Re: No contribution from David Hess since July 18th
Hi Raymond,
Welcome to the 21st century where our members are spread around the globe and local time is a myth and UTC is the only way to avoid confusion. But that creates its own problems as was evident in this case.
I've been caught by this before specifically when I tried to post my press release announcing "Pre-Shrunk Heat Shrink Tubing" at 12:01AM on April 1st.
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message-----
From: Raymond Domp Frank
Sent: Friday, November 02, 2018 11:47 AM
Subject: Re: [TekScopes] No contribution from David Hess since July 18th
On Fri, Nov 2, 2018 at 07:41 PM, Dennis Tillman W7PF wrote:
Dennis,
Your first message said "his last message on this forum is from July
18th."
which is the date I searched. His last post was actually on July 17.
That is why I missed it.
Ha! My date and times are related to UTC and that said July 18th...
Raymond -- Dennis Tillman W7PF TekScopes Moderator
|
Re: No contribution from David Hess since July 18th
On Fri, Nov 2, 2018 at 07:41 PM, Dennis Tillman W7PF wrote: Dennis,
Your first message said "his last message on this forum is from July 18th."
which is the date I searched. His last post was actually on July 17. That is
why I missed it.
Ha! My date and times are related to UTC and that said July 18th... Raymond
|
Re: N channel fet 151-1121-00 -- V10206
Glad to help.
I was misled by those reversed connections many times before I realized why they did it and that it was not a mistake.
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message-----
From: lop pol via Groups.Io
Sent: Friday, November 02, 2018 11:26 AM
Subject: Re: [TekScopes] N channel fet 151-1121-00 -- V10206
Dennis
You are exactly correct. More user failure on my part. Thank you for
pointing that out. On Fri, Nov 2, 2018 at 06:37 PM, Dennis Tillman W7PF wrote:
COMMON MISTAKE: Your photo shows you did not switch the Drain and
the Gate leads when you were using the 7CT1N. I believe when you do
switch them that you will see there is nothing wrong with the FET.
-- Dennis Tillman W7PF TekScopes Moderator
|
Re: N channel fet 151-1121-00 -- V10206
On Fri, Nov 2, 2018 at 07:20 PM, Colin Herbert wrote: Hi Colin,
Hmmm.. I think there was a small clue in the fact that the scope was a 7633. I
might also point out that the Great Detective was Sherlock Holmes - Doctor
Watson was his sidekick...
...and who complimented mr. Watson on his good work in this case? OTOH, there might a clue in the fact that *mr.* Watson was complimented, not *Dr. Watson*. Could it be that we're dealing with a false Sherlock Holmes? Raymond
|
Re: No contribution from David Hess since July 18th
Hi Raymond,
Your first message said "his last message on this forum is from July 18th." which is the date I searched. His last post was actually on July 17. That is why I missed it.
For reasons I can't explain I pressed the wrong button when I searched for his activity on TekScopes and it showed there was none (which I thought was odd).
When I finally pressed the right button just now it showed there was plenty of activity right up to July 17, but none past that.
Groups.io has many nice tools designed to make it easier for the moderator to manage the forum. Now if the moderator could only learn how to use the tools he might be able to do his job better.
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message-----
From: Raymond Domp Frank
Sent: Friday, November 02, 2018 11:23 AM
Subject: Re: [TekScopes] No contribution from David Hess since July 18th
On Fri, Nov 2, 2018 at 07:06 PM, Dennis Tillman W7PF wrote:
Hi Dennis,
My records show he has never posted on TekScopes since we switched to
Groups.io in Dec 2017. There were no posts from him on July 18 of this
year either.
I pm' ed my copy of his message on July 18th as I have it to you.
Raymond -----Original Message-----
From: Raymond Domp Frank
Sent: Friday, November 02, 2018 10:54 AM
Subject: [TekScopes] No contribution from David Hess since July 18th
FYI:
I'm missing contributions from our long time, very active, helpful and
knowledgeable member David Hess. As far as I can see, his last message on
this forum is from July 18th. On October 7th, I sent him a pm but got no
response. No contributions on the HP_... forum either.
