Date   
Re: Packaging 7854 scope for shipment?

David DiGiacomo
 

On Sat, May 25, 2019 at 2:24 PM Brad Thompson
<brad.thompsonaa1ip@...> wrote:
I'm thinking of offering my 7854 FS and I'd appreciate advice on
packaging it
for survival on shipment to U.S. addresses. IIRC, packing the plug-ins and
keyboard separately is advisable, as is double-boxing the mainframe.
I'd plan on swaddling the scope in multiple layers of bubble-wrap, with
a sheet
of resilient foam to protect the front panel.
I have always had success with that basic method. Just to be clear,
the thick soft foam goes over the front before the bubble wrap goes
around. 24" wide bubble wrap should be used. I think it's better to
ship with plugins installed, since they provide extra rigidity to the
plugin bay. You need to have a heavy duty or doublewall box -
ordinary singlewall is too weak. I usually make cardboard or
styrofoam corner blocks.

Re: Packaging 7854 scope for shipment?

Dave Seiter
 

Since boxes of the correct size can be hard to come by, I almost always use cardboard from bicycle shops and construct my own boxes.  The cardboard is free, and you get a custom fit, but it does take a while.  The other advantage is that bicycle box cardboard is heavier than most and usually triwall.  I like to use PE foam planking when I can get it (the type quality electronics get shipped in), and design the outer box as a sacrificial protector of the inner box.  The boxes get large quickly this way, and usually exceed the limit imposed by USPS (108"?), so UPS/FEDEX is about the only shipping method.  Most pack and ship places rarely deal with items that are of similar size/weight/fragility, so they really shouldn't be expected to box up a scope correctly; I know I wouldn't trust them even if they said they had the experience.  
I've heard that Fastenal will ship large items between stores safely, but I've never used them, and they would have the same location restrictions as Greyhound.
-Dave

On Saturday, May 25, 2019, 1:24:07 PM PDT, Brad Thompson <brad.thompsonaa1ip@...> wrote:

Hello--

I'm thinking of offering my 7854 FS and I'd appreciate advice on
packaging it
for survival  on shipment to U.S. addresses. IIRC, packing the plug-ins and
keyboard separately is advisable,  as is double-boxing the mainframe.
I'd plan on swaddling the scope in multiple layers of bubble-wrap, with
a sheet
of resilient foam to protect the front panel.

Our local pack-and-ship store has a bad reputation. Has anyone
successfully used a
commercial mover that offers pack-and-ship services?

If packing turns out to be a hassle, I'll list it for local pickup only.

Thanks in advance, and 73--

Brad  AA1IP
--
Sent from Postbox <https://www.postbox-inc.com>

Re: Packaging 7854 scope for shipment?

 

Hi Brad,
Have you eve received anything that was packed with "Foam in Place". It is simple and quite robust. I have requested it whenever I win something that is fragile and valuable.
Dennis Tillman W7PF

-----Original Message-----
From: Brad Thompson, Sent: Saturday, May 25, 2019 1:24 PM
Subject: [TekScopes] Packaging 7854 scope for shipment?

Hello--

I'm thinking of offering my 7854 FS and I'd appreciate advice on packaging it for survival on shipment to U.S. addresses. IIRC, packing the plug-ins and keyboard separately is advisable, as is double-boxing the mainframe.
I'd plan on swaddling the scope in multiple layers of bubble-wrap, with a sheet of resilient foam to protect the front panel.

Our local pack-and-ship store has a bad reputation. Has anyone successfully used a commercial mover that offers pack-and-ship services?

If packing turns out to be a hassle, I'll list it for local pickup only.

Thanks in advance, and 73--

Brad AA1IP




--
Dennis Tillman W7PF
TekScopes Moderator

REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation of the Tektronix 012-0482-00 cable for the SG503

 

I uploaded a completely revised and improved version of my paper on the 012-
0482-00 cable for the SG503 signal generator.

It is located at

https://groups.io/g/TekScopes/files/Evaluation%20of%20the%20Tektronix%20012-
0482-00%20cable%20for%20the%20SG503%20REVISED%20and%20UPDATED.pdf



It now contains the EXACT SPECIFICATIONS Tek defined for the cable. In
addition I evaluated several 50Ω terminators and I show how to build a
simple 50ohm terminator in 15 minutes that outperforms most of the ones you
can buy.



Dennis Tillman W7PF

Re: "Volts/Div" knob for Tek 2235 needed [ Tek part No : 366-2148-01]

satbeginner
 

My 2 cents: a while back I repaired a 2215A and used the same IRF as a replacement.

