Date   
Re: Tek 497P lithium battery

radioconnection@...
 

I see the manufacturer for the OEM battery went of business. I ordered a 3 volt lithium battery with wire leads. I'll use double sided tape to secure it.

Pete

Re: SMD tweezers (Re: [TekScopes] [OT] surface mount components)

Bob Albert
 

I am not so sure that excitation voltage is an indicator of accuracy, nor frequency.  I own a GR1658 that measures at 1 kHz and 120 Hz and it's ectremely accurate.  It works great in circuit provided the circuit is isolated.  That is, no sneak paths to ground, etc.  So I make sure to deenergize the device and that it's not touching ground leads, etc.  Sitting it on a towel or sheet of paper works.
I can measure capacitance down to fractional pF with it, as well as inductors.  It offers a choice of freuncy as mentioned above and choice of equivalent series or parallel parameters.  In addition, it can make two measurements of ESR with different methods that always correlate well.  One, it shows me the dissipation factor, and two it measures resistance directly.  This works best for larger capacitors so if I want to know ESR for a small capacitor I have to calculate it from knowing D.
Having said all that, this is not an inexpensive toy.  I was lucky to obtain it in fine condition some years ago for $75.  I find it indispensable for my passive component measurements.  I damaged it a couple of times but it was the protection diodes that were easily replaced.  I also built a test fixture that does four terminal measurements so the residual values are very small.  The only down side is that it won't measure at DC, so the resistance of an inductive component will be different for different setups.  That can also be calculated out but it's a nuisance.  So if I want to make such measurements I use either my HP3456A DMM or my older GR1650A.  Further complicating inductor measurements is the nonlinearity of such parts if they have a magnetic core.  In those situtations, excitation voltage is very important; I can measure incremental inductance but there isn't enough control over excitation to give me much confidence.
As you might have gathered, I am a test equipment freak and have lots of fun toys.
Bob

On Monday, May 20, 2019, 6:17:19 AM PDT, Hawker <rick@...> wrote:

That 0.1V or less excitation is very important. I used to have a BK 886 with 0.05V excitation. It could usually accurately read caps in circuit.
I now have a BK880, which is supposed to be more accurate. However it only has a 0.3V minimum excitation voltage and does not read as accurate in circuit as the 886.
What is also important if you want to measure capacitance less than about 470pf (and large inductors) is 100KHz sample frequency. That Mastertech only goes to 10KHz so it isn't going to be as accurate fro smaller value caps or large inductors.  I don't know if 0.1V is low enough, but clearly better than the BK 880's 0.3V, which isn't low enough.

Re: [OT] surface mount components

Alberto I2PHD
 

On 2019-05-20 15:06, David Kuhn wrote:

When I checked out the MS8911 on Amazon, it doesn't look like it does ESR for that price.
Well, the MS8911 does not measure ESR directly. It instead measures the Dissipation Factor, which can then be used to compute the ESR...
From a document on Internet :

 Dissipation factor (tan δ)or DF is defined as the ratio of the ESR and capacitive reactance. It is the Dissipation factor is also known as the tangent of the loss angle and is commonly expressed in percent. Recognized standards express the dissipation factor at specific frequencies typically 120Hz for Aluminum electrolytic and Tantalum capacitors while for film capacitors is 1 kHz and 1 MHz for ceramic capacitors.
Equivalent Series Resistance or ESR for short is the sum of the ohmic losses of the dielectric, materials and connections used in the construction of the capacitor. ESR=DF*Xc=DF/(2*pi*f*C)

--
/*73 Alberto I2PHD*
Keyboard Not Found : Press F1 to continue/

Re: Photo Storage Space Solution, was IMPORTANT: Photos are eating up our storage

 

Hi Esmond,
Thanks for doing that. Screen shots of the CRT of a scope usually do not need to be high resolution.
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of EJP
Sent: Sunday, May 19, 2019 11:52 PM

Pour encourager les autres, I resized 8 photos in my AF501 trigger album to 600x800. Image size went from 1.2M to < 64K. Times eight. Rather worth it I thought.

