Prev: According to their plan, the first 2*3.5TeV collisions will be performedthe 30-th of March. I’m scared, but can not do anything, - all ways lead to catastrophe. LHC/CERN.
Next: According to their plan, the first 2*3.5TeV collisions will be performed the 30-th of March. I�m scared, but can not do anything, - all ways lead to catastrophe. LHC/CERN.
From: default on 14 Mar 2010 11:05
On Sun, 14 Mar 2010 11:52:19 +0530, "pawihte" <pawihte(a)fake.invalid>
wrote:

>Phil Allison wrote:
>> "pawihte"
>>>
>>> What common substance would be acceptable as a lubricant for
>>> consumer
>>> grade volume control pots?
>>
>> ** Pots do not need lubricating.
>>
>> How about you post a question properly for once ?
>>
>> What is the actual problem with the pots ??
>
>This is not about a problem with a particular pot. Many
>inexpensive carbon pots develop intermittent contacts and
>scratchy sounds in audio. This happens both with pots fitted in a
>product by a manufacturer and with pots bought from a shop. Some
>become defective within a couple of months of regular use,
>especially in a dusty environment and/or if they have dc current
>passing through them. Replacing them with better quality pots is
>not always an option. Flushing with a solvent usually makes them
>OK again for a while, but this also takes out the lubricant and
>makes the track wear out more quickly.
>

I've been using WD 40 since the days of turret TV tuners without
problems. But WD is a branded product . . . how about some light
machine oil or kerosene?
--
From: Frnak McKenney on 14 Mar 2010 11:48
On Sun, 14 Mar 2010 10:05:57 -0500, default <default(a)defaulter.net> wrote:
> On Sun, 14 Mar 2010 11:52:19 +0530, "pawihte" <pawihte(a)fake.invalid>
> wrote:
>
>>Phil Allison wrote:
>>> "pawihte"
>>>>
>>>> What common substance would be acceptable as a lubricant for
>>>> consumer
>>>> grade volume control pots?
[...]
>>> What is the actual problem with the pots ??
>>
>>This is not about a problem with a particular pot. Many
>>inexpensive carbon pots develop intermittent contacts and
>>scratchy sounds in audio. This happens both with pots fitted in a
>>product by a manufacturer and with pots bought from a shop. Some
>>become defective within a couple of months of regular use,
>>especially in a dusty environment and/or if they have dc current
>>passing through them. Replacing them with better quality pots is
>>not always an option. Flushing with a solvent usually makes them
>>OK again for a while, but this also takes out the lubricant and
>>makes the track wear out more quickly.
>
> I've been using WD 40 since the days of turret TV tuners without
> problems. But WD is a branded product . . . how about some light
> machine oil or kerosene?

Did someone already mention "contact cleaner" for this purpose?

Relay contacts, TV tuner contacts, and pot wipers. I still have my
father's old can of De-Ox-Id, and it still works (heck, I'm impressed
that it still has usalbe propellant <grin!>). When my old (c.1974)
Kenwood stereo receiver's volume control picks up a little bit of
scratchiness (erratic contact when rotating), one squirt cures it.


Frank McKenney
--
The ultimate result of shielding men from the effects of folly is
to fill the world with fools.
--Herbert Spencer, English Philosopher
--
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut mined spring dawt cahm (y'all)
From: default on 14 Mar 2010 12:00
On Sun, 14 Mar 2010 15:45:35 +0530, "pawihte" <pawihte(a)fake.invalid>
wrote:

>Not at the point of contact at the time of contact, at least not
>in enough thickness to prevent conduction.What about oil-filled
>switches and contactors, eh? The oil or grease simply gets
>squeezed out of the way at the point of contact and then flow in
>again.

I think you have that right. It wouldn't surprise me that the contact
cleaners that "leave no residue" are less effective for that reason.