I added a small 12V fan (don't remember if it was 60 or 70 mm, but the homes were already there), and also because the location for the diode and the small connector were already there on the PCB.

If I remember well Tek used only one rectifier diode and a capacitor, the result was around 9V DC that made the 12V fan run nice and quiet, but it kept everything cool.

I believe the fan was only put in with certain 21xx models because of the higher 43V current, but it worked great with the 2215A.

Succes,

Leo

Re: REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation of the Tektronix 012-0482-00 cable for the SG503

Jim Ford
 

Uh, Dennis, I don't see the 50 ohm termination evaluations, nor the 15-minute high-performance termination in the .pdf.  Do d I miss something?Thanks.Jim Ford Sent from my Verizon, Samsung Galaxy smartphone

-------- Original message --------From: Dennis Tillman W7PF <@Dennis_Tillman_W7PF> Date: 5/25/19 8:35 PM (GMT-08:00) To: TekScopes@groups.io Subject: [TekScopes] REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation of the Tektronix 012-0482-00 cable for the SG503 I uploaded a completely revised and improved version of my paper on the 012-0482-00 cable for the SG503 signal generator.It is located at https://groups.io/g/TekScopes/files/Evaluation%20of%20the%20Tektronix%20012-0482-00%20cable%20for%20the%20SG503%20REVISED%20and%20UPDATED.pdf It now contains the EXACT SPECIFICATIONS Tek defined for the cable. Inaddition I evaluated several 50Ω terminators and I show how to build asimple 50ohm terminator in 15 minutes that outperforms most of the ones youcan buy. Dennis Tillman W7PF

Re: REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation of the Tektronix 012-0482-00 cable for the SG503

Craig Sawyers
 

I uploaded a completely revised and improved version of my paper on the 012-
0482-00 cable for the SG503 signal generator.

It is located at

https://groups.io/g/TekScopes/files/Evaluation%20of%20the%20Tektronix%20012-
0482-00%20cable%20for%20the%20SG503%20REVISED%20and%20UPDATED.pdf



It now contains the EXACT SPECIFICATIONS Tek defined for the cable. In addition I evaluated
several
50 terminators and I show how to build a simple 50ohm terminator in 15 minutes that outperforms
most of the ones you can buy.



Dennis Tillman W7PF
That is really, really interesting Dennis. Your homebrew termination reminded me of a homemade 1GHz
Z0 probe described here http://emcesd.com/1ghzprob.htm

Smith makes the point that his probe could be made even better by using microwave resistors, and it
would be interesting to discover if they would make an even better 50-ohm termination.

Craig

Re: "Volts/Div" knob for Tek 2235 needed [ Tek part No : 366-2148-01]

Jared Cabot
 

I have done a number of upgrades as discussed in this thread on my 2235.

I made a video with all the part numbers and info needed, including the service upgrade on the PSU section, capacitor replacement, fan install, and 510K focus resistor replacements.

Someone might find it useful I guess...

https://www.youtube.com/watch?v=lrXCVg6T-ek

Re: Looking for fan impeller fastener for 2465

Siggi
 

On Tue, Apr 30, 2019 at 10:11 AM machineguy59 via Groups.Io <machineguy59=
yahoo.com@groups.io> wrote:

Parts for the "original" 2465 fan (motor, impeller, collet) are near
impossible to find. Even when found, they are old and made from plastic
that does not age well. Most people make substitutes or convert to muffin
fans as used in the later model 24xx scopes. You can search the group
archives with the term "impeller" and spend an afternoon learning all the
ways others (including me) have been frustrated with this part. I ended up
using a collet from my collection of Dremel tools to replace the collet.
(Re: Removing a 2465 Squirrel cage fan).
A more elegant solution can be found in the pictures archives. Search for
"2465 fan collet repair"Or, if you have access to a machine shop there is a
drawing for making one:
https://groups.io/g/TekScopes/files/Fan%20Collet%20-%20Tek%202465%20O-scope.pdf

I machined a small number of replacement collets from delrin and shipped
one to Jon. On pulling the collet from my own 2465 to get measurements, I
found that it was due for a replacement also. The plastic had started
cracking around the threaded insert, so I've replaced mine too.
The collets I machined are a direct replacement for the original part,
which means they're tapped #4-40 on the narrow end to fit the original
stud. The delrin will hold the thread just fine, the only reason there's an
insert in the original is for production expediency as they're injection
molded.
Now, the original double-threaded stud is #4-40 on one end and #8-32 on the
other with a "9/32 collar in between. The #8-32 side sticks out from the
impeller and serves to pull the collet into the impeller and clamp it on
the shaft. The #4-40 threads go into the collet, but the purpose of those
threads and the "9/32 collar is to push the collet out of the impeller.
So to remove the impeller, start by removing the nut, then use a regular
screwdriver on the slot in the stud while holding on to the impeller. As
you turn the stud counter-clockwise, the "9/32 collar will eventually
contact the inside of the impeller and (gently) push the collet out of the
impeller.

