jurb6006@gmail.com: Jan 24 06:37PM -0800
>"I will try to put in the
drop box."
Too bad. Dropbox doesn't want to display for me. It might be because I used to be a member ad gave it up. I am currently looking for free hosting that is compatible with my browser.
I don't mind an ad or two but I don't want people to have to sign up or sign in and that is what it is doing for me.
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Ralph Mowery <rmowery28146@earthlink.net>: Jan 24 11:23PM -0500
In article <37301d83-be37-4233-9918-209e49cec2b1@googlegroups.com>,
pfjw@aol.com says...
> > works OK except for 1000...
> As already noted, there are almost as many codes as makers. In my (very) old Centerlab Catalog, I did find references to W-Taper pots, but nothing conclusive at all on K or k taper as a specific reference.
> With the additional hint of this being a slider, further googling got me to drill bits, but nothing on pots, linear or rotary.
All that is what makes things 'interisting'. I believe the K is for
Kelvin temperature and that made them use the k for 1000.
Too bad that many companies seem ot use their own code for part numbers.
I really hate the companies that use their part number on standard parts
and if you need to replace them, you are almost forced to go to the
origional company or one of their repair man. Friend in the auto
repair business told me that often a luxulary car part would be the same
as a less expensive model. They use a different number and higher price.
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rickman <gnuarm.deletethisbit@gmail.com>: Jan 25 12:05AM -0500
Phil Allison wrote on 1/23/2018 10:29 PM:
> The code letters used varied alarmingly, A originally meant linear and C =log. Pots coming from Asia used A = audio taper with B = linear and D = log.
> The code letter "E" referred to a "reverse log" pot, useful in instrumentation where the actual gain of a amplification stage must be varied smoothly.
> Strangely, I have not come across a reverse linear pot anywhere.
If you give it a thought, you will realize a linear pot is its own reverse.
The reverse doesn't refer to whether the resistance goes up or down, it
refers to which direction the log curve goes, a log taper or an exponential
taper. A linear taper is the same either way... it's linear.
--
Rick C
Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
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whit3rd <whit3rd@gmail.com>: Jan 24 11:28PM -0800
On Wednesday, January 24, 2018 at 9:05:17 PM UTC-8, rickman wrote:
> If you give it a thought, you will realize a linear pot is its own reverse.
> The reverse doesn't refer to whether the resistance goes up or down, it
> refers to which direction the log curve goes...
Log taper means mimicing log(d) where the deflection (d) goes from
1 to 100 or somesuch. Inverse log taper means mimicing log(1/d) = - log(d)
So, linear taper can mimic 'd', and its inverse can be '-d', as you say.
Or, linear taper can be 'd', and its inverse can be '1/d'.
The '1/d' taper would be a way to make an adjustable attenuator, linear in inverse gain
going from '1' meaning full signal, to '2' meaning 1/2, ... '10' meaning 1/10
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rickman <gnuarm.deletethisbit@gmail.com>: Jan 25 02:57AM -0500
whit3rd wrote on 1/25/2018 2:28 AM:
> Or, linear taper can be 'd', and its inverse can be '1/d'.
> The '1/d' taper would be a way to make an adjustable attenuator, linear in inverse gain
> going from '1' meaning full signal, to '2' meaning 1/2, ... '10' meaning 1/10
Then it is no longer linear.
--
Rick C
Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
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Fox's Mercantile <jdangus@att.net>: Jan 25 01:58AM -0600
On 1/24/18 11:05 PM, rickman wrote:
> reverse. The reverse doesn't refer to whether the resistance goes up or
> down, it refers to which direction the log curve goes, a log taper or an
> exponential taper. A linear taper is the same either way... it's linear.
Congratulations, not only are you ignorant, you have no sense of humor.
--
"I am a river to my people."
Jeff-1.0
WA6FWi
http:foxsmercantile.com
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tabbypurr@gmail.com: Jan 25 12:22AM -0800
On Thursday, 25 January 2018 05:05:17 UTC, rickman wrote:
> The reverse doesn't refer to whether the resistance goes up or down, it
> refers to which direction the log curve goes, a log taper or an exponential
> taper. A linear taper is the same either way... it's linear.
I would very much expect he didn't need to 'give it a thought' to work out something so obvious.
NT
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"pfjw@aol.com" <pfjw@aol.com>: Jan 25 04:13AM -0800
> >"I will try to put in the
> drop box."
> Too bad. Dropbox doesn't want to display for me. It might be because I used to be a member ad gave it up. I am currently looking for free hosting that is compatible with my browser.
Dropbox does not support Samsung devices for what that is worth. Or so they tell me.
