Date   

Re: Digest Number 466

Tom Maguire <tmi@...>
 

Bill,

Try rotating the entire scope to upside down and back while viewing the trace.
It's rare but you can break the inner glass rods in the CRT causing one or more
deflection plates to become misaligned or short to the rest of the gun
structure. This happened on my 575.

Also check the deflection wires to see if the left side has disconnected itself
from the crt. This happened on my 2236.

Then look at the deflection signal (careful of the voltage) at the crt. You
could have a cooked driver like my 5111!

Tom Maguire
TMI Engineering

From: "Bill" <mbhcomp@attbi.com>
Subject: trace

I have a 475 i just got, when the trace is there on the left hand side
there's like a bright dot.When i put a sine wave through, the left hand side
is just a straight vertical line the rest of the wave is perfect.Any ideas
what's doing this would be greatly appreciated.


trace

Bill <mbhcomp@...>
 

I have a 475 i just got, when the trace is there on the left hand side
there's like a bright dot.When i put a sine wave through, the left hand side
is just a straight vertical line the rest of the wave is perfect.Any ideas
what's doing this would be greatly appreciated.

Bill


Re: 3S1 & 3T77 followup

Stan & Patricia Griffiths <w7ni@...>
 

I have not really looked that closely at a 3T77 to know but it would be good
to find this out and write it down somewhere. Could save a LOT of trouble
for someone in the future. This kind of stuff is NOT in the manual,
unfortunately. I think that in most, if not all, cases, the part of the
clip that goes over the top of the diode and holds it against the circuit
board is the grounded end. What I am not sure of is if all of the TD's in a
3T77 have the same end grounded. I look at the schematic should tell you
that. I also think that the "little disc" that you mentioned that is part
of the TD case is how to tell which side is cathode and which side is anode
for that type of TD. I would not really trust the printing on the diode to
tell me that since they could have easily been printed wrong. Not likely
that the diode would be installed wrong inside the case . . .

----- Original Message -----
From: "MJMan" <mjmann420@yahoo.com>
To: "Stan & Patricia Griffiths" <w7ni@easystreet.com>
Sent: Thursday, August 01, 2002 7:17 AM
Subject: Re: [TekScopes] 3S1 & 3T77 followup



--- Stan & Patricia Griffiths <w7ni@easystreet.com> wrote:
I would check each of the tunnel diodes on a curve tracer and make sure
none
of them are installed backwards. they are installed in clips and if
someone
was trouble shooting this 3T77 before you got to it, they could have
removed
the TD's to test them and put them in backwards . . .
Sounds like this will be a future project for now as I guess I'll need a
curve tracer to get any further with it (especially if any of these turn
out
to be bad.) Haven't done much with it other than testing the transistors
and
tubes and cleaning the switches. Just for the heck of it I pulled one of
these clipped diodes and on one side is a part number and a large
disc-shaped
base, the other side has no part number and a small indentation. From what
I
observed they all seem to be installed with the part number side down.

George


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File - Posting Rules

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probes

Bill <mbhcomp@...>
 

Can someone tell me what smt probe will work with a 475?And is there other
probes that will also work like hp etc.Thanks in advance for any help u may
give me.


Bill


7d20 - fail codes

spangledog2000 <wiseold@...>
 

Hello Gents,
I have just purchased a 7D20 digitizer plugin for the 7000
series which
is giving some self test errors on startup. I do not have a service
manual at
the moment and was hoping someone could shed some light on the
following error
codes.

The errors are

6451
6452
occasionally 6453

Any clues as to the source of these errors would be greatly
appreciated.

TIA

Cameron McCauley


original 585a manual for sale on eBay

Mike Allisette <mike.allisette@...>
 

Hi "Tek Fans", thanks for the bandwidth.

I have a few Tek things which I'm "disposing" of firstly here is a 585a
manual which I've just listed on eBay. I can ship worldwide at cost, but
remember like the scopes the manuals are heavy :-)

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&;item=1755525256

Worked for Tek in Guernsey (where I still live) for 10 years (1973-1983).

Regards

Mike Allisette (GU4EON) (Still use TERAC QSL cards for HAM radio!)

PS I've "washed" several scopes in my time as a field repair technician.

PPS If for sale items are a no-no would a list moderator please let me know.

Thanks again


Re: Tektronix museum

donlcramer@...
 

Interesting post, Stan!

