Date   

Re: 475A Problem

Dave Peterson
 

Looks like your "Low Line" light is on, meaning your +55v supply is low. The +55v drives all the low voltage regulators, so that needs to be fixed first. See the power supply calibration procedure in the service manual.

I would guess you have a problem with a rectifier or power supply cap (or both).

I'm more of a 465 guy, so I may very well be off in the 475A details. Is it +55v in 475A as well guys?

Dave

On Sunday, June 20, 2021, 9:26:46 AM PDT, Dick <w1ksz@outlook.com> wrote:

I have a 475A, ex-IBM with DMM Option. It recently developed a problem.
You can see a picture of what it looks like in the Photo's section, under
475A problem.

If you let it run for 10 minutes or so, the problem seems to get better, but not
completely gone.

Probing the DC Voltages while the problem is there shows the -8vdc line has
dropped to -2.1vdc, and the +5vdc line has dropped to +1.0vdc. When the
problem seems to go away, those voltages come back up to normal.

Anyone have any ideas what to look at ?

Thanks for any help,

Dick, W1KSZ


475A Problem

Dick
 

I have a 475A, ex-IBM with DMM Option. It recently developed a problem.
You can see a picture of what it looks like in the Photo's section, under
475A problem.

If you let it run for 10 minutes or so, the problem seems to get better, but not
completely gone.

Probing the DC Voltages while the problem is there shows the -8vdc line has
dropped to -2.1vdc, and the +5vdc line has dropped to +1.0vdc. When the
problem seems to go away, those voltages come back up to normal.

Anyone have any ideas what to look at ?

Thanks for any help,

Dick, W1KSZ


Added album 475A Problem #photo-notice

TekScopes@groups.io Notification <noreply@...>
 

Dick <w1ksz@...> added the album 475A Problem


Re: 465M

Ananda
 

True, given the age of this, that is a good possibility. Thanks.


Re: SG 502 Assistance?

Eric
 

Cory,
Good luck on the SC but be careful in there. It is 10 lbs of stuff in a 2lb box. Also it is a CRT so there is some places where there is sevral thousand volts. 4 - 7 - possibly 21KV it is needed to drive the tube. So take care.
Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of sweetbeats
Sent: Sunday, June 20, 2021 11:24 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] SG 502 Assistance?

Thanks, Eric.

So here’s the trick, my SC 502 scope is n/f at this time so there has been no monitoring of the waveform. My intention is and has been to look at the waveform, but in the short term I wanted to at least learn if the SG 502 was producing anything and at what percent distortion, and knowing my AA 501A seems to be working I hooked things up and here we are.

Getting the scope working is next up.

Cory


Re: 465M

Bert Haskins
 

On 6/20/2021 12:48 AM, adesilva_1999 via groups.io wrote:
Update:

I found the hard way that the Time base/horizontal module was the culprit. It has done some sort of damage on the interface board.

I was able to source another 465M which had a different problem on the display. It was fuzzy and was not a straight line but some funny shape which is hard to explain. Anyway, I got it knowing that it had a working main board and HV parts. Thinking that the funny display was due to the time base, I moved the time base module from my first scope to this second unit which was a bad decision as it started doing the same thing-blowing the fuse!

I was able to find yet another main board and a time base module. These two, along with the vertical module and the power supply (transformer and the heat sink etc.) from my first scope worked like a charm. I had a known good CRT to go with it and the trace looks very clean and well defined now.

Now there is another question for anyone who can help. Why would the trace blank for a split second every now and then?

Thanks for any ideas.
Might just be dirty focus or intensity pots.

Try just running  them back and forth many! times with the power off.





FW: [TekScopes] Another interesting Tektronix web site

Dave Wise
 

Closeup photos available off-list.

I don’t know how to cast something hollow.  Anyway, my goal is to come up with something cheap and easy.  Can you suggest phrases to search for?  “Shock mount” and “vibration isolator” mostly pick up mike stands and heavy automotive/HVAC stuff.

The shape is a hollow ball with a flange at each end and a hole through the axis.  You squeeze the flanges through the mounting holes in the chassis.  With 348-007 (used in Type D and H from the 1950s, now deteriorating) you finish up with screw-washers-nut through the hole to prevent a big shock from tearing the cushion apart.  348-0087 (used in Type 1A6 and 1A7 from the 1960s and may outlive me) is a different material, stiffer, and instead of a screw, it is secured with a plug at each end.  I think 348-0087 would fit in a D or H.

If I had access to the PISL (Purchased Item Source List microfilm “window cards”), I could determine who Tek bought them from - if they bought them - but they’re surely gone now anyway.

Dave Wise

From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Harvey White via groups.io
Sent: Saturday, June 19, 2021 7:38 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Another interesting Tektronix web site

Could you make a mold and cast some sort of rubber?

Harvey


On 6/19/2021 10:10 PM, Dave Wise wrote:
I performed this procedure on one of the chassis cushion mounts in my Type D plugin. (Tek P/N 348-0007-00. 348-0087-00 might work too.)

No effect.

Must be a different rubber.

