开云体育

From: Craig Sawyers <c.sawyers@...>
Sent: Dec 9, 2018 4:53 AM
To: [email protected]
Subject: Re: Tube test adaptor for Tektroinx 575 was: Re: [TekScopes] FS: miscellaneous Tektronix manuals

A center tapped filament transformer, or a 'hum balance' circuit to create an artificial center tap
will do
even better. That circuit was often no more than a 200 ohm pot across the winding, with the wiper
connected to ground, and both filament leads floating above ground. A 2W pot was common for this
use.


Michael A. Terrell

The other common term (at least on my side of the pond) was hum bucker.

Craig

From: Mike Dinolfo <mdinolfo@...>
Sent: Dec 5, 2018 10:53 PM
To: [email protected]
Subject: Re: Tube test adapter for Tektronix 575 was: Re: [TekScopes] FS: miscellaneous Tektronix manuals

Another thing to consider (if you are feeding tube filaments via AC
power) and want to minimize hum is to use twisted pair wiring to
distribute AC power to the tube filament socket connections (rather than
individual single conductor wires which are haphazardly separated from
each other). Twisted pair tends to minimize inductive (magnetic)
radiation within the equipment/chassis that could otherwise occur with
separated wires supplying AC to the tube socket filament pins; the
magnetic field (at 60 hz) can lead to audio hum. Of course, it's also
OK to use single conductor wires which are twisted together in "paired"
wiring for the filament power distribution.

Mike Dinolfo N4MWP

On 12/8/18 8:07 PM, Michael A. Terrell wrote:

The plastic is there to reduce the chance of damaging the device awaiting you on your bench.

Ummmmm.... I use Crescent wrenches from Jamestown NY mostly and none have plastic
and I have a fine touch at mechanicing.? I'd say a vinyl or other plastic coating
or dip layer is just insulation against fine feel on a wrench.? If it reeks, lose it.
If it wiggles around randomly, lose it.

On December 8, 2018 at 7:33 PM "Michael A. Terrell" <mike.terrell@... mailto:mike.terrell@... > wrote:


I don't use the same tools for Electronics and automotive work. I do have several large adjustable wrenches, but they are New Britain. The smaller ones for electronics are Xcelite, and they do have plastic coated handles.

I've also been told that no real mechanic ever uses an adjustable wrench because he has all the proper tools to work on a vehicle.

If that wrench still stinks, it had to stink when he bought it. If so, he should have bought something else. I had someone give me a buncuh of Japanese tools made in the '60s and '70s. They were made of pot metal, and the drill bits were so soft that they unwound while drilling plastic. They were quickly tossed in the scrap for recycling.

I agree about throwing out crap tools, or gather them all up, and only loan them to people instead of your good tools.

The only cheap tools that I have had were either given as cheap gifts, or will be part of what I clean out of my dad's house as we get it ready to sell. He got them from a neighbor who had passed away.

I started buying good quality tools as a teenager, and I still have some of them, 50 years later. The only ones that ever broke, were sold as tools for mechanics. The rest of what is missing were stolen from my truck, or at job sites.


-----Original Message-----
>
>On 12/8/18 8:07 PM, Michael A. Terrell wrote:
>> The plastic is there to reduce the chance of damaging the device awaiting you on your bench.
>
>Ummmmm.... I use Crescent wrenches from Jamestown NY mostly and none have plastic
>and I have a fine touch at mechanicing. I'd say a vinyl or other plastic coating
>or dip layer is just insulation against fine feel on a wrench. If it reeks, lose it.
>If it wiggles around randomly, lose it.

I don't use the same tools for Electronics and automotive work. I do have several large adjustable wrenches, but they are New Britain. The smaller ones for electronics are Xcelite, and they do have plastic coated handles.

I've also been told that no real mechanic ever uses an adjustable wrench because he has all the proper tools to work on a vehicle.

If that wrench still stinks, it had to stink when he bought it. If so, he should have bought something else. I had someone give me a buncuh of Japanese tools made in the '60s and '70s. They were made of pot metal, and the drill bits were so soft that they unwound while drilling plastic. They were quickly tossed in the scrap for recycling.

On 12/8/18 8:07 PM, Michael A. Terrell wrote:

The plastic is there to reduce the chance of damaging the device awaiting you on your bench.

Ummmmm.... I use Crescent wrenches from Jamestown NY mostly and none have plastic
and I have a fine touch at mechanicing. I'd say a vinyl or other plastic coating
or dip layer is just insulation against fine feel on a wrench. If it reeks, lose it.
If it wiggles around randomly, lose it.