Peter Wieck
Melrose Park, PA
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rickman <gnuarm.deletethisbit@gmail.com>: Jan 25 08:06AM -0500
>> refers to which direction the log curve goes, a log taper or an exponential
>> taper. A linear taper is the same either way... it's linear.
> I would very much expect he didn't need to 'give it a thought' to work out something so obvious.
And yet, he mentions he has never seen a reverse linear taper.
--
Rick C
Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
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"pfjw@aol.com" <pfjw@aol.com>: Jan 25 05:22AM -0800
On Thursday, January 25, 2018 at 8:06:29 AM UTC-5, rickman wrote:
> And yet, he mentions he has never seen a reverse linear taper.
Back when I was a journeyman electrician, and therefore was privileged to haze the apprentices, I asked one to fetch me (amongst many other things) a combo-plate from the warehouse like this: https://cdn.gescan.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/b/ibv97532-2.jpg
And when he brought me this:
https://images.homedepot-static.com/productImages/5849af02-96ef-4c79-9192-37a8464488aa/svn/stainless-steel-legrand-pass-seymour-combination-wall-plates-sl18cc5-64_1000.jpg
I sent him back, stating I needed the receptacle on the left.
He got as far as the door before he caught on. And it never happened to him again. Others got all the way to the counter at the warehouse.
Peter Wieck
Melrose Park, PA
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amdx <nojunk@knology.net>: Jan 25 08:00AM -0600
> JB Weld is your best friend. Get a soda-straw or heat-shrink tubing about the same diameter as the shaft, either use the broken piece or a suitable bit of solid material to extend the shaft to the correct length. Mix up the *SLOW* JB Weld epoxy, and use the straw/tubing to hold the shebang together and vertical, but out of the pot, until the epoxy sets up. Let the epoxy fill any voids. The result will be stronger than the original.
> Peter Wieck
> Melrose Park, PA
I have repaired many broken plastic parts.
I have a kit with 0.025" and 0.035" drill bits and
matching steel rods. I put the parts together, then drill
through where inserting a steel pin will give it the most strength.
I epoxy the joint and the pin and put it all together.
I use a Dremel tool to drill the hole and and cut the steel pin off,
after the epoxy sets.
The epoxy I have is Huntsman Fastweld 10, (ex. Ciba-Geigy Araldite)
It is a 5 minute set 24 hour cure.
Mikek
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amdx <nojunk@knology.net>: Jan 25 08:15AM -0600
> He got as far as the door before he caught on. And it never happened to him again. Others got all the way to the counter at the warehouse.
> Peter Wieck
> Melrose Park, PA
In my late teens a father bought his daughter a Volkswagen Beetle,
the first thing he did was send her to go to the gas station* and have
them check the water in the radiator.
Mikek
* back when they had service at gas stations.
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rickman <gnuarm.deletethisbit@gmail.com>: Jan 24 11:57PM -0500
> On Monday, 22 January 2018 20:56:52 UTC, Terry Schwartz wrote:
>> At my last company, I spent the better part of my last 4 or 5 years dealing with water conductivity issues. We produced machines that electrolyzed water into base and acid components in order to produce cleaning chemicals.
<<< snip >>>
> I'd be interested to find out about the production of the cleaning chemicals.
I can tell you it wasn't from electrolysis of water. That produces hydrogen
(H2) and oxygen (O2), not acid and base. Anything else would have to come
from additives to the water.
--
Rick C
Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
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tabbypurr@gmail.com: Jan 25 12:15AM -0800
On Thursday, 25 January 2018 04:58:09 UTC, rickman wrote:
> I can tell you it wasn't from electrolysis of water. That produces hydrogen
> (H2) and oxygen (O2), not acid and base. Anything else would have to come
> from additives to the water.
it's saltwater.
I'm curious when this was patented, if it was.
NT
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rickman <gnuarm.deletethisbit@gmail.com>: Jan 25 08:11AM -0500
>> (H2) and oxygen (O2), not acid and base. Anything else would have to come
>> from additives to the water.
> it's saltwater.
Not really. All water has contaminants. The water he has mentioned was
fresh water with more or less contaminants. Still, it wouldn't be described
as electrolysis of (salt)water if the interesting part was the contaminants.
It would be described as the interesting bits dissolved in water.
--
Rick C
Viewed the eclipse at Wintercrest Farms,
on the centerline of totality since 1998
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"pfjw@aol.com" <pfjw@aol.com>: Jan 25 05:36AM -0800
Apropos electrolysis and water, way back in the day in high-school, my chemistry teacher showed us how to make Hydrogen peroxide using electrolysis. It was crude and not very efficient, and wasteful of resources.
Today, not so much.
https://link.springer.com/article/10.1023/A%3A1017588221369
Under controlled conditions, other products are also possible. I suspect that is what Tennant was doing.
