Date   

Re: (OT) repair tools: Autotransformers/variacs

 

On Mon, Jun 29, 2020 at 10:38 AM, Jean-Paul wrote:


Serious users should avoid the Chinese copies and opt for a good condition
used made in USA model mentioned above.
I Jon,

Why should serious users avoid the "Chinese copies" ?? Why should "used" be preferable to new? Are variacs like bottles of wine?

I was a serious competent professional for many decades. After I retired, the "serious" went away and I am simply a competent user. And as such, I have found nothing inferior in my "Chinese copied variac'. Nothing that I see could give problems to my grandchildren when they inherit this variac.

When you plug your brand name made in USA variac into a power strip cord, you make sure that this power strip is also a used cord made in USA and not a copied new Chinese power cord?

Ernesto


Re: What's the Tektronix part number for a dead spider

 

Do we really need 20 replies to this?
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dick
Sent: Monday, June 29, 2020 7:36 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] What's the Tektronix part number for a dead spider

Where is it located ?

73, Dick, W1KSZ
________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of snapdiode via
groups.io <snapdiode=yahoo.com@groups.io>
Sent: Sunday, June 28, 2020 10:41 PM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: [TekScopes] What's the Tektronix part number for a dead spider

Can you see it?

http://w140.com/tekwiki/images/1/10/1s1_left.jpg

I thought it was funny.








--
Dennis Tillman W7pF
TekScopes Moderator


Re: Tek Purchased Power Supplies, Power One

 

Hi Jay,
LOL
Thank you for saying what I was thinking so much better than I did.
That brought a big smile to my face.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Jay Walling via groups.io
Sent: Sunday, June 28, 2020 10:21 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Tek Purchased Power Supplies, Power One

https://lmgtfy.com/?q=tekwiki&pp=1





--
Dennis Tillman W7pF
TekScopes Moderator


Re: Pacific Measurements or Wavetek 1038 System

Karl Ireland <rf-guy@...>
 

I restored a Wavetek 1038-NS20 to fully working condition.
It is using these modules: 1038-NS20, D14, NS206, and one labled "calibrator output" and "ext ref input".

When I bought it on eBay, I found out that ALL the push-buttons had degraded over time
where they didn't snap in/out when pressed, most of them were permanently pushed in
which locked up the instrument!

I had to remove the 1038-NS20 module from the frame,
disassemble the 1038-NS20 module,
unsolder all the pushbutton switches,
cut open all the switches,
remove the guts,
put each one on my milling machine & machine the internal area larger,
install a new tiny pushbutton switch inside the original switch body and solder the connections,
epoxy it in place,
close-up the switch with the original engraved push-button re-installed.
solder the switches back into the PCB,
re-install the PCB into the 1038-NS20 module,
plug the module back into the frame & power it up for a test.
All the buttons worked! This took an entire weekend to do!


Re: Wikipedia is not an appropriate topic for TekScopes. WAS repair tools: Autotransformers/variacs

Reginald Beardsley
 

On Sat, Jun 27, 2020 at 02:09 PM, Dennis Tillman W7pF wrote:


TekScopes is "All about classic Tektronix test equipment, its use, repair,
and collecting".

What do comments and opinions about Wikipedia have to do with TekScopes?

Dennis Tillman W7pF




--
Dennis Tillman W7pF
TekScopes Moderator
WTF!

Discussions drift because people make statements others don't understand and the explanations often go far afield. It is inevitable.

I was not aware that discussion on TekScopes was restricted to the cognesceti. If that's the case then I certainly don't belong here.

I own 8-10 pieces of Tek gear and about 20-25 pieces of HP gear. And no significant experience with any except for a pair of 106s and a 465. And my recent 11801. It was simply outside my budget until a couple of years ago when old age set in.

"Collecting" test gear borders on being offensive to me. It seems to be a TekScopes obsession. I've never seen an "is an xxxx worth restoring?" post on the HPAK list. These instruments were made to be *used*, not worshiped.

If TekScopes is going "technically correct" I'm simply going to stop reading it.

Reg


Re: Tek 2215 vertical gain

Michael W. Lynch
 

On Mon, Jun 29, 2020 at 05:30 PM, John Shadbolt wrote:


Thanks Mike, very relevant, I cleaned up the beam finder switch and the
difference between bottom and top height is now 1.8 and 2.5 squares (1:1.4) so
an improvment over 2.5 and 4 squares (1:1.6). Beam finder switches clearly
don't get used much!

Regards,
John
John,

Glad to hear that this helped you.

Exercise all those switches vigorously. My 485 took quite some time to become fully functional. I cleaned and used DEOXIT on the thing about 3 or 4 different times before the trace came fully back as it should be. Make sure to use a cleaner that does not leave residue or attract dust.

There are a lot of these switches on TEK scopes and they all suffer from the same malady. Clean everyone that you can find on your 2215.

I find dirty switches and contacts are the number one cause of scope "failures".

Good Luck with your scope.

