Date   
Re: Chinese Cleaning Goo

Vladimir _
 

I think very few compounds will be able to touch the anodized labels on Tek's aluminum panels. The legends on the pushbuttons, on the other hand, are really fragile. Just pressing on the button seems to be enough to smear the printing! I wouldn't try cleaning those even with soap and water.

Re: SG502 Schematic, Component Layout

Albert Otten
 

Just for reference. My SG502 has S/N B075039, just after the changes at B072750 (change info 1-19-1979). The date codes are late 1980 (including soldered-in components and VAR pot).
Looks like bare board A1 is not changed. I checked a few removed and added components and these were simply not installed and soldered in (one C at the rear side). The only number at the board is RJ-2756-01. No number underneath the 10X push rod, mentioned by Raymond. So no 670- or 388- number at all.

Albert

Re: SG502 Schematic, Component Layout

 

On 26 Jul 2017 03:07:55 +0000, you wrote:

Thanks David and Dave for the responses (and reassurance that I'm not off topic). I looked for identifying markings on the board and the chassis, with little success. The only numbers anywhere are the copyright date (1971) and "R0039E" on the upper right side of the board. Other than the front panel graphics, nothing identifying the unit on the chassis either.

I've never learned to read component date codes, so that will take a bit of research before I can report back.

I'll also have to do some reverse engineering in order to identify Q235, as the area around the coaxial jack looks different than the component layout drawing. In particular, there's a TO-style can device with 8 leads that I don't see anywhere on the layout.
That 8 pin TO-99 can is an LM710 comparator made by Fairchild in the
36th week of 1974 so the design is significantly different from the
schematics we have. Internally the LM710 is a two stage differential
comparator so it neatly replaces differential comparator stage Q200
and Q210 and differential comparator stage Q220 and Q230.

It looks like there is a single transistor after the output of the
LM710 because it can only drive a couple milliamps so it requires a
buffer to drive a 600 ohm load.

The LM710 is pretty picky about the supply voltages that it runs on.
Usually these will be +12 volts and -6 volts and it produces a TTL
compatible output at pin 7 of about 0 volts sinking 2 milliamps and
+3.2 volts sourcing up to 5 milliamps. I see a couple of diodes which
are probably zener diodes used to lower the +20 and -20 volt supplies
down to +12 and -6 volts.

All we really need to see is the circuit from pin 7 through that
transistor to the coaxial cable to figure out what is suppose to be
happening. A close up photograph of the front and back of that area
of the board should be enough to figure it out.

It may be that what you are observing is normal. You might try
measuring the output with a 470, 560, or 680 ohm resistor between the
signal and ground.

Re: SG502 Schematic, Component Layout

 

That part number (388-2756-00) is more likely having to do with a switch
> or the push rod

As far as I know 388 numbers are the raw boards without components which will become 670 numbers
after being populated with components.

More and more it is looking to me like Jeff's unit may be an engineering
lab or pilot run unit
You are probably right. I haven't either found any info on anything looking like his board.
Last revision of the board was 670-2215-04. To replace an old board Parts Replacement kit
050-1129-04 was required.

/Håkan

Re: SG502 Schematic, Component Layout

 

Dave,
The S/N is B050415.
The number etched on the PCB at about 0.1" is a bit taller than most but otherwise looks exactly like PN's on many modules, except it's right underneath the push rod and therefore not seen when casually looking at the PCB.

Raymond

Re: Chinese Cleaning Goo

 

`That happens. Windex contains ammonia which can dissolve paint markings. Use just plain rubbing alcohol for cleaning to avoid this problem.

Re: Chinese Cleaning Goo

Jerry
 

I used just a little windex once on the lettering on the buttons on a 7603 and the lettering washed right off. Real bummer.

Re: SG502 Schematic, Component Layout

Jeff Davis
 

Very different, indeed. I'm not even able to correlate parts with the schematic. For example, I'm looking for the square wave current source transistor, Q235, by searching for its 3 bias resistors, a 1K, a 3K, and a 510 ohm. I can't find a 510 ohm or a 3K ohm anywhere on the board.

