Date   
Re: P6042 Story.

Tom Brown
 

Unfortunately, it's not uncommon. I bought one with breaks in multiple conductors in the cable as well but fortunately, all of the breaks were right close to the front panel. I just cut off the cable and reattached it and it's been absolutely fine ever since. I looked for a replacement cable for a while but I think I had about the same probability of finding that cable as I would have finding a job as a retired billionaire.... <laughing>

Tom
AE5I

2440 CCD clock calibration without sg503

Szabolcs Szigeti
 

Hi,


I got so excited on getting my pg502 running and just having a discussion here on 2440 calibration, I though I gave it a try. So I set the pg502 to 250Mhz, connected to the scope and set up as directed by the SM for CCD clock cal with the aliased display.


Here is the result: https://goo.gl/photos/ixDAj7fEon3UPuGu9 https://goo.gl/photos/ixDAj7fEon3UPuGu9


Based on this, I'd say the CCD clocks need adjustment, but I'm not sure if using the pg502 ican be considered correct method to verify and adjust the CCD clock. I don't have an sg503.
What is your opinion? Should I pull the cal jumper and get to the pots or leave it as it is?


Regards,


Szabolcs

Re: Error message after calibrating Tek 2465B

WdJ
 

Roger,

I guess nothing! Some power cycles later, this message will disappeer,
is my experience.

kind regards, Wim.

Op 31-5-2016 om 21:34 schreef @rodd [TekScopes]:

Hi folks,
I suppose this will be an easy one for you.
I bough a 2465B at a very reasonable price with the famous test 04
fail 11 error message.
After cleaning and recapping the LVPS, I calibrated the unit using the
TB 9-6625-2295-35 technical bulletin from US Army.
This was my first time and it took a LONG time.
Everything happened as described in the document, except in Cal 06
(vertical transient respose).
The I supposed to adjust "delta" knob to obtain some degree od
overshoot, but when I turned the knob, a dotted cursor moved at the
bottom of the screen instead.
Anyway, I finished the procedure by aligning the cursor at the top of
the step being fed to the sope.
However, when I changed the jumper from cal to normal and turned the
scope on, I get this message on the screen: All pass 00 <number> push
A/B trig to EXIT.


What was is wrong?
Thanks,
Roger



[Non-text portions of this message have been removed]



[Non-text portions of this message have been removed]

Re: Error message after calibrating Tek 2465B

 

Read up on exerciser 03.

----- Original Message -----
From: @rodd [TekScopes]
To: TekScopes@...
Sent: Tuesday, May 31, 2016 3:34 PM
Subject: [TekScopes] Error message after calibrating Tek 2465B



Hi folks,
I suppose this will be an easy one for you.
I bough a 2465B at a very reasonable price with the famous test 04 fail 11 error message.
After cleaning and recapping the LVPS, I calibrated the unit using the TB 9-6625-2295-35 technical bulletin from US Army.
This was my first time and it took a LONG time.
Everything happened as described in the document, except in Cal 06 (vertical transient respose).
The I supposed to adjust "delta" knob to obtain some degree od overshoot, but when I turned the knob, a dotted cursor moved at the bottom of the screen instead.
Anyway, I finished the procedure by aligning the cursor at the top of the step being fed to the sope.
However, when I changed the jumper from cal to normal and turned the scope on, I get this message on the screen: All pass 00 <number> push A/B trig to EXIT.


What was is wrong?
Thanks,
Roger

Re: Introduction, 2440 cal, 5400 illimination

Szabolcs Szigeti
 

Hi,

I used I think an 1k resistor with a 1000uF electrolytic, plus a 100nF ceramic from my drawer. Connected them right at the input of the scope with a BNC-binding post adapter. It did significantly decrease the noise of the power supply, but still there was some noise picked up from the environment (should move away from the computer), but it did pass the cal.
I'm not sure if the noise needs to be within tolerance, I would assume the scope does some averaging.
Regarding the calibration, I don't have all the equipment, especially not an sg504 or a pg506, so what i did was to assume that the pots and trimmers inside the scope were at their porper setting, since I knew nobody touched the internals of the scope since last cal, as the sticker showed it was not opened. So I Did all the adjustment steps that would not require setting the CCD clocks, as it needs a leveled sine generator. But I did set the CRT adjustment (adjust menu) as I can visually verify that. Also did CM counts preset settings then self cal and ext cal. I used a bench power supply, a 3.5 digit DMM (that was checked to a reference recently, so that was ok.), and a function generator that had about 5-7 ns rise time. I did the position and linearity checks with that, but those need faster rise time, so I decided to live with that.
Since now I have a pg502, with 1ns rise time, and thanks to this group now with 250Mhz frequency, I was able to verify that linearity and position effect passes and also redid the delay and CTE cal with this pulse. I'm curious if I could use the pg502 to verify the CD clock, as at250 MHz with the scopes bandwidth it is more or less a since wave. I was able to get the aliased display required, so I'm studying if I should touch the CCD clocks based on that.