I have a 7A26 on its way to me with serial number B256123. Initially, seeing
the B25 threw me though I've subsequently also come across a B21 serial
number. How far up did they go with 7A26 serial numbers? Any idea how long
it was in production?

Don


In a message dated 8/2/02 8:27:59 AM Pacific Daylight Time,
w7ni@easystreet.com writes:

The 7A26 went over 100,000 instruments and they had to start the last 4
digits over several times, but by the time they needed to do that, they had
already gone past B01 into B03 or B04 and it was not a problem with
duplicating any serial numbers....

...I can look and see what the serial number of the last documented change
was for each product type. This will be very close to the serial number of
the last instrument produced and should provide a very close estimate of
the total produced.


Re: 465 Channel 1 Volt/div Rotary Switch Flakiness

Steve <stever1k@...>
 

That is the same kind of eraser that I used and all I can say is that the scope remains working as of this writing, I have been running it none stop since I have received it and think that it had not been turned on in some time. It is has a very good bright display but I have no way of knowing what I should be doing to the unit to try and get it in as good a shape as I can.

I have read some posts that indicate that I should go through the power supply and check/replace all the electrolytics but have not done that. I wonder if I should?

What I would like to determine is the degree of difficulty in replacing the lams that illuminates the clear plastic dial that is behind the volt/div rotary switch. Mine has burned out and from looking at the assembly it appears to be a big task to get at it. And I have no idea where to get a replacement for the burned out lamp and much less what kind it is?

Has anyone done this procedure before?

Steve

----- Original Message -----
From: Michael Dunn
To: TekScopes@yahoogroups.com
Sent: Thursday, August 01, 2002 8:24 PM
Subject: Re: [TekScopes] Re: 465 Channel 1 Volt/div Rotary Switch Flakiness


At 5:19 PM -0700 2002/8/1, Miroslav Pokorni wrote:
>Now that you used 'soft eraser' to 'fix' your contacts, try to find a
>solvent that would clean the glue left behind eraser when that glue becomes
>hard and prevents contact. The Pink Pearl is something that temporarily
>fixes contacts and leaves a residue that makes life very difficult when
>problem comes back.

I've only ever used the good Staedtler white art erasers. And of
course, make sure you brush off any remaining bits. They seem to
work well. I'd never use a pink one. They're terrible, for
electronics AND erasing!


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contact cleaning

Richard W. Solomon <w1ksz@...>
 

I should mention that De-Oxit does a great job of cleaning contacts, pots,
etc.
I saw it at Radio Shack.

Regards,
Dick, W1KSZ

-----Original Message-----
From: arthurok_2000 [mailto:arthurok_2000@yahoo.com]
Sent: Friday, August 02, 2002 12:58 AM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] contact cleaning


use a piece of white bond typing paper wetted wuth some
type of mild solvent "freon tf, rubbing alcohol, lighter
fluid etc just dont anything that might melt plastic
leared this trick from an old ibm field engineer "they
used a punch card and freon solvent"
anyone have a replacement sweep timing cam assembly
and board or just some contacts for a 465 that was
butchered up ??? "i need a manual too but have a 475
manual its a high serial number 465 "not a b"


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Contact cleaning, general

Tom Maguire <tmi@...>
 

Please throw out the erasers!!!!

They are only good if you are getting paid by the hour or in unusual
circumstances where you are going to dry burnish a gold contact that you intend
to vigorously clean and lubricate afterward.

Personally, I use Cramolin Red and wooden toothpicks instead. Break the
toothpick to form a scraper and work the Cramolin into the oxide. Bond paper is
also very good as someone else mentioned, but you must be careful of scraps.

Then wash the contacts with 99% isopropyl alcohol, MS-230, Tun-O-Wash or similar
solvent but test on plastics close by first. Repeat cleaning and rinsing until
the contacts are bright. DO NOT WORK THEM DRY OR WITH ONLY SOLVENT PRESENT.

Add a small amount of clean Cramolin to the cleaned contact to protect and
lubricate it. You can thin the Cramolin with solvent to get the right amount on
the contact.

