Date   

Re: NVRAM back-up battery change on a 2715..... avoiding disasters

Chuck Harris
 

You are only trying to save the memory in the RAM
that is under the control of the DS1210.

In this instance, I would tack solder a wire onto
the same circuit as the + lead of the cell to be
changed, and ground. Trace the wiring to find a
good spot where you can solder.

I would then parallel a cell of the same type to
hold the power while you are working.

I wouldn't use a power supply, it adds too many
unintended consequences.

You can use a socket, but I wouldn't do that either,
as contacts in sockets can fail for just an instant,
losing your memory.

It will likely be 30 years before you need to do
this job again. Given that timeline, I would weigh
long term reliability more heavily than making a
very infrequent task easier.

-Chuck Harris

@mitrozz wrote:

In 2715 case there is a DS1210s controller chip instead of diodes. But is not so different from your assumption.
I think your procedure will work.
I'm afraid that applying 5V at the card common rail to supply the DS1210 all chips will draw something, sum could be amps, I don't know.
A small battey is enough?
What about if I use a checked "floating" power supply?

I would ask another opinion, this time on the new backup cell.
I read the DS1210 spec. (https://datasheets.maximintegrated.com/en/ds/DS1210.pdf) I can't find any problem to use a standard cylindrical Li-cell, connected with wires and holder, outside the circuit card.
In that way, next time, I can safely replace the battery just when the tek2715 is switched on.
Thank you again.


Re: NVRAM back-up battery change on a 2715..... avoiding disasters

Michele Trozzi
 

In 2715 case there is a DS1210s controller chip instead of diodes. But is not so different from your assumption.
I think your procedure will work.
I'm afraid that applying 5V at the card common rail to supply the DS1210 all chips will draw something, sum could be amps, I don't know.
A small battey is enough?
What about if I use a checked "floating" power supply?

I would ask another opinion, this time on the new backup cell.
I read the DS1210 spec. (https://datasheets.maximintegrated.com/en/ds/DS1210.pdf) I can't find any problem to use a standard cylindrical Li-cell, connected with wires and holder, outside the circuit card.
In that way, next time, I can safely replace the battery just when the tek2715 is switched on.
Thank you again.


Re: human element

oliver johnson
 

John are you shipping , i am intrested on a 7104 crt , but if reasonable enough i would like a complete unit.
On Thu, Nov 7, 2019 at 1:24 PM, John Griessen<@jgriessen> wrote: On 11/7/19 11:38 AM, Nenad Filipovic wrote:
> I live on the other side of the globe
So, where *DO* you live, Nenad?

--
John in Texas (moving to New Mexico soon)
R7844, 7603's, 7904A, 7104's, R7903, 7854, 2230
RM564, RM561B, 321A, 310


Re: 7000 still hard to beat

Jean-Paul
 

Bonjour à tous,

Réminiscence.......my first TEK was at Federal Scientific in 1968, 545 and the just released 453 I think.

Today 51 YEARS later, the lab has 7104, 7904A and 7603. The 7603 is dedicated to Spectrum Analyzers 7L5 5 MHZ or 7L12 1200 MHz. 7904 500 MHz is the workhorse and I accumulated about 50 plug-ins including some very rare ones.

The 7104 1 ghz with MCP CRT is reserved for fast rise wideband work, a heavy and somewhat loud beast, with limited CRT life and beam current time-out. It has the required 7A29 verticals and 7B10, 15 timebases.

In 2014, I wrote a SMPTE Paper ( in the proceedings) on digital audio transmission problems, standards and solutions. I included photos of 7000 scopes on the bench with the broadcast processor. The photos were appreciated by the old timers. The 7A 22 etc was essential for differential measurement of balanced AES/EBU signals.

I have several 2465/7/B, which are fine for general use and portability. Still, the vast array of plug-ins makes the 7000 series outstanding for specialized or difficult measurements.

I just marvel at the fine engineering, functionality and longevity of these decades old machines! A real pleasure to use. Just the ramblings of an old retired EE.

