1. TekScopes@groups.io
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Re: 475A + DM44 refuses to power on

Tom Miller
 

Measure the voltage across each of the bulk filter capacitors.

C1412 =

C1414 =

C1442 =

C1452 =

C1462 =

C1472 =

Report back the measurements.

Regards

On 4/4/2019 1:22 PM, Alberto I2PHD wrote:
Good afternoon all,

my 475A + DM44 was not powered on for about one year. It worked before. Now, switching it on, nothing happens... no lights, no Scale Illumination, no fan running. Except... the DM44 powers on and functions regularly... this should mean that the line fuse, the power transformer, etc. are ok...
Checking with a voltmeter, on the test points of -8V, +5V, +15V, +50V the voltages are at zero. The only exception is the the test point of the +110V which measures +92V....

Any suggestions on what to check further ?
TIA

Alberto
475A + DM44 refuses to power on

Alberto I2PHD
 

Good afternoon all,

my 475A + DM44 was not powered on for about one year. It worked before. Now, switching it on, nothing happens... no lights, no Scale Illumination, no fan running. Except... the DM44 powers on and functions regularly... this should mean that the line fuse, the power transformer, etc. are ok...
Checking with a voltmeter, on the test points of -8V, +5V, +15V, +50V the voltages are at zero. The only exception is the the test point of the +110V which measures +92V....

Any suggestions on what to check further ?
TIA

Alberto
Re: Old Tektronix Books

Daniel Koller
 

Well, good news so far!  My copy of "Typical Oscilloscope Circuitry" arrived today.  It's a "revised edition" from 1962 and it's in very good shape.  The cover smells a bit like soap rather than cigarettes interestingly enough.    But the stamp on the first two pages reads "Property of Collins Radio Co."  Cool.    I recently picked up a Collins-made  R390 for fun.  Wonder if this book and that receiver ever crossed paths.
Still waiting on Stan's book, if the bookseller ever finds me a copy for $38.  Ha ha.   Dan

On Saturday, March 30, 2019, 8:20:45 AM EDT, Dave Daniel <kc0wjn@...> wrote:

Yes, these sellers are called "book jackers" by legitimate sellers. A
book-jacker will advertise a book at a higher price than a legitimate
seller and then sell the book to you. The book jacker buys the book from
the original seller and then ships it to you or has ir drop-shipped to
you from the original seller.

One can sometimes spot this when a book for which one is looking comes
on the market, listed by the original seller, and then shortly
thereafter shows up with the exact same description (word-for-word) as
the original seller's description but at a higher price. Also, it is
sometimes evident that the book jacker lacks experience and card when
packing the book before shipping it to you.

This started happening about fifteen years ago.

Another point that I was going to make in this thread is that the
website bookfinder.com is a good resource to find all copies of a given
book that are available from ABE Books, Alibris, Amazon and the rest of
the other second-hand online book sellers. I almost always try to buy
from book sellers who list their books on ABEBooks or Alibris, and in
many cases, I can purchase used books from sellers from whom I have
purchased in the past (for instance, Zubal books). I don't buy many
books anymore since I have too many now. I have had lots of problems
buying used books through Amazon and I tend to not buy used books
through Amazon anymore.

I found my copy of "Typical Oscilloscope Circuits" in a surplus parts
store decades ago. I don't remember how much I paid for it, but ISTR it
was just a few dollars. I've since collected all of the other Tektronix
"Concepts" series of books; I wonder if they are still out there and, if
so, for how much. At least many of them are available from the TekWiki,
DavMar and K04BB websites (for instance) in PDF form and so have been
preserved in a useful form.

DaveD


On 3/29/2019 4:04 PM, Dennis Tillman W7PF wrote:
Daniel,
Good for you!

It is my impression from watching scarce items like this that there are many companies that will advertise an item at an outrageous price even if they don't have it. They rely on finding some other company that claims to have it and then if you meet the price that justifies them actually hunting down a real copy the will do that and pocket the difference.