Unless someone has another idea, I will look at cushions made for RC helicopter camera mounts.
This one caught my eye:

https://www.amazon.com/HONBAY-Vibration-Rubber-Fright-Controller/dp/B073LPTHCL/ref=pd_di_sccai_4/130-3441475-1604467
HONBAY 24pcs RC Anti Vibration Rubber Balls for Fright Controller Gimbal

On closer look, it's far from ideal. The parts are 13mm overall height, 8mm overall diameter, 6mm hole diameter, approximately 7mm chassis spacing.
The mounting holes in Type D are themselves 8mm diameter (5/16") so the cushions will slip free unless the chassis and subchassis are modified, perhaps by gluing down washers with 6mm ID.
Also the Type D chassis are spaced on approximately 10mm centers, not 7mm, so glue the washer on the bottom side of the upper and the top side of the lower.

I'll report results in a month or so.






Re: SG 502 Assistance?

sweetbeats
 

Thanks, Eric.

So here’s the trick, my SC 502 scope is n/f at this time so there has been no monitoring of the waveform. My intention is and has been to look at the waveform, but in the short term I wanted to at least learn if the SG 502 was producing anything and at what percent distortion, and knowing my AA 501A seems to be working I hooked things up and here we are.

Getting the scope working is next up.

Cory


Wanted: Series 2 or 3 Time Base Module

MaxFrister
 

I’m trying to get a Tek 564 scope working in order to give it away to a 20 year old kid.

I’ve had it for years but never bothered to fix it since it arrived with 2 vertical modules and no timebase. It wasn’t until I pulled it down to work on it that I realized it was set up for XY mode.

I have it limping along (I haven’t so far been able to get the storage function to work) but in order to make it more useful I’d like to add a timebase to it. Let me know if you have one you are willing to sell or trade for.


Need obscure TDS software

alberto.vaudagna
 

I was able to get my hand on some of the pages of the TDS544A Technical manual vol 1 because my interest was to found how to run the various diagnostic procedures that the famous TDS520 CM Vol 2 manual refer.
To my complete amusement I realized that the procedure are executed by a software made by Tek that communicate to the scope via GPIB (or RS232 apparently) when a set of dip switches are selected.
To make the thing even funnier apparently in the software there was some description on what each procedure does.
So basically the manual I have is useless unless I have the proper software.
I will attach the page where the manual speak about this software:

[url]
https://www.dropbox.com/s/3yllrsa6dwfj881/tek1.PNG?dl=0
[/url]

[url]
https://www.dropbox.com/s/u01h91trorhyg3e/tek2.PNG?dl=0
[/url]

[url]
https://www.dropbox.com/s/5sj18k84728mnq/tek3.PNG?dl=0
[/url]

Does anyone of the member is able to dig out this software because I'm almost sure that is available no where as all of this technical manuals.
After having able to study a little bit the situation probably the software is loading custom firmware on the scope that than execute the diagnostic test.
This would make sense I guess but having such tool would be amazing.


Re: Email adresses of group exposed

Jean-Paul
 

As Scott McNealy said in 1999, "You have zero privacy anyway. Get over it."

j


Re: Email adresses of group exposed

 

On Sun, Jun 20, 2021 at 7:36 AM redarlington <rdarlington@gmail.com> wrote:

Every one of the messages in this thread (and the rest probably) show the
email address of the person posting. Pretty normal stuff.

-Bob
Hits the nail on the head.
If you don't want your email address to be known by absolutely
everyone, do not post it to a PUBLIC LIST, for pete's sake. It's only
logical.

Everyone on this thread spends their whole day posting to this list.
Is it a surprise that a piece of software meant to find things finds
your email address where it's used most often? I'd be surprised if it
didn't - that would mean the search engine is broken.

The fact that your email addresses show up on group archives has
nothing to do with tekscopes and everything to do with the fact you
decided to put it there - in a public spot - in the first place.

Don't get upset about this. Don't call on the admin to do anything.
There's nothing to fix here. Just a bunch of people realizing that
this is, in fact, not a secret society of freemasons.

If you're upset your private email address is now public - next time
use a second email address. I personally have >10 which I use in
different contexts depending on what I'm doing.

Your best bet is to relegate the current email address to lists and
other stuff like that, and set up a new private email address.


Re: Email adresses of group exposed

Michael W. Lynch
 

On Sun, Jun 20, 2021 at 12:01 AM, henryfinley wrote:


I don't think it matters much any more. Telephones in the US have been
rendered worthless already because of third world telemarketers
Amen! I get HUNDREDS of calls and E-mails daily, from these scammer. Either the "IRS" or "SOCIAL SECURITY ADMINISTRATION" who are going to "arrest me" if I do not send them a Target Gift card to pay my "past due" obligations. The phone and computer that was once a tool has become a burden. Time to cut the cords and live a simpler life. I hope this can be corrected, but I think that the cat is already out of the bag!

--
Michael Lynch
Dardanelle, AR


Re: SG 502 Assistance?

