Date   

Re: TM506

Stephen
 

On Tue, Jul 21, 2020 at 10:49 AM, Hugh Vartanian wrote:


Hey, Stephen,

No need to invoke any deities here (to the "praying" sign-off in a recent
post), or to threaten your new instrument with re-incarnation as a paper
weight! As previously stated, no rocket science is involved.
Everything you’re familiar with seems simple. I’m obviously out of my comfort zone, and I admit it.

If you can build guitar amps and handle logical/conditional functions in software,
this will all yield to you!
Yes, that’s easy for me.

Same with the transistors in the mainframe. Know that the "don't fix
anything that isn't broken" adage ought not be scoffed at. It will be
better to understand and troubleshoot what you have with some directed
surgical intervention to start, rather than draining your time and energy
changing a bunch of stuff that doesn't need changing, or breaking other
things that aren't now broken, but for the intervention.....
I get the point, and I would usually agree with that. I just want to replace them to start fresh.

Caveats to this judicious change-them-all strategy, surely are the "known"
failure rate of certain components based on history, and whether you are
close to something known to be an issue (i.e. 4 hours into mechanical
disassembly).
Agreed

(I confess to being, within reason, an all-or-nothing
capacitor changer!)
So am I in 50yo guitar tube amps.


Good luck, keep doing the research (multiplexed displays, linear power
supplies, transistors, tek manuals and circuit descriptions, this group and
its history, etc.), ask questions when you are stuck, etc. The problems
will yield.
Thank you.


Re: TM506

Stephen
 

On Tue, Jul 21, 2020 at 09:20 AM, Harvey White wrote:


Aha, tactical problem easily fixed.

There's lots of ways the connectors can be numbered, generally all
confusing.  What you're looking at is the connector maker's nomenclature.

Tektronix (go the the TEK WIKI and get LOTS of documentation on the
frames), started at 1 and went to 28 ON BOTH SIDES.  The board parts
side is side A, and the mostly trace side (bottom) is side B.

Pins 1 (A and B) are at the bottom of the module as seen with normal
module insertion.
I figured it out. The ones I bought (TIP35C and 36C) have the collector in the middle,
but the base and emitter reversed from the ones already installed. I’ll run wires.

The NPN pass transistor for slot 5 (the one before the High Power slot) has all pins shorted. That would be 6A, 7A, and 7B on the connector.


Re: TDS794D with broken Hard drive

Reginald Beardsley
 

I've got a similar size (2-6 GB) IDE drive you can have for shipping, however, I'm in the US, so it may not be worthwhile. When I swap drives I put the old ones in trays so I can swap them. I've got a couple dozen with various operating systems on them (Plan 9 anyone?). I rarely use the small ones now as nothing will fit on them.

Reg


Re: RM545B Looking for a good home (Austin, TX)

Reginald Beardsley
 

And I have an RM545A Tek manual for media rate postage.

Reg


Re: 11801 diagnostic help

Reginald Beardsley
 

Do an auto setup, That display is symptomatic of a bug in the 11801. I see it *all* the time. When I do, I do an auto setup and then reset things. Sometimes it requires an "initialize". Quite annoying.

I still haven't figured out what setting causes it after *many* hours with my 11801.

I just coughed >$$$ to chipxs for an SD-30, but also lucked out and snagged an SD-24 for <$90 all up.

And this is *all* Leo Bodnar's fault! If he hadn't sent me a CSA803A plot with the pulser I bought from him I would never have done this ;-)

You might want to check out this thread:

https://www.eevblog.com/forum/rf-microwave/testing-rf-connectors-and-cables/msg2640531/#msg2640531

Lots of TDR porn.

Have Fun!
Reg


Re: 11801 diagnostic help

John Gord
 

Per,
It looks like you are using a very long delay (30us or so). Can you use a much shorter delay? You may just be seeing the actual jitter of the signal from one edge to another edge 30us later, or you might be seeing the jitter of the delay generator in the CSA 803A.

--John Gord

On Tue, Jul 21, 2020 at 08:04 AM, Perdad wrote:


Hi,

New to this forum and I have tried to search it for relevant answers but
without luck. This thread seems to have a lot people knowling a lot so trying
my luck.

Just bougth an CSA 803A on eBay. The units works fine in that i passes Self
Test and Extended Diagnostics without any error.
I have a SD-14 and a SD-24 head. Using external trigger or using the internal
Pulse Generator for TDR works fine.