--
Michael Lynch
Dardanelle, Arkansas


Re: Tek 2215 vertical gain

 

On Sat, Jun 27, 2020 at 02:37 AM, Michael W. Lynch wrote:

I do not know if this is relevant, but I have a 485 that did a similar thing.
The square wave supplied by the calibrator was fine when the trace was
centered and as you moved the trace away from center, the trace shrank
vertically .. the problem ...a very dirty
beam finder switch.
Thanks Mike, very relevant, I cleaned up the beam finder switch and the difference between bottom and top height is now 1.8 and 2.5 squares (1:1.4) so an improvment over 2.5 and 4 squares (1:1.6). Beam finder switches clearly don't get used much!

Regards,
John


Re: What's the Tektronix part number for a dead spider

snapdiode <snapdiode@...>
 

It's a Allen Bradley pot. Low noise and sealed, really good.

p/n 311-0497-00


Re; OT: Strobe light related -books FS

Brad Thompson
 

Hello--

I'm offering FS a trio of books dedicated to electronic strobe and other high-speed
photographic techniques. All three books are mainly of historical interest and hence are
sold in one batch. As you might expect, these books feature lots of cool illustrations
showing spilled milk,  shattered bottles, explosions, hummingbird tongues and more.
Harold Edgerton's name is prominent in the bibliographies.

Science of Electronic Flash Photography, by Kenneth Karsten, Chilton Book Co., NYC, 1968 ed. not stated. 190 pp. indexed, Includes plans for building
strobe power supply and strobe lights. Hardcover in very good cond., dust jacket in VG- minus cond. (small tear on reverse, edge nicks).
Many photos, line drawings and and schematic illustrations. Interior is unmarked. Previous owner's stamp on flyleaf.

*****
"Strobe" The Lively Light, by Howard Luray, Camera Craft Publishing, 2nd ed., 1954. 144 pp. Hardcover boards
in gold finish, in VG condition, dust jacket in good cond (spine wear. edge nicks. Bibliography, index

*****

High Speed Photography, Its Principles and Applications, by George A. Jones,  John Wiley & Sons, New York,
First Edition, 1952. Hardcover ed. in VG condition, 320 pp. index, illustrated.  Describes electronic flash, streak
cameras,film techniques. Extensive bibliography.

I'm asking $18.00 for the lot of three books, which includes USPS media-mail shipment.

Questions welcomed, PayPal honored.

Thanks, and 73--

Brad  AA1IP


P.S.: I may have some NOS strobe tubes FS if anyone is interested.


Re: What's the Tektronix part number for a dead spider

Dave Seiter
 

What is the thing it's sitting on? An adjustable coil?
-Dave

On Sunday, June 28, 2020, 10:41:33 PM PDT, snapdiode via groups.io <snapdiode=yahoo.com@groups.io> wrote:

Can you see it?

http://w140.com/tekwiki/images/1/10/1s1_left.jpg

I thought it was funny.


Re: What's the Tektronix part number for a dead spider

Dave Seiter
 

One of our cats loves to pee in interesting places, so the Tek gear stacked in my office always has to have "uncomfortable" items placed on top to keep the cat off.  The other cat I don't have to worry about- the only place she pees is on the floor in front of the litter boxes...
-Dave

On Monday, June 29, 2020, 11:00:50 AM PDT, Randy.AB9GO <randy.ab9go@gmail.com> wrote:

Be glad that is all it did.  If there was a "interesting smell" the cat may
pee in or on it.  Don't ask how I know...And mine wasn't on the ground.🤬

Randy AB9GO


Re: What's the Tektronix part number for a dead spider

Dave Seiter
 

Never have found mice, but I did have a problem in Colorado years ago while doing a lot of solo mountaineering. Every night I was sleeping in my car (and I'm sure when I was away too), marmots would gnaw on the underside of my car.  Thankfully, they stuck with the undercoating, and left the wiring and brake lines alone!  I always checked before driving to the next spot.
About the same time, I drove from somewhere in the southern Sierras to Newport beach (SoCal). When I arrived, I wanted to check my oil, so I popped the hood, and something jumped out and ran off.  Probably a large ground squirrel- I'm sure it was really confused, but thankful to be out of the engine compartment!
-Dave

On Monday, June 29, 2020, 08:19:53 AM PDT, Chuck Harris <cfharris@erols.com> wrote:

Spiders in the plugins?  That's nothing!  I don't think
mine would work without the spiders and the stinkbugs.

For me, it is usually some critter trying to pimp my
ride with modifications to the vacuum hoses, wiring
harnesses, undercoating, and any sound deadening material.

Seriously, cars have been made for what, 150 years?

At this point in time, the designers have every millimeter
of the body and chassis in a computer, and know where every
hole the size of a mouse exists in the chassis.  And, they
*still* can't keep mice out of cars?

For starters, they could stop making them out of tasty food.

Wire insulation made out of soy, sound deading made out of
corn, and undercoating made out of what?... Cotton candy?

Sorry for the diversion of the topic.  I just spent another
day de-mousing.

-Chuck Harris



Colin Herbert via groups.io wrote:
Look 210mm from the front panel and 91mm from the base. I think it may have
been trying to calibrate some function..