The reality is that all there needs to be is one copy and these companies make it appear that there may be more than one copy or even many. Daniel discovered that in the case of Stan's book there was only one copy. Now the price has jumped back into the stratosphere where it usually is.

I suspect there isn't more than one (or two at the most) of the Typical Oscilloscope Circuitry books either and now that Daniel bought one of them I think the price will skyrocket like Stan's book did.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Daniel Koller via Groups.Io
Sent: Friday, March 29, 2019 9:45 AM
To: TekScopes <tekscopes@groups.io>
Subject: [TekScopes] Old Tektronix Books

Hi Folks,
    The recent conversation about 500 series scopes prompted Dennis to
recommend two books,
        "Oscilloscopes: Collecting and Restoring a Classic"; ISBN-13:
9780963307156; Publisher: Stanley A. Griffiths; Publication date:
01/28/1992;
        "Typical Oscilloscope Circuitry", (C) 1961, 1962, Tektronix,
Inc., S. W. Millikan Way, P.O. Box 500, Beaverton, Oregon.

It occurred to me that though I have not *needed* those books to
repair my scopes in the past it sure would be nice to have a better
Idea on how the circuits work, and to be able to learn more about the
scopes in general, so I looked them up.
    YESTERDAY, I was able to find a couple copies of Stan's book on
Amazon, used, for about $22.  If I still have the website up at home
and it has not refreshed, I'll get a screen grab for proof, but there
were one or two copies available from at least two sources, through
Amazon.  But TODAY, the least expensive copy is $94.09!!    So, it
seems likely to me that this very discussion, within out closed group,
prompted someone to buy a book or two, and those actions drove up the
perceived demand on a limited resource to raise the price
significantly.
    Question:  Did anyone here, reading those messages yesterday go
ahead and buy Stan's book on line?  What was your price and through
whom did you make the purchase?  I sure HOPE that someone here bought
the book.  Otherwise, I have a more nefarious theory;  The bots are
actively scanning our conversations to manipulate the prices of things
on line.  That is not a pleasant concept.
      I found a copy through Moe's books for $28 and bought it.  Let's
see how the price changes tomorrow.
    As for the Tek book, "Typical Oscilloscope Circuitry", also found 3
copies in good condition for under $20 and bought one.  We'll see
what happens to that as well.
    I just figured I'd throw this out there as an FYI / buyer beware
sort of thing.  Meanwhile, I am looking forward to some fun technical
reading!
Dan
SG 504 leveling head gets a surprise upgrade.

Ancel
 

Hi All:
I did some more work on improving the SG-504 leveling head performance. This improvement happened by accident due to a poor solder joint on one caused me to dig deeper into the impedance matching arena.
I determined that a 0.15dB loss (4Vpp) at the SG504 operating frequencies from 250Mhz thru 1050 Mhz is relatively consistent, from small impedance matching losses in the head as it is in the signal line.
Usually I compensate the hi range using stub tuning via PCB parasitic capacitance to improve the accuracy at the high end (800 to 1050MHz)to around .05dB. This compensation had much less effect on the low range being freq. dependent.
With some impedance matching adjustments on the output of the head it now achieves a sub 0.1dB accuracy across the whole range, indeed usually sub .05dB!
The caveat is with the 6MHz test signal you will see a 6.15dB level outputted @ 4Vpp due to minimal test frequency losses.

Since the SG 504 operational frequencies of interest (250Mhz thru 1050Mhz) are now calibrated to usually reach 0.05dB accuracy @ 4Vpp, I feel the
head is improved with no added costs. Had to add one extra SMT resistor to compensate for small resistive and frequency related losses in the signal path.

So the most recent purchaser, a gentleman from the UK, has the 1st of the new generation in precision leveling heads on its way to him.

I employ a 12Ghz Sensor Head, Boonton 4210 RF microwattmeter to achieve the precision dB measurements.

