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Re: 7000 series carrying handles - how strong are they?

 

With grade 301 with a full hard temper having a minimum tensile strength of 1300 MPa.

Greg
Re: Tek Cover Part Number

 

Gary,

Try 650-0568-00. In the Tek service manual Volume 2 (070-3784-01 available online at ) on page 9-5 is the complete parts list for the cover. The very first line item is believed to be the complete cover assembly however it is not made clear in the description. The hierarchy of parts lists usually state the complete assembly first followed by individual parts breakdown of that item following.

The drawing for the lid follows the parts list.

Greg
Re: 7000 series carrying handles - how strong are they?

 

I was going to say something similar; btw, I recently came across a polymer based material that is both magnetic and an insulator. Not sure how that was accomplished, maybe the iron particles where pre-insulated?

On Aug 18, 2019, at 3:38 PM, Bruce Griffiths <bruce.griffiths@...> wrote:

Not quite correct.
austenitic stainless (300 series) is non magnetic.
Martensitic (eg 422, 440 and 17-4PH etc) and ferritic grades are magnetic.
Hardened martensitic stainless is stronger than austenitic stainless.

Bruce
On 19 August 2019 at 10:21 "Greg Muir via Groups.Io" <big_sky_explorer@...> wrote:


Not having a 7K handy at the time, I am aware that Tek used to frequently use stainless steel in handles. It has reasonably good tensile strength. The TM500 power modules seem to have some sort of alloy embedded in their handles. The simple way to test for stainless is to bring a magnet near it. If no attraction it is stainless.

HP also used stainless in many of their earlier handles as well. But I, too also am conscious of what could possibly happen when lifting these beasts but have never had a "surprise" episode as well.

The best recommendation is to keep your feet away from being under the item you are lifting.

Greg
Re: 7000 series carrying handles - how strong are they?

 

Not quite correct.
austenitic stainless (300 series) is non magnetic.
Martensitic (eg 422, 440 and 17-4PH etc) and ferritic grades are magnetic.
Hardened martensitic stainless is stronger than austenitic stainless.

Bruce

On 19 August 2019 at 10:21 "Greg Muir via Groups.Io" <big_sky_explorer@...> wrote:


Not having a 7K handy at the time, I am aware that Tek used to frequently use stainless steel in handles. It has reasonably good tensile strength. The TM500 power modules seem to have some sort of alloy embedded in their handles. The simple way to test for stainless is to bring a magnet near it. If no attraction it is stainless.

HP also used stainless in many of their earlier handles as well. But I, too also am conscious of what could possibly happen when lifting these beasts but have never had a "surprise" episode as well.

The best recommendation is to keep your feet away from being under the item you are lifting.

Greg
Re: 7000 series carrying handles - how strong are they?

 

Not having a 7K handy at the time, I am aware that Tek used to frequently use stainless steel in handles. It has reasonably good tensile strength. The TM500 power modules seem to have some sort of alloy embedded in their handles. The simple way to test for stainless is to bring a magnet near it. If no attraction it is stainless.

HP also used stainless in many of their earlier handles as well. But I, too also am conscious of what could possibly happen when lifting these beasts but have never had a "surprise" episode as well.

The best recommendation is to keep your feet away from being under the item you are lifting.

Greg
Tek 7 series LCD project!

 

Re: Improving the odds with the 7S11/7T11 Sampling Plugins

 

On Sun, Aug 18, 2019 at 09:37 PM, Nenad Filipovic wrote:



Everything depends on getting the 7T11 to trigger.
Can it free run like the S-53? I suppose not, otherwise you'd hardly say
it's difficult to set. With S-53 in 7S12 I set it to free run (Stability
CW, Level CW, Slope +). The noise I get as a signal on the scope screen is
enough for a good estimate of offset and amplitude. If both of these make
sense I fiddle with the S-53 to trigger, and most of the time get it
stable.
Hi Nenad,

The trigger circuits inside the 7T11 and the S-53 are quite similar. One difference is that the 7T11 can also do "HF Sync", a kind of trigger count down.
Another difference is the implementation of Stability. In the 7T11 the front panel control regulates the heating of an thermistor. In my experience the time constant of this regulation is very large, many many seconds. This makes Stability feeling "spongy". There is also a very slow long term drift, many minutes, while everything is warming up. I also think to remember that the effect of Stability with the 7T11(A) on an plugin extender and side panels removed differs from that with the 7T11(A) in the scope. This makes calibration somewhat trial and error. But for sure the 7T11(A) Stability has a free running range when properly calibrated.
I agree with Dennis that often an annoying lot of fiddling with Stability and Level is needed to make the 7T11(A) triggering satisfactory.

