Date   
Re: 56 pin Harness for TEk TM500

Scott Scheirman
 

(I hope this message is appropriate for this group).

Dan, and the group:

A note from a satisfied customer:



I purchased one of the TM500 extenders from Dan. I was pleasantly surprised at the quality of construction when I opened the package, and then put it away "for later" in case I ever needed it.


Today I noticed that one slot in a TM503 did not seem to work. (I purchased it used, and may never have tested it.).


I plugged in the extender (caution -- line voltage is present on the backplane of a TM503 and maybe others), and then powered up the TM503.


Bingo! The +11.5 volt LED was dark in the "bad" slot, and lit in the other two slots.


I popped the case off, and immediately noticed a burnt trace.


For now I will assume that is why the TM503 was for sale at a low price, but I don't really know. In any event, it should be relatively easy to address.


Bottom line, Dan's extender saved me lots of time. Much appreciated and recommended.


Scott


The usual disclaimers:
I have no business interest in Dan's extender project.
I realize this is rather nuisance compared to "how do I measure 700 ps rise times" and other questions (and answers) on this forum.




~~~
>>I made some extenders for my own use and offered them to the group a while
back. These have test points for the rails, LEDs for all rails, and jumpers
so you can isolate any rail (for example to insert a current meter or to use
a separate power supply for one rail).

I will sell a completely built extender .. or just the PC boards ...

The interconnect cable is a 60 pin ribbon cable. The boards are keyed to
match the TM500(0) modules.

...

Dan

Re: Advise needed - thinning the herd

 

On Mon, 21 Nov 2016 08:41:27 -0800, you wrote:

...

By the time the 7904A comes out the 7104 was already double its speed. Tek
used everything they had learned at that time to redesign the 7904 into the
7904A. They used a lot of the technology of the 7104 CRT in the 7904A CRT.
As a result the 7904A is a rock solid 600+ MHz scope.
And the 7934 was redesigned in the same way with features from the
7104. I thought this made economic sense just based on making maximum
use of their new packaging technologies, consolidation, and having a
design which requires less tweaking during production. The 7844 was
the last 7904 based design but I wonder if Tektronix considered
redesigning it also.

What features did the 7904A CRT get from the 7104? It does not have
distributed horizontal deflection so its horizontal bandwidth is no
better (1 MHz) and as far as I can tell from the schematic, it uses a
scan expansion mesh instead of the box lens from the 7104.

The 7854 display is true analog. Perfectly smooth. It is also digital (It is
really two scopes in one) when you want it to be. In the digital mode it can
either be vector (smooth) or just the X,Y points. There is no rasterizing
going on at all.
The 7854 character generation is rasterized using a 5x7 matrix for
individual characters. I actually prefer the hybrid vector characters
produced by the late 7000 hybrid readout board (very clever) and the
2230/2232.

Since the CRT is driven with 10 bit horizontal and vertical
resolution, it looks exceptionally smooth and this is what makes the
2230/2232 look good even compared to modern LCD displays; the
difference is about 250 dpi versus 72 dpi. I have yet to see a
"retina" display on a modern DSO.

Tektronix was using retina displays before they were cool. HP had a
higher than normal resolution raster CRT display for some of their
early DSOs.

...

Dennis Tillman W7PF

Re: TG501 Help

Albert Otten
 

Hi Guido,

I tried my TG501 together with 7T11A/7S11/S2 in 7704A. Peak-peak:
5 ns: 0.9 V, 2 ns: 1.8 V, 1 ns: 0.7 V.
The waveform at 1 ns looks like a complicated mixture as if the amplitude varies some 20%.
I had ripple in the 7S11 offset out also, distance 83 us. But eventually I found that this ripple simply came from the 7854 I used to display the offset. Same ripple stand-alone, when touching the 10X probe tip somewhere to the 7854 chassis. But I saw more. The "noise" varied between ripples but apart from that is fairly constant in each period. There clearly is some pattern over the periods, so it seems very plausible that this reflects processor actions. The 7704A did not show ripple or whatever when touching the probe tip to the chassis.

Albert

Re: Tek custom banana plugs used in 576 and 577 test fixtures

kc0wox Leeper
 

If they are the same let us know. I'd like to buy some more.

Leonard

Re: Advise needed - thinning the herd

Craig Sawyers <c.sawyers@...>
 