Raymond -- Dennis Tillman W7PF TekScopes Moderator
|
Re: N channel fet 151-1121-00 -- V10206
Hi Colin (laughing)..yes but Dr Watson was the diagnostician, Raymond may have been doing some spin on the blundering Watson who nevertheless
sometimes got Holmes back on track through some seemingly asinine mumble. Watson, who'd been through the Indian campaigns as a surgeon
was nevertheless grievously hurt when he felt Holmes was displeased with him or mocking him or his chronicles.
I think the Tektronix CRO, an arcane thing , a Pandora's box one might argue , may have been designed by Moriarty.
My regards
toggle quoted message
Show quoted text
-----Original Message----- From: Colin Herbert via Groups.Io Sent: Saturday, November 3, 2018 4:20 AM To: [email protected]Subject: Re: [TekScopes] N channel fet 151-1121-00 -- V10206 Hmmm.. I think there was a small clue in the fact that the scope was a 7633. I might also point out that the Great Detective was Sherlock Holmes - Doctor Watson was his sidekick... Colin. -----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Raymond Domp Frank Sent: 02 November 2018 17:43 To: [email protected]Subject: Re: [TekScopes] N channel fet 151-1121-00 -- V10206 On Fri, Nov 2, 2018 at 06:37 PM, Dennis Tillman W7PF wrote: Hi Dennis,
COMMON MISTAKE: Your photo shows you did not switch the Drain and the Gate
leads when you were using the 7CT1N. I believe when you do switch them that
you will see there is nothing wrong with the FET.
So a 7CT1N was used. Well done mr. Watson! Raymond -- Jack
|
Re: N channel fet 151-1121-00 -- V10206
On Fri, Nov 2, 2018 at 11:20 AM, Colin Herbert wrote:
Hmmm.. I think there was a small clue in the fact that the scope was a 7633. I
might also point out that the Great Detective was Sherlock Holmes - Doctor
Watson was his sidekick...
Colin.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Raymond
Domp Frank
Sent: 02 November 2018 17:43
To: [email protected]
Subject: Re: [TekScopes] N channel fet 151-1121-00 -- V10206
On Fri, Nov 2, 2018 at 06:37 PM, Dennis Tillman W7PF wrote:
Hi Dennis,
COMMON MISTAKE: Your photo shows you did not switch the Drain and the Gate
leads when you were using the 7CT1N. I believe when you do switch them that
you will see there is nothing wrong with the FET.
So a 7CT1N was used. Well done mr. Watson!
Raymond
Dennis You are exactly correct. More user failure on my part. Thank you for pointing that out.
|
Re: No contribution from David Hess since July 18th
On Fri, Nov 2, 2018 at 07:06 PM, Dennis Tillman W7PF wrote: Hi Dennis,
My records show he has never posted on TekScopes since we switched to
Groups.io in Dec 2017. There were no posts from him on July 18 of this year
either.
I pm' ed my copy of his message on July 18th as I have it to you. Raymond
|
Re: N channel fet 151-1121-00 -- V10206
Hmmm.. I think there was a small clue in the fact that the scope was a 7633. I might also point out that the Great Detective was Sherlock Holmes - Doctor Watson was his sidekick...
Colin.
toggle quoted message
Show quoted text
-----Original Message----- From: [email protected] [mailto: [email protected]] On Behalf Of Raymond Domp Frank Sent: 02 November 2018 17:43 To: [email protected]Subject: Re: [TekScopes] N channel fet 151-1121-00 -- V10206 On Fri, Nov 2, 2018 at 06:37 PM, Dennis Tillman W7PF wrote: Hi Dennis,
COMMON MISTAKE: Your photo shows you did not switch the Drain and the Gate
leads when you were using the 7CT1N. I believe when you do switch them that
you will see there is nothing wrong with the FET.
