Garrard 301 Motor overheating post servicing

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vinylnick
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Garrard 301 Motor overheating post servicing

Post by vinylnick » 01 Jul 2016 09:00

I am putting to use an oil bearing 301 after a considerable period of storage with its previous owner. It only required a nice clean up and lubrication at suggested points to get singing. It is a noticeable step up from my Technics DD.

Thus having used the 301 for about 3 months I took it up for some deep TLC.

The first call was the main spindle which was serviced as per SOP, not that anything was amiss to start with.

Last week I took up the motor. The clamshells were taken apart carefully and visual inspection didn't suggest anything abnormal. No sign of wear at the Bushes or the rotor shaft. Stator windings looked factory fresh.

The top and bottom clamshells were soaked in gasoline overnight to loosen up any embedded crud and to free up the felt washers if at all they were stiff. After the soak they were left to air dry for a week to allow complete evaporation of the spirit.

After they were dry as a bone, both the bushes were charged with light machine oil which is probably grade SAE10. I kept charging oil as the bushes and bearing assembly kept soaking it. After 2 days they reached saturation and oil was sweating over. I did not take apart the bottom bush housing. Such drastic measures were seemed unwarranted following a visual inspection of the bush and its embedded ball under a magnifier.

Post clean up the motor was assembled back by aligning all the elements carefully. The lugs were tightened/loosened sequentially, checking for smoothness of rotation, hearing for any internal noises etc. In the end the shaft was rotating very freely without any friction or noise. The lug nuts were treated with a drop of Loctite.

After installing the motor back on the board, I felt the vibrations were a wee bit higher. So much so that I could feel them at the cast chassis. But after a couple of hours they settled down a lot and now I can’t feel them on the board. Neither are they audible if I check the chassis with a stethoscope.

It really sings now. Much improved performance. Rumble is zero, wow & flutter almost zero. Respects!

But along came what I think is a major development. HEAT

The motor gets warm in about 20 minutes even without the platter. After about 1 hour it gets pretty hot. Finger-O-meter test says “uncomfortable to touch” for more than 30 seconds. The heat permeates everywhere. Even the speed pulley receives the heat via the spindle shafts and transferring it to the idler.

I don’t particularly remember if the motor generated as much heat in the pre-servicing stage. But I would have noticed it if it were this hot.

It this normal? I am specifically worried about the long term effect on bearings and worse the Idler.

The motor otherwise runs completely free. So much that after powering off the Eddy disk rotates for approx 40 (+/-3) seconds. Timed with a stopwatch.

I work in precision mechanical industry and I am confident that the job was done competently. Absolute cleanness was maintained all along. No damage was brought any part. They were in perfect condition to start with as the board had seen very light usage.

After the overhaul the motor has had about 5 hours of run time and counting. Would it improve after a few more hours?

As I see there is nothing mechanically amiss to cause this abnormal heat. Would the Stators normally generate as much heat? They were removed and put back the way they were. At least I think so.

They were not cleaned with any liquid but simply wiped with a soft cloth. If the Stator is the culprit then I am afraid the heat will degenerate them over time. The coils measure 430 ohm when wired for 230volts.

As I type this the motor is spinning to put on some miles. Do I rush and power it off?

Advises respectfully solicited.

A70BBen
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Re: Garrard 301 Motor overheating post servicing

Post by A70BBen » 02 Jul 2016 05:34

"Uncomfortable to touch/hold" is normal. Those induction motors do generate a lot of heat. If you didn't align the bearing sleeves you could try doing that...they are self-aligning, you sharply RAP the motor with a screwdriver handle or similar while it is running. But it sounds like they are aligned satisfactorily already.

I really should measure the temperature of my 301's motor when fully warm, but never have done it!