EJP




--
Dennis Tillman W7PF
TekScopes Moderator

1502b LCD adjustment pot - where is it?

Alan Ainslie
 

I have a 1502B which is working fine but the LCD is very dark in places. I would expect to see some adjustment.

In fact there seems to be an adjustment pot in the manual (page 6.35) called R1018 - but I really cannot find it. Are there two versions of the manual or hardware?

The unit here is serial B01087x

Electroluminescent panel is stuffed and I have replacement, but I need to be sure that the LCD will adjust before I dive in..

Thanks in advance.

Alan

Re: 1502b LCD adjustment pot - where is it?

Tom Gardner
 

From memory it isn't perfectly obvious.

With it horizontal on your bench, slip it out of the case a couple of inches. Look down on the top edge of the LCD board and you will see figure 6-56.

On 20/05/19 18:52, Alan Ainslie wrote:
I have a 1502B which is working fine but the LCD is very dark in places. I would expect to see some adjustment.

In fact there seems to be an adjustment pot in the manual (page 6.35) called R1018 - but I really cannot find it. Are there two versions of the manual or hardware?

The unit here is serial B01087x

Electroluminescent panel is stuffed and I have replacement, but I need to be sure that the LCD will adjust before I dive in..

Thanks in advance.

Alan

Re: Changing the battery of a 2465B

Chuck Harris
 

A 2445<<B>> with a serial number below B050000, yes.

The 2445/55/65 (Note no "B" suffix) uses no battery,
just a device called an EAROM.

-Chuck Harris

Lee Houde wrote:

Chuck - Does the same hold true for a 2445? One of mine is giving me a battery error. Also, can you provide more information on the Eagle-Pitcher replacement battery? I couldn't find anything suitable cross-referencing the Tek part number so I bought a AA size Lithium battery, planning to use an AA battery holder with it, but if there is a correct battery I would rather go with that.

TIA, Lee



Re: Changing the battery of a 2465B

Chuck Harris
 

If you are getting *any* of the Test04 errors, your calibration
is gone, or was never there in the first place.

There about 180 locations in the saved RAM, NV, or CMOS,
that contain important values related to your calibration.
Each has a parity bit associated with it, and the entire block
of constants has a checksum associated with it.

If any of those checksums has changed, your RAM has lost its power
and forgotten all or some of its data. The thing is, you can't
tell which it is, so you have to assume it is all bad.

The only cogent way to tell the age of your scope is to look at
the dates on the soldered in IC's, and that is slightly earlier
than your scope was sold. The hybrids are not a safe indication,
because they could have been swapped... though if most have
similar dates, they are probably original.

-Chuck Harris

Alberto I2PHD wrote:

On 2019-05-20 15:20, Chuck Harris wrote:
I presume that your 2465B is from before serial number B050000, and
has a battery and cmos ram setup, rather than the later Dallas NVRAM.
Yes, the SN is B012133.
Other than telling me that it was made in Beaverton, Ohio, I don't how to interpret
that number... year of production ? Special features ?
If that is so, it is trivial to replace the battery without losing
your calibration data... not that the data is all that valuable on
a scope so long out of calibration.
This brings to another question... when the 04 error is displayed ? When the checksum
of the RAM is invalid, or when the instrument is actually out of the specifications ?
And in this latter case, how can the firmware tell that ?
Don't use a power supply for the 3V, just use a pair of AA cells, or
any lithium cell. Your soldering iron tip will be grounded (if it isn't,
you should throw it away), and may your calibration constants, by shorting
the battery to ground through the power supply... while you unsolder it.
Yes, I will use a couple of AAA cells for that, and a Weller soldering iron.
The replacement battery is made by Eagle-Pitcher, and is readily available.
Well, I have never opened the instrument, and I thought, apparently wrongly, that a
CR2032 cell could do.
They are sold around here at the supermarket, a 6-pack for 3 Euro. Is that cell sold
by Eagle-Pitcher different from a CR2032 ?