Tom Maguire
TMI Engineering


contact cleaning

arthurok_2000 <arthurok_2000@...>
 

use a piece of white bond typing paper wetted wuth some
type of mild solvent "freon tf, rubbing alcohol, lighter
fluid etc just dont anything that might melt plastic
leared this trick from an old ibm field engineer "they
used a punch card and freon solvent"
anyone have a replacement sweep timing cam assembly
and board or just some contacts for a 465 that was
butchered up ??? "i need a manual too but have a 475
manual its a high serial number 465 "not a b"


Re: 465 Channel 1 Volt/div Rotary Switch Flakiness

Michael Dunn <mdunn@...>
 

At 5:19 PM -0700 2002/8/1, Miroslav Pokorni wrote:
Now that you used 'soft eraser' to 'fix' your contacts, try to find a
solvent that would clean the glue left behind eraser when that glue becomes
hard and prevents contact. The Pink Pearl is something that temporarily
fixes contacts and leaves a residue that makes life very difficult when
problem comes back.
I've only ever used the good Staedtler white art erasers. And of course, make sure you brush off any remaining bits. They seem to work well. I'd never use a pink one. They're terrible, for electronics AND erasing!


Re: Tunnel diode question

Stan & Patricia Griffiths <w7ni@...>
 

Hi Jay,

I did some interesting research in order the answer your question:

----- Original Message -----
From: "Jay Philippbar" <jayphil@cox.net>
To: <w7ni@easystreet.com>
Cc: "Stan Griffiths" <W7NI@teleport.com>
Sent: Saturday, July 27, 2002 9:10 PM
Subject: Tunnel diode question


Hello Stan,

I had purchased a few tunnel diodes from you a few years ago.

Now I have a Tek question for you. My associate and I both own a Tek
S-52 pulse generator plug-in head. They both failed recently and I am
guessing that the tunnel diode may be bad. I do have a service manual
and I will be troubleshooting these next week. Do you have access to
this special device? It looks like a pellet that screws into the rear
of the SMA connector along with a 48 ohms resistor. I could machine an
adapter to make the new diode fit properly, however I wasn't sure if
this was a higher current model that the 4.7 mA devices that you sell.
Here is the info I found out about the S52 Tunnel Diode. It is called CR69
and carries the Tek Part Number 153-0040-00 (or -01, depending on the S52
Serial Number). "153" part numbers are reserved for checked or matched
semiconductors.

It turns out that both the 153-0040-00 and 153-0040-01 are selected from
152-0383-01 and 152-0383-02, respectively, and installed in a holder, as you
have seen. The 152-0383-01 is selected from 152-0383-00 for switching time
of equal or less than 35 ps. The 152-0383-02 (for later serial numbers of
S52) is selected from 152-0383-00 for switching time equal to or less than
37 ps (probably because they had a hard time finding any that would make 35
ps . . . ) Unfortunately, I don't have a SINGLE one of any of those part
numbers in stock, nor do I have an S52 in my collection of 1250 Tek
instruments.

Here are the specs on the 152-0383-00:

Firing current = 50.75 mA plus/minus 5.75 mA (Yes, 50.75 mA is correct. I
think the 284 has a high current TD in it, too, but they are very rare . .
. )
Max Tr = 31 ps
Special case style

This part is used only in the S52 and S51 so there are not a lot of places
to find used ones. The last price I have on this part from Tek comes from a
1994 pricing document and (are you sitting down?) is $1581.00!

So, it appears once again, we have found a Tek part that was made from
"unobtainium". My only recommendation is to try Deane Kidd
dektyr@teleport.com
and Walter at http://www.sphere.bc.ca
or look for another S52 or S51 and pray that it works . . . !

Also, I do not know a source of new mating BSM connectors, but if you are
desparate (you may not be if you can't get your S52 going again . . . ) I
may have one somewhere in my massive "junque box", if only I had time to
look for it . . . Let me know . . . I can try . . . If you are desparate .
. . Maybe Deane or Walter has one . . .

Also, do you know where to find the mating BSM connector that is used on
those S-52's (it's the pulse out connector on the front)?

Many thanks,


Jay Philippbar
Technical Consultant
Electronic R & D
2006 Via Solona
San Clemente, CA 92673
(949) 366-1211 24 Hour order line, leave message
(949) 481-3313 11 AM - 11 PM, Lab BEST WAY
(714) 392-1427 Cellular
(949) 361-8110 Facsimile
OK, Jay. It was fun digging out this info even if it probably was bad news
for you. Sorry about that . . .

