Date   

Re: 7104 versions, and vertical amplifier issue

Jean-Paul
 

Raymond,

These are some faint memories, I have yet to research this connexion, but I am certain our TEK veterans will be able to fill in the history.

One source is the excellent CRT book that Dennis reprinted.

Jon

PS: spoke to our friend Japp. Hope to visit next Autumn.


SG 502 Assistance?

sweetbeats
 

Greetings everybody.

Hope this is an okay place to post this. I’m a member of the TM 500 group as well and will redirect this to there if advised.

I’ve been a member for some years but really essentially lurk as time to tinker with my audio and Tek gear is in limited to non-existent supply.

But the time has come to try and get my stuff working. I have a modest TM 500 setup…mainly using two TM 504 frames loaded with:

SC 502 (needs work…have a couple parts units)
DM 501A (dead…doesn’t appear to power up)
PS 503A (works!)
FG 502 (unknown commodity just yet)
AA 501A (seems to work!)
SG 502 (this seems to work too…more below)

I have additional modules, DC 504 (unknown commodity), an additional PS 503A, PS 501-1, DD 501, and too many mainframes…need to get rid of some…RTM 506, two spare TM 504, and two TM 503.

I want to use my TM 500 gear primarily to maintain/repair analog audio equipment.

Okay.

That’s the rundown.

So I’m working on the SG 502. It cleaned up nice, the frequency range buttons are a bit sticky, but the AA 501A says it is producing <0.004% THD from about 9Hz to 108kHz. Nice! The interesting thing is once you go outside of that range, like almost immediately, the distortion goes up considerably. Like…50% THD and higher. Are there any usual suspects I should address as a given with my SG 502 before doing anything else, or outside of that does anybody have any suggestions for a next step to helping it perform within spec across it’s designed frequency range (5Hz to 500kHz)?

Thanks!

Cory Oace


Re: Type 284

Simon Tregear
 

Chris,

Simon here again.

What is the status of the 7CT1N ?

What model is the DIF probe. ?

And would you ship either to VIC.

Thanks, S

On 17 Jun 2021, at 10:35 am, Chris van Lint <chrisvanlint@bigpond.com> wrote:

I have a taker here in Melbourne Australia for the type 284 PG. Thank you to those who have responded. I do have some smaller items, which could be shipped at a reasonable price. Stuff like a differential probe, a P6230, P6046, P6156, 7S12 with a S-6 and S-52, transistor mounts (013-072/013-069/013-0098-02), a 067-0503-00 Precision DC Divider, a 7T11 pcboard with the reed relays still intact (sorry no TD), a 7CT1N, a 10MHz TCXO and the pre-scaler for the DC508 etc.

Contact me off-line.

Chris


Re: 7104 versions, and vertical amplifier issue

 

On Thu, Jun 17, 2021 at 05:12 PM, Jean-Paul wrote:


A few memories from LBL and LLNL ~ 1960s. (yes I am OLD!)

The original 7104 client was at Defense Nuclear Agency/ Atomic Energy
Commission.

Only after some years was 7104 released for general sales.
Hi Jon,
Do you have any more information on this?

Raymond


Re: 7104 versions, and vertical amplifier issue

Jean-Paul
 

Chris: A few memories from LBL and LLNL ~ 1960s. (yes I am OLD!)

The original 7104 client was at Defense Nuclear Agency/ Atomic Energy Commission.

The "shots' at the Nevada and Pacific test ranges, cost 10s of M$ and months to setup.

Many fast sensors arrayed around the device Ground Zero or surface zero. .

Long buried coax from Shot Cab to Instrument Hut. Imagine dozens of scopes, shock rack mounted set for single trigger.

A neuc or thermonuc detonation is on a nS scale, with exponential decay of temperature, pressure etc. LLNL or Los Alamos was in charge of the shots and often EGG did the instrumentation.

Each 7104 had a scope camera, to record on film.