Thanks for your suggestions.

Re: 2246 no display/odd behavior

Matt
 

Starting at the pots, I ran the exercise pots test from the test menu and A INTEN, B INTEN, and READOUT are all reading fine from 00 to FF. I think this rules out the muxing portion of the circuit. On the analog side, I checked the voltages in and out of the pots, all fine (-2.5 to + 2.5).

Moving to the first test point on the A INTEN circuit I get 4.2-4.3 volts at either end of the A INTEN pot travel where the diagram specifies 3.1-4.2.

Here is my marked up schematic: https://i.imgur.com/pgGF15p.png

Does this suggest possibly faulty Q1001/2/3/4/5? Further, any recommendations on how to test these in circuit instead of shotgunning it?

Re: Changing the battery of a 2465B

Tony Fleming
 

Is 2465 DMS equipped with battery or has CMOS?
Thanks.

On Mon, May 20, 2019 at 2:29 PM Chuck Harris <cfharris@...> wrote:

A 2445<<B>> with a serial number below B050000, yes.

The 2445/55/65 (Note no "B" suffix) uses no battery,
just a device called an EAROM.

-Chuck Harris

Lee Houde wrote:
Chuck - Does the same hold true for a 2445? One of mine is giving me a
battery error. Also, can you provide more information on the Eagle-Pitcher
replacement battery? I couldn't find anything suitable cross-referencing
the Tek part number so I bought a AA size Lithium battery, planning to use
an AA battery holder with it, but if there is a correct battery I would
rather go with that.

TIA, Lee





Re: 2465 repair attempt with (horizontal?) issues, help needed [Solved!!]

satbeginner
 

Minor follow-up:

During the calibration I found two - a bit weird- things:
- I got Limit errors during the Cal2, and
- the Cal3 would always fail...

The limit errors during Cal2 were caused by me, during step 111, 112 you need to set the two dots at the beginning and the end of the screen, but as soon as they are just a little (half a dot diameter maybe) outside but still touching the outer graticule lines, it will cause a limit error later on.

The Cal3 error turned out to be a broken Ch3/Ch4 Hybrid (155-0238-00).
I ordered one at Qservice.eu and that fixed everything, so I have another fully calibrated 2465 in my collection :-)

Un saludo,

Leo

Re: 2465 repair attempt with (horizontal?) issues, help needed [Solved!!]

David Kuhn
 

" so I am a happy bunny!"

Careful, in Europe, isn't "bunny" in most of the menus?

Dave

On Tue, Apr 30, 2019 at 9:08 AM satbeginner <@satbeginner>
wrote:

Hi all,

Here a solution I found for a horizontal problem I had on (one of) my 2465.

The problem was that all horizontal traces, readout, etc. were waaaay too
wide, also the time cursors were not shown.
Also when put in X-Y mode I still had a horizontal line, instead of a dot.


But the good news is: I solved it.

My assumption was that the horizontal shaped line must have been some kind
of deflection??
In a way it was, but not some hum or ripple, it turned out to be the
control of the last set of convergence grids.

On the A9 High Voltage board there is the Edge Focus potmeter (R1864),
that sets the voltage on the vertical convergence grid.
Amplifier U1890B and Q1890 are supposed to invert that voltage as an
inverting voltage follower to be used on the horizontal convergence grid.

After some searching I found that the voltage on the Quad Pole #3 (the
horizontal convergence grid) was always -285V, regardless of the setting of
the R1864 potmeter that did change the voltage on quad pole #4.
It was the €0,03 1MOhm feedback resistor R1891 that went all open :-), so
no feedback so the output went as negative as negative can be.

So, instead of extra focussing the beam it did exactly the opposite, it
spread the beam out completely, hence the line and the way too wide traces!

After replacing that resistor I have about the sharpest trace of all my
scopes, so I am a happy bunny!

Now I will put it all together again and start the calibration.

