HMV 102 with universal autobrake no. 5

[leels1]

I don’t know if it’s any help, but I had similar issues. Adjusting the screw that holds the friction washer and pivot unit in place seemed to help. The pressure it exerts can be adjusted with this method, and thus how it engages the stop/ start.

It’s quite a sensitive unit, but not impossible to get it working.

[nostalgia]

Thanks, "leels1"! I will for sure try adjusting this screw. I am still trying to resolve in my mind how all parts of this autobrake really is working. Thanks again.

[Inigo]

there are good videos in YouTube explaining how it works. As I remember, it takes 5 turntable turns to trigger the brake...

[nostalgia]

This doesn't look correct to me, metal against metal...is it supposed to slide under the turntable?
I have tried to adjust the screw holding the friction washer and pivot, but it does not help.
When playing a record, the needle meets resistance half way through the record ( even when the metal part on the photo is helped under the turbtable), and when removing the turntable the arm also does not move freeely without applying some force halfway through the movement from rest to start position.
I have watched all the videos, they show well how the autobrake is supposed to work, but less about when the autobrake is not working as it should.

Update: I have discovered what is causing the needle to meet resistance, halfway through a record. The previous owner had never been able to make the gramophone work with the autostop, and that's why I got it cheaply in the first place.

Is this a factory error, or what is wrong here. The tone arm movement is halted by the autostop fork section of the tone arm touching and being interrupted by the placement of the autostop itself.

[leels1]

How is that possible? Is something bent out of line or something so it’s not engaging properly?

[nostalgia]

I have no idea what has happened, since both the tone arm and the autostop is secured safely in their screw holes.
The right side of the fork can of course be slightly bent down to pass under the turntable, it is just a matter of 1-2 mm, but the autostop or left fork need to be filed, a mm or two. I see no other option?

Photos are from bird view.

[Phono48]

The whole mechanism that is attached to the motor needs to be moved very slightly to the left, so that the lever on the arm just misses the part that it is hitting at the moment. Loosen the screws that are holding the mechanism and it should be able to move. Note that the arm lever passes very close to the obstruction, so the adjustment is very little. When that is done, Press the arm lever down and swing the shaped arm that is part of the autobrake mechanism over the arm lever until the protruding pin on the arm lever sites between the two parts of the shaped arms. Let me know if you need photos.

Barry

[Inigo]

That's it, it's misplaced: the tonearm long leg must be between the two fork legs. When the tonearm is in the parked position, the short leg engages behind the right brake fork knee...
Watch this explanation if it helps
https://youtu.be/W7Y4XF6f5FE

[nostalgia]

Barry, Inigo, thank you so much for helping me out with this one !
I finally discovered the one screw (out of two screws) on top of the autobrake that can slide a small or two mm to the left or right when being loosened and this way change the position of the autobrake a small mm or two, I had overlooked this fact when reinstalling the autobrake. Now the correct part of the fork is inside the autorbrake too, and the record stops when it should.
The only part left is carefully bending the fork since it makes a terrible noise under the turntable when scratching the downside of this when playing the last minute or so of a record. It for sure is a very delicate autobrake, and everything needs to be set to the millimeter, to avoid problems. I still don't grasp in my head how all parts of this autobrake really works under the turntable, particularly the clock function and the fork attached to it, but I will spend some more time with the videos, to try to get it. Mastering this autobrake seems in many ways as the last frontier when servicing different HMV motors, and thanks to Barry, Inigo and leels1, I have come a lot closer to mastering it this week, after postponing it for months !
Thank you again:)

[Phono48]

Glad you got it fixed! Whoever designed this mechanism must have had a brain similar to that of "Heath Robinson". Bear in mind that if the record you are playing does not have an eccentric lead out, and the soundbox stays still, the brake will kick in after about 6 revolutions of the turntable.

Barry