Once in place on Tek Gear, this two series transistor , start to free run, mean no sync at 50khz rate.
My humble external pulse generator , take his output from the emitter, but according to Tek schematic (PG509), the output is from the base..!!!!.
The thing is that the pulse is not sharp an clean as mi elementary circuits.
Perhaps the manual has a bug, and base/emitter are reversed??.
I will check tomorrow.
Gabriel.
--- In TekScopes@yahoogroups.com, "iglesia_cristiana_arpas_eternas" <iglesia_cristiana_arpas_eternas@> wrote:

Serial connected of two SMD transistor in avalanche mode was tested and
work very fine , as well external triggering at 50khz..
Just remain putting this two series transistor in my Tek gear.

For the record this transistor/pulser was forced to free running at
490Khz pulse rate instead 50Khz and not show appreciable heat according
to my finger, really they switch very well indeed. but probably at
expense of life.
Gabriel.
PS: I'm pretty sure when flea die, reincarnate as SMD transistors!!!.
[:))]
--- In TekScopes@yahoogroups.com, "iglesia_cristiana_arpas_eternas"
<iglesia_cristiana_arpas_eternas@> wrote:

After remove some PCB cooper layer from my external avalanche pulse
fixture, this humble pulser reach the limits of my 2456B rise
time...750pS..!! y like to think that is much better that this, due
2465B limitation.
Next step:try to trigger via external pulse..next:put 2 in
series..next:install in Tek gear.
Some pic:
2465B screen shot.
<http://gyazo.com/a0de4cce5829400bdbf1239e87256d29.png?1364245527>

My humble pulser.
<http://gyazo.com/dfb650d9a6b076fe2b3fcd2952f1d876.png>
Gabriel.
--- In TekScopes@yahoogroups.com, "iglesia_cristiana_arpas_eternas"
iglesia_cristiana_arpas_eternas@ wrote:

I brought this nice and not working generator in ebay from I suppose

Forum member.

Is similar to a PG509 (thanks Forum guys), but better ,since include

a

nice attenuator which allow to obtain 25V to 250mV in 125 step.

The fact is, not come with an internal transmission line pulse

former.

For now I'm using a lenght of RG5858 adjusted to a 40nS pulse.

which

will be winding inside the plugin..

I'm waiting for a Teflon coax from a friend.
At arrival time, the generator not work right due a failure in

avalanche transistor Q100.

Replaced Q100 by a MSH10 and 2N2369 bring it to live but at 1,25ns

pulse time in the best case.

Today I just finish to check in an external fixture the smd

transistor

MMBR941, fortunately seems work fine.

rT=0,85ns(limit of my 2465B)
Natural trigger voltage was 40,5V.
Tek ask for a 75 to 80 V avalanche transistor, my next step is put 2

of them in series and see what once inside the Tektronix gear..

Unfortunately one attenuator step refuse to work,they have 3 slide

kind, near optical inspection show a mechanical failure.

A missing small cylinder transfer the movement between rotating

front

knob shaft/cam to the slide switch.

This small piece was fortunately found under the metallic

attenuator

cover, but seems the bed where be rest has broken retention arm.

Therefore , a more work to do in mechanical fashion...melt with iron

some good plastic and fix it.

If any one has a good reference/tips about the performance of this

smd

transistor will be appreciated.

By the way my test fixture is in itself a miniature pulse generator

which could be useful for some test...and very inexpensive.

Gabriel.

See if you can get the 99% Isopropyl Alcohol from your local pharm. They can order it in.

At the least, use the 91% stuff.


Tom

----- Original Message -----
From: epicfatigue
To: TekScopes@yahoogroups.com
Sent: Wednesday, March 27, 2013 10:24 PM
Subject: [TekScopes] Re: Help Tektronix 466 repair advice



Okay well i will clean all switches and pots.

Ill clean out all the switches using isopropyl Alcohol,

Is it safe to do this with pots? or should i do that then lubricate them with a pot cleaner?

----- Original Message -----

From: epicfatigue

To: TekScopes@...

Sent: Wednesday, March 27, 2013 10:24 PM

Subject: [TekScopes] Re: Help Tektronix 466 repair advice

 

Okay well i will clean all switches and pots.

Ill clean out all the switches using isopropyl Alcohol,

Is it safe to do this with pots? or should i do that then lubricate them with a pot cleaner?

Does anyone here have information on the P6247 Differential Probe? What are the most common failures you have seen? Any repair info (schematics, etc) would be much appreciated.