So it's not hopeless to recal a 2440 with fairly simple equipment. Although I was not able to validate the results, I have seen nothing sine then that would indicate any gross error.


Szabolcs

Error message after calibrating Tek 2465B

 

Hi folks,
I suppose this will be an easy one for you.
I bough a 2465B at a very reasonable price with the famous test 04 fail 11 error message.
After cleaning and recapping the LVPS, I calibrated the unit using the TB 9-6625-2295-35 technical bulletin from US Army.
This was my first time and it took a LONG time.
Everything happened as described in the document, except in Cal 06 (vertical transient respose).
The I supposed to adjust "delta" knob to obtain some degree od overshoot, but when I turned the knob, a dotted cursor moved at the bottom of the screen instead.
Anyway, I finished the procedure by aligning the cursor at the top of the step being fed to the sope.
However, when I changed the jumper from cal to normal and turned the scope on, I get this message on the screen: All pass 00 <number> push A/B trig to EXIT.


What was is wrong?
Thanks,
Roger

Re: PG502 freq too low

Szabolcs Szigeti
 

Hi,


Thanks everyone with the suggestions, It was indeed a resistor issue.

Dan, you were spot on. The 18 ohm resistor was about 40ohms, I replaced that. And yes, the trimmer cap is there, I was able to get up around 280 MHz, so it more than meets the specs now.


Thanks all!


Szabolcs

Re: Tek TDS694C advice pls

 

John,
the idea isn't to call anyone in particular an idiot,
I meant this tongue-in-cheek and tried to use an emoji ( ;-)). No harm done!

If someone who's running two chips as in the photo is unable to use any of
> the four channels as a trigger source, then something else is wrong with the
> scope.
Evidently!

Re: PG502 freq too low

Dan Rae
 

And further to my earlier suggestion to check the value of the 18 Ohm
resistor in series with the variable pot (these are small carbon
resistors which can drift high with age) I see that in mine at least
there /is/ an adjustment for the <4nS range which is /not/ mentioned in
my manual. It's a small ceramic trimmer (10 pF?) just to the rear of the
variable pot and presumably replaces the fixed cap in my manual. My
serial is B033902.

Mine goes up to 270 MHz so I'm not about to play with this but if you
find this trimmer in yours it should get you up to spec.

But with so many suggestions that have been offered that's it from me :^)

Dan

Re: Introduction, 2440 cal, 5400 illimination

bc
 

I guess it's my turn to (try to) calibrate my 2440 (and 2465...)

I was thinking about doing the same and using a power supply and whatever else I can throw together hoping for some sort of accuracy. My 3.5 digit Tektronix DM502 and Fluke 77 also need cal but I think they're the most accurate that I have at this point, and I don't have an arbitrary signal generator - I'll have to depend on crystal oscillators for this. And to build something that has the bandwidth to not have its own losses. My power supply is an analog homemade unit, as well.

But anyway it looks like I will have to do additional RC filtering, the noise on my bench power supplies are horrendous. Perhaps this is one of the reasons for a failure? If it needs to be within 2%, the 0.2V range needs to be within 4mV including noise... 4mV is within the noise of my equipment! How much of an RC constant were you using? I'll need to look for low leakage capacitors to ensure I don't have another voltage divider here adding additional error.

Maybe I will need to get better equipment before attempting calibration.

I definitely know my 2465 needs attenuator var linearity calibration, when I turn the var knobs, the trace shifts by a little. Not sure if this is a potentiometer cal or it's an EAROM calibration but suspecting the latter. A Youtube video on calibrating a 2201's analog section sort of sparked some interest. Though concepts are the same, unfortunately the nitty gritty doesn't apply to either of my scopes... I figure I should cal the 2440 first as if I screw up, I can remove the battery, and I'm no worse off than when I started.

-Ben

Re: PG502 freq too low

 

Make sure the pulse width is not longer than the time between pulses.
If it is, the pulse rate will divide by 2.

HankC, WA1HOS, Boston

Re: 11403 factory default.

 

On 31 May 2016 00:24:25 -0700, you wrote:

...

In think a P6156 Probe is more likely to be used with the 11A52 (600 MHz), 11A71 and 11A72 Modules (both 1 GHz). Oke the P6156 has a lower Probe Tip Capacitance (like the Classic P6048).
High-Z passive probes support the full bandwidth of the 11A34 but only
with a terminated 50 ohm source which has a 25 ohm impedance. The
same applies to any 300+ MHz high-Z input.