Albert
Re: Improving the odds with the 7S11/7T11 Sampling Plugins

 

Dennis Tillman posted a long description of what ge has done to help the 7T11 trigger; this was a week or so ago.

DaveD

Sent from a small flat thingy

On Aug 18, 2019, at 15:36, Nenad Filipovic <ilmuerte@...> wrote:


I would like to hear from others what they do to make the 7S11/7T11
sampling plugins easier and more reliable to use.
Strange that nobody responded, summer vacations? I was really hoping to
hear about this, I currently don't have the 7S11/7T11 but I'm considering
getting them. What I do have is a 7S12 with S-4 and S-53, so I plan to move
the S-4 to (future) 7S11 and find S-6 and S-52 for the 7S12.

Everything depends on getting the 7T11 to trigger.
Can it free run like the S-53? I suppose not, otherwise you'd hardly say
it's difficult to set. With S-53 in 7S12 I set it to free run (Stability
CW, Level CW, Slope +). The noise I get as a signal on the scope screen is
enough for a good estimate of offset and amplitude. If both of these make
sense I fiddle with the S-53 to trigger, and most of the time get it
stable. My overall experience with 7000 series sampling plugins is limited,
obviously 7S12 is not intended for general purpose sampling - requires a
clumsy signal fork to sampling and trigger recognizer heads.

Just a few days ago on eBay there was a 7S11 with S-6 untested for $200,
and it was gone pretty quick. I have no idea how realistic this price was,
seeing it gone now surely does not make it easier...

Best Regards,
Nenad F.
Re: Improving the odds with the 7S11/7T11 Sampling Plugins

 


I would like to hear from others what they do to make the 7S11/7T11
sampling plugins easier and more reliable to use.
Strange that nobody responded, summer vacations? I was really hoping to
hear about this, I currently don't have the 7S11/7T11 but I'm considering
getting them. What I do have is a 7S12 with S-4 and S-53, so I plan to move
the S-4 to (future) 7S11 and find S-6 and S-52 for the 7S12.

Everything depends on getting the 7T11 to trigger.
Can it free run like the S-53? I suppose not, otherwise you'd hardly say
it's difficult to set. With S-53 in 7S12 I set it to free run (Stability
CW, Level CW, Slope +). The noise I get as a signal on the scope screen is
enough for a good estimate of offset and amplitude. If both of these make
sense I fiddle with the S-53 to trigger, and most of the time get it
stable. My overall experience with 7000 series sampling plugins is limited,
obviously 7S12 is not intended for general purpose sampling - requires a
clumsy signal fork to sampling and trigger recognizer heads.

Just a few days ago on eBay there was a 7S11 with S-6 untested for $200,
and it was gone pretty quick. I have no idea how realistic this price was,
seeing it gone now surely does not make it easier...

Best Regards,
Nenad F.
Re: Why does the DC509 have a GHz indicator?

 

Dave,

I may have spoken too soon. I started to think more about the DC509/DP501 relationship and looked into a couple of other TM50x power modules I have here and was quite surprised to find that the "prescale" command is carried through the backplanes in the group of wild card busses Tek uses for various options. This allows the DP501 to directly tell the DC509 that it is in the prescale mode so that the counter can do the correct math for the display. And I have never had the opportunity to use this combination of modules in any other of my TM50x power modules to have discovered this . My bad.

What I did find out yesterday was that, for some reason, this TM502 I use seems to be a special revision apparently for dedicated use with some foreign (non-Tek) modules that required a special configuration of these busses.(backplane contacts A14 & B14 through A28 & B28). I am somewhat aware that there were some of these produced for certain applications.