If you are interested in purchasing my improved SG504 Leveling Head please contact me OFF-LIST at protofabtt@....

cheers,
Ancel
Free equipment, Los Angeles area

John Gord
 

Here is a list test equipment that should really get back into circulation. Pickup only; I live in Venice, CA, a neighborhood of Los Angeles.
(There is some very nice stuff here.)
I don't care if you use it, sell it, or give it away! I just want to get the equipment into circulation instead of letting my kids send it to a landfill someday.
I am cross posting this to Tek, HP, and general test equipment lists.

Contact me by email to arrange pickup.
--John Gord email: johngord (at) verizon (dot) net

Items marked with "*" are known not to work
other items worked when stored away

Tektronix
106 Tek pulse generator
222 Tek DSO
2232 Tek analog/digital scope
224 Tek digital scope
2335 Tek analog scope
2336 Tek analog scope
2445 Tek analog scope
2445 Tek analog scope
2445A Tek analog scope
2445B Tek (no U800, bad PS)
321A Tek analog scope
422 Tek analog scope
453A Tek analog scope
454A Tek analog scope
5103 Tek analog scope
7603 Tek analog scope
7A11 Tek scope plugin
7A11 Tek scope plugin
7A11 Tek scope plugin
7A24 Tek scope plugin
7D15 Tek scope plugin
7D15 Tek scope plugin
7S11 Tek scope plugin
S4 Tek sampling plugin
7S14 Tek scope plugin
7T11 Tek scope plugin
DM501A Tek TM500 plugin
FG501A Tek TM500 plugin
FG502 Tek TM500 plugin
FG503 Tek TM500 plugin
FG504 Tek TM500 plugin*
FG504 Tek TM500 plugin*
PG506 Tek TM500 plugin
SC502 Tek (no crt)*
SC504 Tek
TM503 Tek TM500 mainframe
TM505 Tek TM500 mainframe
Y400 Tek Portable RF analyzer

HP/Agilent
1672G Logic analyzer
3132A display
3310B Function generator
3400A RMS voltmeter
3455A 6 digit DVM
3466A 4.5 digit DVM
3466A 4.5 digit DVM
3468A 5.5 digit DVM
3478A 5.5 digit DVM
3577A Network analyzer
435A Power meter
435A Power meter
435B Power meter
5316A Frequency counter
5316B Frequency counter
8502A Test set
8503A Test set
8566B Spectrum analyzer (complete)
8594E (no YTO)*
8654A Signal generator
8712B Network analyzer
E7495B Base station test set

Misc
616 Keithley digital electrometer*
616 Keithley digital electrometer*
616 Keithley digital electrometer*

6060A/AN Fluke 500MHz synthesizer
750A Fluke Precision divider
8050A Fluke DVM
8050A Fluke DVM
8600A Fluke DVM
8800A Fluke DVM
8800A Fluke DVM

8821Q-R Trilithic spectrum analyzer*

5001 Racal-Dana 5.5 digit dvm
9500 Racal-Dana Frequency counter*

FC130 Beckman Frequency counter

252 ESI Impedance meter
252 ESI Impedance meter
Re: WTB: Dead SD-22, 24 or 26 sampling heads

Bob Koller <testtech@...>
 

I don't know about the modules, but from the picture on tekwiki, the substrates are likely mounted with adhesive, and therefore virtually impossible to remove intact, especially in a complex assembly like that. They might even be soldered down if they needed more thermal conductivity or grounding.
Re: Impedance matching question

Reginald Beardsley
 

David,

These should be good quality:

https://www.ebay.com/itm/Kings-1340-1-M06-BNC-Feed-Through-Termination-Tested-Sold-by-W5SWL/372631591472

I have 8 very good generic Chinese thru terminators which I bought on eBay. But I can't find any information about who I bought them from. TDR testing on my 11801 shows no reflections below 500 MHz which is all you can really expect out of BNC and usable to 3 GHz. My 200 MHz Instek MSO-2204EA shows no reflection, whereas my 1.5 GHz LeCroy DDA-125 shows some.

