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

@0culus
 

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: 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: Why does the DC509 have a GHz indicator?

Greg Muir
 

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

Nenad Filipovic
 


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

Dave Daniel
 

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

Albert Otten
 

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

Tek 7 series LCD project!

Miguel Work
 

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

Greg Muir
 

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?

Bruce Griffiths
 

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=yahoo.com@groups.io> 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?

Dave Seiter
 

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=yahoo.com@groups.io> 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: Tek Cover Part Number

Greg Muir
 

Gary,

Try 650-0568-00. In the Tek service manual Volume 2 (070-3784-01 available online at http://www.arimi.it/wp-content/Strumenti/Tek/492%20Service.pdf) 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?

Greg Muir
 

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

Greg

Re: 2467B focus/astigmatism anomaly...

Chuck Harris
 

Hi Raymond,

The scope has been running all afternoon with the
capacitor removed, and frankly I can't even tell it
is gone... A lot of circuitry for such little affect.

However, the anomaly continues exactly as before.

I think it is time to pick on Q4432, Q4440, and all of
those high resistance resistors in the focus chain.

-Chuck Harris

Raymond Domp Frank wrote:

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: 2440 deal

Robert Simpson
 

Bob Albert and Kevin Oconnor,
Please reply to me by email off line so I can provide an update
reach me at
go_boating_fast@...

Bob (S)

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

evan foss
 

I once carried a 7704A a little over a mile. I don't recommend it but
I would like to point out that my ability to carry it gave out, while
the handle is still in working order.

On Sun, Aug 18, 2019 at 9:39 AM 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.


--
https://github.com/evanfoss

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Re: 2467B focus/astigmatism anomaly...

 

Hi Chuck,

On Mon, Aug 19, 2019 at 01:58 AM, Chuck Harris wrote:


The scope has been running all afternoon with the
capacitor removed, and frankly I can't even tell it
is gone... A lot of circuitry for such little affect.

However, the anomaly continues exactly as before.
Thanks for checking that, so it's off my mind.

I agree re. Q4432, Q4440, and all of
those high resistance resistors in the focus chain.

Interesting and intriguing!

Raymond

Re: TDS460A Will not turn on?

Mlynch001
 

Ravi,

I have became a student of Mr. Carlson's about two years ago, I have watched that particular video on SMPS several times. It all makes sense to me at that level. The board level is where I get lost. The traces and components are so tightly packed that it is difficult (for Me) to determine which part is the one that I need to identify. What Paul describes with a few hand drawn components becomes a quagmire of many times more components. Picking the correct two or three out of a couple of hundred is daunting, to say the least.

The TDS460A uses a totally different power supply from the 460. The one that is shown in that video is an older model, common to the 420 and 460 models, but not the "A" models. I realize that in principle, these work the same. However, they appear to take a completely different approach in construction. Mr. Carlson actually did a video where he repaired that exact SMPS. I watched that video several times as well.

On this board, I see a 8DIP UC3844A, which I assume is the oscillator which starts the whole circuit? Therefore, I assume that it is near to this component that I should find that ZENER Diode, Power Resistor and the Capacitor that Chuck is alluding to in his Million dollar hint? The problem is, I do not immediately see a direct connection to the Main filter caps to these various outlying components. To Chuck's hint, I do see a 47uF 25V electrolytic cap that is in one of the traces from IC2 (opto-isolator) back and finally making it's way to pin7 of UC3844A. There is also an SCR in the line to pin#5 of the second opto-isolator. My current problem is that If UC3844A is NOT the oscillator, then I need to figure out what components comprise that oscillator and work backwards from there.

I greatly appreciate your guidance and great patience. I will stay after this until I figure it out.

--
Michael Lynch
Dardanelle, AR

Re: TDS460A Will not turn on?

Harvey White
 

On 8/18/2019 10:46 PM, Mlynch001 wrote:
Ravi,

I have became a student of Mr. Carlson's about two years ago, I have watched that particular video on SMPS several times. It all makes sense to me at that level. The board level is where I get lost. The traces and components are so tightly packed that it is difficult (for Me) to determine which part is the one that I need to identify. What Paul describes with a few hand drawn components becomes a quagmire of many times more components. Picking the correct two or three out of a couple of hundred is daunting, to say the least.

The TDS460A uses a totally different power supply from the 460. The one that is shown in that video is an older model, common to the 420 and 460 models, but not the "A" models. I realize that in principle, these work the same. However, they appear to take a completely different approach in construction. Mr. Carlson actually did a video where he repaired that exact SMPS. I watched that video several times as well.

On this board, I see a 8DIP UC3844A, which I assume is the oscillator which starts the whole circuit?
The first thing I did when reading this is google (or duck duck go) the UC3844A, which is a PWM controller.  I didn't go any further, but it does have application notes.  TI makes it.  If the power supply designers didn't stray too far from the application circuit, that will be a help.    It looks as if it is intended to be the controller in a power supply, and seems to want between 16 and 28 volts (max) as a power input.

That might help as a start.

Harvey


Therefore, I assume that it is near to this component that I should find that ZENER Diode, Power Resistor and the Capacitor that Chuck is alluding to in his Million dollar hint? The problem is, I do not immediately see a direct connection to the Main filter caps to these various outlying components. To Chuck's hint, I do see a 47uF 25V electrolytic cap that is in one of the traces from IC2 (opto-isolator) back and finally making it's way to pin7 of UC3844A. There is also an SCR in the line to pin#5 of the second opto-isolator. My current problem is that If UC3844A is NOT the oscillator, then I need to figure out what components comprise that oscillator and work backwards from there.

I greatly appreciate your guidance and great patience. I will stay after this until I figure it out.

T912

yoram stein
 

Hello everybody
For the repair of my T912 i need 1 knob Volt/Division ((Tek part 366-1646-00) and 1 x the shaft that goes from its Variable 9red) knob into the potentiometer.
I liven in Amsterdam Netherland. Email: sp856567@.... WhatsApp: -31-65-3206282
Best regards,
Frank

Re: TDS460A Will not turn on?

Ravi Moghe
 

Hi Michael,

I will check the standard circuit for and around UC3844A and provide my thoughts. The photo of your A5 board will also help in understanding component placement on the board that you have.

Currently, I am away from my home and hence, may not be able to share/send detail replies. Kindly excuse me for couple of days.

Warm Regards,