So a 7CT1N was used. Well done mr. Watson! Raymond
|
Re: 425 Mil vertical module needed....seeking
Hi thanks Harvey....yes that's about it.....time saving with a good spares inventory ....replace the faulty aspect of equipment and then send through the system
to component level repairs. Repair was not always attempted and "U/S" tags were plentiful. Reliability and cost were a decision. I recall when aircraft mods were
done in Vietnam conflict we just dumped $millions in unusable inventory, even here. Our (Defence's) vibration and environmental equipment was given to AWA,
which then charged Defence for the use of it. I found that..a kind-of peculiar arrangement. Labour costs yes, but use of the gear wasn't confined to us.
Component level was not always done at Echelon...a level of testing might be done and a decision made whether to send to the manufacturer but at the card level
when it was a card....it may more likely have been tagged 'U/S' scrupulously recorded then binned, later ...perhaps many years later and when security allowed it and the
conflict was over.....go through the 'disposals auctions'. The equipment need to ensure the gear met services' specs was too complex and expensive in some cases.
Reliability warrantied as being certain is primary especially in weaponry and radar you mentioned demands manufacturer-level accuracy. My recollection is that
it was not until after 'Korea' thatmodularisation became common...the TRC77 for example in a small way. Until then changing tubes was the field level repair.
Owing to advice from Dinos I was able to realise what I thought a nightmare, highly inefficient teardown for a small repair was in fact simple...It took about 10 minutes
pull the module once the advice I was given made sense...in the field with spares available it was probably a half hour turnaround. Edgar Allen Poe's fear of the Raven
tapping at his door was no greater than my fear of Tektronix CRO's tapping at my confusion of fear and lust when a Tektronix came sashaying into view. "The best way
to get away from temptation is to give into it" wrote Oscar Wilde,,,"Resist it, and your soul grows sick with longing for the things it has forbidden to itself "
That is mankind's Achille's heel.
One look inside a Tektronix when I was 20 scared me into a sort of misty coma...Milspec radio's...ok....general test equipment ok...BWD CRO's....well ok. Tektronix
aaaaaaaaaaaaagh!! A contact with Tektronix supervisor out at Nth Ryde forty years ago led to hair-raising information on repair costs. I can only thank heaven and
Dinos and Fabio that I bought a Mil unit, unwitting of its advantages. What I thought would be a simple repair isn't at component level but IS at module level.
Reading some of the problems raised even in my brief experience with tekscopes made it clear that this group is an essential part of dealing with Tektronix gear.
One day I suppose, the manufacturers of Prozac and Zoloft will try to buy it out, owing to the business they are losing through the support given each other in forum.
Voila
toggle quoted message
Show quoted text
-----Original Message----- From: Harvey White Sent: Thursday, November 1, 2018 9:38 AM To: TekScopes@groups. Cc: [email protected]Subject: Re: [TekScopes] 425 Mil vertical module needed....seeking On Wed, 31 Oct 2018 08:56:47 -0700, you wrote: Many of the functions of a Mil qualified piece of test equipment (or flightline, I'm extrapolating from that) are as follows: 1) mil qualified parts (for TTL, for instance, expanded temperature range and +/- 0.5 volt tolerance on VCC rather than 0.25 volts) 2) vibration and temperature tolerances 3) (perhaps most important): the ability to repair a unit by (on the flightline) by replacing an whole unit, for instance, a complete power supply, or a vertical channel, or a CRT/display unit, that kind of thing. This is, I suspect, where the (apparently) massive difference in physical construction might come from. Diagnostics wise, you'd go out to the aircraft, diagnose the radar, and find out what is malfunctioning (transmitter, receiver, processor, etc). You'd black box replace the entire unit. That unit would go back to the depot. At the depot, special test equipment (bought from the radar's manufacturer) would diagnose the failing unit to a particular board. That board would be replaced and the unit would be re-tested. The failing board would go back to the manufacturer for testing and repair. Sound familiar? I'm suspecting that the physical construction of this scope allowed this kind of repair. Not sure, though. Harvey Hello Jack,
What you refer to as 425 Mil is, for correctness sake, a 465M or an AN/USM 425.