All this, plus the hand-made cutout makes me wonder if this might be a prototype or some other kind of lab curiosity that somehow escaped into the world.

Re: SG502 Schematic, Component Layout

ArtekManuals
 

Raymond

What is the serial number of your unit?

That part number (388-2756-00) is more likely having to do with a switch
or the push rod

In the case of the SG502 the board part number is typically 670-2215-00
per the manual from serial B010100 up through at B073749 . The board
was updated to 670-2215-01 at serial B073750 . Change sheets relative
to serial B073750 and above are dated 1-19-79. There were NO IC
additions at the time of that change.

More and more it is looking to me like Jeff's unit may be an engineering
lab or pilot run unit, but the date code on the one IC from 1976 is
contradictory since the unit was released in about 1972 ( going by the
manual) although that IC could have been replaced at a later date? Seems
unlikely that a later production after 1979 would have IC's with date
codes dating back to 1974. Something really odd going on here

Dave
manuals@...


On 7/26/2017 10:45 AM, @Raymond [TekScopes] wrote:

On my SG502, the PCB ID (388-2756-00) is etched underneath the push
rod of the X10 switch (top of five), near the switch body.

Raymond



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

Re: SG502 Schematic, Component Layout

 

My SG502 seems to have been made in early/mid '73. Yours seems to be much later. Its PCB layout is *very* different from mine.
I find it strange that the rectangular PCB cutout for the frequency gang-pot is crooked and so seems hand-made.

Raymond

Re: SG502 Schematic, Component Layout

 

On my SG502, the PCB ID (388-2756-00) is etched underneath the push rod of the X10 switch (top of five), near the switch body.

Raymond

Re: SG502 Schematic, Component Layout

Jeff Davis
 

I've uploaded photos of my mystery SG502 to Photos in the album SG502 Internals. Very odd that there are no part numbers marked on the board, nor serial numbers on the frame.

Barring a manual version appearing, looks like I'll need to do some trace bugging to see if I can reproduce at least the square wave output circuit schematic.

Re: Chinese Cleaning Goo

HBcubed
 

Just remember which controls do what on a Tek scope and what the labels
used to say when they’re gone after you spray them with ‘Goo” or cleaning
solvents and wipe them off … then you won’t be laughing

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: Wednesday, July 26, 2017 8:17 AM
To: TekScopes@...
Subject: Re: [TekScopes] Chinese Cleaning Goo





No water.

Never.

Treat it like a teenager - no water. Never. Ever...

Am 24.07.2017 um 16:38 schrieb 'Ron Simmons' rjsimmons@... [TekScopes]:
NEVER clean instrument panels /lettering with ANYTHING other than soap and
water ! Nuff said



-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: Monday, July 24, 2017 10:26 AM
To: TekScopes; Hp Agilent Equipment
Subject: [TekScopes] Chinese Cleaning Goo





Hi Folks,
I have been curious about the "cleaning gels" that I see many examples of
on e-bay and Amazon that one uses to clean gunk out of keyboards and
instruments. These are gel like "goo" that one places over the keyboard
and them peels off, and they supposedly pull dirt, dust and finger oil up
with them. In particular I would like to use some on an HP calculator and
other instruments I have.
Does anyone have any direct experience with these gels? Is there any
particular "brand" or vendor that is better than another, or to be
avoided?
I have read a bunch of reviews that indicate some of them leave a sticky
mess behind. What is their active mechanism? Do any of them have solvents
which can potentially damage an instrument panel?
Thanks for the advice,
Dan







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



------------------------------------
Posted by: "Ron Simmons" <rjsimmons@...>
------------------------------------


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

Yahoo Groups Links



--
Mit freundlichen Gruessen---best regards----cordialement

Dipl.-Ing. Jan Philipp Wuesten (Telefon direkt: 04882-6054551)

Frag'Jan zuerst - Ask Jan First GmbH & Co. KG
Preiler Ring 10 ; D- 25774 Lehe, Germany
Phone: +49-(0)4882-6054551 Fax : +49-(0)4882-6054552
<http://www.die-wuestens.de> (Deutsch, English, Francais)
mail to <FJZ@...> or <FJZ@...>
HR A4788 PI, Vertretung: Wüsten Verw.GmbH, HR B 6295 PI
Registergericht Pinneberg. GF: Jan Wüsten; UStID: DE814610403
**************************************************
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Re: Chinese Cleaning Goo

Jan Wuesten
 

No water.