Vive Tektronix !
Jon In Paris


Re: NVRAM back-up battery change on a 2715..... avoiding disasters

Chuck Harris
 

Every external battery backup is just about the same. The battery will have
a diode connected to allow current to flow from the battery, but not into
the battery. At the same point, +5V will have a diode set to allow current
to flow into the RAM that is being backed up, but not into the battery.

+5V--------->|-------o---------RAM VCC
.....................|.........
+Lithium---->|-------+.........

First, I remove the board from the unit, and set it on an insulated (wood)
bench.

Next, I clip lead, using good clips that won't come off accidentally,
a 3.6V lithium cell, like a tadrian backup cell, to the cathode of the +5V
rectifier, and ground. I don't use a power supply, because I don't want to
think about my grounded soldering iron tip, and grounded desoldering iron
tip shorting out the supply... killing memory.

I then unsolder the old lithium cell, and solder in a new cell. Remove the
clips, and you are done.

-Chuck Harris

@mitrozz wrote:

This is Michele from Italy. I' am a Tek lover too, I have two scopes a 465B and an old monster 556.

Recently I added a S.A. 2715 to renew the ancient HP8558/182T. Now I am in auto-training phase, playing and reading the manuals.

I would ask your help to understand the best way to make sure I have no risk that all normalizing parameter in the NVRAM will not get lost. I don't know the residual life of the backup battery (BT1) located in A11-Digital options board, so my intention is to change it asap.

*1st question : If I change the soldered backup battery NVRAM will remain without power supply for several minutes. In the mean time data will be lost. There is any trick to avoid this situation?
*2nd question : To upload normalizing settings I understood it is necessary a PC service application communicating via RS232. There is any other way to do this work? Data can be displayed on crt screen but is not clear if is possible to simply rewrite manually in same menu.

I have an idea on how to do this work, but probably someone here is more experienced than me and I will wait your answers.
Thanks in advance for your attention.


NVRAM back-up battery change on a 2715..... avoiding disasters

Michele Trozzi
 

This is Michele from Italy. I' am a Tek lover too, I have two scopes a 465B and an old monster 556.

Recently I added a S.A. 2715 to renew the ancient HP8558/182T. Now I am in auto-training phase, playing and reading the manuals.

I would ask your help to understand the best way to make sure I have no risk that all normalizing parameter in the NVRAM will not get lost. I don't know the residual life of the backup battery (BT1) located in A11-Digital options board, so my intention is to change it asap.

*1st question : If I change the soldered backup battery NVRAM will remain without power supply for several minutes. In the mean time data will be lost. There is any trick to avoid this situation?
*2nd question : To upload normalizing settings I understood it is necessary a PC service application communicating via RS232. There is any other way to do this work? Data can be displayed on crt screen but is not clear if is possible to simply rewrite manually in same menu.

I have an idea on how to do this work, but probably someone here is more experienced than me and I will wait your answers.
Thanks in advance for your attention.


Re: Knob repair tips

n4buq
 

If the knob is bored so that the insert is a snug, slightly friction fit when dry, the alignment is natural and the epoxy holds it tightly.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "John Griessen" <@jgriessen>
To: TekScopes@groups.io
Sent: Thursday, November 7, 2019 2:11:09 PM
Subject: Re: [TekScopes] Knob repair tips

On 11/7/19 1:36 PM, n4buq wrote:
I really like Chuck's method, though, as it locks the knurled hub very
nicely
Sure the hub is made for that hot plastic... and if you cool it quick and
hold
with rubber, and it is with its original plastic, just cracked, it is likely
to stay aligned.

If you turn down the hub and leave clearance, how to keep it aligned?


Re: Knob repair tips

John Griessen
 

On 11/7/19 1:36 PM, n4buq wrote:
I really like Chuck's method, though, as it locks the knurled hub very nicely
Sure the hub is made for that hot plastic... and if you cool it quick and hold
with rubber, and it is with its original plastic, just cracked, it is likely to stay aligned.