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dick
Sent: 29 June 2020 15:36
To: TekScopes@groups.io
Subject: Re: [TekScopes] What's the Tektronix part number for a dead spider

Where is it located ?

73, Dick, W1KSZ
________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of snapdiode via
groups.io <snapdiode=yahoo.com@groups.io>
Sent: Sunday, June 28, 2020 10:41 PM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: [TekScopes] What's the Tektronix part number for a dead spider

Can you see it?

http://w140.com/tekwiki/images/1/10/1s1_left.jpg

I thought it was funny.











Re: (OT) repair tools: Autotransformers/variacs

Eric Schumacher
 

Hello Roy
Your experience with plug reversal brings up the importance of every Variac
having an attached isolation transformer. I work on a lot of consumer
electronics (lots of switching and transformer-less-power supplies) and the
isolation saves a lot of scope probe ground leads not mention the scope
user. Back in the ac/dc radio days I used a 100 watt light bulb in series
with my suicide cord since I was so frugal and tubes were so much more
forgiving of short term stress.
With age comes wisdom if you are lucky.
73 Eric WB6KCN

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Roy
Morgan
Sent: Saturday, June 27, 2020 11:17 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] (OT) repair tools: Autotransformers/variacs

Hello Ernesto,

I agree that most of us do not need the overvoltage. I did use it in final
system testing of new equipment to ensure that it would operate properly at
high line voltages.

I think that all but very small variacs have screw terminals that make
connecting for only line voltage maximum easy. And some dial plates can be
reversed to indicate that.

Briefly, the danger from fixed line cord plugs comes from the fact that an
overload usually blows only one fuse, and the plug can be plugged in so as
to put the equipment at full line voltage. Fused line cords I have seen are
not polarized.

I have not thought about suicide cords, but even if the plug is polarized,
the clips on the other end can be connected to the equipment backwards.

Tomorrow I can send you the diatribes.

Roy Morgan
K1LKY Western Mass


File /2018 July - 2445 2465 2467 Capacitor list//Kemet 900 Series Safety Caps Product Training Module.pdf uploaded #file-notice

TekScopes@groups.io Notification <TekScopes@...>
 

The following files have been uploaded to the Files area of the TekScopes@groups.io group.

By: DaveH52

Description:
Safety Caps Product Training


Re: What's the Tektronix part number for a dead spider

Randy.AB9GO
 

Be glad that is all it did. If there was a "interesting smell" the cat may
pee in or on it. Don't ask how I know...And mine wasn't on the ground.🤬

Randy AB9GO

The biggest thing that got into my plugins was my cat. I left a 1S1 on the
ground like a slob and my cat wanted to sit on it.
As he tried to get on top he used one of the tubes as a foot(paw?)-hold and
bent all the pins on the tube.

This message sent to you from my mobile device via speech-to-text
technology.


Re: (OT) repair tools: Autotransformers/variacs

Jean-Paul
 

Hello All: Just saw this after some months of absence.

As a power electronics engineer the variacs are a fundamental tool, over the decades I have accumulated perhaps 50 - 100, all brands and sizes 1.25A...30A and 120V 1 ph to 240V 3 ph.

I have not seen any significant differences Staco Powerstat, Variac, Superior, Gen Rad etc.

The repairs and maintenance are mostly lube the bearing and replace the brushes.

IF they are improperly shipped or treated, I have seen gashes in the windings and wire insulation scraped off but they all still worked.

The problem in shipping is both the weight as well as the delicate windings if it is an open model.

Serious users should avoid the Chinese copies and opt for a good condition used made in USA model mentioned above.

Finally beware that the brush and its mounting finger or plate are at the output voltage and should be respected.

Best Regards,

Jon


Re: What's the Tektronix part number for a dead spider

Greg Muir
 

Was working late one night on a plug-in made by the "other" test equipment manufacturer. The next morning when I went in to continue I had discovered that the "night crew" had been in there trying to help.

https://groups.io/g/TekScopes/album?id=249527

Greg


Re: What's the Tektronix part number for a dead spider

benx618(g)
 

What is the Tek part number prefix for BioParts?


Re: What's the Tektronix part number for a dead spider

 

It is surely an old spider.
But with the right Tektronix part number, one may find it at ebay.


7A26 Probe sense oddity

NigelP
 

Had a strange problem earlier. I have a 7904A fitted with 2x 7A26 and I suddenly found the probe x10 sense wasn't working on just one of the CH1 PI inputs (the same probe was checked on all four PI inputs). Shorting the ring to ground produced the expected OSD IDENTIFY result but touching a 10K resistor there didn't toggle the OSD to x10 (I think 10K is the correct value for this).

I assumed an internal PI issue but randomly pressing the Identify button and switching both the CH2 polarity and the BW (for no particular technical reason.... they were just there at hand!) the problem just disappeared! A 10K resistor then tapped on the ring confirmed the functionality.

Just because it's now working again doesn't stop me from getting curious about what "fixed" it in case there's a next-time!

Anybody got some suggestion as to what might have been the issue? Obviously the probe sense function is based on the degree of current passing into (out of) the ring; it was working for identify, but not for x10.

20901 - 20920 of 189567