Side Note: This teacher partnered with several of the history teachers. He had us collect 'night soil' to make gunpowder when we were studying the Civil War, we had to learn the 'secret code' whereby one could identify an American anywhere, any time (this _was_ the 1960s, remember), and we had to learn the ten (10) reindeer. In any case, a lot of very basic and very useful chemistry and applied science has stuck with me over the years.
Peter Wieck
Melrose Park, PA
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Terry Schwartz <tschw10117@aol.com>: Jan 25 06:06AM -0800
Apparently anyone can be an expert on things they do not understand.
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whit3rd <whit3rd@gmail.com>: Jan 24 05:26PM -0800
On Wednesday, January 24, 2018 at 9:18:36 AM UTC-8, KenO wrote:
> A while ago put a number of HDDs in storage.
> Recently tried to use and noticed that some do Not spin up (all were working when put in storage).
> Had read that sometimes the heads will stick or other factors like lube will cause the disk from spinning.
Yes, motor power is sometimes a problem: first thing to do is listen very hard. If it IS
spinning, don't hit it...
but if it isn't, the motor control will shut down a second after power is applied, so what
you want to do is give the drive a brisk twist just after applying power. Set the drive
on a horizontal surface, flip on power and quickly rap one corner so as to make the
drive twist position slightly... try both directions. You must switch the power off
and wait a few seconds between each trial. Give it a dozen tries (use a stick,
no sense getting bruised).
Apply heat (hair dryer is fine) to warm the case, wait a few minutes, and try again. You just
want the aluminum parts warm so the lubricant softens.
If that doesn't work, examine the drive electronics, sometimes it's just
a shorted diode on the power pins. And, sometimes there's a scorched odor
and a crater in one of the black plastic rectangles...
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tabbypurr@gmail.com: Jan 25 12:11AM -0800
On Thursday, 25 January 2018 00:02:21 UTC, Clifford Heath wrote:
> a Fujitsu Eagle hard drive. Pretty difficult; it took two
> strong people to coordinate a twist on a 60kg drive without
> dropping it.
how many platters did that have??
Even the original 2' wide rusty platter stack didn't come in at 60kg iirc.
NT
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tabbypurr@gmail.com: Jan 25 12:14AM -0800
On Thursday, 25 January 2018 08:11:54 UTC, tabby wrote:
> how many platters did that have??
> Even the original 2' wide rusty platter stack didn't come in at 60kg iirc.
> NT
11x 10.5" platters, 4k rpm, 30 second spin-up time.
NT
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Clifford Heath <no.spam@please.net>: Jan 25 07:44AM +1100
>> how many platters did that have??
>> Even the original 2' wide rusty platter stack didn't come in at 60kg iirc.
> 11x 10.5" platters, 4k rpm, 30 second spin-up time.
I never weighed one, just took a guess. It was a difficult thing
to lift and apply power then a rapid rotational jerk to however.
Then gently lift it back into the rack to avoid crashing anything.
540MB if I recall - I don't even have a thumb drive that small any
more.
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jack4747@gmail.com: Jan 25 02:06AM -0800
Il giorno mercoledì 24 gennaio 2018 18:18:36 UTC+1, KenO ha scritto:
> A while ago put a number of HDDs in storage.
> Recently tried to use and noticed that some do Not spin up (all were working when put in storage).
> Had read that sometimes the heads will stick or other factors like lube will cause the disk from spinning.
when the disk is powered off the heads are parked, and if the heads touch the platters then you can throw the HD in the trash.
If it doesn't spin up it's because the bearings of the motor are stuck. A gentle but firm poke on the side of the disk should help. Also putting the HD in vertical instead of horizontal position when it power up may help. Or shaking it a little.
Bye Jack
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"Rick" <rike22@bellsouth.net>: Jan 25 05:12AM -0600
"John Robertson" <spam@flippers.com> wrote in message
news:mZidnWkj6PCjhvTHnZ2dnUU7-L2dnZ2d@giganews.com...
> (604)872-5757 (Pinballs, Jukes, Video Games)
> www.flippers.com
> "Old pinballers never die, they just flip out."
http://www.alps.com/prod/info/E/PDF/Potentiometer/TAPER.pdf
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tabbypurr@gmail.com: Jan 25 03:31AM -0800
On Thursday, 25 January 2018 09:45:34 UTC, Clifford Heath wrote:
> Then gently lift it back into the rack to avoid crashing anything.
> 540MB if I recall - I don't even have a thumb drive that small any
> more.
sounds like an improvement on:
1956 IBM 350. fifty 24-inch (0.6 m) platters, total capacity (3.75 megabytes).
NT
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