Date   

Re: 465 Scope Question

Dave Hills
 

C1562 is not doing its job, the AC voltage should be much less, I would expect
less than a volt.
You can calculate the DC load current from the measured DC voltage across R1569.

Dave


The input AC voltage at the bridge rectifier CR-1561 is 12.3vac. The AC
voltage on the DC output of CR1561 is 4.5vac.

Thank you,
Bill


Re: Good storage solution for collection of 500-series plugins?

-
 

I agree that it's a good idea but unless it's something that I'm going
to leave for a LONG time I seldom bother and I've never had a problem. I've
stored Tek and other electronics for five plus years in silver bags and all
of it has been fine. I have ammo that has been stored in ammo cans without
desiccant since I reloaded it in the 1960s and it still looks and shoots
like new. In fact, I even have some WW-II US made MIL ammo that still looks
and shoots fine. This is in Florida heat and humidity. As long as
everything is DRY when I seal it, nothing that I've sealed up seems to
deteriorate. But a word of caution, regular ziploc bags are just about
worthless except for keeping the dust off. Moisture passes right through
them.

On Sun, Apr 25, 2021 at 1:43 PM Roy Thistle <roy.thistle@mail.utoronto.ca>
wrote:

On Sat, Apr 24, 2021 at 12:30 PM, - wrote:


I store my plugins in one of the silver colored ziplock anti static bags
If one is going to do that, either displace the air with dry nitrogen
gas... which I assume everyone has... or put in a new (or properly
salvaged) desiccant bag.
Here in the colonies, the military always seems to put them in.
If you don't... unless you live in the Mojave Desert.. you might regret it.

--
Roy Thistle






Re: Unable to see some images in 75th anniversary consolidated pdf

Dave Brown
 

The museum did two projects to celebrate Tek's 75th anniversary. The first was a 75 exhibit slideshow tour. We chose this format since organizing a tour during Covid is a bit challenging. Even doing slides the tour takes 90 minutes. We had 6 different volunteers narrate the slides so the audio quality varies by home setup. The slides have photos of the actual exhibits at the museum with just a few exceptions.

The second project was to post a historic page a day. I started on February 4th, the day the company registered the name Tektronix. I've posted a page a day every day less about 5 days when I was without power and we migrated the website. The last posting was yesterday. Since all the pages have been posted I replaced the individual photos with a PDF. Links to both are on the home page.

Our thanks to the volunteers who took the time to put these together. Both were considerable efforts.

Dave


Re: 465 Scope Question

Bill
 

The input AC voltage at the bridge rectifier CR-1561 is 12.3vac. The AC voltage on the DC output of CR1561 is 4.5vac.

Thank you,
Bill


Tektronix 465B servixe manual containing waveforms 56-70

Torquil Macdonald Sørensen
 

Hi!

Does anyone here have a scanned version of a 465B service manual which
contains the waveforms 56 through 70, as well as the accompanying
oscilloscope settings?

In the one I have they are missing (while some other waveforms are scanned
twice). In another the pages have been cropped so the waveforms are outside
the page.

Best regards,
Torquil Sørensen, Norway


Cannot delay the B sweep on a 465B

Torquil Macdonald Sørensen
 

Hi!

I have a problem with my 465B where the delay time position 10-turn pot for
the B sweep has no effect. Everything else seems to work. Please see this
youtube video for a demonstration:

https://youtu.be/17ZGEw_jOmo

The intensified portion of the A sweep trace always starts on the leftmost
part of the display no matter how much I turn the delay time position knob.
However, the holdoff knob does make the B sweep duration/length vary, in a
periodic manner as I turn the holdoff knob slowly clockwise.

Any pointers for things to check in the circuit ? The voltage rails are
fine. Anyone here seen this problem before?

I have just fixed a problem with a reduced trace length on this scope, by
"cleaning" the X1 Gain pot with IPA. Maybe something similar could cause my
B sweep delay problem?

Best regards,
Torquil Sørensen, Norway


Tek 7844 Alphanumeric Display Issues

Liam Perkins
 

I have a 7844, ser. no. B173417, that works fine but for the character
display which is shifted upward 5 divisions, making of course the top
portion of the display invisible.

According to the 7K-series Readout System on the TekWiki here:

https://w140.com/tekwiki/wiki/7000_series_readout_system

there were three versions of the driver hardware; a) the initial ROM-based
all-analogue, b) the late-80s 2732 EPROM-based system instead of the
earlier analogue ROMS and, c) a third generation readout board designed
around an 80C31 micro‐controller.

Mine is the EPROM version and despite buying hard copy off eBay and
downloading everything off the TekWiki I cannot find a manual describing my
unit so I don't know where to find the pots that'll put the display where
it belongs; assuming that's what is the problem.

Anyone have any experience with this,or access to the correct manual or
the version number of same ?

TIA
Liam @ PEARL, Inc.


Tektronix SA 2782

Vik Danchuk
 

Hi !
can you watch the video and tell us your opinion about it
https://groups.io/g/TekScopes/files/tek%202782.mp4

thanks in advance
Vik


Tek 1503C TDR

warren.stirling@...
 

Hi all,

Does anyone, by faint chance, have a replacement lcd assembly for a 1503C TDR?


Re: 465 Scope Question

Bill
 

I assumed as much since all the other voltages in the low voltage power supply are spot on. While in there I will replace all of them. Was on my list anyway.