Never.

Treat it like a teenager - no water. Never. Ever...



Am 24.07.2017 um 16:38 schrieb 'Ron Simmons' rjsimmons@... [TekScopes]:

NEVER clean instrument panels /lettering with ANYTHING other than soap and
water ! Nuff said
-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...]
Sent: Monday, July 24, 2017 10:26 AM
To: TekScopes; Hp Agilent Equipment
Subject: [TekScopes] Chinese Cleaning Goo
Hi Folks,
I have been curious about the "cleaning gels" that I see many examples of
on e-bay and Amazon that one uses to clean gunk out of keyboards and
instruments. These are gel like "goo" that one places over the keyboard
and them peels off, and they supposedly pull dirt, dust and finger oil up
with them. In particular I would like to use some on an HP calculator and
other instruments I have.
Does anyone have any direct experience with these gels? Is there any
particular "brand" or vendor that is better than another, or to be avoided?
I have read a bunch of reviews that indicate some of them leave a sticky
mess behind. What is their active mechanism? Do any of them have solvents
which can potentially damage an instrument panel?
Thanks for the advice,
Dan
------------------------------------
Posted by: "Ron Simmons" <rjsimmons@...>
------------------------------------
------------------------------------
Yahoo Groups Links
--
Mit freundlichen Gruessen---best regards----cordialement

Dipl.-Ing. Jan Philipp Wuesten (Telefon direkt: 04882-6054551)

Frag'Jan zuerst - Ask Jan First GmbH & Co. KG
Preiler Ring 10 ; D- 25774 Lehe, Germany
Phone: +49-(0)4882-6054551 Fax : +49-(0)4882-6054552
<http://www.die-wuestens.de> (Deutsch, English, Francais)
mail to <FJZ@...> or <FJZ@...>
HR A4788 PI, Vertretung: Wüsten Verw.GmbH, HR B 6295 PI
Registergericht Pinneberg. GF: Jan Wüsten; UStID: DE814610403
**************************************************
Aktuelle Info: Abonnieren Sie unseren Newsletter
Stay updated: Subscribe to our newsletter:
Restez en ligne: Abonnez-vous à notre courriel d'information:

Info: <http://www.wuesten.net/news.htm>
**************************************************

Re: SG502 Schematic, Component Layout

ArtekManuals
 

Dave
I have both the 070-1430-00 (Rev B board) and 070-1430-01 (Rev C
board) manuals and the board layout Rev B & C appear to be very close
if not nearly identical. Neither layout looks like the photos you sent
me . Doesn't appear that the earlier -00 manual I have will help you. It
is possible that there is an even earlier printing of the -00 manual I
suppose with a rev "O" or "A" board. My -00 manual suggests a October
1972 printing (front cover 1072 date)

There is only one IC, U320 on both REV B & C layouts, your photos show
3 IC's (2 DIPS and one 8 pin TO-5) The date codes on your IC's range
from 7436 (36 week of 1974) to 7629 (29th week of 1976) . Assuming no
repair work was done these date codes would suggest the unit was
manufactured after July 1976 . It is not unusual back in those days for
some parts to have been in the warehouse for some time before actual
assembly occurred so the later date code is usually the close indicator
of assembly date . The copyright 1971 is a red herring to some degree as
that is likely the date the artwork was started during the design phase.

You should upload your photos to the "photo" section of the group for
all to see

Sorry I cant be of more help

Dave
NR1DX
manuals@...

On 7/25/2017 11:07 PM, n0dyjeff@... [TekScopes] wrote:

Thanks David and Dave for the responses (and reassurance that I'm not
off topic). I looked for identifying markings on the board and the
chassis, with little success. The only numbers anywhere are the
copyright date (1971) and "R0039E" on the upper right side of the
board. Other than the front panel graphics, nothing identifying the
unit on the chassis either.