Eric
 

EJP,
If I am remembering the spec sheet correctly the aa501A is specified up to 100 Khz and measures harmonics up to 300Khz. But not a fundamental at 300 Khz. This would put the harmonics outside the range of the AA's. When you are looking at the wave form are you looking at the monitor out of the function out? function out is post notch filter and should be only be the distortion components. If you have sine waves on the function out the notch filter Is a little off. The monitor out is just a copy of what was on the input. It should always look good on a scope if not there is other issues that need to be addressed.

Eric

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of EJP
Sent: Sunday, June 20, 2021 2:31 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] SG 502 Assistance?

On Sat, Jun 19, 2021 at 11:45 PM, Eric wrote:

The AA501 has an effective range of 10hz-22Khz ...
That's not what it says in the specifcation. However my AA501 measures my SG502 at >= 50% THD from 124kHz, and the waveform looks perfectly clean, no different from 100KHz where it measures 0.190%. So Cory is at least not alone.

EJP


Re: SG 502 Assistance?

EJP
 

On Sat, Jun 19, 2021 at 11:45 PM, Eric wrote:

The AA501 has an effective range of 10hz-22Khz ...
That's not what it says in the specifcation. However my AA501 measures my SG502 at >= 50% THD from 124kHz, and the waveform looks perfectly clean, no different from 100KHz where it measures 0.190%. So Cory is at least not alone.

EJP


Re: Email adresses of group exposed

redarlington
 

Every one of the messages in this thread (and the rest probably) show the
email address of the person posting. Pretty normal stuff.

-Bob

On Sat, Jun 19, 2021, 9:13 AM Roy Morgan <k1lky68@gmail.com> wrote:

Thanks for the reminder about DuckDuckGo. I have intended to switch.

Not long ago there was an article on BBC News titled something like "What
does Amazon (Google?) know about you?" The article was alarming.

Recent tv ads from DuckDuckGo tell about their intention to help us
improve our privacy. Is that something beyond the functions of the search
engine?

Roy Morgan
K1LKY Western Mass

On Jun 19, 2021, at 10:45 AM, tekscopegroup@miwww.com wrote:

It looks like the search engine crawlers have found a way into the
groups message database.
...

BTW I checked my email hits on the Duckduckgo search, I stopped using
Google and their invasive tracking and siphoning of ones metadata practices
some time ago, and have never looked back since.

https://duckduckgo.com
-=-=-=-=-





Re: Email adresses of group exposed

 

I don't think it matters much any more. Telephones in the US have been rendered worthless already because of third world telemarketers (spam likely). and the internet has become a hodgepodge of spammers, hackers, fake news, and political extremists. I am personally at the point of completely getting rid of these devices just to have some peace. The minuses have overshadowed the pluses to me. My phone number is not mine, my email address is not mine. The crooks own it. Let them use it to cheat each other. The only way anything will be done is for some powerful politician to completely cut off all electronic access to the US, and force those countries to go through a human operator to connect. Then perhaps these countries will begin enforcement within their own countries. The US is the target of the world for scamming. I for one, have had enough.


Re: Email adresses of group exposed

Jean-Paul
 

Rebonjour:

As part of my work involves InfoSec I have some experience:

1.Problem has No connection to what browser or email client you use.

2. A robot web crawler visiting the site and not a member can see the adresses in every quoted reply
eg On Sat, Jun 19, 2021 at 6:10 AM Colin Herbert via groups.io <colingherbert=
blueyonder.co.uk@groups.io> wrote:

3. The privacy and other setting of the groups user control page has no option to hide any email address in a message or quoted reply.

4. Once your address appears, only a matter of time before its sold with millions of other adresses to the spammers.

5. The solution is not with responsibility of group members but for the admin and Groups.io to fix the security gaps that permit complete email adresses to be publicly seen.

6. The Groups.io admin can find may other groups that have fixed this issue.

Best regards.

Jon


Re: 465M

Ananda
 

Update:

I found the hard way that the Time base/horizontal module was the culprit. It has done some sort of damage on the interface board.

I was able to source another 465M which had a different problem on the display. It was fuzzy and was not a straight line but some funny shape which is hard to explain. Anyway, I got it knowing that it had a working main board and HV parts. Thinking that the funny display was due to the time base, I moved the time base module from my first scope to this second unit which was a bad decision as it started doing the same thing-blowing the fuse!

I was able to find yet another main board and a time base module. These two, along with the vertical module and the power supply (transformer and the heat sink etc.) from my first scope worked like a charm. I had a known good CRT to go with it and the trace looks very clean and well defined now.

Now there is another question for anyone who can help. Why would the trace blank for a split second every now and then?

Thanks for any ideas.


Re: Indy! Why does the floor move?

John Griessen
 

On 6/19/21 8:32 PM, Clark Foley wrote:
some maintenance under building 13 at Tektronix led to the discovery of something long forgotten.
See the latest posting from VintageTEK Museum, "Ceramic CRT Molds Found."
https://vintagetek.org/15109-2/
(Sallah says to Indiana Jones when they open the Well of Souls, "Indy! Why does the floor move?")
That is so fine to see those molds. I've done a lot of molding for art's sake...

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