The problem is the Calibrator and Clock outputs that have a very severe noise.
See picture:
https://www.dropbox.com/s/1577fnl5d48iui2/Calibrator_Jitter_CSA803C.jpg?dl=0
Tracing back it looks as if the 'Strobe Drive Board' is the problem. Any
guidance would be helpful.

)) Per


Re: TM506

Hugh Vartanian
 

Hey, Stephen,

No need to invoke any deities here (to the "praying" sign-off in a recent
post), or to threaten your new instrument with re-incarnation as a paper
weight! As previously stated, no rocket science is involved. If you can
build guitar amps and handle logical/conditional functions in software,
this will all yield to you! Pull the data sheets for those chips (love the
truth tables), read up on multiplexed displays (previously covered in an
earlier post), probe around with the scope a bit (assuming you have access
to one*) and you will figure it out.

Same with the transistors in the mainframe. Know that the "don't fix
anything that isn't broken" adage ought not be scoffed at. It will be
better to understand and troubleshoot what you have with some directed
surgical intervention to start, rather than draining your time and energy
changing a bunch of stuff that doesn't need changing, or breaking other
things that aren't now broken, but for the intervention.....

Caveats to this judicious change-them-all strategy, surely are the "known"
failure rate of certain components based on history, and whether you are
close to something known to be an issue (i.e. 4 hours into mechanical
disassembly). (I confess to being, within reason, an all-or-nothing
capacitor changer!)

*A multimeter on dc and ac ranges will tell you a lot in a pinch, are
signals stuck and/or are they doing "something", but please reference
the name of this newsgoup and get a scope if you don't have one. With the
scope, work to pick a sensible signal to trigger on, like the common pin
for the first display, presumably out of the 74145 chip (ok, I haven't
looked at the schematic, but guessing from the chip datasheet!). Just like
debugging a program, start a trace at a breakpoint in the code and probe
away.

Good luck, keep doing the research (multiplexed displays, linear power
supplies, transistors, tek manuals and circuit descriptions, this group and
its history, etc.), ask questions when you are stuck, etc. The problems
will yield.

We love this stuff, as if you couldn't tell.

-Hugh V.


Re: 485 Cordwrap Feet

Jeff Davis
 

Hi Michael,

Thanks for the photo - that's what I pictured from the drawing in the service manual. I'm still mystified how my customer's 485 came by the feet he sent me.

Jeff

________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Michael W. Lynch via groups.io <mlynch003=yahoo.com@groups.io>
Sent: Tuesday, July 21, 2020 1:46 PM
To: TekScopes@groups.io <TekScopes@groups.io>
Subject: Re: [TekScopes] 485 Cordwrap Feet

Jeff,

My 485 does not have cordwrap feet as such. I suppose it just has something like the 2465 series? I posted a picture in the photo section.

Here:

https://nam12.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgroups.io%2Fg%2FTekScopes%2Falbum%3Fid%3D250894&amp;data=02%7C01%7C%7C547ce97c1b73422019b808d82db71f2d%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637309611805858729&amp;sdata=DZOMfXYDeyeHixyq0T8JvYoC%2F18Ysvd3Z47aI7iAr9g%3D&amp;reserved=0

Hope this helps.

--
Michael Lynch
Dardanelle, AR


Re: TDS794D with broken Hard drive

DaveC <davec2468@...>
 

IDE to SATA adapter? That would give you a better selection of drive options. No increase (a la SATA) in speed, though.

Dave

On Jul 21, 2020, at 2:07 PM, Valentin <val72ua@...> wrote:

Hi.
Compact Flash Card Industrial Grade:
https://www.transcend-info.com/Embedded/Products/No-701
and
CF to 2.5’’ IDE adapter like this:
https://www.ebay.com/c/1939054857

Best regards,
Valentin

21 июля 2020 г., в 22:06, Holger Lübben <tekscopesinput@...> написал(а):

Hi!

I have a TDS794D with a dead Hard Disk.

The original drive is a 3.2GB Fujitsu MHD2032AT with an IDE interface.

Does anyone have any suggestions for a modern replacement?
What is the maximum capacity that can be installed?

Holger





Re: TDS794D with broken Hard drive

Valentin
 

Hi.
Compact Flash Card Industrial Grade:
https://www.transcend-info.com/Embedded/Products/No-701
and
CF to 2.5’’ IDE adapter like this:
https://www.ebay.com/c/1939054857

Best regards,
Valentin

21 июля 2020 г., в 22:06, Holger Lübben <tekscopesinput@...> написал(а):

Hi!

