Date   

Re: More uses for TDR?

David DiGiacomo
 

On Sun, Jun 16, 2013 at 5:41 AM, Fred Schneider <fredschneider@planet.nl> wrote:
Tek has a nice book in the concept range about TDR including how to
measure C and L.
I have a scan of the Tek TDR Measurements Concepts book on my website:

http://www.davmar.org/concepts.html


Re: Tek 360 Indicator System on the bay

Michael A. Terrell
 

cheater00 . wrote:

Just thought someone might find it nice to look at:
http://www.ebay.ca/itm/TEKTRONIX-360-INDICATOR-SYSTEM-WITH-160A-POWER-SUPPLY-AND-162-WAVEFORM-GENERATOR-/380467459942?pt=BI_Oscilloscopes&hash=item5895a0b766

I haven't seen any of those since the '70s, when a guy I worked with tried to sell them to me for $200 per module. I bought a better, working scope at the Cincinnati hamfest for $5.


Tek 360 Indicator System on the bay

 


Re: Hello & First Ebay Find

Michael A. Terrell
 

metoorich wrote:

The settings in the picture are all messed up for sure. I've been lucky on a couple, bought them, and they were great scopes, the seller just didn't know how to get the trace going.

What the heck, if you don't get it going just sell it for parts on eBay, most you'll be out, if anything, is $30 to $50 bucks, and you'll get a great start on your Tek knowledge. The only way to learn is to jump in with both feet if you ask me.

Keep an eye on Craigslist, sometimes a $50 - $100 Tek 465/475/485 will pop up, but you have to grab it fast.
Has anyone tried this site: http://www.list-alert.com/

You have to create an account and a custom search. Then you will be emailed when something matching your search is found on local Craig's list. I may try it, but I was just curious as to whether anyone else used it.


--- In TekScopes@yahoogroups.com <mailto:TekScopes%40yahoogroups.com>, "yankee495" <yankee495@...> wrote:

Hello everyone. I studied for days what to look for when trying to
by a good scope just from a picture. I wanted a 475 but ended up with a 468. I like old stuff from electronics to lawn mowers. Have 2 early 70's Wheelhorse tractors so I'll end up with a 475 or 485 yet.

First, you guys are pretty sharp. Everywhere I go they say to come
here. I looked it over...no trace but it is not setup right for a trace. Channel one is selected and the trigger for it is set to external and the intensity is all the way down. I missed a cracked knob but it is hanging on there.

The digital display says 43.20 and 18.00 in the two pictures of it.
I didn't study hard enough because I didn't know 43.20 is probably errors. I looked at what the guy had and could see he plugs them in and posts them. Then I seen a youtube video where the trigger source lever just flops and hangs there. I hope this one is not just hanging in the ext position.

I'd like to get it going fairly easy and work out the wrinkles like
some of the "lucky" ones have. I got out bid on a 475 with "tilted trace" and another 475 that was described as "Trace on Ch1 is slightly wider than 2. When I touch the knob, it goes fuzzy". So I bought a 468 with buy it now!

I'll be sure and post what I find and fix even if it never does work
right as it is a puzzle and every piece helps, right?

I'm by Joplin, Mo. and it is in Houston, Texas and won't be shipped
until Monday so I think I may have it by Wednesday or Thursday. It might go to Kansas City (UPS) or St. Louis (Fedex) depending on how he ships it.

So, if you were a betting man what do ya think? I probably paid too
much but I'm hoping it is in fair working condition and when you bid on one of those people are willing to fight ya for it. I was tired of waiting and like I said I'll snag me a 475 at Christmas when everyone is spending their money on other things.

This is my first venture into buying a used 30+ year old scope from
a picture. I have the manuals and am loaded for bear as they say...I just hope it is not a big angry grizzly!

Bi-polar bears are even worse! ;-)


http://www.ebay.com/itm/171057434738

It doesn't look like it's been abused, and I've tackled worse looking jobs. At least you can find the manuals and there are plenty of them available, in case you need a bunch of parts. Even items you can't fix will help refine your troubleshooting skill set, if you pay attention and keep good notes.


Re: Testing P6046 with Tek 7k scope

ditter2
 

--- In TekScopes@yahoogroups.com, David <davidwhess@...> wrote:

On Fri, 14 Jun 2013 03:48:31 -0000, "Steve" <ditter2@...> wrote:

Believe it or not, this was probably not known in 1963, when the probe was designed.

BTW, the P6046 was the longest running design with active circuits in it at Tektronix, in production hearly 50 years. Some passive probes such as the P6006 and original P6015 lasted even longer. During its life, almost every transistor type was replaced due to obsoescence. Some in the front end of the amplifier transistors had multiple replacement cycles! I managed the P6246 project, which was the 1.3 GHz active differential probe that replaced it. It took 3 design project attempts to succeed replacing it over the years (the first two were canceled for not achieving design goals) and was the first design to use a SiGe ASIC at Tek. The project was challenged in fact that Tek sold the SiGe process, along the the custom IC designers during the ASIC design cycle!

