Date   

Re: Yahoo is up for sale, get ready for a disaster...

Peter Gottlieb
 

I wonder how? I'll drop them a note and ask.

So who wants to run it?


Peter

On Apr 12, 2016, at 1:32 PM, 'David C. Partridge' @perdrix [TekScopes] <TekScopes@...> wrote:

groups.io will download all extent group messages (they claim)

Dave

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: 12 April 2016 17:48
To: TekScopes@...
Subject: Re: [TekScopes] Yahoo is up for sale, get ready for a disaster...

I grabbed the name and will prep things further later this evening, also set up whoever wants to run it.

Now for how to replicate those Yahoo messages...

Peter

On Apr 12, 2016, at 12:33 PM, Tom Gardner tggzzz@... [TekScopes] <TekScopes@...> wrote:

Looks good. Who is going to grab the name?

On 12/04/16 16:48, Chuck Harris cfharris@... [TekScopes] wrote:

It is all free,
For up to 1GB attachment and files storage.
Then $10/month for 10GB.


------------------------------------
Posted by: Peter Gottlieb <hpnpilot@...>
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------------------------------------

Yahoo Groups Links


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


Re: Yahoo is up for sale, get ready for a disaster...

 

groups.io will download all extent group messages (they claim)

Dave

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: 12 April 2016 17:48
To: TekScopes@...
Subject: Re: [TekScopes] Yahoo is up for sale, get ready for a disaster...

I grabbed the name and will prep things further later this evening, also set up whoever wants to run it.

Now for how to replicate those Yahoo messages...


Peter

On Apr 12, 2016, at 12:33 PM, Tom Gardner tggzzz@... [TekScopes] <TekScopes@...> wrote:

Looks good. Who is going to grab the name?

On 12/04/16 16:48, Chuck Harris cfharris@... [TekScopes] wrote:

It is all free,
For up to 1GB attachment and files storage.
Then $10/month for 10GB.

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



------------------------------------
Posted by: Peter Gottlieb <hpnpilot@...>
------------------------------------


------------------------------------

Yahoo Groups Links


Re: Yahoo is up for sale, get ready for a disaster...

Malcolm Hunter
 

On 12 April 2016 at 18:28, 'David C. Partridge'
@perdrix [TekScopes] <TekScopes@...> wrote:

Does anyone know anything about http://groups.io? Seems like a good
alternative to Yahoo Groups. Question is, how long will they be around? And
how long will they remain free? Any opinions on this service?
​I was thinking the same. Looking at the groups already on there, we would
probably be one of the most active.

Malcolm​


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


Re: Yahoo is up for sale, get ready for a disaster...

 

Does anyone know anything about http://groups.io? Seems like a good
alternative to Yahoo Groups. Question is, how long will they be around? And
how long will they remain free? Any opinions on this service?


Re: 7613 with 7L12 problem

Malcolm Hunter
 

On 12 April 2016 at 18:22, 'James A.R. Koehler' jark@... [TekScopes] <
TekScopes@...> wrote:

I have no manuals for either the oscilloscope frame or the
plug-in. Is there a simple adjustment to bring the lower digital data
back up onto the observable screen?
​You can find the manuals here:​

http://w140.com/tekwiki/wiki/7613
http://w140.com/tekwiki/wiki/7L12
http://bama.edebris.com/manuals/tek/7L12

Malcolm


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7613 with 7L12 problem

Jim Koehler
 

Hi all,

I have a 7613 with 7L12 spectrum analyzer plug-in; I have been using it for years. It is old but everything works well except for the lower digital display. This shows the spectrum width and resolution and, over the years, it has been gradually creeping downward so that now, one can only see the tops of the letters. The upper digital display which shows the vertical scale is in, I think, its normal place. There is no noticeable drift of either digital display from when I turn it on to several hours later so I don't think this is a temperature problem; the lower digital display is just mostly off the bottom of the screen all the time.

I have no manuals for either the oscilloscope frame or the plug-in. Is there a simple adjustment to bring the lower digital data back up onto the observable screen?

Jim, VE5FP


Re: Does anybody have a 7K series viewing hood?

Malcolm Hunter
 

On 12 April 2016 at 17:42, HankC @HankC [TekScopes] <
TekScopes@...> wrote:

I heard of someone who made a hood from a square plastic flower pot; the
kind the nursery sells plants in.

​Sounds like a simple task for a 3d printer too.

Malcolm​


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


Re: My 2465 just died

 

Congratulations.  I don't think the 6800 fails very often.

