HMV-102 Auto-Brake Friction Too High

[leels1]

All of your washers appear to be located in the same order as the other example, except as you point out, that one of your washers is a smaller diameter. I'd guess that it not so critical. What may be critical is that your washers look notably thicker than those in the other example.

It shouldn’t matter unless they’re massively too thick as adjusting the screw should compensate.

Just thinking, are the two springs present on the left side of the autobrake, and are they the correct tension? If they’ve been stretched it won’t work, and too short the same.

The parts with the friction washers should be scrupulously clean too in order to produce the friction. I’ve taken the orange washers off, cleaned and roughed up with some sandpaper, then cleaned all the metal parts to make sure no grease.

They’re not hard to get working despite the reputation, I found anyway!

[leels1]

With the Autobrake Mark I there are no such things as "constant drag" (it will actually engage if the tonearm stands perfectly still) or "push needed at the end" (it actually waits for a reverse pull of the tonearm), I once again suggest watching my boring videoclip linked above to get an idea of how this masterpiece of mechanics/watchmaking works before posting messages like these, which - I am very sorry to say - belong to the "misinformative" cathegory.

It is amazing how well (and over engineered!) this brake is.
I’ve never had any drag on any autobrakes on many HMV machines that I’ve noticed. HMV made tens of thousands of 102s and can’t imagine no one would have noticed or commented on undue wear.

How would you be able to measure the force exerted as the tone arm moves across the record with/ without the autobrake on? Is there a specific device that could be used?

[Marco Gilardetti]

Just thinking, are the two springs present on the left side of the autobrake, and are they the correct tension

Ditto. As I also mentioned in the videoclip, these springs are quite often missing and/or replaced with inappropriate spares.

They’re not hard to get working despite the reputation, I found anyway!

Agree in full, but this is true only once the user has made the effort to understand how and when the autobrake will engage, otherwise any repair attempt will be to no avail. As a matter of fact, my educated take on why it was so short lived, despite possibly being the most versatile and efficient autobrake ever engineered, is that most customers were and are very reluctant to do even the slightest effort to understand how it works and what to expect, back then and now just as well. Proof for that is how often it can be read here and elsewhere that "it stops the turntable erraticly even if the tonearm sits still absolutely untouched" - which is exactly what it was engineered to do!

It is amazing how well (and over engineered!) this brake is.

Words can hardly say how much I do agree with this sentence! The definitive autobrake - perhaps just too good to be understood by the average customer.

I’ve never had any drag on any autobrakes on many HMV machines that I’ve noticed.

Agree once again. In my opinion autobrakes of this type (just as well as the Type 3, which I also covered in another clip) deploy such low friction over such a long leverage that their presence/absence is absolutely negligible, and I doubt it is measurable at all considered the context (super heavy tonearm, super heavy soundbox, inaccurate tracking, approximate bearing, etc.).