If you turn down the hub and leave clearance, how to keep it aligned?


Re: Knob repair tips

n4buq
 

I've done similar by glueing the plast parts together and boring the hole slightly larger. I really like Chuck's method, though, as it locks the knurled hub very nicely (at least I presume it would - haven't tried it yet).

Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Dave Brown" <davebr@...>
To: TekScopes@groups.io
Sent: Thursday, November 7, 2019 1:26:47 PM
Subject: Re: [TekScopes] Knob repair tips

I turn the diameter of the metal hub down just enough so it fits within the
remnants of the knob. They I use epoxy and glue it all together. I only have
examples of gears on the vintageTEK website but it works equally well with
knobs.
https://vintagetek.org/repairing-knobs/

Dave




Re: TDS3044B repair

David Kuhn
 

https://www.youtube.com/watch?time_continue=261&v=iVU0YPIeovM

http://lcdparts.net/UBDetail.aspx?ProductID=3796

Looks like a perfect solution for the NEC on the TDS3000 series and in the
NEC 65BLM05 Display (virtually the same display as the one TEK uses) in the
instruments I do a lot of work on.

Unlike the video, I would not remove the paper exposing the glue when
installing the strips. I don't want those LED strips permanently in my
LCDs in case they fail.

Dave

On Wed, Nov 6, 2019 at 11:40 PM Harvey White <madyn@...> wrote:

If you have some familiarity with LCD displays, or CRT displays with
separate drive, then *if* the signals are good, you should be able to
recognize them. If they're bad, however, well.... Let alone which test
point is what......

Harvey


On 11/6/2019 10:08 PM, Tom B wrote:
Hello All,

I am just catching up on this thread.

There is a youtube video on replacing the CCFLs with LEDs here
https://www.youtube.com/watch?v=iVU0YPIeovM

The part number for the TDS3000 (no letter) display is listed in the
service manual as an NEC NL6448AC20–06. These displays are available
on ebay and other places for about $60US. I think the part number
for the B model is NL6448BC20-08, but I am not 100% sure of that.
These displays are running about $80-$100US. The only difference I can
find in the in the datasheets between NL6448AC20–06 and the
NL6448BC20-08 is that the -08 model has higher luminance.

Can anyone verify the part number on the TDS3000B display?

I will check for the for the signals that Harvey mentioned when I have
time. The pins that go to the display are really hard to get to
because of the way this thing is built. There are the test points on
the main board, but the service manual makes no mention of what they
are for.

Tom Bryan
N3AJA


On 11/6/2019 10:58 AM, Harvey White wrote:
This is the first item that came up when searching for CCFL LED
replacements

https://urldefense.com/v3/__https://www.ccflwarehouse.com/__;!b9GWhakWANQ!1VZO1N_UzGPrK5tvZk-sSIE3W2ulp1zapXqXmDScqYhd9jWmbO6SGjvZhNdA$

no idea if they have anything that will fit.

I have made CCFL replacement strips for some odd displays, the older
Optrex DSTN color displays and the FG0800 8 inch VGA display.

Due to the lack of 12 volts in a battery operated project, all of
them are designed to run the LEDS in parallel, at about 15 ma per
led, about 9 per 4 inch strip. The strips are designed to be
stacked, resulting in parallel operation.

Whether or not the lamps can be reasonably replaced depends on the
manufacturer. In the Optrex displays, remove a screw, swing a shield
aside, and pull out the tube. In the FG0800, it's more involved (and
takes 4 strips), even more if you wanted the side. The silly tube is
a top, left, and bottom assembly.

The replacement should be made to run off the (suspect 12 volts)
supply, and a simple PWM would easily replace the inverter. I'm sure
it varies wildly.

I know there's a market out there, and the more common the display,
perhaps the easier it is to find the LED replacement, or even the
tube itself (which I'd recommend unless you want to go LED).