There is no contest. The 7904A is faster and better designed internally than the 7904.
The 7904A is much faster than the spec suggests. If you put a 7A29/7B10 in there it is almost as
fast as the 7104 (I forget what I measured on my 7904A, but it was certainly over 700MHz) - but
without the microchannel electron multiplier of course. In a sense it is not surprising since it
uses many of the same hypcon hybrids that the 7104 does. I've heard it said on this forum that Tek
deliberately underspecced the 7904A to keep product differentiation.

The P7001 is a curiosity. It required a separate DEC PDP-8 or PDP-11 to do anything useful. Keep
it if
you want but it was rapidly superseded by the
7854 and then, later, by almost all digital scopes when they started appearing.

Dennis Tillman W7PF
https://info.yahoo.com/legal/us/yahoo/utos/terms/
I'd like a P7001 if only for completeness sake, and the fact that is has an electric knitting core
store in there. But yes - if you look at the Tek catalogues, it is kind of scary the racks of what
was then very serious computers to make it strut its stuff. But that was in the era that Tek
introduced a bunch of ludicrously expensive hardware, like several kB of disc storage for tens of $k

Craig

Re: Tek custom banana plugs used in 576 and 577 test fixtures

 

Hi Leonard.
Thanks for the photo. Those are the "collet" style banana plugs I am looking
for. I believe I found a source. I ordered a few to see how well they will
work in my application.
Dennis Tillman W7PF

-----Original Message-----
Sent: Monday, November 21, 2016 7:52 AM
Subject: Re: [TekScopes] Re: Tek custom banana plugs used in 576 and 577
test fixtures

Here's a picture of some I found but I don't remember where or when. It's
been quite a few years.

http://golddredgervideo.com/kc0wox/lcmeteradapter/lcadapter3.jpg

Leonard
------------------------------------
Posted by: kc0wox@...
------------------------------------

Re: Advise needed - thinning the herd

David DiGiacomo
 

On Mon, Nov 21, 2016 at 9:41 AM, Dennis Tillman <@Dennis_Tillman_W7PF> wrote:

There is no contest. The 7904A is faster and better designed internally than
the 7904.
On the other hand, the 7904 is the fastest fanless scope around*, so
if you like quiet, it could be a better choice.


* Some very late model 7904s have a fan, most do not.

Re: Advise needed - thinning the herd

 

You made very good choices.

There is no contest. The 7904A is faster and better designed internally than
the 7904.

When Tek came out with the 7904 it was the fastest lab scope available by
far, but they stretched all of their engineering capability to get it to
work at 500MHz.

By the time the 7904A comes out the 7104 was already double its speed. Tek
used everything they had learned at that time to redesign the 7904 into the
7904A. They used a lot of the technology of the 7104 CRT in the 7904A CRT.
As a result the 7904A is a rock solid 600+ MHz scope.

The 7854 display is true analog. Perfectly smooth. It is also digital (It is
really two scopes in one) when you want it to be. In the digital mode it can
either be vector (smooth) or just the X,Y points. There is no rasterizing
going on at all.

The P7001 is a curiosity. It required a separate DEC PDP-8 or PDP-11 to do
anything useful. Keep it if you want but it was rapidly superseded by the
7854 and then, later, by almost all digital scopes when they started
appearing.

Dennis Tillman W7PF

-----Original Message-----
Sent: Monday, November 21, 2016 7:43 AM
Subject: [TekScopes] Re: Advise needed - thinning the herd

Thanks everyone for your inputs. It sounds like the following are the most
popular:

7854 - it's fast and it has GPIB

7904(A) - it's faster

7104 - it's *really* fast , especially in XY mode
7834 - analog storage
7603 - it's only 3-bay, but it has a large display

I'd like to stick with 4-bay models, but I might keep a 7603 for when old
age sets in. :)

So now, some follow up questions:

Which is preferred 7904 vs 7904A?
Is the extra bandwidth of the 7904(A) the only advantage over a 7854?
For the 7854, is the display smoothly analog, or is it plotted in a raster,
post sampling?

Another question. I have a p7001 unit that I picked up without a scope.
Is it compatible with anything besides the 7704(A)? And mainly....is it
USEFUL? Is it worth the effort to install it in a scope?

Now that that's done I need to go through and see exactly what I have in
the herd. I know I have at least three 7104's, a 7934, two (maybe three)
7834's, one or two 7904(A?)'s, and a 7704(A?). Also picked up a 7844 a
while back. I have a 7603, and maybe a 76x3 storage unit.

What I don't have is a 7854. Anyone have one for sale?