Un saludo,

Leo



Re: Old Tektronix Books

Roy Morgan
 

Dave and others,

I was lucky to get a copy of "Typical Oscilloscope Circuits”, and have read about half of it.

I wonder what scope the schematic examples are taken from. They certainly look genuine.

Does anyone know?

On Mar 30, 2019, at 8:20 AM, Dave Daniel <kc0wjn@...> wrote:
...
I found my copy of "Typical Oscilloscope Circuits" in a surplus parts store decades ago.
Roy Morgan
K1LKY since 1958
k1lky68@...

Re: Old Tektronix Books

ROLYNN PRECHTL K7DFW
 

I wonder what scope the schematic examples are taken from. They certainly look genuine.
========================================================================


1961 publication eliminates some.

The power supply might be a 531/535/541 but I'm not going to spend any time with this since the manuals are on TekWiki.



Rolynn

OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

 

Last month my computer hard drive crashed and I lost all my web browser
favorites.



One of the favorites I lost came from a previous post on TekScopes a few
years ago if I remember correctly.



Does this ring a bell with anyone?

It was a web based application that would do an analysis of an eBay seller
you chose, to determine what percentage that seller accepted when they
listed their auction as "Or Best Offer". It took a while to run because it
had a way to search through eBay history if I remember correctly.



I have searched google for hours without success.



Please reply OFF LIST to dennis at ridesoft dot com if you know what this is
called.

Thanks in advance,

Dennis Tillman W7PF

Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

loyde downie
 

actually, i would also like the same info...
reply off-list to mdownie at digital-associates dot com

thanks

mike downie

On 5/21/2019 2:56 PM, Dennis Tillman W7PF wrote:
Last month my computer hard drive crashed and I lost all my web browser favorites. One of the favorites I lost came from a previous post on TekScopes a few years ago if I remember correctly. Does this ring a bell with anyone? It was a web based application that would do an analysis of an eBay seller you chose, to determine what percentage that seller accepted when they listed their auction as "Or Best Offer". It took a while to run because it had a way to search through eBay history if I remember correctly. I have searched google for hours without success. Please reply OFF LIST to dennis at ridesoft dot com if you know what this is called. Thanks in advance, Dennis Tillman W7PF

Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

nonIonizing EMF
 

I'd like the info also. nonionizingemf at gmail dot com.

Thanks in advance!

Re: OT: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

Daniel Koller
 

Hi all,  With all due respect to OP Dennis, this IS on topic, given that a lot of my Tek equipment came from e-bay, and I suspect that is also true of a lot of others here.  Got my 7854 on e-bay, after watching prices for months, and I snagged it for under $200 including shipping. 
     Please add me to the list if anyone knows of such an app.  I'm happy to take a reply off-line as well, but it's probably helpful to the group as a whole.
Dan

On Tuesday, May 21, 2019, 6:12:27 PM EDT, nonIonizing EMF <nonionizingemf@...> wrote:

I'd like the info also.  nonionizingemf at gmail dot com.

Thanks in advance!

App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

John Dickens
 

Please post this for everyone to see. Thanks, John

On May 21, 2019, at 5:19 PM, Daniel Koller via Groups.Io <kaboomdk=yahoo.com@groups.io> wrote:

Hi all, With all due respect to OP Dennis, this IS on topic, given that a lot of my Tek equipment came from e-bay, and I suspect that is also true of a lot of others here. Got my 7854 on e-bay, after watching prices for months, and I snagged it for under $200 including shipping.
Please add me to the list if anyone knows of such an app. I'm happy to take a reply off-line as well, but it's probably helpful to the group as a whole.
Dan

Re: App that keeps track of "Or Best Offer" auctions on eBay to tell you what a seller will accept.

ROLYNN PRECHTL K7DFW
 

Please post this for everyone to see. Thanks, John
================================================================


Not an app but this is what I use to purchase TEKTRONIX items.

<https://www.goofbid.com/ebay_best_offers_tool.html?gbo_username=&gbo_submit=>


Rolynn