I strongly urge you to get one of Leo's pulsers:

http://www.leobodnar.com/shop/index.php?main_page=product_info&cPath=124&products_id=295&zenid=a6e3da2d1240f48cb10c362696eefebf

and learn to do TDR testing of connectors and cable. That will allow you to buy connectors on eBay and return those which test bad. The major problem I have found with Chinese BNC adapters is the male connectors have intermittent connections. Unfortunately, I only figured how to test them long after the return period had ended.

I'd been playing around testing connectors on my 11801 using some 20 GHz SD-26 heads and the calibrator output and am quite blown away by the sensitivity. I can see the reflection from an SMA-F to N-F and an N-M to BNC-F stack and from an SMA-F to BNC-F. In both cases the reflections are above 700 MHz.

Reg
Re: TM504 backplane repair

Chuck Harris <cfharris@...>
 

Desoldering stations are great, but you have to use them
in ways that let them be really effective.

First, it is very important that the solder joint be clean,
fluxed, and has a solder in it that you can melt.

Second, once the tip settles into the pad as the surface solder
melts, count to 3 to make sure it is melted clear through.

Third, after the count, gently wiggle the tip from side
to side to make sure the pin is really free.

Fourth, turn on the vacuum while still wiggling a little bit.
This is to clear the solder from all sides of the pin.

One thing you don't want to do is scrub the pad with the tip
while you are wiggling... be gentle as the PCB adhesive is
very vulnerable when it is hot.

If a pad won't clear all the way through, re solder it and
try again.

Ground planes are the Achilles heels of desoldering stations.
You can turn the heat up a little, and increase the count to
10. Sometimes you just cannot win without adding some heat
with another soldering iron, or an underboard heater.

-Chuck Harris



Colin Herbert via Groups.Io wrote:

OK, so I bought a de-soldering station, but I don't seem to be able to free the mangled contact easily. I can also see that trying to remove the entire 56-pin connector would be a major task. I am going to try a few more ideas before I give up and forget the one mangled contact, but if I can remove it eventually, I may then just replace it with a good one, if I can.
Colin.
Re: 2215A with short trace only when free running

tom jobe <tomjobe@...>
 

Hi Torquil,
Thank you for posting your 2215A story here on Tekscopes, and for posting the link to the excellent discussion several of you are having about your 2215A over on the EEVblog.
I lack the knowledge to participate at the level you guys are discussing this problem at, but I do wonder if you still have a signal on both horizontal inputs to the CRT under the conditions when the trace compresses to half of the screen's width?
Having the luxury of a good working 2215A on hand to compare to is very helpful, especially when it is combined with the knowledge levels you and the others possess.
I'm a big fan of the simple Tektronix scopes such as the 2213A, 2215A, 2235 and 2235A. They were made into the early 1990's I believe, so they are still quite useful and very repairable today.
tom jobe...

On 4/3/2019 6:58 AM, torquil@... wrote:
Hello there!

I just posted this question over at EVVblog.com today, but just learned about this place, so I'm putting it up here as well:

I recently bought a used (obviously) Tektronix 2215A which has a problem that I would like to repair. Fortunately, I have access to another 2215A which is working fine, so I can compare behaviours between the two.

In a nutshell, the problem seems to be that when the trace is "freerunning"/not triggering, the horisontal extent of the trace is compressed to about half the width of the display. When triggering on a normal input signal, the horisontal extent is fine and covers the entire width.

I went through the "baseline trace" procedure in the service manual on both scopes. On the problematic scope, the baseline trace is short. On the working scope, it covers the entire width. With a normal sinusoid input and using "PP auto" triggering, both scopes show a nice trace that covers the entire screen width.

I have a few other observations, which might be caused by the same underlying problem on the problematic scope:

1) When selecting "A trigger source: line", I get no trace. On the working 2215A with a sinusoid input from my cellphone, it shows an "unsynchronized" trace, is it should since the input is not synchronized to the line voltage.