I don't recommend the use of normal Readout Probes with TekProbe Interface Instruments (like your 11A34). Damage to the Probe Interface Connector(Ring) is very likely.
I remember this warning from Tektronix. The problem was with older
Tektronix readout probes like the P6062 and P6063 which have a very
stiff readout connector pin which would gouge the TekProbe interface.

Re: Tek TDS694C advice pls

John Miles
 

No, the idea isn't to call anyone in particular an idiot, but to point out
that someone would have to be one in order to claim that the modification
works without bothering to verify that all four channels can still serve as
trigger sources.



If someone who's running two chips as in the photo is unable to use any of
the four channels as a trigger source, then something else is wrong with the
scope.



I think I've used combinatorial logic triggering once in my life, and that
was on another scope. I agree that's a good candidate for the no-free-lunch
rule violation, as it's pretty difficult to test exhaustively.



-- john, KE5FX



From: TekScopes@... [mailto:TekScopes@...]
Sent: Tuesday, May 31, 2016 3:53 AM
To: TekScopes@...
Subject: [TekScopes] Re: Tek TDS694C advice pls





Obviously that's the first thing that anyone who isn't a complete idiot
would verify after
such an unconventional "fix."
Firstly, I wouldn't call everyone making an operating error a complete
idiot. Secondly, not everyone is immediately aware that trigger source
selection allows each of the four channels as trigger source independently.
Combined, one may see a triggered CH4, not realising for a moment that
they're still triggering on CH1. You may call me a complete idiot if I'm
wrong ;-).

Did you try logic triggering, using all 4 channels for establishing
conditions?

My TDS694C won't trigger on CH3 nor CH4 after trigger chips 3 and 4 died. I
wrote about this elsewhere and earlier.

My observation while they were still alive but overheating was that forced
cooling #3 or #4 (cold spray) temporarily returned CH3 and CH4 respectively
back into operation. I don't think that "blowby" of the cold spray distorted
these observations.

If what is stated in the EEVBlog post is correct, CH3 and CH4 would be
served by trigger chip #3; In the 'blog, Chip 2 was moved to the #1 position
and chip #4 to the #3 position.

If #3 serves CH3 and CH4, that would be good news. I'd only need someone who
can safely move my #2 chip to position #3...

Raymond

Re: P6042 Story.

 

A few months ago, I offered to try and repair one of these that a friend of mine had purchased "for parts". It turned out that the probe cable was interrupted about 30 cm from the probe body. Took some fiddling with a TDR to find the spot but it worked! Also, there was a short between two connecting wires in the socket inside the probe body.


Raymond

Re: P6042 Story.

Albert Otten
 

Some time ago I bought a P6042 for 90 euro. At my request the seller first send me pictures to show that there was nearly no noise in the highest sensitivity settings. Fine noise-free traces indeed, but he used no signal input. When I tested the unit it didn't show any DC response. It appeared that 3 of the wires in the cable were broken! I offered the seller to try a repair but he preferred to have me return the unit. Maybe I had also better take the risk and repair the cable.

Albert

Re: Tek TDS694C advice pls

 

Obviously that's the first thing that anyone who isn't a complete idiot would verify after
such an unconventional "fix."
Firstly, I wouldn't call everyone making an operating error a complete idiot. Secondly, not everyone is immediately aware that trigger source selection allows each of the four channels as trigger source independently. Combined, one may see a triggered CH4, not realising for a moment that they're still triggering on CH1. You may call me a complete idiot if I'm wrong ;-).

Did you try logic triggering, using all 4 channels for establishing conditions?

My TDS694C won't trigger on CH3 nor CH4 after trigger chips 3 and 4 died. I wrote about this elsewhere and earlier.

My observation while they were still alive but overheating was that forced cooling #3 or #4 (cold spray) temporarily returned CH3 and CH4 respectively back into operation. I don't think that "blowby" of the cold spray distorted these observations.

If what is stated in the EEVBlog post is correct, CH3 and CH4 would be served by trigger chip #3; In the 'blog, Chip 2 was moved to the #1 position and chip #4 to the #3 position.

If #3 serves CH3 and CH4, that would be good news. I'd only need someone who can safely move my #2 chip to position #3...

Raymond

Re: 11403 factory default.

Egge Siert
 

Hi,

First you must execute the Initialize Button in the Utility Menu. After that you can see in the Utitility Menu the Color Button. Executing this will give you the Color Menu and on the right side (below the Colour Array) you see the Default Colour All Button. Thats it.

See also the free downloadable 11403 User Manual on:


http://w140.com/tekwiki/wiki/11403 http://w140.com/tekwiki/wiki/11403

You can also use P6134's instead of P6134C's. P6134's are a little cheaper (around USD 20.00).