- Steve
What made the P6046 uniquely useful? Was it that it could be used
with any oscilloscope?

I assume it performed better or was easier to use than a 7A13 plus a
set of calibrated x10 probes.
The P6046 was the only way to get 1 mV/div sensitivity with high CMRR at high frequencies. Toward the end of its life, it was used extensively by disk drive designers. The read channel in a disk drive is entirely differential. Read channels were running at 121 MHz before the P6246 was introduced. Designers could get by with only 100 MHz babdwidth from the P6046 because the response remained single pole well beyond 121 MHz. The designers did not need an accurate amplitude measurement of the waveform, but only a rough view of the waveshape and crude SNR measurement, so the amplitude roll off did not really impact what they were trying to do. An ironic point was that at this time, the probes were always used with LeCroy scopes. LeCroy truly enjoyed a 100% monolopy on the disk drive design market during this era. How they achieved this was one of the main factors in my decision to leave Tek to go to LeCroy.

- Steve

-


Re: Hello & First Ebay Find

metoorich
 

The settings in the picture are all messed up for sure. I've been lucky on a couple, bought them, and they were great scopes, the seller just didn't know how to get the trace going.

What the heck, if you don't get it going just sell it for parts on eBay, most you'll be out, if anything, is $30 to $50 bucks, and you'll get a great start on your Tek knowledge. The only way to learn is to jump in with both feet if you ask me.

Keep an eye on Craigslist, sometimes a $50 - $100 Tek 465/475/485 will pop up, but you have to grab it fast.

--- In TekScopes@yahoogroups.com, "yankee495" <yankee495@...> wrote:

Hello everyone. I studied for days what to look for when trying to by a good scope just from a picture. I wanted a 475 but ended up with a 468. I like old stuff from electronics to lawn mowers. Have 2 early 70's Wheelhorse tractors so I'll end up with a 475 or 485 yet.

First, you guys are pretty sharp. Everywhere I go they say to come here. I looked it over...no trace but it is not setup right for a trace. Channel one is selected and the trigger for it is set to external and the intensity is all the way down. I missed a cracked knob but it is hanging on there.

The digital display says 43.20 and 18.00 in the two pictures of it. I didn't study hard enough because I didn't know 43.20 is probably errors. I looked at what the guy had and could see he plugs them in and posts them. Then I seen a youtube video where the trigger source lever just flops and hangs there. I hope this one is not just hanging in the ext position.

I'd like to get it going fairly easy and work out the wrinkles like some of the "lucky" ones have. I got out bid on a 475 with "tilted trace" and another 475 that was described as "Trace on Ch1 is slightly wider than 2. When I touch the knob, it goes fuzzy". So I bought a 468 with buy it now!

I'll be sure and post what I find and fix even if it never does work right as it is a puzzle and every piece helps, right?

I'm by Joplin, Mo. and it is in Houston, Texas and won't be shipped until Monday so I think I may have it by Wednesday or Thursday. It might go to Kansas City (UPS) or St. Louis (Fedex) depending on how he ships it.

So, if you were a betting man what do ya think? I probably paid too much but I'm hoping it is in fair working condition and when you bid on one of those people are willing to fight ya for it. I was tired of waiting and like I said I'll snag me a 475 at Christmas when everyone is spending their money on other things.

This is my first venture into buying a used 30+ year old scope from a picture. I have the manuals and am loaded for bear as they say...I just hope it is not a big angry grizzly!

One last thing...On the forums where I was reading, the dates that people brag about them coincide with the rise in prices. That is another reason I hit buy it now...I expect them to increase in price as more people "discover them". I have at least one friend who will most likely buy one when I show him this one.

So here is the link...what do you think? Be honest now.

John

http://www.ebay.com/itm/171057434738


Re: 2430A waveform processor IC

metoorich
 

Wohoooo... I love it when I get lucky. I reseated the U470 processor and it cleared the error.

--- In TekScopes@yahoogroups.com, "metoorich" <richard@...> wrote:

Bob, did you ever get this problem fixed? I just inherited a 2340A that fails test 5100.

--- In TekScopes@yahoogroups.com, "bob98033" <bob98033@> wrote:

I have a 2430a which fails self test #5100. Anyone have Waveform microProcessor u470 156-2380-00?
bob


Re: FW: Lorn Ray

Brad Thompson <brad.thompson@...>
 

On 6/16/2013 11:56 AM, Lorn Ray wrote:
<snippety-poo>
Hello--

How appropriate for the TekScopes group: for Lorn, a [cathode]
Ray of hope<g>. [1]

Dunno how this spam has suddenly originated, but it's apparently
infiltrating a number of newsgroups.