Thanks in advance,

Paul

I think I've heard of a French scope (CSF?) that went to several GHz but
don't know the details or how the transient response was. Anyone have
any details?

Don Black.

On 28-Mar-13 9:04 AM, Dennis Tillman wrote:

Hi Steve,
Yes, I was referring to "production scopes", and more specifically to
"conventional analog production scopes". Few people other than you would
know of the few, exotic, exceptions that exceeded the 1GHz limit. I am
aware
of scopes other than you cited that exceeded the 1GHz bandwidth but as you
point out they can be quite strange due to the engineering constraints
reality imposes at that frequency.

For example B&H Engineering in Yonkers NY modified the 7104 to push it to
3GHz. They were able to do this because the incredible MCP CRT of the 7104
has a 3dB deflection point in excess of 3GHz (this is documented in
the 7104
Service manual). The vertical system of the 7104 was completely removed by
B&H and they developed a single ended 3GHz vertical plugin based on a
DC to
3GHz module they designed (which had over 20% ringing at some
frequencies).

This vertical amplifier had to bypass the interface connector on the
back of
the plugin via SMB connectors that were mounted in 2 of the 4 holes at the
top of the shroud on the rear of the plugin. Once past the interface, I
believe the vertical signal was mated directly to the 7104 delay line.
Only
one CRT deflection plate was driven. I have two different B&H vertical
plugins (one has a variable delay line and the other does not) but I have
yet to find a B&H mainframe. As far as I know their scope relied on
Tek 7B10
and 7B15 time bases which were not modified so this scope would have had
trouble triggering at anything beyond what those time bases are
capable of.

It may seem like the 3GHz capability of the 7104 MCP CRT would make it
possible for Tek to have built an even faster 7104 but that was not
the case
for many reasons: The 7000 series was not designed for it and the cost
would
be prohibitive to adapt it to higher frequencies; Digital scopes were
catching up rapidly; The low cost dedicated scopes were taking their
toll on
the more expensive general purpose laboratory scopes like the 7000.

I don't believe that the 519 has better linearity than the 7104. I haven't
done a test personally although I briefly had a 519 in my home. It wasn't
mine so I didn't dare turn it on for fear that I might damage it. I
use the
7104 extensively and have never noticed a single anomaly when compared
to 3
7603s, a 7844, 7854, or 7934. John Addis and Bruce Hofer at Tek were
issued
US patent 4132958 for the Feedbeside Compensation circuit that
corrects the
amplifiers of the 7104 for thermals which is what I think you are
referring
to.

I have seen a 519 working at the VintageTEK museum and it would be
virtually
impossible to measure linearity on that tiny 2cm x 6cm screen accurately
enough to compare it to the 7cm x 9cm of the 7104. If you can get a more
precise definition of what the EG&G folks were referring to by
'linearity' I
think we can persuade the folks at the museum to do a direct comparison of
the 519 to the 7104 and take some 'linearity' measurements.

Dennis

-----Original Message-----
From: Steve
Sent: Wednesday, March 27, 2013 1:17 PM

--- In TekScopes@yahoogroups.com <mailto:TekScopes%40yahoogroups.com>,
"Dennis Tillman" <dennis@> wrote:

The 7104 that Dick is selling is the fastest analog scope ever made.
By coincidence I took this CRT photo on mine yesterday which will give
you an idea of what it is capable of. This is a 2GHz 350mV signal
displayed on the
7104 with the identical plugins that Dick has in his 7104. The 7104 is
spec'd at 1GHz. The gain at 2GHz is down by about 9X but there it is
triggering and the waveform is clear as a bell.
Dennis

Dennis,

You need to qualify that statement a bit. The 7104 is the fastest
production conventional analog scope ever made. Key qualifiers: Production
and Conventional.

The former Soviet Union built scopes for government use that were faster.
As with their scan converter digitizers, the CRTs were very long (well
over
a meter), allowing low deflection angles. These were custom built and not
sold outside of a few government labs. I have never seen one, but have
heard accounts directly from former users. They did not have microchannel
plates, so cameras were needed for single shot capture. The amplifiers
were
not DC coupled.

Iwatsu had a couple of models of scan converter based "analog scopes" that
were faster as well. These are funny animals - in one sense they act like
an analog scope, but the display is digital. No memory, and conventional
scope trigger only (no view of the pre-triggered portion of the waveform).
But they have color LCD displays with unique colors for each channel's
trace. The scan converter requires much less deflection angle than a
conventional human viewed CRT, the target being only a couple of
millimeters
high. Hence the exotic amplifier chain used in the 7104 is not required to
drive it. They are still fast amplifiers however.