I've never learned to read component date codes, so that will take a
bit of research before I can report back.


I'll also have to do some reverse engineering in order to identify
Q235, as the area around the coaxial jack looks different than the
component layout drawing. In particular, there's a TO-style can device
with 8 leads that I don't see anywhere on the layout.









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

Re: SG502 Schematic, Component Layout

Jeff Davis
 

Thanks David and Dave for the responses (and reassurance that I'm not off topic). I looked for identifying markings on the board and the chassis, with little success. The only numbers anywhere are the copyright date (1971) and "R0039E" on the upper right side of the board. Other than the front panel graphics, nothing identifying the unit on the chassis either.

I've never learned to read component date codes, so that will take a bit of research before I can report back.


I'll also have to do some reverse engineering in order to identify Q235, as the area around the coaxial jack looks different than the component layout drawing. In particular, there's a TO-style can device with 8 leads that I don't see anywhere on the layout.

Re: tekcats software for an 11301

Jerry
 

Ignore my comments about the negative voltages as I was measuring them in the wrong place. I would assume they are correct at this point since the various front panel controls work.

Pressing EA at this point gives me a main amplifier failure so I am going to progress thru the checks and adjustments listed in the manual that support diagnosing that failure.


I also found a section where they suggest you pull the battery, short the pins for 5 seconds and re-install the battery. This seems to have corrected my issue with the scope init bringing up a blank screen.


Thanks


Jerry

Re: tekcats software for an 11301

Jerry
 

Here's where I am after getting the software running:

Scopes perceived issue is that the trace is fat. I can't tell if this is a CRT issue, sweep or triggering. I've been thinking it is a CRT problem as at one time I was able to get a pretty decent trace of a 1Mhz signal by varying the main trace brightness as I changed the horizontal timebase. Basically, as I changed the horizontal timebase to a higher time period (e.g. 1 sec is higher than 50us) the trace would get fuzzy as more complete cycles were on the display.


Overall, the character display and registration is decent. It's just the signal trace that is off.


Using the software, I have proceeded to check some functions:


0) Whenever the scope initializes, the display goes blank and I have to reset the brightness with the front panel control. This is why I was thinking the EPROM or the EPROM based constants were hosed.


1) So I backed up the constants and loaded them back in after setting the switches as in the manual. This seemed to work but had no impact on the issue at hand. I was really just testing to see if the EPROM was functioning and if there was a checksum that would have failed, etc.


2) I tried loading the default constant file. Again, no impact on either the signal trace width or the brightness issue after a scope initialization.


3) I tried setting the brightness using the menus. Generally, it presents a dot or trace and asks if it is dim or bright in two levels or O.K. In all cases I can't see the dot, line, etc without spinning the front panel control brighter.


4) I tried some of the autocal and other tests in the software without luck. The enhanced accuracy fails unless I bring the brightness up with one of the controls on the scope logic board.


5) I checked the voltages again on connector P91. Some of these should be down around -1,900V and they are sitting at zero. This is confusing as one of the deep negative voltages should vary from -1,100V to -1,900V depending on the setting of the astig Front Panel control and it is sitting around zero even though the astig control seems to work. Having typed all this I am now wondering of they used a coma for a period and maybe the voltage is -1.9V opposed to -1,900. They are all supposed to be referenced to ground and I tried many of the labeled ground lugs with the same results.


5) One test sets the horizontal registration and width using pots 183 and 183. That test was right on the money which I find interesting given the issue I have with the beam thickness but that does use a stored waveform. Having typed this I am going to store a waveform and see if the issue disappears which will ppoint me to triggering opposed to basic CRT voltages.


Though I have the software running I am not having much luck using it to diagnose the issue. I will keep reading and plugging along as I don't have much money invested in it other than the $12 manual from Artek and the fact I dropped my Surface Pro 3 on the cement floor when I was reading the manual. So I would like to see it run after wasting $1,800 of the Surface.


Thanks for the help. There has to be someone on here that worked on the 11000 series!'


