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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. () 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.

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.

From: "John Griessen" <john@...>
To: [email protected]
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?

From: "Dave Brown" <davebr@...>
To: [email protected]
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.


Dave

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


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

;!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:

;!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.

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!

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