Stan
w7ni@easystreet.com


Re: Tektronix museum

Stan & Patricia Griffiths <w7ni@...>
 

Hi Miroslav,

I have not yet taken look at those museum pages, but I will. Thanks for the
info.

You are right about the numbers being too high on the scope numbers for
those models. I have asked Tektronix for quantity produced info before but
they never want to share that information with anyone. I guess they regard
it as "company confidential" or something. Even so, I have a pretty good
way to estimate the numbers right here. As you probably know, Tek starts
numbering at 101. For the very early instruments, it really was number 101,
and that is the actual number of the first production instrument. Later,
they added leading zeros and the first production instrument carried the
number "000101". Still later, for instruments built in Beaverton, the first
production instrument would carry the number "B010101" with the "B" meaning
Beaverton ("G" was for Guernsey, "H" was for Herenveen, and I think "070"
was for Tokyo.) In any case, they would increment the last four numbers.
In the "B01" series, if they made a major change in the instrument, they
would increment to "B02" but the last 4 digits remained in sync with "B01"
numbers. This would work fine until you got to 9999 instruments, which was
not often. (The CA got to over 70,000 instruments but they were not using
the "B01" type of serial numbers on the CA.) (The 7A26 went over 100,000
instruments and they had to start the last 4 digits over several times, but
by the time they needed to do that, they had already gone past B01 into B03
or B04 and it was not a problem with duplicating any serial numbers.

Well, you probably also know that Tek kept very good records on each and
every change that was made to the circuitry in each instrument as they
evolved. This was all documented in the "Modification Summary" of each
product, including the serial number of the exact time of the circuit
change. Since I have almost all of the Modification Summaries, I can look
and see what the serial number of the last documented change was for each
product type. This will be very close to the serial number of the last
instrument produced and should provide a very close estimate of the total
produced. So for the 7500 Series, got the following results:

7503 approximately 1100 produced
7504 approximately 1100 produced
7514 approximately 1100 produced
7704 approximately 2000 produced

I thought the rest of the guys might like to know this stuff, too, so I
copeid it and your message to me to the whole list. I hope you don't mind.

Stan
w7ni@easystreet.com

----- Original Message -----
From: "Miroslav Pokorni" <mpokorni2000@yahoo.com>
To: "Stan Griffiths" <w7ni@easystreet.com>
Sent: Monday, July 29, 2002 2:01 PM
Subject: Tektronix museum


Hello Stan,

Have you seen this museum, one of the two that lately I came across in
Germany: http://www.helo.de/helo/museum/tek/7000/7000.htm . One problem is
that I can not understand much of German.

I did not know about 7500 series. I did see 7B50 and wandered what they
were
for, now I can see.

The big surprise to me was production run: for each of tree scopes (7704,
7504 & 7514) the production is put to around 60K, that is an awfully large
number. What do you think, how real it is?

The other site: http://www.tekscope-museum.de/Credits/credits.html , is
full
of your name. Check it out, if you did not do it already.

Regards

Miroslav Pokorni


Re: 465 Channel 1 Volt/div Rotary Switch Flakiness

Miroslav Pokorni
 

Now that you used 'soft eraser' to 'fix' your contacts, try to find a
solvent that would clean the glue left behind eraser when that glue becomes
hard and prevents contact. The Pink Pearl is something that temporarily
fixes contacts and leaves a residue that makes life very difficult when
problem comes back.

The erasers were cures invented by 'board swappers' in computer industry. It
did solve their problem for that day, but caused lot of problems for anyone
coming to this machine afterwards; the softness of eraser was ratcheted up
and at times eraser for ink had to be used (some of them had fine ground
sand to increase hardness).

Regards

Miroslav Pokorni


Re: 465 Channel 1 Volt/div Rotary Switch Flakiness

stever1k <stever1k@...>
 

--- In TekScopes@y..., "stever1k" <stever1k@h...> wrote:
My 465 seems to work just fine except that the Ch1 input rotary
switch is flaky and it will distort the display a lot. Wiggling it
around will cure the problem but seems temporary. Ch2 switch is ok
and no problems.

Using the calibrator as an input I can get a nice looking waveform
although with some overshoot on Ch1 no problems and nice display
with no overshoot on Ch2 input.

When it goes wacky the display using the calibrator input has
diminshed amplitude and looks like all you see is the leading edge
and then a decay. Looks more pulse like. If I wiggle the switch a
lot it will come back and look normal.