2) Pushing "single sweep" while in "PP auto" trigger mode doesn't always result in a trace. It seems very unreliable. On the working 2215A, it always shows one trace.

3) Sometimes the trigger LED flickers when moving the "A intensity" knob.

4) Say I have a full trace covering the entire screen width with a sinusoid input and "PP auto" triggering. If I then turn the "Volts/DIV" until the trace becomes very flat, it will stop triggering and then the trace width suddenly reduces to about half the screen width. So when the triggering is not happening, the width is reduced, as mentioned. This should not happen, of course, and does not happen on the working 2215A that I'm comparing to.

5) On more thing: Say I have e.g. the baseline trace going (which occupies half the screen width) and set the "TIME/DIV" knob so that the trace moves very slowly. If I use the "single sweep" trigger button, the first sweep starts all the way from the left of the screen and travels across the entire screen, but every subsequent trace is "compressed".

So it seems to me that after a trigger event, the trace will go across the entire width, but when there has not been a trigger event, the trace is compressed in the horizontal direction...

So my conclusion is that it has to have something to do with the part of the timebase circuitry that controls the horizontal amplifier. The input to the horizontal amplifier seems to be wrong whenever there has not been a trigger event. When there has been a trigger event, everything seems fine. The vertical behaviour of the trace is working fine.

Any ideas?

The only thing I have done so far inside the scope is to check the power supply voltage test point on the main board as specified in the service manual, and the values were perfect. The 100 VDC test point measured 100.0 VDC on my DMM...

For reference, here is the post at evvblog.com: https://www.eevblog.com/forum/repair/tektronix-2215a-with-short-trace-only-when-free-running/

Best regards,
Torquil Sørensen, Norway
Re: Wanted: Earth leads with croc-clip for P6139A

David C. Partridge
 

Yes I'm in the UK. You may be able to send them quite cheaply (about ten dollars for up to 8oz) if you use a pre-paid padded envelope 1st class international mailer.

Anyone closer?

David

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Stephen Hanselman
Sent: 04 April 2019 17:34
To: TekScopes@groups.io
Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A

OK, I do have a bag of 6 inch long "ring" mount style and have verified them on my P6139. They have an alligator clip on the end.

Are you in the UK? Shipping will be more than the cost of the clips I'm afraid

steve

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Stephen Hanselman
Sent: Thursday, April 4, 2019 8:35 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A

I’m pretty sure I have a bundle of those I’ll check when I get to the office

Regards,

Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
DISCLAIMER:
This e-mail and any attachments are intended only for use by the addressee(s) named herein and may contain legally privileged and/or proprietary information. If you are not the intended recipient, any dissemination, distribution or copying of this e-mail and any attachments is strictly prohibited. If you have received this e-mail in error, please immediately notify me and permanently delete the original and all copies and printouts of this e-mail and any attachments.
On Apr 4, 2019, at 06:22, David C. Partridge <david.partridge@...> wrote:

No, those are the older ones the ones I'm looking for look like this:

<https://www.ebay.co.uk/itm/113327487469>

Dave

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Colin Herbert via Groups.Io
Sent: 04 April 2019 13:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A

Would these do?

https://www.ebay.co.uk/itm/10pcs-New-Oscilloscope-Scope-Probe-Ground-L
eads-w
ith-Alligator-Clip-Tektronix-HP/222659358233?ssPageName=STRK%3AMEBIDX%
3AIT&_
trksid=p2060353.m1438.l2649

They have a length of 7 inches (17.5 cm). I bought some a while ago
and they are fine, if possibly not genuine Tek. He also has the "witches hat"
grabbers for P6139, etc. probes. Be careful, though, as while he will
offer combined postage, eBay doesn't seem to go along with that. It
took me some time to get combined postage when I bought three items
from him. Of course, this might have improved, now.