73--

Brad AA1IP

[1] For group members whose first language is not English,
this sentence comprises a pun on the cliche "a forlorn ray
of hope".


FW: Lorn Ray

Lorn Ray
 


Re: 2430A waveform processor IC

metoorich
 

Bob, did you ever get this problem fixed? I just inherited a 2340A that fails test 5100.

--- In TekScopes@yahoogroups.com, "bob98033" <bob98033@...> wrote:

I have a 2430a which fails self test #5100. Anyone have Waveform microProcessor u470 156-2380-00?
bob


Re: TEK7104 display readout problem

 

Hi,

I have seen leaky transistors in the vertical amp input circuit cause that type of interference.


Jerry Massengale



-----Original Message-----
From: Yiu On Tony C
To: TekScopes
Sent: Sun, Jun 16, 2013 1:14 am
Subject: [TekScopes] TEK7104 display readout problem

 
Dear Members:

Anyone can help? My TEK7104 had repair for unstable display , which is cause by connection intermittent of vertical amplifier ( IC body pin connection).

The symptom is display readout character move ( and distort ) by change the location of vertical trace ! before repair did not have the issue.

I did calibrate vertical system by no improvement .

Regard
Tony Cheung
JUN 16 2013


Re: 7V10 Voltage Monitor Album is on the forum

keithostertag <keitho@...>
 

Thanks Dennis for such great documentation! A lot of effort! I only wish there were a way to make the images larger (easier to read).

Keith Ostertag


OT: Need info on Waters M-6000A HPLC pump

Ed Breya
 

Oops, I think I accidentally sent just the subject line by itself. Here's the message.

I'm looking for any free/cheap manuals or any info for this HPLC pump, especially the schematics for the step motor control circuit and pressure transducer. It seems like there should be some here familiar with this stuff.

I looked at some HPLC-related groups, but they don't seem very active. I've also posted this to the manuals exchange group.

Ed


Re: how to finess a knob off

Jim <n6otq@...>
 

If you see this in the next few minutes and you have cable TV, put it on Spike NOW and catch the pending episode of "Muscle Car."  They show some ways to get frozen bolts loose, and you might get some ideas.

Otherwise -- the new WD-40 penetrating oil spray is good.  Kroil is excellent.

73
Jim N6OTQ


From: Jerry
To: TekScopes@...
Sent: Sunday, June 16, 2013 8:28 AM
Subject: [TekScopes] how to finess a knob off

hello all/ need some Ideas how to remove a knob on inner shaft of a horizontal position control /inner is the 10x switch/needed to be removed to access the screws under the thin nameplate panel to remove a board for repair / board is broken /but pulled to hard and shaft now pulled out of control/ hopefully repairable/ its not set screw type knob just the splitshaft type knob still cant pull it from shaft/ any ideas  appreciated
thanks  Jerry



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Re: how to finess a knob off

Don Black <donald_black@...>
 

We used to do a similar think with tight TV knobs. We used a strong length of twine (string - builders line is good) and just wrapped a single turn around the shaft behind the knob. Then pull both ends hard away from the panel and the knob should come off. It stops marking from something like a screwdriver, just look at each situation to make sure it won't do anything bad like snap a thin section knob. usually works a treat.

Don Black.

On 17-Jun-13 12:02 AM, Brad Thompson wrote:
 

On 6/16/2013 9:28 AM, Jerry wrote:
> hello all/ need some Ideas how to remove a knob on inner shaft of a
> horizontal position control /inner is the 10x switch/needed to be
> removed to access the screws under the thin nameplate panel to remove a
> board for repair / board is broken /but pulled to hard and shaft now
> pulled out of control/ hopefully repairable/ its not set screw type knob
> just the splitshaft type knob still cant pull it from shaft/ any ideas
> appreciated
>
Hello--

By coincidence, I just posted the following suggestion to another
newsgroup. While I doubt that it's applicable to Jerry's predicament,
it may help someone else avoid damaging an expensive or hard-to-find
instrument control knob. [1]

Before you damage a knob, try this:

If the knob in question is fastened to its shaft with a setscrew,
remove the screw and place a droplet of Kroil or other penetrating
oil in the setscrew hole.

Next, obtain a short length (i.e., a few inches) of ribbon cable
as is used in computer disk-drive cables. Using a sharp knife,
separate the conductors in the cable's center, approximately
halfway along the cable.

Push the ribbon cable's opening over the knob and slip
the conductors under the knob between the knob and panel.
Grasp the cable's free ends and gently pull. With any luck,
the knob should slide off without damage.

In contrast to the "pry with a screwdriver" approach,
the ribbon cable applies even pressure to two sides of
the knob.