Jerry

Re: SG502 Schematic, Component Layout

 

On 25 Jul 2017 18:19:27 +0000, you wrote:

I apologize for the somewhat off topic question, but this group seems to be the nexus of Tektronix knowledge in general, not just oscilloscopes. I'm attempting to troubleshoot the square wave output of an SG502 sine wave generator plug in, but I'm having trouble correlating the schematic and board component layout from the manuals I have with what's actually in front of me on the board.
Discussion of the SG502 and other non-oscilloscope Tektronix
instruments is not off topic at all.

I have two copies of the manual, and in both, the component layout is Rev C, Nov 1976 and the schematic is Rev D, Nov 1976. The most obvious disconnect is that on the physical board I see two ICs in the lower left corner of the board, while the layout shows only one - plus lots of other differences in the details. Another disconnect is that the physical board has a 600 ohm, 1% resistor in series with the square wave output, while the schematics show it as parallelled to ground.
That is the service manual and schematic that I have also.

The date on the circuit board is around 1971 or so (don't have the board handy to look at as I write this). No serial number that I can find anywhere on the unit itself.
That is odd. There should be a serial number somewhere on the frame
either as part of a sticker or written on the aluminum.

Instead of looking at the date on the circuit board, what is the
circuit board's Tektronix part number and what are the date codes on
the components?

Now, I don't REALLY need the square wave output to work. But my OCD is driving me to fix it anyway. Would sure appreciate anyone who might have another version of the schematic / component layout or some ideas of how I might proceed.

By the way, the actual problem is that the high side of the square wave is rounded and exceeds the 5v open circuit value by a volt or two. Perhaps a bad diode? Would be a lot easier to troubleshoot if I had confidence that the schematic matched the circuit board...
Unless there was a major change in the design, the 600 ohm resistor
should be going from the output to ground and the output should switch
between ground and +5 volts with a sharp and clean edge.

If the voltage is high, then the transistor current source and
switching is going to saturate causing rounding. It is not marked on
the schematic but make sure the voltage at the base of Q235 is +15
volts. Q235 provides the constant current of 8.6 milliamps which
across the 600 ohm output resistor produces +5 volts.

Re: Probe bandwidth

 

On Tue, 25 Jul 2017 04:01:53 +0000 (UTC), you wrote:

David, it makes a lot of sense that the measurement technique appropriate for low frequency work wouldn't apply to VHF and UHF.  I guess I had better think about what I'm trying to do, rather than just scooping up a high frequency probe with expectations of it allowing me to make 500 MHz measurements.
The precautions needed to measure signals that have significant high frequency content are not to be ignored.  For now, as I have said, I will use my current instrumentation until such time as I have a specific need.
Tektronix used to make coaxial t-adapters so that a probe could be
directly attached to a coaxial transmission line for measurement.
Probes with low input capacitance like low-z probes and active probes
work great to very high frequencies however they have a very limited
input voltage (power) range.

At high power, a directional coupler or coupling network can be used.
A coupling network is essentially a high power low-z probe which might
only be AC coupled.

I would love to have a VNA or at the very least an impedance bridge that goes to 30 MHz.  Actually I do have one but it's not simple to use and doesn't cover a wide impedance range, nor does it have good resolution in the range I need.
I have a spectrum analyzer with a tracking generator.  It hadn't previously occurred to me that, rather than a tracking generator, a noise generator would suffice.  Any comments on that?  Noise generators are available at low cost but I don't know what parameters are important.
Bob
Like Ed says, using a noise generator for scalar network analysis has
the least dynamic range. I suspect it is the alternative for when you
lack a tracking generator although some low frequency network
analyzers, dynamic signal analyzers or whatever they are called,
support it directly for reasons that I do not remember. EDN has an
article discussing the three methods, impulse, swept, and noise, which
can be used with an oscilloscope FFT but they also work with a
spectrum analyzer:

<http://www.edn.com/design/test-and-measurement/4441000/Measure-frequency-response-on-an-oscilloscope>

An oscilloscope which returns the phase results of its FFT can also do
vector analysis with a swept or impulse test signal.