I believe that use of some earlier version counter modules may either still require backplane modifications or forcing the user to multiply the reading by 16 to get the correct result.

Sorry for the confusion! I still learn something new each day.

Greg
Re: 2467B focus/astigmatism anomaly...

 

Hi Chuck,

On Sun, Aug 18, 2019 at 07:52 PM, Chuck Harris wrote:


C4403's intended purpose is to make moving changes to the
focus as the trace moves about on the screen.
Yes

Lifting one leg should stabilize the focus issues, if C4403,
or the dynamic focus circuitry, is part of the problem.
I'm curious, probably easy to do.

Raymond
Re: 7000 series carrying handles - how strong are they?

 

As the proud owner of both a 7904A and a 7104, I can attest to this concern. Fortunately, my HP 8664A sig gen provides the perfect spot for the 7104 to rest in the corner of my benches, where I don't have to move either one often...it is significantly heavier than the 7904A. Let's not even talk about how massive the 8664A is. :o)

Safest option is definitely going to be a rolling cart if you have to move it a lot, closely followed by lifting it from the bottom.

Sean
Re: 7000 series carrying handles - how strong are they?

 

For a 7104, I'd think about carrying it from the bottom, but that said, I've never done it, nor have I ever heard of one of the 7K straps breaking (unlike the 500 series, which are mostly broken, or at least disintegrating at this point.)
-Dave

On Sunday, August 18, 2019, 02:39:31 AM PDT, Nenad Filipovic <ilmuerte@...> wrote:

Well I suppose this sounds silly, but I just can't get over it. This thin
metal sheet inside the handle is surely tough, high tensile strength steel,
but somehow subjectively it doesn't nearly impress as the rugged 465
handle, for example. In my head thin metal sheets tear and crack. Every
7000 handle end I inspected showed some minor bending around the hole where
it pulls against the main screw.

So my question is, has anyone ever had that handle crack or snap? 7000s are
no longer costly lab instruments handled with utmost care, today we use
them in our homes, shops... They get transported probably a lot more
frequently than they were intended to, possibly against some rules which
were in power back then, now forgotten or never even known. Should the
instrument be supported by your other hand from below?

I don't use my 7104 often, but when I do I need to carry and lift it on the
table. And every time I get shivers in my feet. Some reassurance would help.

Best Regards,
Nenad F.
Re: Tek 2465B Startup Woes

Chuck Harris
 

Looking at your precise ripple values gives me the feeling
that you simply measured them using the AC(RMS) function of
your DVM. If that is the case, the true P-P ripple is more
like 2.8 times the values you measured.

When a -8V DC signal with a lot of ripple is measured on a
DC DVM, you tend to get a reading that is an average of the
ripple.

I would say your first task should be to recap your supply,
all of your ripple values look too high. In some cases, way
too high.. remember 2.8x RMS -> VP-P, and tek's specs for
ripple are in VP-P.

As to the voltage jumping up to 16V when you removed the load,
that is normal, as the series regulator can leak enough current
to make the incredibly light load your DVM presents, all the
way up to the unregulated supply's value.

-Chuck Harris

Stan wrote:

Thanks for the reply, Chuck!

Here are the power supply voltages and ripples, as measured at J119:

-15 measures -15.001 V with 0.99 mV of ripple
+5 measures +4.991 V with 33.86 mV of ripple
-15 UNREG measures -18.293 V with 28.1 mV of ripple
+10 REF measures +10.009 V with 1.34 mV of ripple

-5 measures -2.899 V with 8.71 mV of ripple <<
+15 measures +15.010 V with 0.58 mV of ripple
+87 measures -+86.799 V with 1.08 mV of ripple
+42 measures +42.484 V with 1.10 mV of ripple

-8 measures -4.291 V with 30.4 mV of ripple <<
+5 measures +4.978 V with 0.96 mV of ripple

So clearly there is something wrong with the -5 and -8 supplies. I measured the unregulated output of the -8 supply at J232A Pin 5 (interconnect between the A3 and A2A1 boards), and it was -8.3. When I removed the interconnect, the voltage jumped up to -16.5.