It confused me at first, as I didn't recall there was ever a 425 oscilloscope.
For what I know, the 465M is electronically similar to the civilian 465 (but even at electronic diagram level, there ARE differences), but, for the sake of assemblies or sub-assemblies, they're essentially two completely different oscilloscopes (i.e the boards are physically different).
As mentioned on this () page of the TekWiki website, the 465M is more similar to the civilian 455, than it is to the 465.
I can't really tell by how much they are similar, but you may be able to compare them by yourself by looking at the service manuals of both, which are available on the TekWiki website.
The page for the civilian 455 is here:
I don't know much of either (455 or 465M) but, coincidentally, there's a seller on a Brazilian auction site, selling the modules of a Tektronix 455:
I can't tell how similar those modules are (to your 465M) and if they can serve as parts donors, but if you find out that they may help, you can try to contact the seller, or I can help you with the purchase and shipping of the module (or the parts) to your location, for their advertised cost and shipping expenses to your place.
Note: I have no affiliation with the seller (and don't even know if I know them, since the auction site only reveals the seller after you purchase the item).
I normally wouldn't even make this offer, as shipping from Brazil is usually prohibitive and the parts are not even mine... But since you're so far away down under, I think that shipping from anywhere will be just as difficult.
Please let me know if you want my help, or maybe some other folks in the group will chime.
Krgrds,
Fabio
On Tue, Oct 30, 2018 at 06:52 PM, Jack wrote:
Hi. I'm a new member finding my way. I bought a lot of Tektronix scopes for
the services when with Defence during Vietnam era and visited Tektonix at
North Ryde (NSW)
to see about repairs to (I think it's a 564) I still have....still not working
I guess after having a new very high voltage insulated transformer wound for
CRT filament...two actually, the other must be around "somewhere". I
developed a healthy fear of Tektronic CRO's owing to the prices Tektronix
charged for repairs..
I have a 425 Mil with broken switch.in Vertical section It's unrepairable.
Whilst I could sooner or later find a parts CRO, sight unseen on eBay for
example, it may also be on the way out. I think the plastic used in Tektronix
may be the lowest quality amongst high quality devices , or maybe they just
specify 'shall be or a type formula and manufacture which will maintain all
utility until the end of time'
I was directed to your group (Hi...there) . To get to the essential point
Would some person have a reasonably low mileage vertical module, complete,
which I could buy? Please advise me if so....Australia would be best of course
but 'anywhere'. Also...to undo some confusion...I've been told 425 and 465 are
"intrinsically" the same CRO...obviously without the Mil labelling... . Does
that mean parts are interchangeable?
One reason I ask is that I was also told that the 425 being Military contract
and Mil Spec was built to be readily pulled down for field repairs. Is that
true?...Is that a quality the 465 does not replicate? if so it may mean that
...just as an example...the vertical amp module from a 465 may have some
mounting differences from the 425.
On the other hand it may not. Perhaps someone familiar with this type will
bring me to a state of awareness even wisdom regarding my CRO. ...oh... other
than having one channel down it seems to work ok and 'oh' again...when I
originally pulled it down a piece of curved springy metal fell out. Whence it
exactly originated I have no idea...'somewhere inside'. .It may be a method
of maintaining the case at frame potential, under pressure as one reassembles
the CRO...so perhaps it 'jammed' between a plate on the chassis and the
bottom cover. It could have come from elsewhere or it might not be from the
CRO at all.....That said, Im pretty sure I saw an exploded view one time where
this curved metal piece as shown hanging in mid-air underneath the chassis.
Have I been able to find that particular exploded view again (that was 3 years
ago)...of course not!!
Any passing of knowledge wisdom common sense mindfulness and most of all
perhaps a complete vertical amplifier will be very well received.
--
Jack
-- Jack
|
Re: No contribution from David Hess since July 18th
Hi Raymond,
My records show he has never posted on TekScopes since we switched to Groups.io in Dec 2017. There were no posts from him on July 18 of this year either.