This scope is in really nice cosmetic and physical condition so I decided to get it going again even though I don't need it. This old equipment deserves our respect in my opinion. I will also learn quite a bit along the way!!

Thanks for the reply!!

Bill


Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful? GROUNDING ISSUE

Shaun M
 

Mac,

Thanks for posting this. I encountered exactly the problem you described and I had just started to troubleshoot it: I thought perhaps I had a bridged solder connection somewhere. Problem solved!

Shaun Merrigan


Re: 465 Scope Question

Dave Hills
 

Bill,
C1562 most likely has failed. If it has you should see a large AC ripple voltage across it.
VR1522 is functional. If it were not, ALL the regulated voltages would be off, as they all
are referenced to it.

Dave


Started out with no -8vdc. Replaced the bridge rectifier now I have -6.5vdc.
The power transistor Q1566 checks out as OK. Lifter C1569 but that didn't
help. The voltages on Q1566 are ok except the Collector voltage is a little
over =3vdc when it should be +5vdc. I'm going on the assumption that
something downstream is dragging down the -8vdc but is not a dead short.

Sound reasonable?

All the other Low Voltage power supplies are dead on in voltage.
Bill


Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful? GROUNDING ISSUE

Mac Perkins
 

Many thanks to Jared for his elegant design, I've been meaning to build one of these for some time.

After building the test unit and starting to test frames, I encountered a problem in the beta test positions of the switch.

The BNC connector is not isolated and is wired across the meter HI and LO posts, The toothed lug washer shorts the LO terminal to ground through the front sub-panel and the frame of the module.

Fortunately the 5K1 resistors seemed to limit the current available and prevent damage.

My solution was to connect the BNC ground lug to the GND terminal with a short wire rather than the pad provided which connects to the meter LO terminal . It is still a good idea to disconnect the oscilloscope in the beta measuring positions as even the 1 meg scope input influences the reading significantly.

-Mac


Re: Unable to see some images in 75th anniversary consolidated pdf

Tom Lee
 

Hi Dave,

I don’t know if anyone has replied to you, but they’re referring to a pdf now available at vintagetek. It’s currently featured on their front page. You’ll enjoy reading it, I’m sure!

—Cheers,
Tom

Sent from my iThing, so please forgive typos and brevity.

On Apr 25, 2021, at 12:24 PM, Dave Voorhis <voorhis@gmail.com> wrote:

On 25 Apr 2021, at 19:40, Tommy <tommy@rausberg.se> wrote:

The subject line pretty much tells it: most images are there but some don't show on my computer (Howard's First Scope and World War Two, for example).
Anyone else seeing this or is it my computer ?

While they were presented one by one all were viewable but it would be nice to have the whole thing...
Where, and what, is this 75th anniversary consolidated PDF?

It wounds interesting, but I’ve never heard of it.






Re: Unable to see some images in 75th anniversary consolidated pdf

Lyle Bickley
 

Hi Tommy,

I suggest you download the PDF rather than viewing it "online". Various
browsers do different things with images, etc.

I've looked at the PDF with Acrobat and okular (on Linux) and all the pictures
are fine...

Cheers,
Lyle
--
On Sun, 25 Apr 2021 11:40:08 -0700
"Tommy" <tommy@rausberg.se> wrote:

The subject line pretty much tells it: most images are there but some don't
show on my computer (Howard's First Scope and World War Two, for example).
Anyone else seeing this or is it my computer ?

While they were presented one by one all were viewable but it would be nice
to have the whole thing...






--
73 NM6Y
Bickley Consulting West
https://bickleywest.com

"Black holes are where God is dividing by zero"


Re: Unable to see some images in 75th anniversary consolidated pdf

Tommy
 

Jus realised he pdf displays ok in Firefox, go figure...

Sorry for the wasted bandwidth.


Re: Unable to see some images in 75th anniversary consolidated pdf

Glydeck
 

Tommy,

Downloaded and tried the pdf on several readers and it seems ok. Maybe you’re using an older version of Acrobat?

George

On Apr 25, 2021, at 1:54 PM, Tommy <tommy@rausberg.se> wrote:

https://vintagetek.org/tek_75/





Re: 465 Scope Question

Mark Vincent
 

Bill,

Check the ac voltage across C1562. It sounds like your filter condenser is bad. If the cap is bad, replace it with 3300-4700mfd 25V UHE type. These are the best I have found for ESR and life. Filter condensers in these and 7603s seen to give problems and replacement is necessary.

Also check VR1522. I have never seen one of the 9V zeners be good. Yours is likely open. I know it may not make a difference in the output voltage. I change these in my units with BZX85B9V1.

Mark


Re: Unable to see some images in 75th anniversary consolidated pdf

Tommy
 


Re: Unable to see some images in 75th anniversary consolidated pdf

Dave Voorhis
 

On 25 Apr 2021, at 19:40, Tommy <tommy@rausberg.se> wrote:

The subject line pretty much tells it: most images are there but some don't show on my computer (Howard's First Scope and World War Two, for example).
Anyone else seeing this or is it my computer ?

While they were presented one by one all were viewable but it would be nice to have the whole thing...
Where, and what, is this 75th anniversary consolidated PDF?

It wounds interesting, but I’ve never heard of it.

5221 - 5240 of 186847