I went LED because the power consumption in battery operated
equipment goes down by 50 to 75%, and I'm not happy with 1600 volts
running around an experimental setup.

So give these people a try, they seem to be going laptop, so no idea
what else they do.


You might also want to look here:

https://urldefense.com/v3/__https://www.plazmo.com/collections/raw-ccfl-lamps/products/ccfl-backlight-for-tds3000-oscilloscope__;!b9GWhakWANQ!1VZO1N_UzGPrK5tvZk-sSIE3W2ulp1zapXqXmDScqYhd9jWmbO6SGtNxwsuf$

10 dollars.

Harvey


On 11/6/2019 10:03 AM, David Kuhn wrote:
" there are commercially
available LED backlight kits to replace the CCFL lamps. "

I would be in your dept if you could point me to an LED replacement
for the
fluorescent tubes in the NEC displays like that are used in the TDS3000
series (no bloody A, No bloody B or C). I'll get the actual NEC LCD
part
number and reply again later. I wonder if the LED replacement is
made to
run off the fluorescent tube inverter supply? I ask that because that
supply has software control line to control the brightness. LET is
probably off or on, unless it is designed to run off the inverter or a
software equivalent inverter is available (retrofitting old
equipment not
designing new stuff).

dave

On Tue, Nov 5, 2019 at 2:31 PM Harvey White <madyn@...>
wrote:

On 11/5/2019 1:59 PM, David Kuhn wrote:
Sorry for the response delay.

I am in Lewistown, PA. How cheap are the displays and where are you
finding them? I have found the ones, used in the Ultrasonic
instruments
I
mentioned, on Alliexpress, and EBAY (haven't ordered any from either
one),
but I can not find the backlight tubes, which I find is usually the
problem
with the displays. The displays may be just slightly different
than in
the
TDS3032, but if so, only mechanically. The connectors are the
same, and
I
really think the part numbers are the same. It's not a real easy
replacement in those TDS scopes. It looks easy, but it's a pain
in the
butt.
Depending on the manufacturer of the display, there are commercially
available LED backlight kits to replace the CCFL lamps.
You may want to buy the TDS3GV on EBAY. I can't use a TDS3032
without
one,
but I have written a lot of service software in VBA and VB6 that
automatically sets up the scopes and gets data from them. I can also
project my TDS3032 to the 32" TV mounted on the wall above it (an
older
Sceptre with VGA input) and that's pretty cool.

Again, if the cables are seated well, I doubt the LCD is bad with an
all-white display. My thoughts are a main PCB issue. A TSD3GV could
prove
me wrong.
If you find an all white display, then depending on the type of
display
(positive or negative) you'd suspect no signals to it, or improper
signals.

The display is likely to take either 5 or 3.3 volts, recent ones
that I
have take 3.3. Older STN displays can take 5. The white is the
result
of the backlight working, but no active pixels at all (hence no
polarization, etc....).

Like a CRT display, you'll be looking for a horizontal sync (at
perhaps
30 Khz), vertical sync (say 60 or so Hz), a DE (likely at horizontal
rate and active high), and a pixel clock at about 25 or so Mhz. You'd
also expect supply voltages to be somewhere on the display. If the
timing is right and the voltages are there, then the display ought
to be
showing something. If not, then look at the other pins, they
should be
R,G,B digital signals, either in 565 (for a 16 bit panel) or 666
(for an
18 bit panel). If there's any activity on them, then with the right
sync signals, they ought to be giving something on the display.

Harvey



Dave

On Tue, Oct 29, 2019 at 10:55 PM Tom B <tbryan@...> wrote:

Hi Dave,

I tried the "B Trig" and nothing happened. Displays are fairly
cheap
but I don't want to buy one unless I have to.

Thank you for the offer. I would be a long while before I make
it up
that way.

What town are you in?

Tom

On 10/29/2019 4:52 PM, David Kuhn wrote:
I'm in central, PA, about 3 hours from you if you ever want to
come up
and
try it here with one of my VGA/GPIB modules.