Makes you think the switch is very dirty and clearly intermintent,
Is there any easy way to clean these things or am I just going to
have to find a replacement?

Hope you good scope guys can give me some advice.

steve

Well I have fixed the problem, on the circuit board where the input
stage is for the channel there is a cover and under that cover is
where my problem was. Seems there are two little pots (I think) on a
plug in module and when the module was wiggled it made a good
connection. I took the module out and cleaned the pins with a very
soft eraser to remove the oxidation and it fixed the problem.

The last remaining problem is the light that illuminate the various
ettings on the rotary switch is dead burned out. I hate to think
what it takes to replace them or even where to find them. How big a
job is to replace that lamp?? Where would I get one from..Not Radio
Shack I bet.

Steve


465 Channel 1 Volt/div Rotary Switch Flakiness

stever1k <stever1k@...>
 

My 465 seems to work just fine except that the Ch1 input rotary
switch is flaky and it will distort the display a lot. Wiggling it
around will cure the problem but seems temporary. Ch2 switch is ok
and no problems.

Using the calibrator as an input I can get a nice looking waveform
although with some overshoot on Ch1 no problems and nice display
with no overshoot on Ch2 input.

When it goes wacky the display using the calibrator input has
diminshed amplitude and looks like all you see is the leading edge
and then a decay. Looks more pulse like. If I wiggle the switch a
lot it will come back and look normal.

Makes you think the switch is very dirty and clearly intermintent,
Is there any easy way to clean these things or am I just going to
have to find a replacement?

Hope you good scope guys can give me some advice.

steve


Scope probes available....

luis torrealba <lt57ven@...>
 

I have 2 Lots (2 Probes each) of hardly used:

P6137 10X Passive probes, up to 400Mhz (with right
2400 Scope) Readout & ID for 2400 Series
Oscilloscopes.

Asking $250CND for both lots or $150CND each lot,
as always negotiable.

If you are interested, please contact me directly at:

lt57ven@yahoo.ca



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Re: new to me 535A Questions?

Dave Wise
 

From: amacbradley [mailto:macbradley@earthlink.net]

Hi Everyone, with particular thanks to those who sent or posted
answers. Thought I'd give an update and ask one more question.
The scope works great. The Type D had a wire broken on the vertical
position pot, I soldered it back on and it works/worked. I'm still
not sure it works right.
Get a manual for the same or later serial number. You'll never
figure out how to calibrate it on your own, due to the several
interacting balance adjustments inside.

The Type K works great! Nice sharp traces
some 40 years old.
That's a good simple amp, but I'm prejudiced in favor of
the L (which I have), which is a K plus a x10 AC booster
for those low-level signals.

Anyway, when I run a voltage from the CAL OUT to the input, the
screen shows a reduced voltage. Say for example 3 volts amplitude
(after probe x volts/cm etc) when the CAL OUT is delivering 5.2 volts
according to a digital voltmeter. And sometimes the waveform
has "slumped shoulders" on the leading edge of the waveform.
Any ideas?
Mac
Your procedure is open to interpretation. If you put a DMM
on the CAL OUT jack, you will not get the meter reading you
perhaps expected. The calibrator output is a square wave
where the negative peaks are 0 and the positive peaks are
the voltage on the knob, in other words, peak-to-peak,
which is perfect for calibrating a scope but not much
good for a meter. A meter will give various wrong readings,
depending on whether it is DC, VAC (averaging) or VAC (true-rms).
No meter that I know of reads peak-to-peak.

IIRC, you calibrate the calibrator by setting it to OFF and
reading DC V on an internal test point. You adjust an internal
tweak for exactly 100VDC. See the manual for the full info.

As for the slumped shoulders, you most likely haven't adjusted
your probe's compensation. The crudest form of probe is
a simple resistive voltage divider. As soon as you use it
at frequencies above a few kHz, you will find that the
scope's input capacitance drags down the response. In the
time domain, this translates to a rounded leading edge on
sharp waveforms. To compensate, all "real" probes contain
a small capacitor, so the resistive divider has a capacitive
voltage divider in parallel with it. If the capacitive divider
and the resistive divider have the same ratio, the probe will
convey all frequencies equally. Since different scope inputs
have different capacitances, the probe's capacitor is adjustable.
When you move the probe from scope to scope, you should always
check the compensation and adjust as needed.

Regards,
Dave Wise

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