Date   
Re: 100 Tek Photos

John Miles
 

I love the drop test in img159.jpg. The look on the (engineer's?) face says it all!

-- john, KE5FX

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Kurt
Rosenfeld
Sent: Wednesday, September 11, 2019 8:01 AM
To: TekScopes@groups.io
Subject: [TekScopes] 100 Tek Photos

https://drive.google.com/drive/folders/1YoJB_t2OX3jd6xqaJcXolzmO09kzH8zU

I didn't take the photos and don't know anything about them. All I did is scan
them. Enjoy.

Re: 577 step generator stopped working

DW
 

Thanks for are the replies

Using a volt meter I decided to check both Q384 AND Q386 pulled out of circuit.
+ is positive meter probe and - and negative meter probe Fluke 77IV

Q384
+E -B 5.744k
+B -E 0.742V
+B -C 0.618V
Reverse polarity check test passed

Q386
-E +B 5.587k
-B +E 0.712V
-B +C 0.659V
Reverse polarity check test passed

I think both transistors are okay. Now is a good time to order new thermal insulators for these transistors. I hear thermal insulators can fail eventually over time.

Re: 7603 filter caps - ripple voltage and Adapters

Roy Thistle
 

On Sat, Sep 7, 2019 at 04:01 AM, tinkera123 wrote:


the Ripple current data
Yes, I take Iac,max, to be the maximum ac ripple current, at the listed temperatures (across the table header row), for the B41262, 105 degree C rated capacitors. The R in the Iac,R refers to "reference"... I thinks it's used somewhere, as a parameter, in the engineering equations.
Everything else being equal, you could take the ripple current as being twice the load current, but, that's very approximate.
If someone has an old Sprague catalog, maybe you could match the ripple current of the replacement to the Sprague one.
Nichicon and Panasonic brands are reputed to be good.
Everything else being equal, heat is the biggest enemy of Aluminum electroytics, both external (ambient), and internally generated heat.
Assuming the same ambient heat, and a good manufacturer, if you choose a higher temperature rated capacitor (say 105 C, or higher, relative to 85 C)... then the game says you will get better life, and less failure; but spend more money. The caps should be more heat tolerant, and live longer.
replacement of just the dead cap?? or replacement of all 7 filter caps on this Board?
Well how long have they been cooking in there for? As I recall the 7603 has a pretty compact linear power supply, with the transformer near those filter caps, to help cook them. You could measure the capacitance and esr, in circuit... maybe. Once you take them out to measure them... seems like... unless you're ultra cheap like me... seems like a waste of time to solder those old ones back in again. You could replace the bad one and look to see if the ripple is in spec. If you are operating the 7603 (or it has been operated) for long on periods, or in a "hot" location, or clogged up fan... maybe the other filter cap(s) are cooked out, or will cook out too, relatively soon.. or maybe not. For me, I don't like "operating" on a circuit board, unless I have to.

Re: 2465 DVS Repair - was; Re: [TekScopes] Wanted; Person to repair Tektronix 2465 DVS

jhalbrecht
 

I got the paddle switch out of the donor without incident.

Chuck and group,

Perhaps I could check some voltages on the 2465 dvs (original / first model) A5 board next in an attempt to solve the "Test 05 Fail 42' triggering problem before digging into replacing the paddle switch into the 2465 switch board assembly.

 - Jeff

On 9/10/2019 5:21 PM, jhalbrecht wrote:
Thanks Chuck,

Progress report.

This afternoon I started with the 2445 donor. I got all the knobs off and the bezel without breaking any of it. Another fella contacted me wondering about the bezel from the 2445. I wonder if there are different version of the bezel? This one has GPIB status lock / Srq / Rem.

O.K. Guess I'll see if I can extract the paddle switch assembly.

Thank you for your help and encouragement. Other list(s) members too.

 - Jeff

On 9/8/2019 3:01 PM, Chuck Harris wrote:
Certainly.

Remove the four torx screws in the rear feet, and the two torx screws
in the center top and bottom of the rear panel.  They are different
sizes.

Using a pair of needle nosed pliers (really thin pointed nosed pliers),
as prying tools, first lift, and then stick the points of the pliers
under the skirts of the grey knobs, that are under the CRT screen, and
pry them upwards.

[The pliers should be open, and their needle nose points should be
touching the knob skirts on either side of the shaft, and the body of
the pliers should be resting on the bezel edge, when you pry up gently.]

Remove the plastic strip along the top of the bezel.  It has an edge that
overhangs the bezel, and several tiny plastic fingers that break easily, so
be careful.  You will now see several flat head torx screws. Remove them,
and the several (including the feet) that are exposed along the bottom bezel.

The bezel ring will now come off.  Watch the poly carbonate protective sheet
that is in front of the CRT it will want to fall on the ground and get
scratched.

The panel unit on the right side of the scope is a mild press fit into the
finger stock around it, and has two ribbon cables, one grey, and one brown,
pcb material that need to be removed from the A5 controller card.

The panel unit unstacks when you remove the obvious screws here and there.

You should be able to figure out what you need to do with the paddle switch
at this point.

-Chuck Harris

jhalbrecht wrote:
On 9/8/2019 8:50 AM, Chuck Harris wrote:
The 2465 and 2445 do not have a battery, using an EAROM
instead.  It trades capacity, and number of write cycles
for the limited lifetime of a battery.
Any advice on how to replace the CH 2 coupling paddle?