I have a TDS794D with a dead Hard Disk.

The original drive is a 3.2GB Fujitsu MHD2032AT with an IDE interface.

Does anyone have any suggestions for a modern replacement?
What is the maximum capacity that can be installed?

Holger



Re: 485 Cordwrap Feet

Michael W. Lynch
 

Jeff,

Looking at 2 different manuals, one from 1977 and one from 1978; both show the same 2465 like cabinet foot P/N348-0298-00 and no indication of any other type ever being used. The manuals that I have list parts from S/N B010100 and up, so it would appear that these units all use the same part. Perhaps you could somehow incorporate the 465 cord wrap feet into the 485 style cabinet foot?

--
Michael Lynch
Dardanelle, AR


Re: 485 Cordwrap Feet

Michael W. Lynch
 

Jeff,

My 485 does not have cordwrap feet as such. I suppose it just has something like the 2465 series? I posted a picture in the photo section.

Here:

https://groups.io/g/TekScopes/album?id=250894

Hope this helps.

--
Michael Lynch
Dardanelle, AR


Re: TM506

Harvey White
 

Aha, tactical problem easily fixed.

There's lots of ways the connectors can be numbered, generally all confusing.  What you're looking at is the connector maker's nomenclature.

Tektronix (go the the TEK WIKI and get LOTS of documentation on the frames), started at 1 and went to 28 ON BOTH SIDES.  The board parts side is side A, and the mostly trace side (bottom) is side B.

Pins 1 (A and B) are at the bottom of the module as seen with normal module insertion.

The low numbered pins are power connections and the two pass transistors.  Pins 14A/B through 28A/B are reserved for module connections and have little or no standard for connection. They're reserved on the backplane so that the various slots could be dedicated to a particular module which is connected on the backplane to another dedicated module slot.  The power supply tester module (tek built but I don't think ever released to the public) uses only pins 1A/B through 13A/B

Many of the modules (especially digital ones) have 7400 series TTL which draws a LOT of power.  To keep the power dissipation in the plugin down, depending on the module, the +5 could be made in the module, but with the NPN pass transistor used mounted on the frame.  (3 volts minimum across transistor is good design,  11.5 volts supplied as bulk, and the 5 volts needed gave you 3.5 volts or so to play with).

The old S100 bus computers had an 8 volt bulk supply, used 7805 regulators on the boards, which regulators needed a 3 volt drop to work properly.  Some newer regulators don't need that large a drop.

Check the supply currents on your counters from the manual, you'll see they need a lot of power for 5 volts.  Some later designs (TM5000), sometimes had a switching regulator in the module for the 5 volts, as did some tektronix scope plugins that needed a LOT of 5 volts.

Harvey

On 7/21/2020 3:40 PM, Stephen wrote:
On Mon, Jul 20, 2020 at 10:54 PM, <scm@...> wrote:

You should be able to figure out what the pinouts are with an ohmmeter.
According to my diagram, the collectors go to pins 7B (NPN) and pins 11B
(PNP); the emitters go to pins 7A (NPN) and pins 10A(PNP) and the bases go to
pins 6A(NPN) and 11A(PNP) on the backplane connectors. Also the collectors are
the metal cases if the package is T03 or other metal case from that vintage.
I assume that by 7A or 7B etc..., you’re referring to the side on which the pins are. But I don’t have that. I have pin 1 to 28 on the right side, and A to AF on the left side. That’s when looking at the unit from the front, with the High Power slot (being the 6th) and the POWER switch on the right.
BTW, on the 5th slot, pins 7 and H (the one across) have continuity... They shouldn’t.



Re: TM506

Stephen
 


Re: TM506

Stephen
 

On Mon, Jul 20, 2020 at 10:54 PM, <scm@...> wrote:


You should be able to figure out what the pinouts are with an ohmmeter.
According to my diagram, the collectors go to pins 7B (NPN) and pins 11B
(PNP); the emitters go to pins 7A (NPN) and pins 10A(PNP) and the bases go to
pins 6A(NPN) and 11A(PNP) on the backplane connectors. Also the collectors are
the metal cases if the package is T03 or other metal case from that vintage.
I assume that by 7A or 7B etc..., you’re referring to the side on which the pins are. But I don’t have that. I have pin 1 to 28 on the right side, and A to AF on the left side. That’s when looking at the unit from the front, with the High Power slot (being the 6th) and the POWER switch on the right.
BTW, on the 5th slot, pins 7 and H (the one across) have continuity... They shouldn’t.