From: "drpaulr2001@... [TekScopes]" <TekScopes@...>
To: "TekScopes@..." <TekScopes@...>
Sent: Tuesday, April 12, 2016 10:36 AM
Subject: Re: [TekScopes] Re: My 2465 just died

  Success! I replaced the main processor with a new 68B02 and the scope is now fully functional.
That was easier than I thought it would be.
Regards,Paul



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Re: Tek 475: square wave leading corners too rounded?

Tom Gardner
 

On 12/04/16 02:50, David @DWH [TekScopes] wrote:

On Tue, 12 Apr 2016 00:41:36 +0100, you wrote:

On 11/04/16 22:01, Dave Voorhis voorhis@... [TekScopes] wrote:

The output from both the 475's internal calibrator and the calibrator
output from a cheap new DSO (a Gratten GA1042CAL) reveals slight
rounding -- though a slightly different shape from each calibrator -- on
the leading corners.

Is this a problem with the scope?
The Gratten is a 40MHz 1GS/s scope, I believe. That ought to have a 10%-90%
risetime of ~9ns. If a 60MHz probe is added, the combined risetime should be
~10.5ns.

The Tek 475 is a 200MHz machine, so ought to have a risetime of ~1.75ns, or 6ns
when combined with a 60MHz probe.
It usually does not work like that for oscilloscope probes. At least
with Tektronix, they make it a habit of specifying the bandwidth *at
the probe tip* so a 100 MHz probe used with a 100 MHz oscilloscope
yields 100 MHz. When they refer to a "100 MHz probe", what they
really mean is a probe intended for use with oscilloscopes up to a
bandwidth of 100 MHz. Other manufacturers in general seem to have
followed this rule.
Hmmm. Not sure.

I can believe that for "modern" scopes where the probe informs the scope of its frequency response and the scope compensates before displaying the waveform.

I'm less convinced for older scopes where they didn't specify exactly which probes worked with the scope.

For example, my 485 specs the scope bandwidth 350MHz/50ohm, 250MHz/1Mohm. Separately it lists the bandwidth of various probes with the scope, different ones being 350/330/250/200MHz. The last is with a 9' P6053A. The 6053B spec is that the bandwidth is >115MHz with a >225MHz scope.

But all of that is academic to the OP's question.


Re: Yahoo is up for sale, get ready for a disaster...

Peter Gottlieb
 

I grabbed the name and will prep things further later this evening, also set up whoever wants to run it.

Now for how to replicate those Yahoo messages...


Peter

On Apr 12, 2016, at 12:33 PM, Tom Gardner tggzzz@... [TekScopes] <TekScopes@...> wrote:

Looks good. Who is going to grab the name?

On 12/04/16 16:48, Chuck Harris cfharris@... [TekScopes] wrote:

It is all free,
For up to 1GB attachment and files storage.
Then $10/month for 10GB.

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


Re: Does anybody have a 7K series viewing hood?

 

I heard of someone who made a hood from a square plastic flower pot; the kind the nursery sells plants in.
 HankC, Boston WA1HOS

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


Re: My 2465 just died

 

great job



Jerry Massengale

-----Original Message-----
From: drpaulr2001@... [TekScopes] <TekScopes@...>
To: TekScopes <TekScopes@...>
Sent: Tue, Apr 12, 2016 10:36 am
Subject: Re: [TekScopes] Re: My 2465 just died






Success! I replaced the main processor with a new 68B02 and the scope is now fully functional.
That was easier than I thought it would be.
Regards,Paul

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









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


Re: Tektronix 465 No Trace, No Dot

 

I don't have a manual, nor schematic, for a 465 scope. So I can't make
any guesstimates as to what the "impedance" level is for the circuitry
associated with the high voltage point that you have measured. Also, I
don't know whether any neon bulbs should be lit, or not lit; although I
suspect that any neon lamps associated with the CRT are probably surge
suppression devices and should be unlit under normal operation and
circumstances- although neon lamps in amplifier circuits are a different
matter, as they might be for level shifting (and therefore will be
normally lit). Perhaps other Tekscopes group members can comment.

Mike N4MWP

On 04/12/2016 12:07 PM, w7qed@... [TekScopes] wrote:

Hi Mike,

Mine does indeed have the 5kv option (aerospace surplus is wonderful...).


Given that I have the same reading on both these meters, I think it is
safe to assume the cathode voltage is undesirably low. But I will
borrow a proper probe later this week from a friend and make sure.


What do you think the output impedance is of that circuit, and how
much current can it handle?


Also, should those neon bulbs be lighting up in the high voltage
section? They are not right now, thought I'd ask.


Thanks,


--E





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Re: Tektronix 465 No Trace, No Dot

Roger Evans
 

The neon's only light if a fault causes excessive grid cathode voltage. They may flash on switch off.