------------------------------------
Posted by: cwilkson@...
------------------------------------

Re: Tek custom banana plugs used in 576 and 577 test fixtures

kc0wox Leeper
 

Re: Advise needed - thinning the herd

Chris Wilkson
 

Thanks everyone for your inputs. It sounds like the following are the most popular:

7854 - it's fast and it has GPIB

7904(A) - it's faster

7104 - it's *really* fast , especially in XY mode
7834 - analog storage
7603 - it's only 3-bay, but it has a large display


I'd like to stick with 4-bay models, but I might keep a 7603 for when old age sets in. :)



So now, some follow up questions:


Which is preferred 7904 vs 7904A?
Is the extra bandwidth of the 7904(A) the only advantage over a 7854?
For the 7854, is the display smoothly analog, or is it plotted in a raster, post sampling?


Another question. I have a p7001 unit that I picked up without a scope. Is it compatible with anything besides the 7704(A)? And mainly....is it USEFUL? Is it worth the effort to install it in a scope?



Now that that's done I need to go through and see exactly what I have in the herd. I know I have at least three 7104's, a 7934, two (maybe three) 7834's, one or two 7904(A?)'s, and a 7704(A?). Also picked up a 7844 a while back. I have a 7603, and maybe a 76x3 storage unit.


What I don't have is a 7854. Anyone have one for sale?

Re: TG501 Help

Albert Otten
 

Hi Guido, w.r.t. that trace jumping up and down. What happens when you trigger from the trigger output and insert an attenuator in the marker output coax line? The jumps amplitude could reduce accordingly, or stay the same.
W.r.t. those ripples at the 7S11 offset output, I don't see any source for that in the TG501/TM500. The 7704A switches at 40 kHz; 25 us or perhaps 50 us is too far from your measured period time I think.
You could eliminate the 7T11 by using an ordinary time base like a 7B80. The between samples time produced now by the 7S11's internal generator are deliberately not constant ("modulated"). That might help to identify the source of the ripples.
Albert

A precision CRT 1955 video

Miguel Work
 

https://www.youtube.com/watch?v=q5dhfhMItQc



De: TekScopes@... [mailto:TekScopes@...]
Enviado el: lunes, 21 de noviembre de 2016 12:13
Para: TekScopes@...
Asunto: Re: [TekScopes] New colour LCD scopes from China



On 20 Nov 2016, at 18:34, ironcoder@...<mailto:ironcoder@...> [TekScopes] <TekScopes@...<mailto:TekScopes@...>> wrote:


I own a 465 and 455M. I really like them both. I trouble shoot with them almost every day. It is a hobby, I am retired. I looked at some of the new scopes being sold from China and am just blown away by the price in real dollars. Is there a catch to buying one of these?

I have a pair of fairly low-end Chinese digital scopes — a 25mhz Owon and a 40mhz GAtten — and they’re fine for most of my hobbyist purposes. However, I really enjoy using my 475, and my 7623, and even my clunky old Solartron CD1400, which I don’t get from clicking through menus on the digital scopes. It’s like the difference between driving a vintage motorcycle vs driving a new Toyota Corolla. The latter may be newer and more refined, but which is more fun?

Re: New colour LCD scopes from China

Dave Voorhis
 

On 20 Nov 2016, at 18:34, ironcoder@... [TekScopes] <TekScopes@...> wrote:


I own a 465 and 455M. I really like them both. I trouble shoot with them almost every day. It is a hobby, I am retired. I looked at some of the new scopes being sold from China and am just blown away by the price in real dollars. Is there a catch to buying one of these?

I have a pair of fairly low-end Chinese digital scopes — a 25mhz Owon and a 40mhz GAtten — and they’re fine for most of my hobbyist purposes. However, I really enjoy using my 475, and my 7623, and even my clunky old Solartron CD1400, which I don’t get from clicking through menus on the digital scopes. It’s like the difference between driving a vintage motorcycle vs driving a new Toyota Corolla. The latter may be newer and more refined, but which is more fun?



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

Tek 492B not properly switching the LPF/Preselector relays (preselector driver?)

David Feldman
 

Have a 492B spectrum analyzer which isn't properly switching the two latching coax LPF/Preselector relays that choose LPF (band 1) or YIG (band >1) - it appears possibly one of the relays doesn't switch, while the other does (but not yet sure which one.) It arrived to me in this condition, so I don't know what might have caused this nor when it developed (I initially suspected failed input limiter causing no signal on band 1, but that wasn't the culprit.)