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
Raymond Domp Frank
Sent: Friday, November 02, 2018 10:54 AM
To: [email protected]
Subject: [TekScopes] No contribution from David Hess since July 18th
FYI:
I'm missing contributions from our long time, very active, helpful and
knowledgeable member David Hess. As far as I can see, his last message on
this forum is from July 18th. On October 7th, I sent him a pm but got no
response. No contributions on the HP_... forum either.
Raymond -- Dennis Tillman W7PF TekScopes Moderator
|
ok, all I recall is I was told ( by the counter tech at tektronix in sunnyvale when my 475 went in for cal service eons ago... ) the case had to be on for something due to sensitivity/shielding and that is why the holes were in the case . so that info was false!!! gee, go figure.....they (he) most likely did not want anyone opening the scope except them.......
thanks for the correction and updating the info.
¸é±ð²Ô¨¦±ð
toggle quoted message
Show quoted text
On 2018-11-02 10:12 a.m., Chuck Harris wrote: I don't remember it that way. The entire 475 can be calibrated
sitting out of its case on the bench. The entire 465 family can
be calibrated sitting out of its case on the bench.
The adjustment holes in the case are an indication that some of
the more sensitive circuits are not very stable, and require
occasional touch-up by the operator.
-Chuck Harris
¸é±ð²Ô¨¦±ð wrote:
check the side of the case there may be "holes" for some of the sensitive
adjustments. there are on a 475 and the case needs to be installed for those
adjustments.
¸é±ð²Ô¨¦±ð
On 2018-11-02 5:34 a.m., Chuck Harris wrote:
Definitely not normal! If tektronix needed you to put a special
shield there, there would be a shield with a part number specified
in the list of things required for calibration.
|
Re: No contribution from David Hess since July 18th
He's active on EEVBlog forum, last post was yesterday.
;u=93452
toggle quoted message
Show quoted text
On 02/11/18 17:53, Raymond Domp Frank wrote: FYI:
I'm missing contributions from our long time, very active, helpful and knowledgeable member David Hess. As far as I can see, his last message on this forum is from July 18th. On October 7th, I sent him a pm but got no response. No contributions on the HP_... forum either.
|
No contribution from David Hess since July 18th
FYI:
I'm missing contributions from our long time, very active, helpful and knowledgeable member David Hess. As far as I can see, his last message on this forum is from July 18th. On October 7th, I sent him a pm but got no response. No contributions on the HP_... forum either.
Raymond
|
Re: N channel fet 151-1121-00 -- V10206
COMMON MISTAKE: Your photo shows you did not switch the Drain and the Gate leads when you
were using the 7CT1N. I believe when you do switch them that you will see there is nothing wrong
with the FET.
With a 7CT1N, you must be careful to exchange the gate and drain leads. This is due to a short cut
the
designers took when they were faced with squeezing some of the very flexible capabilities of a
575/576/577 curve tracer into a small plug-in with limited power capabilities.
If you look above and below the banana jacks you see the following lead pairing between a bipolar
transistor and a junction FET: Emitter-Source, Base-Drain, Collector-Gate. The same letter
combinations (E-S, B-D, C-G) are present on the 7CT1N socket adapter. Well Dennis - I learned something there! I have a 7CT1N (no surprise there!) and have only occasionally used it for low power bipolars. I would have missed the oddball electrode mapping between bipolar and FET entirely. Thanks for that clarification Cheers Craig
|
Re: N channel fet 151-1121-00 -- V10206
Hi Raymond,
That was the easy part, the photo shows he was using a 7633 scope (lucky guy to own one of those) so it had to be a 7CT1N.
Slightly harder was verifying that the traces on the screen are what happens when you forget to switch the Gate and Drain leads on a 7CT1N.
For years I thought Tek made a mistake and they put the letters down that way in error. But eventually I discovered that by swapping the gate and drain connections it saved them from having to add a switch on an already tight front panel to reverse the polarity of the gate steps which is needed when you are testing a FET. On a 576 and 577 there is a push button switch that lets you reverse the polarity of the gate steps for testing JFETs.