Only after some years was 7104 released for general sales.

From an optimist in the Nuclear Age...

Jon


Re: 7104 versions, and vertical amplifier issue

cmjones01
 

An update: I love this scope. I'm a thousand miles away from my usual
lab at the moment, and had to solve a problem for a client. This
required measuring the length of a particular state on a 600MHz clock
signal which occurs once, at startup, after a FPGA programming phase
which takes several seconds. Usually I'd just reach for the digital
scope, but all I have here is the 7104. Seeing the 600MHz clock is, of
course, no sweat for it. But the MCP really comes in to its own when
looking for a one-shot event. Set the trigger, select single-sweep
mode, crank up the intensity, start up my circuit and bingo - clear as
day, there's the pulse on the screen. All 14 microseconds of it.
Plenty clear enough to see and measure in normal room light.

Amazing stuff.
Chris

On Wed, Jun 16, 2021 at 9:31 PM Chris Jones <chris@stumpie.com> wrote:

Good news: the scope now works. I cleaned and reseated the Y output hypcon U862 a couple of times but nothing changed. Then I cleaned and reseated the driver U842 and, for good measure, swapped its elastomer and plastic frame with U862. Now I have full vertical sweep, and a usable scope.

There are lots of niggles remaining: both 7A29s have attenuator contact problems (the attenuation factors are randomly wrong) as well as an odd effect rounding the end of the leading edge of the calibrator waveform, which I suspect is due to the feed-beside adjustments. The 7B15 is reluctant to trigger and the plug-in connectors have various intermittent issues, as I'd expect on a scope which has been stored for a while.

Chris

On Wed, 16 Jun 2021, 16:57 Mark Vincent, <orangeglowaudio@gmail.com> wrote:

Chris,

The Hypcons are sensitive to being clean and the contacts being aligned right. You should remove each and clean the contacts on the chip and connector. Also do this to the other ICs and transistors. The square mounting frames for the Hypcons should be put on with an even pressure on all sides. The screws are tightened to snug in opposite corners at a time as the lug nuts on the wheel of a vehicle. I did add good heatsink compound to the Hypcons and the heatsinks. Roger is right about making sure the coax connectors are also cleaned. It is possible the neck pins have oxidation on them. Check the voltage at the input of the vertical if cleaning does not fix the problem. It is possible the problem is earlier. One dirty contact somewhere can cause headaches in finding it. Many here will agree to this having seen it enough times.

IF yours looses sync in the readout, the 741 IC under the handle on the horiz. board towards the rear will be bad. I had this happen in mine. It will occur when it warms a little. This happened in mine after a minute with the left side off. The trace will remain normal. This information is only in case this happens to yours or anyone else's.

Jon is right about keeping the intensity low. When I use mine, the intensity is enough to see the line and readout. When a trace is on the screen, I turn the intensities up a little. The intensities I keep it at are so that it is barely visible until I raise it enough to see a trace and readout which is still low. The yellow LED will not come on the way I keep the two set. It may be easier to use a lamp on the circuit while keeping the screen in a low light level to ensure the trace seen is safe for the MCP.

Mark





Re: Tek 2230, almost fixed but with a problem out of my competences

Albert Otten
 

Federico, perhaps easier to do is a continuity test between R701 pin 5 and U781/6, with your DMM at resistance measurement. One lead fixed to that pin 5. The other, extended with a length of insulated wire and blank tip, probing/touching the pins of U781. It doesn't harm when you touch the wrong pin.
Albert


Re: Tek 2230, almost fixed but with a problem out of my competences

Albert Otten
 

On Thu, Jun 17, 2021 at 09:34 AM, Pitpat wrote:

Hi, i didn't understood that pin 6 was still to be tested, i thought that the
one i got from pin 5 of the weighted resistor was sufficient.
It's just to verify that that there is no interruption between that pin 5 and U781/6.
IIRC you had a contradictory situation where that pin 5 was well negative (<< -0.27 V) while U781/1 was -8.6 V.
Anyway, today i fiddled a bit with a hook tipe probe around pin 6, could it be
-0,27v ? it seems not to change with all the slower sweep settings.
That must have been U781/7. But nevertheless good to know that the non-inverting input is ok.
I've also noticed that sometimes when the time base knob is rotated fast
enough for just a fraction of a second the correct readout appears and then it
switch back to the unknown, that means that the MUX should be fine right?
Could perhaps be mechanical stress on some board when you rotate the time/div knob?