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Re: Garrard 301 Motor overheating post servicing

Post by folkishienne » 02 Jul 2016 08:34

The soaking of the clams with bearings affixed is not advised. Any varnished lubrication and detritus will have leached out from the bearing either to it's surface or indeed the felt reservoirs which themselves need to be replaced. The vibration transference may be to do with the central linkage (Pitch control linkage)note the x3 small springs in the hub are they stretched? or when observing the underside does the linkage pass through its arch of movement on the level or is it twisting / touching the motor even? (This can happen if you removed the central linkage when removing the motor.

vinylnick
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Re: Garrard 301 Motor overheating post servicing

Post by vinylnick » 03 Jul 2016 08:36

A70BBen wrote:"Uncomfortable to touch/hold" is normal. Those induction motors do generate a lot of heat. If you didn't align the bearing sleeves you could try doing that...they are self-aligning, you sharply RAP the motor with a screwdriver handle or similar while it is running. But it sounds like they are aligned satisfactorily already.

I really should measure the temperature of my 301's motor when fully warm, but never have done it!
Thank you.
That heat does seem a little unusual. I will be surprised if friction is causing it given how freely the shaft rotates.

vinylnick
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Re: Garrard 301 Motor overheating post servicing

Post by vinylnick » 03 Jul 2016 08:59

folkishienne wrote:The soaking of the clams with bearings affixed is not advised. Any varnished lubrication and detritus will have leached out from the bearing either to it's surface or indeed the felt reservoirs which themselves need to be replaced. The vibration transference may be to do with the central linkage (Pitch control linkage)note the x3 small springs in the hub are they stretched? or when observing the underside does the linkage pass through its arch of movement on the level or is it twisting / touching the motor even? (This can happen if you removed the central linkage when removing the motor.
Thank you.

Wouldn't this cause increased friction? I reported earlier the shaft runs very very freely. I cant hear any grinding noise.

Now the misdeed has be done do you think this would self correct over a period of usage? Any suggestions on reversing this situation? I am loath to dismantle the bottom bearing housing and would try to keep any intervention to minimum.


The pitch control linkage is free of any interference. But one of the springs is more stretched than the other tree. As a result the central point is slightly offset. But I cant discern any vibration in the motor board. Putting a stethoscope to the chassis I can hear just the slightest motor noise which I think is normal.

Update:
I loosened up the lug nuts by less than a quarter turn. This lead to dropping of the spindle by about .05mm. The eddy disk height too needed readjustment to prevent fouling with the magnets.

I cant really say for sure but maybe the heat and vibration have reduced a little.

tele88
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Re: Garrard 301 Motor overheating post servicing

Post by tele88 » 03 Jul 2016 10:24

The temp.from the motor is about 40-max 45 degrees probably the bearingfriction is to high.For a good revision it is recommended to replace the ball from the trustbearing . In the vibration report I made you can see the difference between fore and after revision.
Scan_20160703 (2).jpg
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LPfan
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Re: Garrard 301 Motor overheating post servicing

Post by LPfan » 03 Apr 2019 09:09

Hallo to all Garrard fans :)

Posting after a long break, I wanted to start a fresh thread but noted that a discussion has already taken place on the very same issue, so reviving this thread.

I took my 301 out of storage last week, it was hibernating for five years. Carried out the usual checks and lubrication procedures and fired up the motor, standing alone out of the chassis. It runs silent and smooth, however, the temperature rose to 60°c in half an hour. Switching on a wall fan that was about 8' away near the ceiling brought the motor down to 45°c in twenty minutes.

IMO the problem is due to the clamshell. The rotor has blades on each end, but I could not feel any air escaping from the slots and holes in the lower clamshell. This is due to the upper clamshell having no such holes for air ingress, so air circulation cannot be established. The upper clamshell is designed like that for better shielding but this affects ventilation.

One solution as I see is to make a shroud around the motor cage with a fan on the rear side. The other option is rather drastic, drill holes in sides of the upper clamshell.

What do you all say?