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David C.
Partridge
Sent: 04 April 2019 12:03
To: TekScopes
Subject: [TekScopes] Wanted: Earth leads with croc-clip for P6139A

I'm looking for the earth leads with crocodile clip to fit the P6139A
and similar probes.

I have the ones that connect to mini-grabbers, but lack the croc-clip
versions.

Does anyone have these available?

Cheers, David
Re: Impedance matching question

David Berlind
 

Now that I've read and processed more about impedance than I care to admit, I'm wondering if there's anyone in the group has some extra BNC pass-through terminators that they don't need. Namely 50, 75, and 600 ohm for now (I don't have the option to change input impedance on my scopes).

thanks if anyone has these and would be willing to part with them.
Re: WTB: Dead SD-22, 24 or 26 sampling heads

Reginald Beardsley
 

Does anyone know if the SD-24 has a pair of the same modules as the internal calibrator inside or if they integrated the same circuit into the input module?

What are the chances that a dead SD-24 has salvageable pulse generators?
Re: Using a 5103dn as a low freq spectrum analyzer

ROLYNN PRECHTL K7DFW
 

The trick is to have a swept oscillator covering the frequency range of interest. The HP 8106A or similar would be ideal,
=======================================================================

Should this be 8601A?

Rolynn
Re: TM504 backplane repair

Colin Herbert
 

I suppose I should mention that I live in Wimbledon, South-West London. Yes, close to the All-England Lawn Tennis and Croquet Club.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of bobh@...
Sent: 22 March 2019 16:34
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM504 backplane repair

I agree with you on the age factor maybe not being the real issue. Many
connector failures are due to just slamming the plugin into the
mainframe. Unfortunately the plugin edge connectors don't always align
just right with the socket of the TM interface connector.

Proper insertion is to put the plugin in the mainframe and feel for the
proper alignment of the plugin edge connector with the socket of the
interface connector in the TM, then push the plugin home.

Of course check for incompatible family barriers and never insert
plugins with the mainframe energized.

Bob.

On 3/22/2019 3:02 AM, Adrian wrote:
Hi Colin,

Replacing the connector sounds like the right thing to do - not sure I
agree that using a NOS part is risky, there's a quadzillion backplane
connectors out there that have /not/ cracked with age after all, but I
order from Digikey regularly and could order up a new one if you want.

I'm more than happy to lend a hand. How practical that is for you I'm
not sure -'London' covers a big area!

If you are north(ish) of London then I'm just outside Cambridge and
should have enough stuff around to do that and fix any issues that may
arise, I've re-capped a couple of my TM500 series chassis and while a
little 'awkward' in parts there's nothing too tricky about taking them
apart.

Either shipping it to me or a visit - with free, quite passable coffee
- would work fine. Oh, no cost (other than return postage) of course!

Adrian

On 3/21/2019 3:22 PM, Colin Herbert via Groups.Io wrote:
a) Unsolder the entire faulty connector and replace it with the new
one - this looks like a formidable task, since there are a total of
56 pins to unsolder and re-solder and access isn't straightforward
but it would be the most ideal option, I think. Unfortunately I don't
have a de-soldering tool, only a solder-sucker and some poor
de-soldering braid (I suppose I could buy a de-soldering tool).
Re: TM504 backplane repair

Colin Herbert
 

OK, so I bought a de-soldering station, but I don't seem to be able to free the mangled contact easily. I can also see that trying to remove the entire 56-pin connector would be a major task. I am going to try a few more ideas before I give up and forget the one mangled contact, but if I can remove it eventually, I may then just replace it with a good one, if I can.
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of bobh@...
Sent: 22 March 2019 16:34
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM504 backplane repair

I agree with you on the age factor maybe not being the real issue. Many
connector failures are due to just slamming the plugin into the
mainframe. Unfortunately the plugin edge connectors don't always align
just right with the socket of the TM interface connector.

Proper insertion is to put the plugin in the mainframe and feel for the
proper alignment of the plugin edge connector with the socket of the
interface connector in the TM, then push the plugin home.