Before that. Power it up while holding in the "B TRIG" button
(might
be
different on the TDS3014), which on my TDS3032's causes a
RESET. I've
had
that fix display issues after replacing the battery NVRAM in in the
scope.
The display in the TDS3032, is the exact same LCD used in the GEIT
Phasor
XS and USN60 instruments. I have worked on many. I have never
seen
the
LCD fail on those instrument where it's all white. Typical, if not
broken,
is smeary displays that lines seems to go out of sync. Dim, of
course
with
broken backlight tubes.

Dave

On Mon, Oct 28, 2019 at 10:50 PM Tom B <tbryan@...> wrote:

Hi Rich (?),

Thanks. I am located in Maryland near Washington DC.

If anyone in the Washington DC area has a TDS3GV that I could come
over
and quickly test my scope with, I would appreciate it.

Tom Bryan
N3AJA


On 10/28/2019 10:29 AM, Oz-in-DFW wrote:
I'd still remove and reseat both ends.

Where are you in the world? I have a VGA/serial/GPIB card in
my 3014
that we might be able to mate with your scope briefly.














Re: Knob repair tips

Dave Brown
 

I turn the diameter of the metal hub down just enough so it fits within the remnants of the knob. They I use epoxy and glue it all together. I only have examples of gears on the vintageTEK website but it works equally well with knobs.
https://vintagetek.org/repairing-knobs/

Dave


human element

John Griessen
 

On 11/7/19 11:38 AM, Nenad Filipovic wrote:
I live on the other side of the globe
So, where *DO* you live, Nenad?

--
John in Texas (moving to New Mexico soon)
R7844, 7603's, 7904A, 7104's, R7903, 7854, 2230
RM564, RM561B, 321A, 310


Re: Upgrading a TDS3BAT

Miguel Work
 

Mine is working with lithium, I have some notes.

Here you can find some information:

https://www.eevblog.com/forum/testgear/tek-ths720a-portable-scope-teardowndiscussion/

Regards

-----Mensaje original-----
De: TekScopes@groups.io [mailto:TekScopes@groups.io] En nombre de Magic_Smoke
Enviado el: jueves, 7 de noviembre de 2019 15:51
Para: TekScopes@groups.io
Asunto: [TekScopes] Upgrading a TDS3BAT

Hello all,

I picked up a tired TDS3BAT (NiCd chemistry, probably containing a failed cell or two) and I was pondering my options for rehabilitation. I will admit I have not even taken the thing apart yet, but in the modern era of batteries we find ourselves I cannot help but think of rewiring it to use lithium cells instead. Does anyone have experience or documentation for these units, and if such a change is practical? I imagine the charging circuit would need replacing, depending on how much of the work happens on the battery side vs. the scope side I am hoping dropping in a dedicated lithium charger will do the trick. Has anyone actually tried this, though? Any pitfalls? Thanks!


Re: I personally don’t think Craig should quit

Nenad Filipovic
 

I live on the other side of the globe and never met any of you, but I
highly appreciate the personal, human element in this group's discussions.
That's what makes friends, and friendship is better than this.
I hope no one quits the group just because we're all - humans.

Nenad.


Re: Tektronix Spectrum Analyzers

Roy Thistle
 

On Mon, Nov 4, 2019 at 11:52 PM, Dennis Tillman W7PF wrote:


One of the experts on the 490 series is our own John Miles who has written
quite a lot of software for various instruments which you can download from
his web site at
http://www.ke5fx.com/gpib/readme.htm
One might also try the following link, for some interesting and well written service notes on 49x SA
http://www.ke5fx.com/49x_notes.pdf
Roy


Re: Upgrading a TDS3BAT

Magic_Smoke
 

Perhaps I should add the goals I have for this project, starting from the highest priority:
1. Not burning down my house
2. Not killing my scope
3. Proper charge readout on the scope
4.Charging while in the scope, but external-only charging is perfectly suitable (and probably safer)

As long as at least the first two goals are met, I am open to suggestions!