Regards,

wart
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Re: Garrard 301 Motor overheating post servicing

Post by wart » 10 Apr 2019 09:31

Imho it's not overheating. Sounds normal for Garrard 301 motor.

SupaWales
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Re: Garrard 301 Motor overheating post servicing

Post by SupaWales » 11 Apr 2019 23:34

I have a Garrard 401.

Not exactly the same motor but similar.
It runs hot, always has done.

Years ago I maintained loads of Garrard SP25 from Mk1 to Mk4.
The motors also ran hot.
They were a slimmed down version of the bigger motors.

There never seemed to be a problem with them running hot.
The decks were in disco consoles and they got thrashed 7 nights a week.
Only ever had one actual motor fail.. one of the coils went open circuit.

DSJR
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Re: Garrard 301 Motor overheating post servicing

Post by DSJR » 12 Apr 2019 11:36

301's and 401's were designed for 24/7 running in a broadcast environment I remember. As long as the lubes can take this, I wouldn't worry.

Main issue for me is the dire motor 'rumbles and whines' they can all too easily transmit to the stylus and fancy-foo plinths be damned! To hear a vinyl LP without this added noise and convex soundstaging (even from a serviced re-plinthed example) is a revelation. Much as I love the look of a 401, I don't know if I could go back to one in all honesty...

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Re: Garrard 301 Motor overheating post servicing

Post by SupaWales » 13 Apr 2019 00:24

@DSJR..

I know the 401 isn't the quietest turntable out there, but mine seems pretty good for a massive idler drive.

It's sheer musicality over my Dual CS505-3 or Revolver Rebel seals the deal for me, along with it's bass extension compared to the Dual & Revolver. The Garrard seems able to find an extra octave compared to them.

I really don't find the slightly elevated noise floor a problem even with very quiet classical music.

Mine is mounted on a 2 piece ash plinth with springs sold as Linn LP12 replacements between the top & bottom.
Squash balls in recesses are used as feet

The whole lot including the 401 & SME 3012 arm weighs just under 30Kg.

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Re: Garrard 301 Motor overheating post servicing

Post by DSJR » 14 Apr 2019 18:25

Extra bass on vinyl *can* be added colouration, as so much was often removed below around 60Hz when cutting the master acetate. If you like what it does, then good on you sir - Heck, I sold, set up and owned Linn LP12's in the middle of their 'fruitbox' era, so I'm a fine one to talk - they're much better now at silly-high prices though these days. Top idlers do have this 'bass thing' and I agree, it can be addictive. I was 'saved' though by a mastering and cutting engineer who put me straight on a few things :D Enjoy your deck but please be aware what it's doing to the music the deck 'system' reproduces...

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Re: Garrard 301 Motor overheating post servicing

Post by toaster999 » 27 Apr 2019 16:55

not sure you've heard a decent 401? rumble and whine??

wart
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Re: Garrard 301 Motor overheating post servicing

Post by wart » 11 May 2019 12:20

DSJR,
"Rumble and wine" is not the design fault, it's due to worn pulley and worn idler wheel.
You can make idler wheel rubber round again on lathe. And there are plenty of new pulleys for sale.

Afterwards other usual maintenance can be done - stripping the motor, oiling, new plinth etc. But core of reducing rumble in Garrard is to make wow and flutter normal again.

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Re: Garrard 301 Motor overheating post servicing

Post by Matthew_DK » 20 May 2019 10:55

tele88 wrote:
03 Jul 2016 10:24
The temp.from the motor is about 40-max 45 degrees probably the bearingfriction is to high.For a good revision it is recommended to replace the ball from the trustbearing . In the vibration report I made you can see the difference between fore and after revision.

Scan_20160703 (2).jpg
Where can find a new thrust ball for the buttom bearing in a 401 motor? I have just refurbished my 401 motor, replaced the lower bushing with a new on and the motor is running quite good now, but im interrested in maybe trying out the ball aswell. I only cleaned and lubed to original ball.

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