Of course check for incompatible family barriers and never insert
plugins with the mainframe energized.

Bob.

On 3/22/2019 3:02 AM, Adrian wrote:
Hi Colin,

Replacing the connector sounds like the right thing to do - not sure I
agree that using a NOS part is risky, there's a quadzillion backplane
connectors out there that have /not/ cracked with age after all, but I
order from Digikey regularly and could order up a new one if you want.

I'm more than happy to lend a hand. How practical that is for you I'm
not sure -'London' covers a big area!

If you are north(ish) of London then I'm just outside Cambridge and
should have enough stuff around to do that and fix any issues that may
arise, I've re-capped a couple of my TM500 series chassis and while a
little 'awkward' in parts there's nothing too tricky about taking them
apart.

Either shipping it to me or a visit - with free, quite passable coffee
- would work fine. Oh, no cost (other than return postage) of course!

Adrian

On 3/21/2019 3:22 PM, Colin Herbert via Groups.Io wrote:
a) Unsolder the entire faulty connector and replace it with the new
one - this looks like a formidable task, since there are a total of
56 pins to unsolder and re-solder and access isn't straightforward
but it would be the most ideal option, I think. Unfortunately I don't
have a de-soldering tool, only a solder-sucker and some poor
de-soldering braid (I suppose I could buy a de-soldering tool).
Re: 11801 triggering

Albert Otten
 

Chris,

Your message appeared while I was typing (and eating...). Your observation explains why Autoset refused to obey when I used FP clock output as external trigger input! I thought it was because of the relatively short pulse character of the clock output.

Albert

On Thu, Apr 4, 2019 at 05:00 PM, cmjones01 wrote:


On Thu, Apr 4, 2019 at 4:28 PM Reginald Beardsley via Groups.Io
<pulaskite@...> wrote:

Why can't I trigger off the internal clock output using the external trigger
input?

If your 11801 is anything like my CSA803A, the internal clock output
disappears when I select external triggering. I've just tried it.

Chris
Re: Using a 5103dn as a low freq spectrum analyzer

Roy Morgan <k1lky68@...>
 

On Apr 4, 2019, at 10:14 AM, kim.herron@... wrote:

Hi all!

I've got an old 5103, and wondered if anyone had ever tried using one to check LF bandpass filter curves or IF bandpass on old tube radios, using the X-Y mode? Any info would be appreciated
Kim,

I am not familiar with the thing, but from what I see on the tek wiki pictures, it seems have a horizontal sweep external input. This would let you use it as a sort of spectrum analyzer with a separate sweep generator. The 2 mc band bass rating of the vertical plug-ins would not matter if you use an IF/RF detector to detect the signal of interest - the output of an IF filter or IF stage, or even the output of an RF amplifier stage in a receiver.

The trick is to have a swept oscillator covering the frequency range of interest. The HP 8106A or similar would be ideal, but there are other swept oscillators of later sorts. You feed the sweep signal (ramp) to the horizontal channel of the scope, the swept IF or RF signal into the circuit under test, and the output of the stage under test to the vertical channel, either from an IF/RF detector (simple diode with cap and resistor or even the detector of the radio itself) or the straight IF signal.

Slow sweep rates are used for crystal filter alignment in receivers to avoid ringing effects. To figure out what frequency is at any point on the sweep, you can add in the signal from another non-swept oscillator, or in the case of the 8106 if you have the no-very-common “Digital Marker Generator" 8100 it created 4 markers for you at settable points in the sweep frequency range.

My memory is faint but I used to have at least one of the 500 series scope plug ins that did all that for you. I am hoping to find it in my long-neglected storage unit to use with my 547 and 545B. (The 1L5 covers 50 Hz to 990 kHz and the 1L10 a higher frequency range.). The performance of these things is modest, but it wold make radio IF strip alignment quite easy.