Is it reasonable to assume that the problem may well be with the filter capacitors on the A2A1 board? I suspect that a shorted or leaky C1350 may be pulling down the -8 line, and thereby pulling down the -5 line through CR1334.

The next step is to remove the LVPS. I plan to do that later today.

Thanks,
Stan
Re: 2467B focus/astigmatism anomaly...

Chuck Harris
 

Hi Raymond,

I agree that C4403 needs to be investigated. It will be
a week, or so, before I have any parts in hand to try.

C4403's intended purpose is to make moving changes to the
focus as the trace moves about on the screen.

Lifting one leg should stabilize the focus issues, if C4403,
or the dynamic focus circuitry, is part of the problem.

Something killed Q4402, be it old age, physical abuse, or
a random zap from C4403. Ordinarily, I would think that the
backwards diodes CR4410 and CR4411 should have protected against
all but the largest insults... Maybe they are compromised
too?

-Chuck Harris

Raymond Domp Frank wrote:

On Sat, Aug 17, 2019 at 03:14 PM, Chuck Harris wrote:


My thought is the only way a new astigmatism voltage for optimal focus can be
required is if the beam current has changed between the gun's anode #1 and the
astigmatism lens. If you can believe the stacking of the electrodes shown in
the schematic, the focus lens comes before the astigmatism, and after the
anode #1.

And, it is the toughest to meter, as it is 1.4KV roughly, and about 15M
resistance.

I didn't give Q4432 much thought... perhaps I should, as it would shift the
focus
electrode voltage quite nicely... It is an MPSA94, which is about as you
surmised,
VCBO and VCEO = 400V
The beam current definitely changes each time between turning intensity down and up again, as the case describes. Although I can understand a jittery/jumping Q4432 role, is there a reason *not* to suspect C4403 leakage? You *did* find a broken Q4402 earlier, didn't you? And where/how does the intensity down/then up scenario cause Q4432 to make its jump, since normally there's (virtually) no (change in) current in the focus electrode circuit? Still sitting on my earlier post...

Raymond
Re: P6249 Oscillation

 

Hi, there is a peculiar property with emitter followers and FET source followers. Under some circumstances they will provide a negative input impedance. This with a certain source impedance will start an oscillation. To prevent this from taking place a series RC link is normally placed from base or gate to ground. This might be a hint for you.
G?ran
Re: Tek 2465B Startup Woes

 

Thanks for the reply, Chuck!

Here are the power supply voltages and ripples, as measured at J119:

-15 measures -15.001 V with 0.99 mV of ripple
+5 measures +4.991 V with 33.86 mV of ripple
-15 UNREG measures -18.293 V with 28.1 mV of ripple
+10 REF measures +10.009 V with 1.34 mV of ripple

-5 measures -2.899 V with 8.71 mV of ripple <<
+15 measures +15.010 V with 0.58 mV of ripple
+87 measures -+86.799 V with 1.08 mV of ripple
+42 measures +42.484 V with 1.10 mV of ripple

-8 measures -4.291 V with 30.4 mV of ripple <<
+5 measures +4.978 V with 0.96 mV of ripple

So clearly there is something wrong with the -5 and -8 supplies. I measured the unregulated output of the -8 supply at J232A Pin 5 (interconnect between the A3 and A2A1 boards), and it was -8.3. When I removed the interconnect, the voltage jumped up to -16.5.

Is it reasonable to assume that the problem may well be with the filter capacitors on the A2A1 board? I suspect that a shorted or leaky C1350 may be pulling down the -8 line, and thereby pulling down the -5 line through CR1334.

The next step is to remove the LVPS. I plan to do that later today.

Thanks,
Stan
Packrats anonymous (saving T&M tech documentation)

 

There are a lot of retired Tek, HPAK and other T&M company employees on these lists who doubtless know others who are not on the lists.

Do you have or know people who might have unreleased documentation such as schematics, factory calibration procedures, etc for old gear? I'd especially like to rescue the Tek 11801/CSA803 from an early demise due to a lack of component level repair data. But this is a general plea.

The engineers who designed the old gear are gradually passing away. Most families will simply discard Dad's file cabinet of old papers and manuals. I'd like to rescue as much of that as I can. A lot of people would have kept a personal copy of the schematics of a board they designed, but would never give away company proprietary data to 3rd parties.

