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HMV-102 Auto-Brake Friction Too High
Posted: Sun Jan 21, 2024 6:58 pm
by MasterJack555
So I have a very good condition 102 from 1931 which has only the autobrake as it should. The autobrake works pretty much as its supposed to except that no matter what I do the autobrake's friction/resistance is too high. About half way through every record, the record will start repeating as the force from the record grooves moving the tone arm is not enough to overcome the autobrake arm's friction. I have taken the autobrake apart more than once, cleared it of any debris, oiled it, found out you shouldn't oil it and cleaned it of any oil, and I've tried loosening the brake's friction screw but then the screw starts loudly scraping against the bottom of the platter.
Any help or advice as to how to fix this issue would be greatly appreciated! I have also included a couple pictures of the part of the auto-brake that's giving me trouble.
Re: HMV-102 Auto-Brake Friction Too High
Posted: Mon Jan 22, 2024 7:05 am
by Marco Gilardetti
I don't know if there were variants of the Mark I autobrake (shouldn't be, as it was short lived), however your unit looks wrongly assembled, with some inverted parts.
If you look to the very first frames of
this videoclip of mine you will immediately see that the huge red washer (indicating "no oil here") shall be well exposed on top, and not hidden below other components.
Re: HMV-102 Auto-Brake Friction Too High
Posted: Thu Jan 25, 2024 11:12 am
by Oedipus
Thank you, Marco, a masterly exposition of the No 5 autobrake -- yes, Mark 5, not Mark 1!
Re: HMV-102 Auto-Brake Friction Too High
Posted: Thu Jan 25, 2024 4:03 pm
by leels1
Apart from the assembly looking like it’s incorrect, that tiny screw just below the friction washer is what tightens/ loosens the friction (red arrow). It might take some setting up to get it totally correct but it should work.
Had the same where the tone arm wouldn’t move across the record and just stuck!
Ideally take it apart at that part too and give it a good clean so there’s no gunk/ rust stopping it move freely.
Re: HMV-102 Auto-Brake Friction Too High
Posted: Thu Jan 25, 2024 4:08 pm
by leels1
Does this help you see in what order it fits together?
Re: HMV-102 Auto-Brake Friction Too High
Posted: Sun Jan 28, 2024 4:00 pm
by MasterJack555
leels1 wrote: Thu Jan 25, 2024 4:08 pm
Does this help you see in what order it fits together?
Yes this does thank you! It also points out another issue: My machine only has a single large red washer instead of the two (one on top and one on bottom) that yours has which may also be contributing to the issue.
Re: HMV-102 Auto-Brake Friction Too High
Posted: Sun Jan 28, 2024 5:59 pm
by JerryVan
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.
Re: HMV-102 Auto-Brake Friction Too High
Posted: Mon Jan 29, 2024 9:28 pm
by BassetHoundTrio
My reply may get some heated responses, but I never use any auto-brake as it causes lateral drag on the tonearm, which is less than ideal. When I began using the fabulous Burmese Colour Needles, I found if the auto-brake was on, the needle would get blunt and distort before long, but when I dis-engaged the auto-brake, all was well.
Re: HMV-102 Auto-Brake Friction Too High
Posted: Mon Jan 29, 2024 11:59 pm
by Inigo
I used to do the same in my 194, especially if I was using the tonearm counterweight. That small constant drag is noticeable, don't say the push needed at the end to trig the autobrake, this also can ruin the needle point. And the 194 has a very good tracking alignment, but the 102 with its short arm has a terribly skewed angle, mainly on the outer rim of a record. I've noticed that playing à record many times in the 102 greys the grooves really fast in some cases.
Re: HMV-102 Auto-Brake Friction Too High
Posted: Tue Jan 30, 2024 4:18 am
by Marco Gilardetti
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.
