开云体育

Adrian,

My 7912AD runs happily with no extra cooling, I think the interior layout is designed to pull air past the major boards. I have had it running for a couple of hours with no problems. The graticule and main intensities change markedly in the first 10 minutes or so but this is mentioned in the manual.

Most of your images that look 'wrong' have multiple spots rather than continuous traces and I notice you still have the graticule turned on even though the brightness is fairly minimal. One image shows a graticule with rotated and misplaced spots. Try turning the graticule intensity down to minimum, that should turn the graticule generator off and remove one of the possible culprits.

When it is working it looks really good!

Roger

On Tue, 03 Jul 2018 22:46:01 -0700, you wrote:

Hi Keith,
If you have the extension shaft to pot couplers available, I'd be very interested. They are the cast aluminum with plastic insert ones with 2 #4 set screws, like on the "var" knobs on the voltage combo controls. I have 2 that are broken that i cobbled together some Mexico style repairs on. One with shrink tube because the plastic was broken, the other with a brass standoff that i drilled and tapped. I could probably use a few other small parts too. Like the cord wrap plastic tabs. I'll look up the proper names if you want me to.

If they are the same as the ones in a 7A18, 7A26 and so on, I may have
some. What's the shaft diameter?

Harvey

Thanks, Russ

Hmm, I think we are getting there! See 'Getting there'* in album:

/g/TekScopes/album?id=62098&p=Name,,,20,1,0,0

So what did I do? Well not a lot except move the stuff to a different bench and, more importantly I suspect, switched things on early today before the sun moved round - well, ok it stayed still(ish) but the planet rotated - and started warming up the barn.

It ran happily for about 15 minutes then collapsed in a heap again, let it cool off for 5 minutes and it ran for a couple more then failed again. So something is getting hotter than it likes.

There is no cooling in this thing other than in the PSU, I wonder if it was assumed it would be mounted in a blown rack? I've put it up on blocks with a desk fan blowing across it and we'll see if that helps but I'm going to swap out all the tant caps I can see on A38 and A28 for a start!

* Sorry about the Non-Tek scopery lurking in the background - hope I don't get struck off!

Thanks again for all the help and advice,
Adrian

I'm sure this problem is fully on the 7854 side. Do by any chance these WW
articles have any info on 7854 readout mods? Any hint where I could
find/download them?

Best Regards,
Nenad Filipovic

The same article (as 7L5) was also in the 7854 archive. There were no other specifically for this problem
There was another about readout issues which may, or more likely, may not fix your problem.
You can find it here:

/H?kan

Hi Keith,
If you have the extension shaft to pot couplers available, I'd be very interested. They are the cast aluminum with plastic insert ones with 2 #4 set screws, like on the "var" knobs on the voltage combo controls. I have 2 that are broken that i cobbled together some Mexico style repairs on. One with shrink tube because the plastic was broken, the other with a brass standoff that i drilled and tapped. I could probably use a few other small parts too. Like the cord wrap plastic tabs. I'll look up the proper names if you want me to.

Thanks, Russ

I didn't realize I had that exact same scopemobile, here are some pictures of the drawer that may or may not help :

/g/TekScopes/album?id=62217

As you can see there are no runners or anything, and the thing at the top of the back obviously keeps it from falling out. In the last picture you can see that the drawer is lockable by that hole, which I checked and it does have corresponding hole on the main thing. (I don't want to call it a mainframe of course)

As far as I can see, you probably need brute strength to get it to come out. If it is not locked then, what else is there ? No rails no nothing. It just fits in the space.

In the back it seems to have a recess but it ends with a piece of sheet metal that blocks any attempt to push from the rear. The handle is attached by 2 screws and that's it. Your work is not cut out for you.

My best recommendation at this time is to pry between the lo locking surface you see in the last of the photos where it mates with the main thing. Ideally if you have the right prying tool (fat chance) you should attempt to attack it from the side as high as possible, as close to the drawer and the frame as you can get to avoid bending it all up.

Sorry I didn't catch this earlier, there is a handle from a 422 that's been giving me the blues obscuring the model number. Nit bottom line, there are no complex runners or rollers or any of that shit. Looks like they wanted to hold to the KISS theory on that.

If you have other people around you might be better off prying on all the points at once, that should minimize any damage. Two on the handle, two on the bottom. One guy each side. Or your olady if you have one, this is not like pulling a car out of a ditch.

(one time when I was young the cops gave us until the tow truck got there to get my car out of the ditch, we did ! I was driving sideways on slicks through the park with ice and snow. If that wasn't stooopid enough, I had bald tires in the front, three guys pushing and me on the clutch to get us out)

Anyway, a bit of "friendly" persuasion should do it.

On Mon, Jul 2, 2018 at 04:21 pm, David C. Partridge wrote:

H?kan,

Do you have scans of the Wizards Workshop articles. They sound like an
incredibly useful reference.