Albert


Re: Tek 2230, almost fixed but with a problem out of my competences

Pitpat
 

Hi, i didn't understood that pin 6 was still to be tested, i thought that the one i got from pin 5 of the weighted resistor was sufficient.
Anyway, today i fiddled a bit with a hook tipe probe around pin 6, could it be -0,27v ? it seems not to change with all the slower sweep settings.
I've also noticed that sometimes when the time base knob is rotated fast enough for just a fraction of a second the correct readout appears and then it switch back to the unknown, that means that the MUX should be fine right?


Re: 7104 versions, and vertical amplifier issue

cmjones01
 

On Wed, Jun 16, 2021 at 11:33 PM Raymond Domp Frank <hewpatek@gmail.com> wrote:

On Thu, Jun 17, 2021 at 12:06 AM, cheater cheater wrote:

The Soviets had 3GHz direct display scopes.
AFAIK, the 7104 was (claimed to be) the only general-purpose, commercially available plugin 'scope with a bandwidth of 1 GHz.
I also have an interest in Soviet scopes, and own a couple of their
7000-series-inspired models plus many of the plugins (always looking
to complete the set!). What I find striking is just how common Tek's
products are in the "west" versus how uncommon their Soviet
equivalents are in their part of the world. I've spent quite a while
trawling the Russian-speaking internet looking for accessories for my
Soviet scopes, and there's simply not all that much out there. I think
they were built in relatively small numbers and, because of the course
of history since then, many have been scrapped. Indeed, search for any
Soviet equipment part number and most of the links will be for sites
advertising its precious metal content and offering to scrap it.

In contrast, even something as exotic as the 7104 isn't at all rare,
even though it was originally incredibly expensive and purchased only
by well-funded laboratories and government contractors. Even today, 40
years after its introduction, anyone who wants one can probably find
one, and they're not even expensive. I paid £150 (less than $200) for
mine in the UK including the full set of "correct" plugins, and all
that was needed to get it going was a dose of contact cleaner. That
means that this extreme high-end technology is available to small
businesses like mine, amateurs and experimenters. It strikes me as a
curious consequence of the cold war's technology race.

Chris


Re: 7104 versions, and vertical amplifier issue

Jean-Paul
 

Bonjour, I am unaware of any French scopes with 1 GHz BW,

CRT scopes I have seen here in France were 100 MHz or less.

RE Russian scopes, most of their electronics in were heavy copies of US models.

до свидания
do svidaniya


Re: 7104 versions, and vertical amplifier issue

Tom Lee
 

Perhaps you are thinking of this, or possibly a predecessor (if there was one): https://vintagetek.org/7250-digitizing-oscilloscope-2/

At 60kg weight, it's not quite portable.

--Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 6/16/2021 18:47, Dave Seiter wrote:
Didn't the French  have a 1GHz GP scope?   Or am I thinking of a French version of the 519(ish, and maybe not portable either)?
-Dave
On Wednesday, June 16, 2021, 03:35:29 PM PDT, Tom Lee <tomlee@ee.stanford.edu> wrote:
I believe that is a fair statement.

-- Tom


Re: 7104 versions, and vertical amplifier issue

Dave Seiter
 

Didn't the French  have a 1GHz GP scope?   Or am I thinking of a French version of the 519(ish, and maybe not portable either)?
-Dave

On Wednesday, June 16, 2021, 03:35:29 PM PDT, Tom Lee <tomlee@ee.stanford.edu> wrote:

I believe that is a fair statement.

-- Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 6/16/2021 15:33, Raymond Domp Frank wrote:
On Thu, Jun 17, 2021 at 12:06 AM, cheater cheater wrote:

The Soviets had 3GHz direct display scopes.
AFAIK, the 7104 was (claimed to be) the only general-purpose, commercially available plugin 'scope with a bandwidth of 1 GHz.

Raymond





Re: Type 284

Chris van Lint
 

I have a taker here in Melbourne Australia for the type 284 PG. Thank you to those who have responded.  I do have some smaller items, which could be shipped at a reasonable price.  Stuff like a differential probe, a P6230, P6046, P6156, 7S12 with a S-6 and S-52, transistor mounts (013-072/013-069/013-0098-02), a 067-0503-00 Precision DC Divider, a 7T11 pcboard with the reed relays still intact (sorry no TD), a 7CT1N, a 10MHz TCXO and the pre-scaler for the DC508 etc.

Contact me off-line.

Chris


Re: P400 Probe for Tek 222

Craig Cramb
 

I have P400 and P850 probes. These are for the 222A,222PS,224 series units. $135ea + USPS first class or priority I can send pictures and any other info you may want.

Please only contact offline at electronixtoolbox at Gmail dot com

Not for the 222 model that is a different probe.

Craig


Re: 7104 versions, and vertical amplifier issue

 

Agreed

On Thu, Jun 17, 2021 at 12:35 AM Tom Lee <tomlee@ee.stanford.edu> wrote:

I believe that is a fair statement.

-- Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 6/16/2021 15:33, Raymond Domp Frank wrote:
On Thu, Jun 17, 2021 at 12:06 AM, cheater cheater wrote:

The Soviets had 3GHz direct display scopes.
AFAIK, the 7104 was (claimed to be) the only general-purpose, commercially available plugin 'scope with a bandwidth of 1 GHz.

Raymond









Re: 7104 versions, and vertical amplifier issue

Tom Lee
 

I believe that is a fair statement.

-- Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 6/16/2021 15:33, Raymond Domp Frank wrote:
On Thu, Jun 17, 2021 at 12:06 AM, cheater cheater wrote:

The Soviets had 3GHz direct display scopes.
AFAIK, the 7104 was (claimed to be) the only general-purpose, commercially available plugin 'scope with a bandwidth of 1 GHz.

Raymond




Re: 7104 versions, and vertical amplifier issue

 

On Thu, Jun 17, 2021 at 12:06 AM, cheater cheater wrote:


The Soviets had 3GHz direct display scopes.
AFAIK, the 7104 was (claimed to be) the only general-purpose, commercially available plugin 'scope with a bandwidth of 1 GHz.

Raymond


Re: 7104 versions, and vertical amplifier issue

Dave Seiter
 

Although they probably weren't "portable" like the 7104.  In the photos I've seen, they were more like installations.
-Dave

On Wednesday, June 16, 2021, 03:06:49 PM PDT, cheater cheater <cheater00social@gmail.com> wrote:

On Wed, Jun 16, 2021 at 6:36 PM Jean-Paul <jonpaul@ix.netcom.com> wrote:

Rebonjour à tous

Bon courage, sure you will fix it,

The 7A29 have very special elastomeric switches AC/DC and attenuator that are prone to intermittents.

Use special precautions in cleaning as per manual.

Enjoy

Jon

PS  This fine instrument is a real classic, the fastest analog CRT scope ever, originally for US AEC nuclear weapons testing.  We are very lucky to have such a great design revitalized and in our labs. Vive la Tektronix !
The Soviets had 3GHz direct display scopes.


Re: TEK576 looking for repair parts

Mlynch001
 

Bob and the rest of the folks at Vintage Tek are the best! They have helped me out several time with rare parts.

--
Michael Lynch
Dardanelle, AR

2921 - 2940 of 186377