HMV motor not revolving: spring issue?

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Paolo_MK68
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HMV motor not revolving: spring issue?

Post by Paolo_MK68 »

Good morning,

after having always functioned without a single problem, suddenly the motor (type 271-D) of one of my 102 refuses to spin the turntable.
I have wound up the spring as usual but nothing happened. Actually the mechanism is not completely stuck: I gently tried to revolve the turntable by hand, but it moves only counter-clokwise (i.e. the opposite of the normal rotation)against spring resistance. I checked the motor to see whether something got in between the gears but apparently there's nothing abnormal, plus all the mechanism has been serviced recently and it's well greased/oiled.
Then I realized that after the last time I played the gramophone I left the spring completely wound down without applying the turntable brake. I have a very basic knowledge about these motors, but could it be that the spring lost contact with the notch in the interior of the barrel due to the turntable flywheel effect?
Thank you for any suggestion.

soundgen
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Re: HMV motor not revolving: spring issue?

Post by soundgen »

Paolo_MK68 wrote:Good morning,

after having always functioned without a single problem, suddenly the motor (type 271-D) of one of my 102 refuses to spin the turntable.
I have wound up the spring as usual but nothing happened. Actually the mechanism is not completely stuck: I gently tried to revolve the turntable by hand, but it moves only counter-clokwise (i.e. the opposite of the normal rotation)against spring resistance. I checked the motor to see whether something got in between the gears but apparently there's nothing abnormal, plus all the mechanism has been serviced recently and it's well greased/oiled.
Then I realized that after the last time I played the gramophone I left the spring completely wound down without applying the turntable brake. I have a very basic knowledge about these motors, but could it be that the spring lost contact with the notch in the interior of the barrel due to the turntable flywheel effect?
Thank you for any suggestion.
YES ! you should never leave a motor completely wound down as the spring centre can be opened out by the spinning turntable or by someone spinning it as well , you need to open up the spring barrel and reform the centre around the spring arbor, unfortunately this doesn't always succeed and then the answer is a new spring !

https://www.ebay.co.uk/itm/133593787304

Phono48
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Re: HMV motor not revolving: spring issue?

Post by Phono48 »

Paolo_MK68 wrote: I have wound up the spring as usual but nothing happened.
In that case the spring can't have come unhooked from the centre, or it wouldn't wind at all!

Barry

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Re: HMV motor not revolving: spring issue?

Post by JerryVan »

Phono48 wrote:
Paolo_MK68 wrote: I have wound up the spring as usual but nothing happened.
In that case the spring can't have come unhooked from the centre, or it wouldn't wind at all!

Barry
Do you feel ever increasing resistance from the spring as you wind it? Does it wind forever without the feeling of being fully wound?

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Paolo_MK68
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Re: HMV motor not revolving: spring issue?

Post by Paolo_MK68 »

JerryVan wrote:
Phono48 wrote:
Paolo_MK68 wrote: I have wound up the spring as usual but nothing happened.
In that case the spring can't have come unhooked from the centre, or it wouldn't wind at all!

Barry
Do you feel ever increasing resistance from the spring as you wind it? Does it wind forever without the feeling of being fully wound?
Hello, thank you to all for you answers.

@Barry: that makes sense, actually I could not explain to myself how it's possible for the spring to unhook and still feel an increasing resistance while turning the handle

@JarryVan: yes! I could feel the spring increasing its resistance, but I did not insist on winding it up completely.

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Re: HMV motor not revolving: spring issue?

Post by Inigo »

Might be that the auto brake lever near the tonearm base is set in the ON position? One never knows... :roll: or maybe the auto brake is engaged, badly positioned or whatever... Did you try removing the turntable?
Inigo

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Paolo_MK68
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Re: HMV motor not revolving: spring issue?

Post by Paolo_MK68 »

Inigo wrote:Might be that the auto brake lever near the tonearm base is set in the ON position? One never knows... :roll: or maybe the auto brake is engaged, badly positioned or whatever... Did you try removing the turntable?
Hi Inigo, I'm sorry no one of the conditions above apply... :) I checked the auto-brake lever position, I removed the turntable, I took the chance to dismantle every bits screwed on the upper board to clean and polish the wood with a good wax, in hope that this demonstration of loving care would persuade the motor to spin... nope!
In the next days I'll remove the motor from the board and have another look, but I do not dare to disassemble it. In case of persistent malfunctioning I'm afraid that the only way out will be sending the motor to my favourite gramophone engineer 800 km from where I live! :shock:

p.s.: the missing speed indicator plate needs to be re-nickeled, therefore I did not reattach it!
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Re: HMV motor not revolving: spring issue?

Post by JerryVan »

Can you post some pics of the motor from various vantage points? Maybe one of us can spot the trouble.

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Paolo_MK68
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Re: HMV motor not revolving: spring issue?

Post by Paolo_MK68 »

JerryVan wrote:Can you post some pics of the motor from various vantage points? Maybe one of us can spot the trouble.
Hello, here are the pics and at the same time what I think is the solution of the problem.

Following the above suggestion for which I thank you all, I tried to reason forgetting the spring, and I almost concluded that the culprit of the malfunction was somehwere in the gears. Looking here and there I noticed that the only evident reason for the spindle stoppage were the little screws locking the brass collars of the speed regulator on its shaft, which immediately banged into the turntable shaft gear whenever the motor tried to catch speed.
I noticed also on the cylindrical spacers that the two screws locking the shaft sleeves were somewhat loose, and therefore may be the shaft itself ended misplaced and caused the interference between the screws and the spindle gear. I moved slightly the shaft to the right and tighten the screws to lock it in place. The motor started to turn, caught speed, and the interference did not happen any more!

I'm pretty sure a professional gramophone engineer will shudder in horror, and I myself am not sure to have worked in a totally correct way, but this is the solution I found at the moment. Now I have only to reassemble the motor under the board and check if everything will work, especially the speed regulator lever.
Feel free to correct me or express your criticism anytime.
Thank you again and have a good evening.

p.s.: I beg your pardon in advance should my explanation be not clear or the english terminology less than correct! :roll:
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003.jpg

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Re: HMV motor not revolving: spring issue?

Post by JerryVan »

I believe you've figured it out! The only danger was working on the governor while the spring is still wound, but you managed to set things right without a "runaway" motor. You may find that by moving the governor over as you did, the speed indicator my now be off a bit. Or, perhaps it will now be more accurate, since the governor seems to have slipped over into an incorrect location, which you have now remedied. Suffice to say, it may be different than it was before. :) Just the same, you did the right thing. As for your English, it's better than that of a lot of Americans :) .

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