On December 8, 2018 at 6:29 PM John Griessen <john@... mailto:john@... > wrote:


On 12/8/18 8:07 PM, Michael A. Terrell wrote:

> > The plastic is there to reduce the chance of damaging the device awaiting you on your bench.

> Ummmmm.... I use Crescent wrenches from Jamestown NY mostly and none have plastic

and I have a fine touch at mechanicing. I'd say a vinyl or other plastic coating
or dip layer is just insulation against fine feel on a wrench. If it reeks, lose it.
If it wiggles around randomly, lose it.

On 2018-12-08 2:38 PM, oliver johnson via Groups.Io wrote:

Hi all I for one have more scopes than i can or will ever use , but for

some strange reason i keep getting them . For me it just fixing them that i
enjoy and once fixed it goes in the pile that i have , speaking of pile i
am looking for one last tek to complete my dual beam collection, 7844 is
the last tek needed for dual beam collection, if anyone has one reasonable
please let me know, thanks and keep the hobby going .


This thread really makes me wonder how many collectors have a succession
plan for when we can't take care of them all any more.

How many have lined up a Will, or executor who will successfully be able
to rehome your collection to a museum or suitably responsible individual?

The "wife seeks to get rid of 97 of husband's instruments by Sunday,
local pickup only", that we see semi-regularly now, is far from the
worst case scenario.

--Toby


Disclaimer: I haven't

On Sat, Dec 8, 2018 at 1:39 PM, TomC<tomc@...> wrote: On

12/7/2018 3:15 PM, Craig Sawyers wrote:

Now just what do I do if I have to display more than 12 waveforms at

once ?

Ah - you can do that with a single 7844

How?

From: Jim Olson <v_12eng@...>

You could make the Crescent (adjustable) into a proper mechanics wrench and take the d**n plastic cover off. No self respecting Crescent wrench would have a cover on it. hehe.`

On December 8, 2018 at 5:23 PM Dave Seiter <d.seiter@... mailto:d.seiter@... > wrote:


I got a new Gerber lock blade knife as a gift about 20 years ago which had very strong perfume smell. After ten years it still smelled, but I just checked it and it now has no smell, so now I can actually use it!
A VFD arrived from China two weeks ago, and it's now outgassing on my porch because the smell is so strong.
I much prefer the smell of working Tek gear! You know, now that I think about, I do have a P6032 probe kit that has a fruity/medicinal smell.
-Dave

From: Anthony via Groups.Io <keantoken@... mailto:keantoken@... >
To: [email protected] mailto:[email protected]
Sent: Saturday, December 8, 2018 4:13 PM
Subject: Re: [TekScopes] Capacitor sniffing

I think some electronics vendors perfume their stuff. I have gotten several appliances which had a soapy perfumy smell without the usual electronic smell which I guess is nice but makes me suspect they sprayed the inside with Febreeze or something that coats the electronics and keeps the smell inside.
I had a failing computer mouse and I recognized the smell of a failing capacitor right away. It's a weirdly fruity, sickly sweet smell. If you want to know what that smells like then just hook up a capacitor backwards.
As for other components, I think they are all loaded with fire retardants so usually you get an overwhelming smell of bromine. It smells similar to chlorine and iodine, which are on the same column in the periodic table. The other components of the smell are usually burnt plastic or burnt epoxy, which I suppose could be identified if you had some practice, but this isn't particularly helpful since almost all components are covered in epoxy or plastic.
Enameled wire has it's own smell which can often be distinguished from the other smells.
Another common smell is just the usual outgassing of cheap solvents used by Chinese manufacturers in their plastics. I have a cheap adjustable wrench which I never touch because the rubber handle cover reeks and I can't wash the smell off my hands after using it. Probably not useful for diagnostic purposes.
A faulty switch, for instance in the flasher in the dash of a car tends to just be singed black plastic which does not really melt since the plastic used in quality switches isn't the kind that melts. The dielectric grease is usually fine and needs a higher temperature than the plastic to break down. The smell is not really like burnt plastic and more like the burning of something organic, but not really like burning leaves or wood. It's an easier smell to live with than the smell of burning plastic.
On Saturday, December 8, 2018, 11:27:27 AM CST, Craig Cramb <electronixtoolbox@... mailto:electronixtoolbox@... > wrote:

My experience with failing capacitor is the strong smell of raw fish. Sometimes I can smell it as soon as the unit arrives or definitely during case removal. I don’t think I’ve noticed a soap/perfume smell.

Craig