485 Cordwrap Feet

Jeff Davis
 

I had a customer approach me about developing a replacement cord wrap foot for the Tektronix 485. He sent me one of his that was mostly intact - but it led to some questions that I'm now posing to the group.

The 485 service manual shows that the cord wrap looks a lot like the cord wraps on a 2465, i.e. two assemblies, one right side and one left side, that extend from the bottom to the top, and the cord wraps around the two of them.

On the other hand, what my customer sent to me looked more like a foot from a 465, i.e. 4 pieces, one on each corner, with flanges to hold the cord. The cord wraps around the four pieces located at each corner.

Did early and later versions of the 485 have different cord wraps? If so, are they interchangeable? I can only find one version of the service manual, and it shows the 2465-like cord wraps.

Would greatly appreciate anyone who could shed light on this mystery.

Thanks,
Jeff / N0DY
www.n0dy.com


Re: Cleaning the screen of a TDS744A ?

David Slipper
 

Many thanks :-)

Dave

On 21/07/2020 17:10, Roy Thistle wrote:
On Tue, Jul 21, 2020 at 01:35 AM, David Slipper wrote:

What is the best way to get greasy finger prints off the plastic sheet that is
in front of the CRT

From page 6-5 in Zenith's scan of the "TDS 684A & TDS 744 Service Manual" on Tekwiki at
http://w140.com/tekwiki/images/d/d6/070-8992-02.pdf

"Clean the light filter protecting the monitor screen with a lint-free cloth dampened with either isopropyl alcohol or, preferably, a gentle, general purpose detergent-and-water solution."


It appears... looking at the mechanical parts drawing... the "light-filter" is not a separate numbered component (not listed as such, in the "Mechanical Parts List") but is part of/comes with the front panel assembly? or with the display frame? So how do you remove it? So what's the "plastic filter's" material? could be acrylic or polycarbonate? ... and it's hard to tell the difference between between acrylic and polycarbonate, just by looking.

For the nervous, who want to do de-fingerprinting service... I'd start with the lint-free (supposed to be really lint free, and anti-static is better too... like Kimwipes)... I'd start with the general purpose detergent (a.k.a., mild dish detergent) and lint-free cloth... and then move up to the alcohol...if detergent doesn't work.
For fingerprint "grease" (fingerprint "grease" isn't just grease)... a detergent, and water, solution works better than the alcohol, in my opinion... in the following way. If you can remove the plastic filter?, clean it with the detergent solution, and then flush the soapy filter with distilled water... preferably, from a squeeze bottle... so you get a pressurized stream... this flushes the hopefully emulsified, and dissolved, fingerprints from the plastic filter.
Other solvents are a big no-no... they are probably going to damage the plastic... so no acetone, naptha, et. al.



.


TDS794D with broken Hard drive

Holger Lübben
 

Hi!

I have a TDS794D with a dead Hard Disk.

The original drive is a 3.2GB Fujitsu MHD2032AT with an IDE interface.

Does anyone have any suggestions for a modern replacement?
What is the maximum capacity that can be installed?

Holger


Re: rackmouint 545B on CL in Austin

Chuck Harris
 

Your post came through just fine. Attachments are not allowed
on this group.

-Chuck Harris

Steve Raasch wrote:

Hi -

That's my ad. I posted to this forum first, but am a new user, and I guess the moderator didn't care for it.

That picture is NOT mine, but mine is in very good shape. Very clean and worked the last time I plugged it in, though that was a long time ago.
There's even some interesting history that I'll share with whoever takes it.

-Steve




Re: 7J20

Kurt Swanson
 

Dennis,

Should the time come come to part with the 7J20, I will certainly keep you in mind. As I mentioned before, I'm really not fishing for a buyer: I also have a long unfulfilled interest in optical spectroscopy. which is why I grabbed this thing in the first place. Unfortunately, it is also now pretty clear that I will likely never find the missing parts, so I will likely just hold on to it, and when the time comes, it would likely be part of an interesting trade.

In the mean time, if anyone turns up a J20, please let me know.

Thanks - Kurt