Dennis Tillman W7PF
toggle quoted message
Show quoted text
-----Original Message-----
From: Raymond Domp Frank
Sent: Friday, November 02, 2018 10:43 AM
On Fri, Nov 2, 2018 at 06:37 PM, Dennis Tillman W7PF wrote:
Hi Dennis,
COMMON MISTAKE: Your photo shows you did not switch the Drain and the
Gate leads when you were using the 7CT1N. I believe when you do switch
them that you will see there is nothing wrong with the FET.
So a 7CT1N was used. Well done mr. Watson!
Raymond -- Dennis Tillman W7PF TekScopes Moderator
|
Re: N channel fet 151-1121-00 -- V10206
On Fri, Nov 2, 2018 at 06:37 PM, Dennis Tillman W7PF wrote: Hi Dennis,
COMMON MISTAKE: Your photo shows you did not switch the Drain and the Gate
leads when you were using the 7CT1N. I believe when you do switch them that
you will see there is nothing wrong with the FET.
So a 7CT1N was used. Well done mr. Watson! Raymond
|
On Fri, Nov 2, 2018 at 06:12 PM, Chuck Harris wrote:
The adjustment holes in the case are an indication that some of
the more sensitive circuits are not very stable, and require
occasional touch-up by the operator.
I've never had a need to do any of these adjustments externally, "in the field" so to say, using 464, 465(B), 466 and 475(A) scopes for decades. The "construction" allows unguided poking at least 1.5" into the 'scope without vision and is asking for involuntary scopeslaughter if a metal screwdriver is used. Since these 'scopes were used in all kinds of harsh environments, I can imagine that field adjustment was done in extreme temperature use. Raymond
|
Re: N channel fet 151-1121-00 -- V10206
Hi,
COMMON MISTAKE: Your photo shows you did not switch the Drain and the Gate leads when you were using the 7CT1N. I believe when you do switch them that you will see there is nothing wrong with the FET.
With a 7CT1N, you must be careful to exchange the gate and drain leads. This is due to a short cut the designers took when they were faced with squeezing some of the very flexible capabilities of a 575/576/577 curve tracer into a small plug-in with limited power capabilities.
If you look above and below the banana jacks you see the following lead pairing between a bipolar transistor and a junction FET: Emitter-Source, Base-Drain, Collector-Gate. The same letter combinations (E-S, B-D, C-G) are present on the 7CT1N socket adapter.
BTW: If you need one they are available here for $0.95:
toggle quoted message
Show quoted text
-----Original Message-----
From: lop pol via Groups.Io
Sent: Friday, November 02, 2018 9:21 AM
After messing around this is the trace I get.
/g/TekScopes/photo/77313/0?p=Name,,,20,1,0,0 -----Original Message-----
From: lop pol via Groups.Io
Sent: Friday, November 02, 2018 8:56 AM
I just put this fet (151-1121-00) on the curve tracer and get
nothing. should I follow the same procedure to trace this fet as a
151-1042-00 --- S2089? Or is something different? The 151-1121-00 in
the manual says VN 3 whatever that means. -- Dennis Tillman W7PF TekScopes Moderator
|
Re: N channel fet 151-1121-00 -- V10206
On Fri, Nov 2, 2018 at 10:23 AM, Craig Sawyers wrote:
Not precisely sure what I'm looking at. Is that the said FET on a 7CT1N in
your 'scope? Because if it
is, I would say that was an ex-FET. It has gone to join the choir eternal.
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of lop pol via Groups.Io
Sent: 02 November 2018 16:21
To: [email protected]
Subject: Re: [TekScopes] N channel fet 151-1121-00 -- V10206
After messing around this is the trace I get.
/g/TekScopes/photo/77313/0?p=Name,,,20,1,0,0
Yes that is the fet in the curve tracer. I hope I didn't blow it up trying to curve trace it.
|
Raymond Domp Frank