Particles rubbed off the pot as a cause are probably secondary to
oxides on the contact fingers.
--
From: John Larkin on 14 Mar 2010 14:28
On Sun, 14 Mar 2010 19:06:43 +1100, "Phil Allison" <phil_a(a)tpg.com.au>
wrote:

>
>"pawihte"
>> Phil Allison wrote:
>>> "pawihte"
>>>>
>>>> What common substance would be acceptable as a lubricant for consumer
>>>> grade volume control pots?
>>>
>>> ** Pots do not need lubricating.
>>>
>>> How about you post a question properly for once ?
>>>
>>> What is the actual problem with the pots ??
>>
>> This is not about a problem with a particular pot. Many inexpensive carbon
>> pots develop intermittent contacts and scratchy sounds in audio. This
>> happens both with pots fitted in a product by a manufacturer and with pots
>> bought from a shop. Some become defective within a couple of months of
>> regular use, especially in a dusty environment and/or if they have dc
>> current passing through them. Replacing them with better quality pots is
>> not always an option. Flushing with a solvent usually makes them OK again
>> for a while, but this also takes out the lubricant and makes the track
>> wear out more quickly.
>
>
>** Totally mangled nonsense - the track of a carbon ( or other) pot has no
>lubricant applied during manufacture.
>
>Any lubricant that resided on the track would prevent operation - cos
>lubricants are insulators.
>
>Rapidly evaporating solvents are rarely any use for fixing noisy pots while
>slow evaporating ones that leave a thin oil residue are very good at the
>job.
>
>Also, rotary pots do not get " dust " inside them.
>
>What actually causes all the trouble is a when a mix of fine carbon
>particles from the track and grease from the shaft bearing accumulate on the
>fingers of the two wipers and render them partially non conducting. Also,
>the metal to metal wiper contacts suffer from surface contamination by the
>moisture and sulphides in the air - a thin oily film helps prevent any
>recurrence of this. The oil must be thin that rotating the pot displaces
>all of it from the contact areas.
>
>A mix of oil and petroleum solvent has a very low surface tension so easily
>travels by capillary action to cover all the insides of a pot.
>
>There is a very famous product that fits the bill exactly ...... W
>something ......
>
>One uses only a small amount ( a few drops) and then rotates the pot many
>times to help it do the trick - repeating the process only if necessary.
>If the pot is still noisy - replacement is the only option.
>
>BTW
>
> Some 100mm fader pots I looked at a week back did not respond to the above
>treatment - when opened up I found the finger contacts on the slider were
>worn completely away !!!
>
>
>
>.... Phil
>
>

I have a lot of, way too many, old Tektronix scopes and plugins, some
dating back to the all-tube days. The pots get noisy after a few
decades on storage. A small spritz with contact cleaner - the RatShack
stuff works fine - and a few good twists fixes them right up. If the
back has openings, I spray it in there; if not, it can usually be
blasted into the shaft bushing.

John

From: pawihte on 14 Mar 2010 15:25
pawihte wrote:
> What common substance would be acceptable as a lubricant for
> consumer grade volume control pots? It's no good recommending a
> branded product to me as I live in a place where such products
> are unlikely to be available. Thanks.

Thanks to those who posted helpful replies. It's been a long time
since I had to bother with noisy pots. When I did such things
regularly, contact cleaners were just things I read about in
foreign magazines. I think they're available in local shops now.
Anyway, the stuff I found inside pots were accumulated dust, lint
and unidentified fuzz and grit that were sometimes so thick that
I'd still prefer to open up the pot, wash it with a solvent and
then apply the lubricant manually.


First  |  Prev  |  Next  |  Last
Pages: 1 2 3 4 5 6
Prev: According to their plan, the first 2*3.5TeV collisions will be performedthe 30-th of March. I’m scared, but can not do anything, - all ways lead to catastrophe. LHC/CERN.
Next: According to their plan, the first 2*3.5TeV collisions will be performed the 30-th of March. I�m scared, but can not do anything, - all ways lead to catastrophe. LHC/CERN.