I believe Iwatsu made these through the late 1990s.

The Tek 519 also has 1 GHz BW, but is direct access (input drives the CRT,
having no amplifiers) and weird deflection factors like 1.37 V/cm. The
calibrated area of the CRT is only 2 divisions high, one on either side of
ground. While these restrictions are very limiting, I have heard from
users
at EG&G that it actually has better vertical linearity that the 7104. I
have never seen a working 519 and can not verify that statement, but I
remember hearing that the linearity and thermal compensation in the
7104 are
not as good as in other Tek lab scopes. Some tradeoffs needed to be
made to
design this wonderful scope.

Steve

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

Yahoo! Groups Links

----- Original Message -----

From: daniel

To: TekScopes@...

Sent: Wednesday, March 27, 2013 2:09 PM

Subject: [TekScopes] Tek475: L1511 location.

 

Hi all.

Need help to find out, where is that inductor located.

Is part of 1khz calibrator 5vdc source along with a 150uf cap, to avoid 1khz noise, entering to 5v source .

Just could found C1511, its OK.

Guees L1511 is shorted cause I can see 1mseg period noise(20mv),on two
channels although they are shorted to GND.

Thanks in advance.

Serial connected of two SMD transistor in avalanche mode was tested and
work very fine , as well external triggering at 50khz..
Just remain putting this two series transistor in my Tek gear.

For the record this transistor/pulser was forced to free running at
490Khz pulse rate instead 50Khz and not show appreciable heat according
to my finger, really they switch very well indeed. but probably at
expense of life.
Gabriel.
PS: I'm pretty sure when flea die, reincarnate as SMD transistors!!!.
[:))]
--- In TekScopes@yahoogroups.com, "iglesia_cristiana_arpas_eternas"
<iglesia_cristiana_arpas_eternas@> wrote:

After remove some PCB cooper layer from my external avalanche pulse
fixture, this humble pulser reach the limits of my 2456B rise
time...750pS..!! y like to think that is much better that this, due
2465B limitation.
Next step:try to trigger via external pulse..next:put 2 in
series..next:install in Tek gear.
Some pic:
2465B screen shot.
<http://gyazo.com/a0de4cce5829400bdbf1239e87256d29.png?1364245527>

My humble pulser.
<http://gyazo.com/dfb650d9a6b076fe2b3fcd2952f1d876.png>
Gabriel.
--- In TekScopes@yahoogroups.com, "iglesia_cristiana_arpas_eternas"
iglesia_cristiana_arpas_eternas@ wrote:

I brought this nice and not working generator in ebay from I suppose

Forum member.

Is similar to a PG509 (thanks Forum guys), but better ,since include

a

nice attenuator which allow to obtain 25V to 250mV in 125 step.

The fact is, not come with an internal transmission line pulse

former.

For now I'm using a lenght of RG5858 adjusted to a 40nS pulse.

which

will be winding inside the plugin..

I'm waiting for a Teflon coax from a friend.
At arrival time, the generator not work right due a failure in

avalanche transistor Q100.

Replaced Q100 by a MSH10 and 2N2369 bring it to live but at 1,25ns

pulse time in the best case.

Today I just finish to check in an external fixture the smd

transistor

MMBR941, fortunately seems work fine.

rT=0,85ns(limit of my 2465B)
Natural trigger voltage was 40,5V.
Tek ask for a 75 to 80 V avalanche transistor, my next step is put 2

of them in series and see what once inside the Tektronix gear..

Unfortunately one attenuator step refuse to work,they have 3 slide

kind, near optical inspection show a mechanical failure.

A missing small cylinder transfer the movement between rotating

front

knob shaft/cam to the slide switch.

This small piece was fortunately found under the metallic

attenuator

cover, but seems the bed where be rest has broken retention arm.

Therefore , a more work to do in mechanical fashion...melt with iron

some good plastic and fix it.

If any one has a good reference/tips about the performance of this

smd

transistor will be appreciated.

By the way my test fixture is in itself a miniature pulse generator

which could be useful for some test...and very inexpensive.

Gabriel.

 

Hi Steve,
Yes, I was referring to "production scopes", and more specifically to
"conventional analog production scopes". Few people other than you would
know of the few, exotic, exceptions that exceeded the 1GHz limit. I am aware
of scopes other than you cited that exceeded the 1GHz bandwidth but as you
point out they can be quite strange due to the engineering constraints
reality imposes at that frequency.