73--

Brad AA1IP

[1]: note that some knobs are held to their shafts by a
split nut hidden beneath a removable cap set in the
knob's center. Pry off the cap and you'll find a brass
insert that clamps to the control's shaft.



Re: how to finess a knob off

stefan_trethan
 

Heat may help, penetrating oil if certain metals are involved.

I would clamp the shaft and lever the knob off using pressure on the
whole circumfence of the knob, with a washer or a plate with a hole.
If there is a recessed brass or aluminium insert I would use a piece
of tubing or similar sleeve to apply pressure only to the insert, not
the plastic.

ST

On Sun, Jun 16, 2013 at 3:28 PM, Jerry <kj6ntl@yahoo.com> wrote:
hello all/ need some Ideas how to remove a knob on inner shaft of a horizontal position control /inner is the 10x switch/needed to be removed to access the screws under the thin nameplate panel to remove a board for repair / board is broken /but pulled to hard and shaft now pulled out of control/ hopefully repairable/ its not set screw type knob just the splitshaft type knob still cant pull it from shaft/ any ideas appreciated
thanks Jerry



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Yahoo! Groups Links



Re: how to finess a knob off

Brad Thompson <brad.thompson@...>
 

On 6/16/2013 9:28 AM, Jerry wrote:
hello all/ need some Ideas how to remove a knob on inner shaft of a
horizontal position control /inner is the 10x switch/needed to be
removed to access the screws under the thin nameplate panel to remove a
board for repair / board is broken /but pulled to hard and shaft now
pulled out of control/ hopefully repairable/ its not set screw type knob
just the splitshaft type knob still cant pull it from shaft/ any ideas
appreciated
Hello--

By coincidence, I just posted the following suggestion to another
newsgroup. While I doubt that it's applicable to Jerry's predicament,
it may help someone else avoid damaging an expensive or hard-to-find
instrument control knob. [1]

Before you damage a knob, try this:

If the knob in question is fastened to its shaft with a setscrew,
remove the screw and place a droplet of Kroil or other penetrating
oil in the setscrew hole.

Next, obtain a short length (i.e., a few inches) of ribbon cable
as is used in computer disk-drive cables. Using a sharp knife,
separate the conductors in the cable's center, approximately
halfway along the cable.

Push the ribbon cable's opening over the knob and slip
the conductors under the knob between the knob and panel.
Grasp the cable's free ends and gently pull. With any luck,
the knob should slide off without damage.

In contrast to the "pry with a screwdriver" approach,
the ribbon cable applies even pressure to two sides of
the knob.

73--

Brad AA1IP

[1]: note that some knobs are held to their shafts by a
split nut hidden beneath a removable cap set in the
knob's center. Pry off the cap and you'll find a brass
insert that clamps to the control's shaft.


Re: More uses for TDR?

stefan_trethan
 

Typically motor testers use capacitive coupling to the sparkplug wire with a clamp.
But I suppose nothing other than high cost and inconvenience would stop you from using a HV probe.

ST


On Sun, Jun 16, 2013 at 2:24 PM, jerry massengale <j_massengale@...> wrote:


Hi,

I wonder if you could do comparative analysis of spark plugs and wires. That also brings up the question of using a scope to check the spark voltage. How to do the connection? How you make an inductive or resistive connection?


Jerry Massengale



-----Original Message-----
From: cheater00 . <cheater00@...>
To: TekScopes <TekScopes@...>
Sent: Sun, Jun 16, 2013 6:25 am
Subject: [TekScopes] More uses for TDR?

 
Hi guys,
I have been wondering whether a TDR had other uses than "there's a
cable fault X meters from here" or "your long long line is not
properly terminated".

For one thing, I know you can use a TDR to measure soil quality
because the electrolyte content changes the resistivity (and therefore
resistance) of soil, allowing it to sink more or less of the signal
depending. But could the same effect be used on more resistive things,
such as say a capacitor, resistor? Would attaching a TDR to a spool of
unterminated coax (to get a late reflection), terminating that with a
resistor, yield information on its resistance? What about a capacitor,
would a TDR be useful for finding out about its properties?

I also read you could use a TDR to measure stray capacitance between
e.g. a trace or via and the ground plane. Is a TDR going to measure
quantities of interest to someone doing analog audio design - or are
we talking about minutiae only important to people doing very high
speed electronics?

What other uses does a TDR have?

Cheers,
Damian




how to finess a knob off

Jerry Barr
 

hello all/ need some Ideas how to remove a knob on inner shaft of a horizontal position control /inner is the 10x switch/needed to be removed to access the screws under the thin nameplate panel to remove a board for repair / board is broken /but pulled to hard and shaft now pulled out of control/ hopefully repairable/ its not set screw type knob just the splitshaft type knob still cant pull it from shaft/ any ideas appreciated
thanks Jerry


Steven Creswick

Steven Creswick
 

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