In any case, if anyone finds themselves needing one of those collets for a
repair, send me a message (off-list) and I'll ship you one for postage - so
long as my supply lasts at least.

49xp 27xx extender boards??? Is there a need or supplier?

radioconnection@...
 

Does anyone make extender boards for these analyzers? I am finding that I need a set to work on a few boards on my 497P.

Doing a search they seem to be extremely rare.

Does anyone else have a need for a set to work on the top set of boards? I see a guy in Rhode Island who makes boards for the HP gear, and he
says he will any extender if there is a need. If enough of us need an extender board he might be inclined to offer a kit.

I'd be willing to contact him if there is enough interest in our group, but I'd need some technical data on the pin spacing and connectors used for those cards
to make sure I am asking for exactly what is needed.

Pete.

Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

Kevin Oconnor
 

@dave
Terapeak (now an Ebay
subsidiary) DOES provide actual selling price information for BIN and
OBO sales. You CAN find out what something really sold for. And the
discounts are usually significant - but not always.
Now that is an interesting new tidbit. Never heard of them.
K

Re: 49xp 27xx extender boards??? Is there a need or supplier?

Bob Koller
 

Norway Labs made extenders for the 49x SA's. I am not sure if they still have any, but give them a call next week at 503-924-5846.

Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

Kevin Oconnor
 

I stand corrected! There was a time eBay did not charge FVF on shipping domestic, only international. I do mostly free shipping and missed that change.

Kevin

Re: REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation of the Tektronix 012-0482-00 cable for the SG503

 

Hi Jim,
It starts on page 10 and runs to the end of the document (page 17)
Dennis

-----Original Message-----
From: Jim Ford, Sent: Saturday, May 25, 2019 10:31 PM

Uh, Dennis, I don't see the 50 ohm termination evaluations, nor the 15-minute high-performance termination in the .pdf. Do d I miss something?

Thanks.Jim Ford





--
Dennis Tillman W7PF
TekScopes Moderator

Re: 2246 no display/odd behavior

Matt
 

I measured voltages at all test points: https://groups.io/g/TekScopes/photo/90936/0/schem1.png

Green text: measurement in spec
Red text: measurement out of spec
Blue text: unknown spec but I measured

Hoping someone may be able to make some sense of it - I'm out of ideas. Thanks.

Clock error on TDS3034

 

I recently bought a nice TDS3034.
Unfortunately, its clock has a problem: I may set date and time but it does not keep it, not even without a restart.
Could this be just a bad backup battery and if so, could the calibration state be affected, either already or when replacing the battery? Does this model have a Dallas NVRAM?
I’m not at home so I haven’t had time to check amplitude calibration etc. nor opened the case. Fast edge seems ok (have a Leo Bodnar pulser with me).
Thanks for any responses!
Raymond

Re: REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation of the Tektronix 012-0482-00 cable for the SG503

 

Hi Craig,
Yes, that homebrew 1GHz probe article at http://emcesd.com/1ghzprob.htm was
one of the most useful things I ever came across.
Everyone should read it. It is so practical. It overcame my fear of high
frequency design. It influenced a lot of things I have made since.

That article, and another one I read on how to make the perfect terminator,
have made it possible for me to improve my TDR skills to the point where I
am at the most sensitive scale on the TDR and able to see some very subtle
stuff. The 7S12 TDR is a wonderful plugin. It is definitely one of my very
favorite things to use. Extremely fast pulses have always fascinated me, and
when I discovered they can tell you so much about a cable I was hooked. I
check every new cable I get on a TDR before I will use it.