But it seems to me that all you’d need is a swept oscillator with sweep signal output and you are in business.

Roy

Roy Morgan
K1LKY since 1958
k1lky68@...
Re: 11801 triggering

Reginald Beardsley
 

No joy. Selecting external triggering also turns off the calibrator.
Re: 11801 triggering

Albert Otten
 

Reg,

I think you gave the answer yourself: the rising edges of the waveforms are very close, so there is not enough time between trigger event and start of Cal output rising edge.
In my CSA803A I can view the rising edge of the FP clock output on a SD-26 when I set the CSA for internal triggering. And that is the rising edge starting at about 30 ns, so not the next one after 10 us. The (in my case slow) Cal output starts at about the same time position.
I tried the same as what you did when I was interested in trigger jitter of the external trigger input. IIRC Autoset even refused to obey.
As a nice exercise have a look at that next rising edge of the FP clock output (after 10 us). Jitter is about 200 ps rms.

Albert

On Thu, Apr 4, 2019 at 04:27 PM, Reginald Beardsley wrote:


Why can't I trigger off the internal clock output using the external trigger
input?

The rising edge of the waveforms is very close, but the falling edge of the
calibrator is around 60 ns later than the falling edge of the internal clock
output.

Leo's square wave pulser triggers fine, so it's not an issue with the external
trigger input.

The user manual says nothing about the required delay time between the trigger
and the waveform and appears to have been written by someone who had never
used a sampling scope.

I have tried both slopes, AC & DC coupling and the whole range of trigger
levels, but it refuses to trigger. I've compared the 11801 internal clock and
calibrator signals and Leo's pulser signals on a 200 MHz DSO.

I'm quite baffled. I thought I understood how a sampling scope works, but
there is clearly something important that I don't understand.

Reg
Re: Wanted: Earth leads with croc-clip for P6139A

Stephen Hanselman
 

OK, I do have a bag of 6 inch long "ring" mount style and have verified them on my P6139. They have an alligator clip on the end.

Are you in the UK? Shipping will be more than the cost of the clips I'm afraid

steve

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of Stephen Hanselman
Sent: Thursday, April 4, 2019 8:35 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A

I’m pretty sure I have a bundle of those I’ll check when I get to the office

Regards,

Stephen Hanselman
Datagate Systems, LLC
3107 North Deer Run Road #24
Carson City, Nevada, 89701
(775) 882-5117 office
(775) 720-6020 mobile
s.hanselman@...
www.datagatesystems.com
a Service Disabled, Veteran Owned Small Business
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On Apr 4, 2019, at 06:22, David C. Partridge <david.partridge@...> wrote:

No, those are the older ones the ones I'm looking for look like this:

<https://www.ebay.co.uk/itm/113327487469>

Dave

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Colin Herbert via Groups.Io
Sent: 04 April 2019 13:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] Wanted: Earth leads with croc-clip for P6139A

Would these do?

https://www.ebay.co.uk/itm/10pcs-New-Oscilloscope-Scope-Probe-Ground-L
eads-w
ith-Alligator-Clip-Tektronix-HP/222659358233?ssPageName=STRK%3AMEBIDX%
3AIT&_
trksid=p2060353.m1438.l2649

They have a length of 7 inches (17.5 cm). I bought some a while ago
and they are fine, if possibly not genuine Tek. He also has the "witches hat"
grabbers for P6139, etc. probes. Be careful, though, as while he will
offer combined postage, eBay doesn't seem to go along with that. It
took me some time to get combined postage when I bought three items
from him. Of course, this might have improved, now.

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David C.
Partridge
Sent: 04 April 2019 12:03
To: TekScopes
Subject: [TekScopes] Wanted: Earth leads with croc-clip for P6139A

I'm looking for the earth leads with crocodile clip to fit the P6139A
and similar probes.

I have the ones that connect to mini-grabbers, but lack the croc-clip
versions.

Does anyone have these available?

Cheers, David
37941 - 37960 of 193795