In think a P6156 Probe is more likely to be used with the 11A52 (600 MHz), 11A71 and 11A72 Modules (both 1 GHz). Oke the P6156 has a lower Probe Tip Capacitance (like the Classic P6048).


I don't recommend the use of normal Readout Probes with TekProbe Interface Instruments (like your 11A34). Damage to the Probe Interface Connector(Ring) is very likely.


Greetings,


Egge Siert

Re: SMPS Danger.

stefan_trethan
 

$30 for a power supply? You can get them for half that. Yea it's crazy.

To see financial cost of injury quoted like that is strange to me.

ST

On Tue, May 31, 2016 at 6:38 AM, 'Dennis Tillman' @Dennis_Tillman_W7pF
[TekScopes] <TekScopes@...> wrote:
I'm amazed that a PCs SMPS can sell for as little as $30. That is just
astounding to me. It means it cost less than $15 in parts, labor, testing,
and hopefully UL certification (I'm not so sure they are UL certified). For
that price they are clearly throw-away items. The lack of schematics and the
inherent danger of working on something that is connected directly to the
power line multiplies the danger at least 10 fold. So for me the risk/reward
calculation says that unless this thing was worth $300 it isn't worth the
risk to repair it.

I think you were extremely lucky. A visit to the ER (which you surely would
have needed if the fragment had been one mm closer to your eye would have
increased the cost to somewhere above $3,000.

I wish I could say I never did anything stupid. I did some pretty stupid
things too which I survived. Other smarter people than me have perished in
similar situations. Thanks for sharing your 'stupid' moment.

I can only hope that this is the last time we hear an SMPS story. Those
things are worse than nasty, they're deadly.

SMPS == DANGER

Dennis Tillman W7PF

Re: SMPS Danger.

 

Usually PC power supplies fail because of worn out aluminum
electrolytic capacitors which are easy enough to replace. In my
opinion they are routinely under specified as older power supplies
lasted longer. These days they all seem to fail a couple months after
the warranty expires.

On Mon, 30 May 2016 21:38:36 -0700, you wrote:

I'm amazed that a PCs SMPS can sell for as little as $30. That is just
astounding to me. It means it cost less than $15 in parts, labor, testing,
and hopefully UL certification (I'm not so sure they are UL certified). For
that price they are clearly throw-away items. The lack of schematics and the
inherent danger of working on something that is connected directly to the
power line multiplies the danger at least 10 fold. So for me the risk/reward
calculation says that unless this thing was worth $300 it isn't worth the
risk to repair it.

I think you were extremely lucky. A visit to the ER (which you surely would
have needed if the fragment had been one mm closer to your eye would have
increased the cost to somewhere above $3,000.

I wish I could say I never did anything stupid. I did some pretty stupid
things too which I survived. Other smarter people than me have perished in
similar situations. Thanks for sharing your 'stupid' moment.

I can only hope that this is the last time we hear an SMPS story. Those
things are worse than nasty, they're deadly.

SMPS == DANGER

Dennis Tillman W7PF

Re: SMPS Danger.

 

My father has some stories and photographs from his time at LRL. One
of a Tektronix 500 series oscilloscope shows time running backwards
because the magnetic field from the experiment pulled the sweep
backwards. Another shows an explosion from *inside* the CRT; it looks
like a bad Hollywood special effect. He said when that happened, they
had two 500 series oscilloscopes side by side and an arc ran between
their chassis.

He told a story about some big test they did where one guy had to push
the "start" button on a wall sized control panel. The first time he
did it, there was a wiring mistake and the panel exploded. After
repairs when he went push the button again, he had a man sized
Plexiglas shield with a hole right where the button was and he pushed
it with a stick.

I like the old MIDI standard which used RS-232 like signaling but with
optocoupler isolation. I wish a modern version had taken hold.

On Tue, 31 May 2016 06:27:15 +0200, you wrote:

I use the Linear Technology DC1747A-A for isolated RS232.
It's very nice, but makes some minimal noise, so if you need it really
quiet with no Y capacitors you are probably better off with
optocouplers or a piece of fiber.

What do we learn from this all?
Don't do stupid things. You don't get paid enough. If you are not sure
yet that what you are doing isn't stupid, stop and think.

It's not copyright infringement to learn from other people's mistakes.

A colleage managed to discharge a 400V 68uF cap directly into a tiny
25V electrolytic cap. The can was launched off with enough force to
give him a bloody cut just under his eye. We made some polycarbonate
shields after that. The "safety" vents don't bloody work if you are
looking at an instantaneous steam explosion. It's like making a weak
spot in the side of a boiler and crossing your fingers.

ST