For example B&H Engineering in Yonkers NY modified the 7104 to push it to
3GHz. They were able to do this because the incredible MCP CRT of the 7104
has a 3dB deflection point in excess of 3GHz (this is documented in the 7104
Service manual). The vertical system of the 7104 was completely removed by
B&H and they developed a single ended 3GHz vertical plugin based on a DC to
3GHz module they designed (which had over 20% ringing at some frequencies).

This vertical amplifier had to bypass the interface connector on the back of
the plugin via SMB connectors that were mounted in 2 of the 4 holes at the
top of the shroud on the rear of the plugin. Once past the interface, I
believe the vertical signal was mated directly to the 7104 delay line. Only
one CRT deflection plate was driven. I have two different B&H vertical
plugins (one has a variable delay line and the other does not) but I have
yet to find a B&H mainframe. As far as I know their scope relied on Tek 7B10
and 7B15 time bases which were not modified so this scope would have had
trouble triggering at anything beyond what those time bases are capable of.

It may seem like the 3GHz capability of the 7104 MCP CRT would make it
possible for Tek to have built an even faster 7104 but that was not the case
for many reasons: The 7000 series was not designed for it and the cost would
be prohibitive to adapt it to higher frequencies; Digital scopes were
catching up rapidly; The low cost dedicated scopes were taking their toll on
the more expensive general purpose laboratory scopes like the 7000.

I don't believe that the 519 has better linearity than the 7104. I haven't
done a test personally although I briefly had a 519 in my home. It wasn't
mine so I didn't dare turn it on for fear that I might damage it. I use the
7104 extensively and have never noticed a single anomaly when compared to 3
7603s, a 7844, 7854, or 7934. John Addis and Bruce Hofer at Tek were issued
US patent 4132958 for the Feedbeside Compensation circuit that corrects the
amplifiers of the 7104 for thermals which is what I think you are referring
to.

I have seen a 519 working at the VintageTEK museum and it would be virtually
impossible to measure linearity on that tiny 2cm x 6cm screen accurately
enough to compare it to the 7cm x 9cm of the 7104. If you can get a more
precise definition of what the EG&G folks were referring to by 'linearity' I
think we can persuade the folks at the museum to do a direct comparison of
the 519 to the 7104 and take some 'linearity' measurements.

Dennis

-----Original Message-----
From: Steve
Sent: Wednesday, March 27, 2013 1:17 PM

--- In TekScopes@..., "Dennis Tillman" wrote:
>
> The 7104 that Dick is selling is the fastest analog scope ever made.
> By coincidence I took this CRT photo on mine yesterday which will give
> you an idea of what it is capable of. This is a 2GHz 350mV signal
> displayed on the
> 7104 with the identical plugins that Dick has in his 7104. The 7104 is
> spec'd at 1GHz. The gain at 2GHz is down by about 9X but there it is
> triggering and the waveform is clear as a bell.
> Dennis

Dennis,

You need to qualify that statement a bit. The 7104 is the fastest
production conventional analog scope ever made. Key qualifiers: Production
and Conventional.

The former Soviet Union built scopes for government use that were faster.
As with their scan converter digitizers, the CRTs were very long (well over
a meter), allowing low deflection angles. These were custom built and not
sold outside of a few government labs. I have never seen one, but have
heard accounts directly from former users. They did not have microchannel
plates, so cameras were needed for single shot capture. The amplifiers were
not DC coupled.

Iwatsu had a couple of models of scan converter based "analog scopes" that
were faster as well. These are funny animals - in one sense they act like
an analog scope, but the display is digital. No memory, and conventional
scope trigger only (no view of the pre-triggered portion of the waveform).
But they have color LCD displays with unique colors for each channel's
trace. The scan converter requires much less deflection angle than a
conventional human viewed CRT, the target being only a couple of millimeters
high. Hence the exotic amplifier chain used in the 7104 is not required to
drive it. They are still fast amplifiers however.

I believe Iwatsu made these through the late 1990s.

The Tek 519 also has 1 GHz BW, but is direct access (input drives the CRT,
having no amplifiers) and weird deflection factors like 1.37 V/cm. The
calibrated area of the CRT is only 2 divisions high, one on either side of
ground. While these restrictions are very limiting, I have heard from users
at EG&G that it actually has better vertical linearity that the 7104. I
have never seen a working 519 and can not verify that statement, but I
remember hearing that the linearity and thermal compensation in the 7104 are
not as good as in other Tek lab scopes. Some tradeoffs needed to be made to
design this wonderful scope.

