HMV 97 (portable) tonearm disassembly

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nostalgia
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HMV 97 (portable) tonearm disassembly

Post by nostalgia »

Has anyone disassembled a HMV 97 (portable) tonearm? I plan change exchange the tonearm on this red HMV 97, since the outer end ( soundbox end) is warped. However, as we can see, the tonearm base on this tonearm has a base with ball bearings, and after unscrewing the small bolt that locs the tonearm to the base, there are still some correct movements to be made to remove the arm. I have carefully tried to widen the opened lock/collar after removing the small bolt that locks the tonearm to the base, using a small screwdriver, but I am very hesitant to use more force as it looks now without asking if someone successfully has made this operation in the past. Maybe the ball bearings need to get out at this stage shown on the photo?
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HMV 97 tonearm base.jpg

Phono48
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Re: HMV 97 (portable) tonearm disassembly

Post by Phono48 »

There should be a cap over those ball bearings (look on your blue one). Once the nut is undone, the arm just lifts out, but there may be some old grease that is holding it in. If the cap is there, but you have removed it for illustration, put it back on to ensure the ball bearings don't fall out. You don't need to force the gap in the arm socket open any further, the arm will come out when the nut and bolt are just loosened.

Barry

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nostalgia
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Re: HMV 97 (portable) tonearm disassembly

Post by nostalgia »

Thanks for replying Barry. I removed the cap just to take the photo. Do you mean I should put the cap back before removing the tonearm? Are the ball bearings connected down there, in a ring? I have tried to apply force to remove the tonearm, but it will not disconnect. I have two red 97 models, both rather tatty in appearance, but will try to make one complete, by switching tonearm etc. I am hesitant to apply more force, but maybe that is what it is all about due to hardened grease....

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Re: HMV 97 (portable) tonearm disassembly

Post by Phono48 »

Replace the cap, then swing the arm either to the left or right, until it's limit is reached, then push the arm further so that the whole base of the arm revolves in the socket. This should free it, then the whole arm lifts out complete with the captive ball bearings, but if removal is difficult, then don't bother, just swap the front part of the arm by taking off the small bracket that stops the front part (crook0 from dropping when, for instance, changing needles, then unscrewing the crook and replacing it with the undamaged one.

Barry

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Re: HMV 97 (portable) tonearm disassembly

Post by nostalgia »

I unfortunetaly am not able to do this. The tonearm does not have a limit to the right or left on my machine, it just rotates around endlessly..and around. I have to change the complete tonearm, since the bracket that stops the front part from dropping, also is missing on this tonearm. I can see the ball bearings are loose balls swirling around in the socket, but also a metal ring construction shows only half of the balls, preventing them to get be relased upwards. The only thing that I can see that possibly will release the arm is to widen the gap on the back side of the socket, but I worry it will break if I put too much force on it.

Update: The only way to remove the tonearm on my machine, is to remove the balls on the ball bearing one by one throgh the gap at the back side of the socket, by widening this space. After doing that, the tonearm would most probably be released. To avoid putting big pressure on this gap by widening it, I was lucky to find a spare bracket for the mid section of the arm, from a donor machine. Problem solved, and lesson learned, meaning the tonearm on the 97B is not easlily removed !
Last edited by nostalgia on Thu Feb 11, 2021 6:36 am, edited 1 time in total.

Phono48
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Re: HMV 97 (portable) tonearm disassembly

Post by Phono48 »

Glad you got the problem sorted, but I still can't see where difficulty lay! The arm on the 97 has got to be the easiest one to remove! The only time the arm does not have a limit stop is when the autobrake actuating bracket is not fitted to the base of the arm, as it is that that limits the stopping position, (see the close-up of the arm base. (1st photo). I took the arm out of one of my 97s in 10 seconds flat! The photos show the two parts of the assembly, the arm and the socket. Is your any different? Just curious!

Barry
Attachments
P1050470.JPG
P1050469.JPG
P1050468.JPG

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Re: HMV 97 (portable) tonearm disassembly

Post by nostalgia »

This explains it all...the tonearm on my 97 B machines look totally different. Now we know that there are two different tonearm sockets for the 97 model. All my machines has this (terrible) solution....Maybe on all 97B models, or not? Is your machine a 97B? This tonearm rotates..and rotates...

It looks like someone has used a hacksaw sawing half way through the base, but actually this "saw mark" are on all my 97B machines, maybe to allow the gap to be opened wide without destroying the (pot) metal? I anyway was happy about not having to widen the gap to release the ball bearing...
Attachments
97B tonearm (3).jpg
97B tonearm (2).jpg
97B tonearm.jpg
Last edited by nostalgia on Thu Feb 11, 2021 6:35 am, edited 1 time in total.

Phono48
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Re: HMV 97 (portable) tonearm disassembly

Post by Phono48 »

How odd! I've just checked my three 97s, and they are all "C"s, and all have the same arm base as in my pictures.

Barry

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Re: HMV 97 (portable) tonearm disassembly

Post by nostalgia »

When we thought we knew "everything" there was to know about these machines, we can still make some new discoveries, Barry.
Interesting observations, and I can well undestand why HMV dropped the tonearm base found on the 97B mode, and replaced it with the design on your 97C.
Here is a photo of the same tonearm socket that is found on my red 97B, also found on my blue and black 97B ( blue color worn off on the blue socket)
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97B tonearm sockets.jpg

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Re: HMV 97 (portable) tonearm disassembly

Post by soundgen »

replace the whole horn and tone arm , easy peasy ! :D

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