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Seized spring box
Posted: Fri Dec 20, 2024 6:59 pm
by Thomps
I just got my first wind up gramophone player. It’s a National Band portable machine in a briefcase box. After 20 or so successful plays the spring box appears to have seized- presumably because of the decades-old grease inside it. It’s partially wound and I’m not sure whether I should wind it up further in the hope it will free itself and I can unwind, dismantle and clean, or whether it’s best to try dismantling as is rather than put even more tension into it. Any advice please?
Re: Seized spring box
Posted: Sat Dec 21, 2024 10:23 am
by JerryVan
Thomps wrote: Fri Dec 20, 2024 6:59 pm
I just got my first wind up gramophone player. It’s a National Band portable machine in a briefcase box. After 20 or so successful plays the spring box appears to have seized- presumably because of the decades-old grease inside it. It’s partially wound and I’m not sure whether I should wind it up further in the hope it will free itself and I can unwind, dismantle and clean, or whether it’s best to try dismantling as is rather than put even more tension into it. Any advice please?
Don't put any more tension on it. If you need to disassemble it, you'll only need to back off on that tension. Describe exactly what the motor is doing, and not doing. Obviously, the motor is not running. Can you manually rotate the turntable, or is it jammed in place? If you were to try, could you actually wind it further, or is that jammed solid? While the spring may need cleaning and grease, I'm thinking that being able to play ~20 sides before the trouble began suggests another problem, (I'm leaning towards a bad, or jammed, gear).
Re: Seized spring box
Posted: Sat Dec 21, 2024 3:49 pm
by Thomps
For the last few plays it seemed to drag a little - the winding needed a little ‘topping up’ after a minute or so to keep the pitch correct even though it wasn’t very close to winding down. Then during a track it went quite quickly from playing to stopped. I lifted the needle but it wouldn’t start turning again by itself despite being wound. I turned the turntable by hand a few revolutions and then it seemed ok so I allowed it to completely unwind, including playing some more music on it towards the end. With hindsight I probably should have stopped there but instead I gave it a few winds and this time it wouldn’t turn the turntable. The turntable won’t turn now. Something is seized - I assume it’s something inside the spring box as everything I can see looks ok. It is hard to be sure though as the turntable spindle and all of the cogs are all joined , stuck in position
Re: Seized spring box
Posted: Sat Dec 21, 2024 3:50 pm
by Thomps
I can still wind up the spring box more- the question is whether I should!
Re: Seized spring box
Posted: Sat Dec 21, 2024 4:25 pm
by JerryVan
Thomps wrote: Sat Dec 21, 2024 3:50 pm
I can still wind up the spring box more- the question is whether I should!
No. You shouldn't. Can you post some pics of the motor, especially showing the gears?
Re: Seized spring box
Posted: Sun Dec 22, 2024 2:11 am
by Inigo
You mustn't try to disassemble the motor if there is tension in the spring. Be careful... The spring has an enormous force.
But you can extract the motor board or even the motor and examine if there is something between the gears, dirt, a loose needle (typically the gramophones have lost needles that could have been trapped by the gears), a piece of cloth or even bugs or small animals inside, mouse nests...
The are threads in the forum about what we find inside of gramophones the very first time we dismantle the boxes... Very curious! Be ready to find anything that should not be there.
It could also be a fibre gear that is worn and blocked.
I'd there is something jammed between the gears you can try rotating the gears by hand in reverse, WITHOUT DISMANTLING THEM IF THERE IS STILL TENSION IN THE SPRINGS. Also by gripping the spring barrel with your hands and slightly rotating it inside the motor you can evaluate how much remaining force is there.
Re: Seized spring box
Posted: Thu Dec 26, 2024 10:18 am
by Thomps
I can’t see anything that shouldn’t be there, and the teeth etc all seem to be in good order. Having left it for several days, today I was able to turn the turntable by hand and release a little tension - but after a very short time, the turntable started rotating independently of the shaft that should drive it. The only movement in the motor box now is that shaft moving very slightly (up and down rather than rotating) which moves the speed regulator slightly too. The rest stays stuck solid.
Re: Seized spring box
Posted: Thu Dec 26, 2024 12:01 pm
by Thomps
I’ve taken these two sections apart. The spring is free to twist in either direction and spring back. The winding mechanism seems fine turning slightly stiffly in one direction only. The rest appears to turn (also a little stiffly) but the turntable turns fairly independently of the shaft that drives it - so presumably it needs a new c clip.
My guess is that it will work fine now if I re-assemble and wind it up - but I wonder if the problem was old grease in the spring which means it will soon get stuck again. If so it might be better to dismantle, clean and re-grease now?
Re: Seized spring box
Posted: Thu Dec 26, 2024 12:28 pm
by Thomps
This is stuck fast. I assume it should turn freely? Should it have a bearing fixed in the case that allows it to turn?
Re: Seized spring box
Posted: Thu Dec 26, 2024 1:02 pm
by DanP58
Try penetrating oil , Kroil brand works very well . Apply it let it sit and it should loosen up
Dan