Wizards Workshop was an internal Service magazine distributed to all Field Offices.
It contained service tips and mod info on pretty much any supported Tek product.
I don't recall how often it came, possibly on a monthly basis. Articles for each instrument
were then saved together on microfiche and added to the collection of the instrument.

So the answer to your question is no but I have pretty much all on microfiche.

Nedad, I'l check on 7854 tomorrow.
/H?kan

Adrian,

I don't know what the rep rate of your pulser is but if you aim for one or two cycles of a square wave or just two edges if the mark space ratio is very large, that should be an unambiguous trace. It looks like you have at present 1usec/div and many pulses per usec so a very detailed trace.

Regards,

Rpger

Thanks, Really enjoyed the story.

From: [email protected] [mailto:[email protected]] On Behalf Of
zenith5106

This problem was addressed In a WW (Wizards Workshop) article from 2-85

which

said it was fixed by Mod 50646. It is only a change of one resistor value

in the 7L5:

Change R2340 on the Vertical Board (A200A2) from 150k to 49.9k.
/H?kan

Hi H?kan,

Thanks for your response, I already tried all reasonable values of R2340.
In effect this means that I tested all TS1 ROW addresses from 2 to 9 (the
suggested value of 49.9k equals ROW=5). And although readout display
becomes perfectly correct for ROW values of 2, 4, 5, 6, 7, 8 and 9, in all
of these cases the 7854 Acquire command fails to obtain/set the scale
factor.

I'm sure this problem is fully on the 7854 side. Do by any chance these WW
articles have any info on 7854 readout mods? Any hint where I could
find/download them?

Best Regards,
Nenad Filipovic


On Tue, Jul 3, 2018 at 1:21 AM, David C. Partridge <
david.partridge@...> wrote:

H?kan,

Do you have scans of the Wizards Workshop articles. They sound like an
incredibly useful reference.

Dave
-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of
zenith5106
Sent: 02 July 2018 23:02
To: [email protected]
Subject: Re: [TekScopes] 7854 readout does not conform to specification?
(7L5 problem)

This problem was addressed In a WW (Wizards Workshop) article from 2-85

which

said it was fixed by Mod 50646. It is only a change of one resistor value

in the 7L5:

Change R2340 on the Vertical Board (A200A2) from 150k to 49.9k.
/H?kan

Thanks Roger, I'll look at that, the 7A29/7B90P and generators (one of leo Bodnars fast pulsers and an HP 8657B) produce sensible looking traces in a 7854 but that doesn't mean they aren't getting mangled in the 7912!

I have got through the calibration/adjustment procedure up to "Storage Triggering". My problems now are twofold. I can't understand Section #3 - "Check/Adjust Storage NORM Trigger DC Balance" (P4-89 in the manual). Apart from the fact that the storage triggering has a deal of jitter, I can't get step (e) to make sense. I am supposed to "use the A TRIGGER LEVEL to align the point where the sine-wave's leading edge intersects the center horizontal graticule line with the 2nd vertical graticule line". Because of the the jitter and the fact that the triggering fails when I adjust the A TRIGGER LEVEL, this is impossible. Am I doing something wrong (quite possible), or is the manual giving me the wrong information? Help!
If anyone has an idea of how I can eliminate the jitter, that would be nice, too. There is no jitter in "NON STORE" operation. I was hoping it would just be something simple like a switch needing cleaning, or an IC needing reseating, but nothing has given me any clues so far...
Colin.

Indeed it is now that I googled "Esterline Angus Chart Recorder."
Fantastic eye Tom. OK, since I do not own an Esterline Angus Chart
Recorder, is there anyone in this group that has one that matches this? And
who wants it? Let me know.

It's the front from an Esterline Angus chart recorder.


And if anybody knows what the glass part on the right

So, just fyi.. I went back to the PO and asked "What about the media mail
option?" ... Bascially, it was "Oh, that? $3.17" (for what was originally
$11.80). Pretty shocked that, like Dave says, they neglected to offer that
option in the first place when I requested "least expensive shipping
option."

On Tue, Jun 26, 2018 at 2:38 PM, Artekmedia <manuals@...>
wrote:

They are trained NOT to tell you. You have to ASK for it or as the
previous poster said it is available through PayPal shipping includes
tracking. Tell them it just a "manuscript" and DO NOT INCLUDE any
correspondence. You put a one page letter in there and suddenly it is a 1st
class mail

For a description google is your friend

-DC
ArtekManuals.com

On 6/26/2018 1:40 PM, John Griessen wrote:

On 06/26/2018 11:26 AM, David Berlind wrote:

what is "media mail?" when I go to the post office, they offer me a slew
of options.. but "media mail" is not one of them.

use paypal shipnow to get a label for media mail with a little extra
discount.

--
Dave
Manuals@...
www.ArtekManuals.com

"No kidding, CWRU offered you a job? That's my alma mater; I got my BSEE there in 1988."