If I drive the relays manually with +/-12V bench supply, both switch normally and I can therefore see signals in band 1 (via LPF) and other bands (via preselector.)

When the preselector driver card is supplying the switch pulse, I see +/- 10V (this seems low) with duration of 100 mSec (this seems normal) under load. The relays together measure ~60 ohms (the two relay coils are in parallel), so the preselector driver and DC supply rails are being asked for 200 mA or so for the 100 mS pulse duration.

The microcontroller drives an 8-bit latch on the preselector driver board - the logic state is as expected.

The power supply rails are +17, -15V and the preselector driver uses a pair of bipolar transistors to momentarily connect either rail to the latching relay control line.

When I force the relays into Band 1 (via LPF), the unit passes self cal and is otherwise behaving normally.

Any suggestions as to where to look next?

Tks,

Dave

Re: TG501 Help

 

Why they just didn't suggest peaking the 2ns and
1ns out with a RF voltmeter will always be a mystery I
guess ??
An RF Voltmeter showing the amplitude won't distinguish between 1, 2 or 5 ns.
Looking at the circuit, I can imagine that adjusting purely based on amplitude could result in serious misadjustment in the form of a significant subharmonic content of the intended signal appearing at an output without it becoming apparent until the signal is used to adjust a 'scope...

Raymond

Re: Tek custom banana plugs used in 576 and 577 test fixtures

Dale H. Cook
 

At 01:04 PM 11/20/2016, Dennis Tillman wrote:

GR first described their new "banana" plug patch cord in 1924 in the GR Experimenter Magazine. Officially it is called a TYPE 274 Plug by GR. Hirschmann and Co. called their creation a "Bananenstecker". There are no pictures of the construction of either one so I still have no idea who came up with the "collet" construction variation.
The first GR catalog issued after 1924 was Catalog E in 1928, and the Type 274 connectors are illustrated on page 135:

http://www.ietlabs.com/pdf/GR_Catalog/GenRad_CatE1-1928.pdf

Dale H. Cook, GR / HP Collector, Roanoke/Lynchburg, VA
http://plymouthcolony.net/starcity/radios/index.html

Re: TG501 Help

 

The service manual says that the 1ns market should be greater than or
equal to 200mV with a 1GHz 5S14 so your S4 should show an even higher
level.

This might be a good place to use an S1 sampling head but I doubt it
really matters except that your S4 should show a higher level.

On Mon, 21 Nov 2016 00:13:31 +0100, you wrote:

Hi,

The 120mV (p-p) is measured with the 7S11/S4/7T11 combo. The S4 is 50Ohms in. And yes, i used the trigger out as external trigger for the 7T11. And I did tweak the settings of the 1/2/5nS outputs more than once.

The whole sine jumps up and down on the screen; it really looks like the DC component is not stable. That's why i looked at the offset out of the 7S11. Which is not clean. (signal every 35.7us on the DC component; dying out 23MHz sine for some 1.2us). But i don't know if this is related. Also don't know if it is the TG or the sampler which is doing this (maybe it is even the 7704A mainframe, that i could test i guess by using another mainframe). i'll have a go at that, i have a 7623A to try.

The adjustment procedure for the TG501 says to use a sampling scope for adjusting the 5/2/1 signals (5S14). I used the 7S11/7T11. Don't have anything else at the moment.

Cheers,
Guido

Re: TG501 Help

 

The TG501 service manual confirms what Guido said; it recommends a
5S14 which has a 1 GHz bandwidth and 50 ohm inputs so your TDS694C is
more than good enough and there is no need for high impedance probes.

According to the manual, with the 1 GHz 5S14, the 5ns and 2ns markers
are suppose to be greater than or equal to 750mV and the 1ns market is
suppose to be greater than or equal to 200mV. They should be even
greater with a higher bandwidth oscilloscope.

On Sun, 20 Nov 2016 19:44:03 -0400, you wrote:

What bandwidth is needed for this TG501 cal? I have an in-cal TDS694C,
3Ghz scope with 4Ghz probes for Hi imp sampling.

Re: New colour LCD scopes from China

Tom Brown
 

Hi Michael-

I guess it comes down to what you prefer, but I wouldn't swap a good 465 for a pile of software based scopes. But, then, I also have a Type 555 next to my bench.... :-)


Tom

Re: TG501 Help

ArtekManuals
 

The output of the 1ns is really just a 1 GHz sine wave


On 11/20/2016 6:44 PM, AncelB mosaicmerc@... [TekScopes] wrote:

What bandwidth is needed for this TG501 cal? I have an in-cal TDS694C,
3Ghz scope with 4Ghz probes for Hi imp sampling.

--
Dave
Manuals@...
www.ArtekManuals.com