The article on terminator design contained a very simple, practical
explanation of how to arrive at the perfect shape.
I forgot all of the details but it goes something like this:
Start by attaching a 50 ohm resistor across the two contacts of a BNC
connector.
A TDR will show you the resistor has lead inductance and capacitance to the
BNC body. The result is big reflections and poor HF response.
That can be improved if you use two 100 ohm resistors in parallel across the
BNC. That improves the inductance but adds capacitance from the bulk of each
resistor to the BNC. So the inductance went down a little but the
capacitance went up a little.
Next try four 200 ohm resistors in parallel. Spread them around the center
pin to the outer ground to lower the capacitance between them. But there is
now a little more capacitance and a little less inductance.
On and on. Eventually you end up with a circular cylinder of resistive
material. The cylinder diameter reaches the outer ground connector of the
BNC and it has a tiny hole in the middle that connects it to the center pin
of the BNC.
The cylinder has no lead inductance but it has a lot of bulk capacitance. If
you turn the cylinder to a thin disk you will reduce the bulk capacitance to
an absolute minimum.
Now there is no more lead inductance and the only capacitance between the
center pin and the outer ground lead is swamped by the disk's intrinsic 50
ohm resistance.
A thin resistive disk turns out to be the ideal shape for the resistance of
a terminator. It applies to any kind of coax connector.

Notice that all of the so called inexpensive terminators use a single 50 ohm
resistor inside them. Many times you can spot those easily from their shape.

They are never going to have a good response. They will have the worst
possible response a terminator can have.

Microwave resistors might make a small improvement to the terminator but
since a BNC has very limited frequency response, 2GHz typical or up to 4GHz
best case, that will prevent microwave resistors from making a big
difference. The benefit to BNC connectors is they are big enough to work on
and there is enough room to put a few surface mount resistors around their
center pin.

You have to switch to SMA connectors to get higher performance. Their
diminutive size makes it impractical to build your own terminators without a
really good surface mount setup.

Dennis Tillman W7PF

-----Original Message-----
From: Craig Sawyers, Sent: Saturday, May 25, 2019 11:57 PM
Subject: Re: [TekScopes] REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation
of the Tektronix 012-0482-00 cable for the SG503

<snip>

That is really, really interesting Dennis. Your homebrew termination
reminded me of a homemade 1GHz
Z0 probe described here http://emcesd.com/1ghzprob.htm

Smith makes the point that his probe could be made even better by using
microwave resistors, and it would be interesting to discover if they would
make an even better 50-ohm termination.

Craig




--
Dennis Tillman W7PF
TekScopes Moderator

Evaluation of the Tektronix 012-0482-00 cable for the SG503

 

Brian Cockburn was kind enough to proofread my paper. Unfortunately I didn't know Brian could do this before I uploaded it to TekScopes.
He caught the following things I need to correct:

Page 1, Paragraph 1, should read:
3. “How is the 012-0482-00 different from any other coaxial cable”?

Page 1, paragraph 3, sentence 2 should read:
If it isn’t kept with the SG503 it might be mixed with all the other coax cables, abused, and/or discarded, because it was not flexible enough or long enough, etc.

Page 6, paragraph 1, sentence 4 should read:
The diameter of this cable is 0.190-inches and it is as flexible as other coax so it is not made from the same cable as the 012-0482-00.

Page 9, paragraph 1. The very first character, a lower case Greek epsilon, should be removed.

Page 12, Figure 12 caption, second sentence should read:
The response varies from -10mρ to 45mρ.

Page 13, Figure 13 caption, second sentence should read:
The response is >70mρ.

Page 14, Figure 14 caption, first sentence should read:
The response of my homemade terminator goes from +22mρ to -14mρ.

Page 16, Figure 17 caption, first sentence should read:
The response of my homemade terminator after the final change I made is +20ρ, -11ρ which corresponds to 52.04Ω and 48.91Ω respectively.

Thank you Brian.
Dennis Tillman W7PF




--
Dennis Tillman W7PF
TekScopes Moderator

Re: REVISED, UPDATED, EXPANDED, and IMPROVED Evaluation of the Tektronix 012-0482-00 cable for the SG503

Craig Sawyers
 

Next try four 200 ohm resistors in parallel. Spread them around the center pin to the outer ground
to
lower the capacitance between them. But there is now a little more capacitance and a little less
inductance.
On and on. Eventually you end up with a circular cylinder of resistive material.
Dennis Tillman W7PF
Quite a long time ago I bought some disc 50-ohm resistors that have a hole that takes a centre pin
of a BNC. Bought them from https://www.surplussales.com/ ages ago.

It would be interesting to see what the HF performance was as compared with four discrete surface
mount.

Craig

Re: 497p front panel cal failure (CF and Ref Lvl)

radioconnection@...
 

Happy dance. Found a few runs damaged due to capacitor leakage. One was a through hole under one of the tantalum bodies. Also lost a ground connection to an IC pin and to the common ground returns for both axial lead tantalum caps. She is calibrating and happy as a clam.

Pete