Actually it came through a friend of mine who works there, said he was sure I would get it. I taught him basic electronics decades ago. He offered to introduce me to the right people etc., which was nice of him but then, if someone vouches for you, and you don't do well... And I had no experience with anything of the type. I had a pretty good job at the time anyway so, so much for that.

They're simply called Case now. All their emails changed to @case.edu.

They are one of the better schools around though, not a diploma mill to say the least. I hear they got a bio hazard lab level whatever that is, well not quite like the movie Andromeda Strain, but there aren't many outside the government.

Foreign enrollment in US schools has dropped, but places like Case, UWM, MIT and some others are still pulling them in from all over the world. So I'm told anyway.

Dave,

It IS all there in the schematics, I just managed to miss the crucial one! Schematic <14> is the updated 6802 processor board, it uses 4k EPROMS instead of 1k EPROMS and the SRAMs are also four times the density so the memory fits on the CPU board.

Aside to Adrian and Chris:

The right hand side of the TV image that Adrian uploaded shows what looks like the beginning of a 'sensible' trace at the top of the screen. That adds to the feeling that the 7912 is trying to display a very strange signal. When the display blooms due to charge spreading in the target (and some bending of the read beam) it rapidly loses any fine scale detail and I wouldn't expect it to look like Adrian's XY images even after thresholding.

Roger

Yes, thanks Colin! And if anybody knows what the glass part on the right is
(in the original photos) and wants it, please let me know. Someone
suggested it might be a blast shield of some sort. But I don't see how it
can be affixed to the OS-245 (the milspec 7603).

On Tue, Jul 3, 2018 at 9:39 AM, Colin Herbert via Groups.Io <
colingherbert@...> wrote:

For anyone who is following this thread, I took three photos and some
measurements of the catches on my 7623A Option #8 and emailed them to
David. I wasn't too sure that I should be putting these photos on the Forum
and I wasn't confident that I knew how to, anyway. I also gave him the
address of Nielsen Hardware, but they don't seem to list the catch and have
an eye-watering minimum order, apparently.
So, if anyone has an option #8 that they are parting-out, I reckon David
would like to hear from you.
Colin.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of David
Berlind
Sent: 02 July 2018 20:34
To: [email protected]
Subject: Re: [TekScopes] What are these Tek parts for?

wow.. awesome . .thanks for providing that. Yes, would love some photos and
do you know where I can go to get those parts? Or, am I really just subject
to digging around the aftermarket?

On Mon, Jul 2, 2018 at 3:29 PM, Colin Herbert via Groups.Io <
colingherbert@...> wrote:

I have a 7623A with option #8 (the front cover). The catch hooks on the
scope itself also have a thicker metal stand-off under the hook. If you
can't get the proper items, I can take some measurements and photos to
help. The relevant Tek part numbers are:

105-0390-00 Catch, clamping Nielsen
Hardware Corp. Part No. SC-B-83314
213-0119-00 Screw, tapping, 4-24 x 0.375 inch, pan head, steel.
Central Screw Co.
361-0480-00 Spacer, latch
Tektronix

Good Luck, Colin.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of

David

Berlind
Sent: 02 July 2018 16:58
To: [email protected]
Subject: Re: [TekScopes] What are these Tek parts for?

OK. It appears you are correct about the left part. I now realize that my
OS-245 (milspec 7603) is missing the receiving side of the clips to which
the cover attaches. I've added photos to the aforementioned online image
album <>. So, I'd like to

find

those clips if someone know where I can get them. Either that, or I'll

have

to fabricate them. I bump into these sorts of clips all the time (trying

to

think if there something around the house I can harvest them from).

But the other part pictured does not match up to anything I can tell.

On Mon, Jul 2, 2018 at 6:43 AM, Colin Herbert via Groups.Io <
colingherbert@...> wrote:

One of those looks like the front cover for a series-7000 scope (option
#8). It even still has the foam bits for holding probe parts. I've no

idea

what the other thing is, but could it be some kind of implosion screen?
Colin.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of

David

Berlind
Sent: 02 July 2018 02:14
To: [email protected]
Subject: [TekScopes] What are these Tek parts for?

Two parts... some sort of cover.. but I don't think it's for anything I
own. Smells like an old Tek scope too! If I have no need for this and
someone else does, I'd be happy to stick it in a box if you cover

postage.

For anyone who is following this thread, I took three photos and some measurements of the catches on my 7623A Option #8 and emailed them to David. I wasn't too sure that I should be putting these photos on the Forum and I wasn't confident that I knew how to, anyway. I also gave him the address of Nielsen Hardware, but they don't seem to list the catch and have an eye-watering minimum order, apparently.
So, if anyone has an option #8 that they are parting-out, I reckon David would like to hear from you.
Colin.

Roger

I think the 6802/MPU info is? in the Change section at the end of the manual. Why Tek did not include an updated schematic I? cant say unless the schematic didnt change ?

Dave
manuals@...

--
Dave
Manuals@...
www.ArtekManuals.com