Date   
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

Re: Old Tektronix Books

Dave Wise
 

Where? I found the Concepts series, but Typical Oscilloscope Circuitry is not a Concepts book.

Thanks,
Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of ROLYNN PRECHTL K7DFW <k7dfw@...>
Sent: Tuesday, May 21, 2019 1:15 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Old Tektronix Books

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

Tektronix 310A CRT issues

Brenda
 

Hello everyone! I have a Tektronix 310A serial number 016911 that I have had in my shop area for quite some time. When I first got it, I only got a very faint trace and was only sweeping 3 divisions instead of the full 10 divisions. I shut it down and most of the electrolytic caps were much hotter than the tubes themselves, so that was pretty much a full recap in my eyes. I finally got around to recapping this old 310A, dialed in all the power supplies (-150V, +100V and +300). The 300V was off by 1V when the -150 was set. At this point, I have a trace, not very bright, but the sweep was fairly accurate with my function generator along with the vertical amplifier. Not bad with all 6BQ7's instead of 6DJ8's! So this tells me that this scope is partially operational which I am happy about. But I digress now..

Onto the CRT circuit itself, when the scope is operating, The Focus control is turned all the way to the 3'o clock position, and my intensity is turned to about 10'o clock position and I have a dim, but very sharp trace. But the center 4 divisions around the middle where the vertical and horizontal with the smaller divisions is very dim. What I have done to check things is I checked all the resistors in the HV circuit, most were almost dead on with a few that where slightly high but well within the 20% tolerance as stated on the resistor. I did not mess with any of the capacitors as they are the ceramic type, but know that it's possible that 1 or more my be bad. After that, I took some voltage measurements according to the schematic for the CRT circuit, which is below:

V704 (6AQ5) Plate voltage: 477V
V704 (6AQ5) screen voltage taken at pins 1 and 7, Upper reading should be -41V and measured -44.4V (Intensity turned CCW)
" " Lower reading should be -45V and measured -49.2V (Intensity turned CW)

V701A (12AU7) Plate voltage taken at pin 1, Upper reading should be +47V and measured 44.8V (Intensity turned CCW)
" " Lower reading should be +75V and measured 136.7V (Intensity turned CW)
V701B (12AU7) Plate voltage taken at pin 6, Upper reading should be -1.8V and measured -1.4V (Intensity turned CCW)
" " Lower reading should be -3.5V and measured -116.7V (Intensity turned CW)
V701B (12AU7) Screen voltage taken at pin 7 should be -155V and measured -155V.

I did try substituting V701 for a know good working 12AU7 and the readings were pretty much the same, so I put the original back in. I am only a novice hobbyist, and slowly learning about electronics, but I am confused with the readings. I should also mention that in regards to the trace being dim and sharp, once you turn the intensity past 11'o clock position, the trace starts to defocus and dims out even more. I have also tried cleaning the pins on the CRT and the socket as well. I did however notice that the CRT is from Sylvania. I know that the earlier 310's, Tektronix had to outsource to Dumont for the CRT's until they could start making their own. So is this Sylvania a replacement that someone installed or did Tektronix outsource to them as well?

Sorry for the lengthy post, I wanted to get as much detail in as possible to help get this little guy up and running! Thanks so much for your help!

Brenda

Re: Old Tektronix Books

Dave Daniel
 

Where what?

DaveD

Sent from a small flat thingy

On May 21, 2019, at 20:26, Dave Wise <david_wise@...> wrote:

Where? I found the Concepts series, but Typical Oscilloscope Circuitry is not a Concepts book.

Thanks,
Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of ROLYNN PRECHTL K7DFW <k7dfw@...>
Sent: Tuesday, May 21, 2019 1:15 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Old Tektronix Books

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




497P frequency counter question? How to turn on?

radioconnection@...
 

I think the dip switches are set to enable the frequency counter option in 497P, but I do not have a clue as to how to tell whether it is working or not. What push button enables the counter on the 497P front panel, and what should I see when and if the counter is really enabled? I've never seen a function not defined error while randomly trying to figure out what does what.

Pete

Re: 497P frequency counter question? How to turn on?

John Miles
 

What's your serial #? Before B020000, the 497s were derived from the 492A hardware and didn't support the counter feature. If your front panel doesn't have a COUNT button, then that's the case with your unit.

What I'm not sure about offhand is whether the B020000 through B030000 series had counter support. Post-B030000 they definitely did, because those were basically relabeled 494As.

The good news is that while you may not be able to enable the counter with the firmware and/or hardware you have, the 492As were free of the nasty SMT electrolytics and are going to be more reliable as a result despite being a couple years older.

-- john, KE5FX

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
radioconnection@...
Sent: Tuesday, May 21, 2019 6:25 PM
To: TekScopes@groups.io
Subject: [TekScopes] 497P frequency counter question? How to turn on?

I think the dip switches are set to enable the frequency counter option in 497P,
but I do not have a clue as to how to tell whether it is working or not. What
push button enables the counter on the 497P front panel, and what should I see
when and if the counter is really enabled? I've never seen a function not
defined error while randomly trying to figure out what does what.

Pete

Re: 497P frequency counter question? How to turn on?

radioconnection@...
 

B0202199

Looks like most parts are late 1990 date codes.

Spectrum Analyzers

Gary Robert Bosworth
 

Does anyone know the exact differences between a Tektronix 495P Spectrum Analyzer and a 496P Spectrum Analyzer? They have the same input frequency range, but apparently have a completely different front control panel.

Latest firmware for TDS210 and TDS2CM?

Jared Cabot
 

Hi,

I have an old TDS210 scope with TDS2CM comms/math module and I was wondering if anyone knows what the latest firmware revisions for these modules is, and if anyone has these firmware files?

I was reading that some changes were made in the later firmwares and I have itchy fingers if my unit is an earlier rev.

Thanks!