Upgrading a TDS3BAT

Magic_Smoke
 

Hello all,

I picked up a tired TDS3BAT (NiCd chemistry, probably containing a failed cell or two) and I was pondering my options for rehabilitation. I will admit I have not even taken the thing apart yet, but in the modern era of batteries we find ourselves I cannot help but think of rewiring it to use lithium cells instead. Does anyone have experience or documentation for these units, and if such a change is practical? I imagine the charging circuit would need replacing, depending on how much of the work happens on the battery side vs. the scope side I am hoping dropping in a dedicated lithium charger will do the trick. Has anyone actually tried this, though? Any pitfalls? Thanks!


Re: A few pics from a new-to-me exhibit in the National Museum of Nuclear Science and History

Daniel Koller
 

I'm no nuclear science history expert, but wrt the original post,  that 535 seems out of place.  The criticality experiments were generally carried out in the 1940's and the 5 series was not available till the 1950's.  Afterall, by 1945 they knew what it took to make a pile of uranium go off.
But in the 1950's the techniques of Nuclear spectroscopy were being developed and that scope would have been at home reading the pulse outputs of scintilation counters.  I used such scopes in Columbia University's undergraduate physics labs in the 1980's for just such pulse counting.   they had not updated the labs in 30 years (!!) so it was very much like working in the 1950s
Someone correct me if I am wrong in my time estimates.
Dan

On Wednesday, November 6, 2019, 10:02:59 PM EST, <sdturne@q.com> wrote:

On Sat, Nov  2, 2019 at 01:10 AM, battyhugh wrote:


If you are in Minneapolis - on the S side of the bridge across the river on
the W side (if I remember correctly) - there is another relic - you have to
decend about 6 stories down - there are masses of HB spec analysers and a
rather large Van de Graffe generator - - very strange (I saw it in early 90's)
- A Dr Weiblen was working at that time on using high voltage pulses to bust
up moon rock. It would be rather interesting to document the remaining
residues of the 50's and 60's (on the marshes near Palo Alto is an old radio
transmission facility - might be interesting... but wait.. there's more!
Hmmm, is it an abandoned site or is someone taking care of it?


Re: I personally don’t think Craig should quit

Lawrance A. Schneider
 

I’m an old man. As a boy, I valued the knowledge base that they had acquired; I actively sought out elderly people for that reason. As an old man, I still value that knowledge base.

I hope you do not quit! As an old man, I understand the challenges age brings about. If you feel you cannot keep up, I understand.

Still, I hope you do not quit.

larry'


Re: Knob repair tips

Dave Voorhis
 

Excellent, thanks! That’s what I'd vaguely remembered.

On 7 Nov 2019, at 12:57, Chuck Harris <cfharris@...> wrote:

I wouldn't, as you really have to be gentle here.

Even the elastic bands, if too tight, will leave
a depression when the knob is in the molten state.

You want the bands stretched a bit, but not even
close to tight.

You should have some compressed air to cool the center
on hand, as the hub can retain heat a lot longer than
you might think. A water dunk would be ok, if the
set screw is removed afterwards, and the knob let to
dry thoroughly.

-Chuck Harris

Tim Phillips wrote:
from Tim P (UK)
................ or use an adjustable hose-clamp ('Jubilee clip') to hold
the bits onto the hub ?

Tim




On Thu, 7 Nov 2019 at 12:36, Chuck Harris <cfharris@...> wrote:

Because the plastic has shrunk, you need to increase
the space for the center hub. The easiest way I have
found is to assemble the parts as well as you can, and
then wrap some rubber bands around the knob to provide
tension.

Then take a soldering iron, and heat the center hub.

The instant the plastic relaxes, remove the heat, and
cool the hub by blowing on it.

After all is done, a drop of acrylic solvent glue will,
seal the deal, so to speak.

-Chuck Harris