type: jpg upper_housing_in_place.jpg (198.0 KB, 80 views)
File Type: jpg motor_together.jpg (279.5 KB, 80 views)
File Type: jpg clarks_table_running.jpg (203.1 KB, 93 views)
File Type: jpg Motor all apart.jpg (200.9 KB, 91 views)
__________________
"Extraordinary claims require extraordinary evidence." - Carl Sagan
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need help with Phono Cartridge for Thorens TD-166-MKII sonictonicmusic Analogue Source 5 24th July 2013 09:43 PM
Thorens TD-124 newbie neil_kaye Analogue Source 6 17th March 2008 03:44 AM
Thorens TD-125 MKII Parts needlenose Analogue Source 9 12th March 2005 11:08 PM
Transformer for Thorens TD-166 MKII Peter Menting Analogue Source 5 30th August 2003 07:15 PM
Thorens TD 124 MKII question louis Analogue Source 3 2nd July 2003 04:27 AM


New To Site? Need Help?

All times are GMT. The time now is 06:49 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2