In many instances, the companies have lost their copies whether by design or misfortune such as the Santa Rosa fire. The packrats are our last chance at preserving the information needed to keep some of the old gear alive.

I am volunteering to scan and secure official permission from the respective companies for release of the information to BAMA, TekWiki, etc. I will not publicly release anything I get until I have secured the required permissions.

If you have or know of someone who has such material, please contact me off list. I live in central Arkansas, but I have a sister who lives in the Bay area, has a winery in Santa Rosa and a tasting room in Sonoma.

Have Fun!
Reg

PS If I could get my hands on the source code for an 11801 I'd fix the ^%*&^* FW. Most likely by rewriting it from scratch. It drives me mad, but I love the beast.
Re: P6249 Oscillation

 

I wish it were so simple as a ground lead. If you put the probe tip on the
scope calibration ground, it still oscillates. I tried all of the
combinations of direct leadless ground connections to the calibration and
scope ground I can think of, and it has no effect on the oscillation. I
also tried all eight inputs on my two scopes and cleaned the connections on
the scope with de-oxit compound. No effect.

Eventually I will cut into the probe tip and probably destroy it. Perhaps
if I knew how it was put together I could avoid destroying it. I suspect
that the Fet input transistor gets damaged in some probes which leads to
oscillation. The fact that I have two probes without the oscillation
means that it does not have to happen.
In any case, this probe is far far superior to my old P6201 probes.

Any chance you are interested in math and continued fractions? I have
some interesting unpublished formulae.
Jerry

On Mon, Aug 12, 2019 at 4:27 PM Lawrance A. Schneider <
llaassllaaass@...> wrote:

Hi,

Perchance a silly question, but as a fellow fizzilist, how long is the
ground lead? Maybe a resnoant problem?

On Aug 12, 2019, at 1:36 PM, wjlentz@... wrote:

4 P6249 probes passed through my hands that have 1 MHz oscillation. On
one probe, this oscillation only shows up after a 5 minute warmup. The
oscillation can be as large as 467 millivolts on one probe which makes it
mostly useless. On another probe the oscillation is smaller and
manageable. The probes that have oscillation meet rise-time specs and
have no dc offset. I have one very expensive P6249 probe that has no hint
of oscillation.

I have two TDS 694C 3 GHz oscilloscopes and needed an active probe with
higher impedance than my 500 ohm passive probes. The TDS 694C is wired to
power the P6249 4 GHz probe with +/-5V and +/-15 supplies and a data and
clock pin interface to the TDAS694C.. I have the Tek manual which only
shows a block schematic for the part that connects at the oscilloscope but
not what is actually in the active probe tip. The oscillation shows up
on all eight of the inputs for the two TDS 694C scopes I have.

Is there any information about what is in the probe tip such as a
schematic? Is there any way to open the sealed probe tip? Would reducing
the +/- voltage to the probe tip at the scope connection, which can be
opened, help the problem?
All I hear from repair places is that they do not work on this probe.
Local sources of the probes are asking more for the probe than I paid for
my TDS 694C scopes.

I have the 1 GHz and 1.5 GHz versions of the probe which do not use the
+/- 15V supply and have no hint of oscillation, but I do need the bandwidth
for my photon counting business.
www.marinaphotonics.com.
I designed the PV16 1.5 GHz 65db gain amplifier discriminator for my
photon counter which is in a 29mm cube and does not oscillate, so I have
some knowledge of electronics. At this point I admit that I am just
stubborn and want to fix the probe problem rather than go to another probe.
Jerry the fizzilist
PS that's what happens to physicists when they get older
Re: 7000 series carrying handles - how strong are they?

 

I don't use my 7104 often, but when I do I need to carry and lift it on the
table. And every time I get shivers in my feet.

Nenad
Well with age of any metal I would be concerned. At 46+ lbs. The one I used to own was on a Tek cart. Which saved my Back and Feet. I think getting a Tek cart would be a good option for you. Yes they are also bulky but at least you are assured you won¡¯t risk damage to instrument or yourself.
Craig
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