Steve

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

Yahoo! Groups Links

 

--- In TekScopes@..., "Dennis Tillman" wrote:
>
> The 7104 that Dick is selling is the fastest analog scope ever made. By
> coincidence I took this CRT photo on mine yesterday which will give you an
> idea of what it is capable of. This is a 2GHz 350mV signal displayed on the
> 7104 with the identical plugins that Dick has in his 7104. The 7104 is
> spec'd at 1GHz. The gain at 2GHz is down by about 9X but there it is
> triggering and the waveform is clear as a bell.
>
>
>
> Dennis

Dennis,

You need to qualify that statement a bit. The 7104 is the fastest production conventional analog scope ever made. Key qualifiers: Production and Conventional.

The former Soviet Union built scopes for government use that were faster. As with their scan converter digitizers, the CRTs were very long (well over a meter), allowing low deflection angles. These were custom built and not sold outside of a few government labs. I have never seen one, but have heard accounts directly from former users. They did not have microchannel plates, so cameras were needed for single shot capture. The amplifiers were not DC coupled.

Iwatsu had a couple of models of scan converter based "analog scopes" that were faster as well. These are funny animals – in one sense they act like an analog scope, but the display is digital. No memory, and conventional scope trigger only (no view of the pre-triggered portion of the waveform). But they have color LCD displays with unique colors for each channel's trace. The scan converter requires much less deflection angle than a conventional human viewed CRT, the target being only a couple of millimeters high. Hence the exotic amplifier chain used in the 7104 is not required to drive it. They are still fast amplifiers however.

I believe Iwatsu made these through the late 1990s.

The Tek 519 also has 1 GHz BW, but is direct access (input drives the CRT, having no amplifiers) and weird deflection factors like 1.37 V/cm. The calibrated area of the CRT is only 2 divisions high, one on either side of ground. While these restrictions are very limiting, I have heard from users at EG&G that it actually has better vertical linearity that the 7104. I have never seen a working 519 and can not verify that statement, but I remember hearing that the linearity and thermal compensation in the 7104 are not as good as in other Tek lab scopes. Some tradeoffs needed to be made to design this wonderful scope.

Steve

--- In TekScopes@yahoogroups.com, "stv4st" <sforrest.au@> wrote:

Hello to all!
First post...

Not quite your classic CRT Tek scope (and if there is a more appropriate forum please do direct me...) but I have an issue with a TDS220.

I bought it with a TDS2MM installed - the reason I got it in fact. Some little time later it started not starting. Sometimes when turning on the screen would just show a series of horizontal lines. Power cycling seemed to get it going (and self test was all PASSED). Then, one day, it failed in use, just the lines.

Removing the TDS2MM, the scope powered up OK, but there seems to be something screwy with the contrast. I re-installed the module and again the lines. The I put the TDS2MM into another TDS220 and all is good.

I think the issue is with the 1st TDS220. PSU not up to it? And I have just noticed a "blooming" (phase reversal?) in the lower RH corner of the display :o(

I had hoped to sell one of these scopes, and clearly I would like to keep one working with the TDS2MM.

Any thoughts?

Stephen
-----------

You could easily swap the P/S between the scopes to find out.

However the pins on the mainboard that connects to the module are quite short therefore it is very important that the module is fully seated in its compartment. If not, symptoms like scrambled display, scope won't start at all, module not recognized or all blank display may appear. Make sure it is pushed down all the way.
/Håkan

Could well be the PS.
Open it and put a scope on the power supply outputs with and without
the interface.

ST

On Tue, Mar 26, 2013 at 1:09 PM, stv4st <sforrest.au@...> wrote:

Hello to all!
First post...

Not quite your classic CRT Tek scope (and if there is a more appropriate forum please do direct me...) but I have an issue with a TDS220.

I bought it with a TDS2MM installed - the reason I got it in fact. Some little time later it started not starting. Sometimes when turning on the screen would just show a series of horizontal lines. Power cycling seemed to get it going (and self test was all PASSED). Then, one day, it failed in use, just the lines.

Removing the TDS2MM, the scope powered up OK, but there seems to be something screwy with the contrast. I re-installed the module and again the lines. The I put the TDS2MM into another TDS220 and all is good.

I think the issue is with the 1st TDS220. PSU not up to it? And I have just noticed a "blooming" (phase reversal?) in the lower RH corner of the display :o(

I had hoped to sell one of these scopes, and clearly I would like to keep one working with the TDS2MM.

Any thoughts?

Stephen





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

Yahoo! Groups Links