HMV 102 with universal autobrake no. 5

[nostalgia]

This blue HMV 102 came into my hands today, and there is a problem with the main spring, it is broken or slips at one end, I have not yet had the time to check. However, this is the first time I have got hold of an early 102 with this no 5 autobrake. There is a small cotton thread at the end of the brake, that I already have removed. I believe this is substituting a broken/lost small spring, even if I can't see this detail on the brake in the HMG book. This autobrake looks very complex to my eyes, and I think it is causing the motor to have problems. I am tempted to remove it completely, do you agree? I have a few manual brakes that for sure will work much better, if I at all can repair this auto brake, something that I doubt.
I upload some photos of this motor, also as a reference for this motor and autobrake.

The machine has a 5A soundbox, that looks good. I guess this machine originally was equipped with a no 16 soundbox, that is luckily removed.

[Phono48]

Oh dear, the infamous "universal" brake rears it's head again! I have two 102s with this brake, and know from experience that they are a nightmare to get working correctly. However, apart from the missing spring, everything seems to be present, so it would be worth the trouble to get it going correctly. I will take and post photos of mine tomorrow, just to double - check. Whilst admitting that they are not the most reliable of autobrakes, when the DO work, they are trouble-free about 90% of the time, and just require a tweak occasionally. I wouldn't remove it, or add a manual brake, both of which would detract from the machines originality.

Barry

[nostalgia]

Thank you Barry, much appreciated.
I will try to see if I can make it work then, and see if I can find a small spring from another source, if it will work. It can be interesting to look closely at this autobrake, trying to understand how it works.

[Phono48]

As you can see, there is another tiny spring on the reverse side, in case yours is missing. The long spring is a fairly weak one, so you may need to experiment with various ones.

Barry

[nostalgia]

Thanks a lot for posting the photos, Barry. I have the small spring on the back side, luckily. I will try to look at some different autobrakes that are found on some scrappy portables, and see if one can be used. Thanks to your detailed photo, I am actually able to see the size of the spring in detail. I will also try to understand how this autobrake is working, since at the time of writing this, I still have not grasped how it is functioning. I will clean all the parts, check the spring etc..before trying to reinstall the autobrake.

[Inigo]

For some cases, not this (i don't have this brake) I use recycled ballpen springs, there's a type which is long and weak... Just in case you find it difficult to find...

[Phono48]

I will also try to understand how this autobrake is working, since at the time of writing this, I still have not grasped how it is functioning.

I'll try to explain as best I can. You will have to re-instal the brake in order to see how it works. Then replace the small eccentric circular plate and nut that you had to take off in order to remove the assembly. Now wind the motor, and you will see that as that eccentric plate revolves, it causes the curved plate (on the right) with the teeth at both ends to rock backwards and forwards. Now move the tone arm inwards VERY SLOWLY, and you'll see that the striker arm that is hit by the turntable hub (as on the usual 102 autobrake) starts to move into the centre. It is knocked backwards by the rocking plate, but when the arm comes to the end of the record, and either stands still on a record with no run-out groove, or moves in and then backwards, as in a record that does have a run-out groove, then the rocking plate will gradually engage with the teeth on the striker arm, and move it in fully to be struck by the turntable hub, and thus stop the turntable. Note, though, that in the case of the record not having a run-out groove, so the arm stays still, it can take quite a few seconds before the mechanism goes through it's paces and stops. Good luck!

Barry

[Marco Gilardetti]

I am tempted to remove it completely, do you agree?

Disagree in full. The Universal Autobrake is the reason why the machine you have in your hands is interesting, otherwise it would just be "yet another" 102, one of the most common gramophones in the world.

Here's a video in which it is explained in detail how it works and - most important of all - how it has to be expected to operate, the timing and delays that it has, which are important to understand otherwise you might have the impression that it's operating erratically or not operating correctly:

https://www.youtube.com/watch?v=W7Y4XF6f5FE

[nostalgia]

Barry, Inigo, Marco, thank you for taking the time to respond in detail to my post, I will try to make it work, and try to find a compatible spring. Thanks for suggesting a spring, Inigo..and thanks for writing in detail Barry ! It is much appreciated.
The autobrake will maybe be the challenge of the summer, but mastering also this autobrake would be a fulfilment.
And yes, I agree...the autobrake makes the machine interesting, Marco...and to make it work, would be great. I was yesterday able to find an old post on the forum, where it was suggested that this brake was better removed and replaced with a manual brake, and that caused my initial feeling it maybe should be removed, but I absolutely prefer to make it work, if it is possible.
Thanks again, I will after servicing the machine, tell if I was able to make it work.

Update: Vow, Marco...what a great video you have made ! Thanks a lot for posting the link

[Marco Gilardetti]

Thank you!

If you can't locate a proper spring, you may temporarily try with a rubberband, as rubberbands are easy to find and come in all sizes. As written earlier by Barry, it should exert only a feeble recall force, not a strong force that would stuck the parts in place.

Remember that the "red washer" area is painted red as a reminder that it shouldn't be lubricated. Personally I would try the autobrake "as is", possibly it will work at first try. Only in negative case I would try to disassemble and clean parts like the red washer area, which is an adjustable friction and once disassembled needs to be readjusted by trial and error.