I have measured the cathode voltage on a 454 and on a 485 with a 20k/V meter and both measured within the expected tolerance on a working scope. The 465 may of course be different!

Regards,

Roger


Re: Yahoo is up for sale, get ready for a disaster...

Tom Gardner
 

Looks good. Who is going to grab the name?

On 12/04/16 16:48, Chuck Harris cfharris@... [TekScopes] wrote:

It is all free,
For up to 1GB attachment and files storage.
Then $10/month for 10GB.


Re: Tektronix 465 No Trace, No Dot

Tom Gardner
 

On 12/04/16 17:07, w7qed@... [TekScopes] wrote:

What do you think the output impedance is of that circuit, and how much current can it handle?
I used a 3*33Mohm+100kohm voltage divider to ground. Of course I don't know how much that dragged the cathode voltage down, but I have no reason to suspect it was significant.

No, I don't claim the technique was safe, nor do I recommend it.

Also, should those neon bulbs be lighting up in the high voltage section? They are not right now, thought I'd ask.
They ensure the grid-cathode voltage isn't excessive. On mine they fire when the power is turned off, for several seconds.

There's another neon in the PSU, and it flashes every second or so.

Caution: I've only been fettling 465/485s since February.


Re: Tek 465 - No B Trace visibility

Ian van der Neut
 

I remember now what the issue is with the glue not being allowed to spread.
There's a drum inside a drum. You're trying to glue the shaft to the inner
drum without glueing the inner drum to the outer drum. However from your
description it seems a real possibility that the inner drum no longer
catches onto the outer drum when the knobs are locked. In that case I
believe there's no remedy.

Someone correct me if I'm wrong.

Ian.
On 12 Apr 2016 4:38 pm, "Neil Elver neil.elver@... [TekScopes]" <
TekScopes@...> wrote:



Okay that is definitely worth a try. Thank you! This is truly a great group
- I feel like everyone's been through these machines many times before.

I'll let you know how it goes.

On Tue, Apr 12, 2016 at 9:36 AM, Ian van der Neut ivdneut@...
[TekScopes] <TekScopes@...> wrote:



On Tue, Apr 12, 2016 at 4:24 PM, Neil Elver neil.elver@...
[TekScopes] <TekScopes@...> wrote:



Okay, that's what I was afraid of but makes sense. Has anyone managed
to
repair one of these time delay knob assemblies? Or is it a 'source and
swap' repair? I'm picturing a swiss watch inside ...
I'm pleased to say I have repaired it, with the guidance of a forum
member
(you know who you are Raymond!). This is what you're looking at:

http://fergus.7bits.nl/~ian/tek/DSCI0268-small.JPG

The rear (left on the photo) is the drum for the delayed time base and it
probably is slipping on the shaft. Taking it apart is not possible, but
you
can get some super glue down in there. I used a paper clip with a drop of
super glue on it several times and dropped the glue about 3/4 inch down
into the rear of the drum. You must take care that the glue doesn't
spread
too far away from the shaft!

I think Raymond will be able to explain better why preventing the glue
from
spreading too far is vital.

Good luck.

Ian.

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Re: Tektronix 465 No Trace, No Dot

Elliott Li
 

Hi Mike,

Mine does indeed have the 5kv option (aerospace surplus is wonderful...).


Given that I have the same reading on both these meters, I think it is safe to assume the cathode voltage is undesirably low. But I will borrow a proper probe later this week from a friend and make sure.


What do you think the output impedance is of that circuit, and how much current can it handle?


Also, should those neon bulbs be lighting up in the high voltage section? They are not right now, thought I'd ask.


Thanks,


--E


Re: Yahoo is up for sale, get ready for a disaster...

Chuck Harris
 

One of the groups I subscribe to has already made a shift over
to groups.io.

Groups.io is setup by (as I recall) the head techie over at yahoo
groups.

He is setup to suck all of the files, pictures, posts and membership
information out of a yahoo group, and set it back up in groups.io

It is all free, and sofar it has been flawless.

-Chuck Harris

Stefan Trethan stefan_trethan@... [TekScopes] wrote:

Perhaps google groups would work? It has similar email and web based
posting options.

ST

On Tue, Apr 12, 2016 at 10:47 AM, Gordon @GordonW
[TekScopes] <TekScopes@...> wrote:

It doesn't look like there's email capability. Personally I loathe web
only forums and I'm not on my own.

Gordon


Re: My 2465 just died

Paul Richardson
 

Success! I replaced the main processor with a new 68B02 and the scope is now fully functional.
That was easier than I thought it would be.
Regards,Paul