  - Jeff


-Chuck Harris

jhalbrecht wrote:
On 9/6/2019 3:22 PM, Jeff Albrecht wrote:
On 9/6/2019 3:03 PM, Chuck Harris wrote:
The serial number is on the front panel.
s/n B030668

This is the hardest version of the 2465B scopes to work
on.  It is packed full of boards and cables that most don't
have.
I've pretty much decided to sell these rather than attempt to repair myself or hire
the work out. Still I keep thinking about making a stab at the repairs. I don't know
why but I feel a little guilty not fixing it. I'm prone to overthinking decisions a
bit...

Dropbox of images;
https://www.dropbox.com/sh/ul4i0xnaakb01gf/AADPNQDCigzyeN9vELEndWNJa?dl=0
I've added three new images since first sharing the link. IMG_5796 A5 board and
IMG_5803 main board. and IMG_5784 beam finder output.

I have a couple donor 2445 that have the coupling lever and  A and B SEC/DIV knobs.

Can anyone tell me the steps to replace the CH 2 coupling lever? Would I just need to
remove the front bezel? See IMG_5756.jpg.

Anything special to know or gotchas to replace those knobs?

Is there a test point where I can measure the current voltage of the settings backup
battery.

I have the service manual. I saw in a video there is a test point where you can
easily measure several voltages, but I can't find the chart of voltages and
tolerances for it in the manual.

Thanks, - Jeff







Source located for 1n3717 tunnel diodes

Malcolm S
 

I've noted that these parts are becoming rare and insanely expensive. I
purchased four of these from Standard Supply Electronics in Salt Lake City
(who recently absorbed Ballard Electronics' stock) for a surprisingly low
price; they honored the pricing Ballard set years ago. (I resisted the
temptation to buy 'em all, and I hope the TekScopes group will as well.
Don't hoard these, as those of us who actually need them should not have to
pay the astronomically exorbitant prices set by National Semiconductor and
the like.) There are now eight of these diodes left in stock, but you will
not find them inventoried on the store's website. You will have to contact
them directly by phone and ask their sales department about them. I hope
this is helpful for some of you. --Malcolm

Re: 100 Tek Photos

Bob Koller
 

Thanks!

In picture 142, I believe that Deane Kidd appears in the lower right of the frame.

100 Tek Photos

Kurt Rosenfeld
 

https://drive.google.com/drive/folders/1YoJB_t2OX3jd6xqaJcXolzmO09kzH8zU

I didn't take the photos and don't know anything about them. All I did is scan them. Enjoy.

Re: 2465 DVS Repair - was; Re: [TekScopes] Wanted; Person to repair Tektronix 2465 DVS

Chuck Harris
 

There are two bezels that I know about, differing in
the way the cover is installed. The older version has
a pair of latches on the right and left side. The newer
version uses a cover that has a lip that fits over the
edge of the bezel to latch.

-Chuck Harris

jhalbrecht wrote:

Thanks Chuck,

Progress report.

This afternoon I started with the 2445 donor. I got all the knobs off and the bezel
without breaking any of it. Another fella contacted me wondering about the bezel from
the 2445. I wonder if there are different version of the bezel? This one has GPIB
status lock / Srq / Rem.

O.K. Guess I'll see if I can extract the paddle switch assembly.

Thank you for your help and encouragement. Other list(s) members too.

- Jeff

Re: 2465 DVS Repair - was; Re: [TekScopes] Wanted; Person to repair Tektronix 2465 DVS

jhalbrecht
 

Thanks Chuck,

Progress report.

This afternoon I started with the 2445 donor. I got all the knobs off and the bezel without breaking any of it. Another fella contacted me wondering about the bezel from the 2445. I wonder if there are different version of the bezel? This one has GPIB status lock / Srq / Rem.

O.K. Guess I'll see if I can extract the paddle switch assembly.

Thank you for your help and encouragement. Other list(s) members too.

 - Jeff

On 9/8/2019 3:01 PM, Chuck Harris wrote:
Certainly.

Remove the four torx screws in the rear feet, and the two torx screws
in the center top and bottom of the rear panel. They are different
sizes.

Using a pair of needle nosed pliers (really thin pointed nosed pliers),
as prying tools, first lift, and then stick the points of the pliers
under the skirts of the grey knobs, that are under the CRT screen, and
pry them upwards.

[The pliers should be open, and their needle nose points should be
touching the knob skirts on either side of the shaft, and the body of
the pliers should be resting on the bezel edge, when you pry up gently.]

Remove the plastic strip along the top of the bezel. It has an edge that
overhangs the bezel, and several tiny plastic fingers that break easily, so
be careful. You will now see several flat head torx screws. Remove them,
and the several (including the feet) that are exposed along the bottom bezel.

The bezel ring will now come off. Watch the poly carbonate protective sheet
that is in front of the CRT it will want to fall on the ground and get
scratched.

The panel unit on the right side of the scope is a mild press fit into the
finger stock around it, and has two ribbon cables, one grey, and one brown,
pcb material that need to be removed from the A5 controller card.

The panel unit unstacks when you remove the obvious screws here and there.

You should be able to figure out what you need to do with the paddle switch
at this point.

-Chuck Harris

jhalbrecht wrote:
On 9/8/2019 8:50 AM, Chuck Harris wrote:
The 2465 and 2445 do not have a battery, using an EAROM
instead. It trades capacity, and number of write cycles
for the limited lifetime of a battery.
Any advice on how to replace the CH 2 coupling paddle?

- Jeff


-Chuck Harris

jhalbrecht wrote:
On 9/6/2019 3:22 PM, Jeff Albrecht wrote:
On 9/6/2019 3:03 PM, Chuck Harris wrote:
The serial number is on the front panel.
s/n B030668

This is the hardest version of the 2465B scopes to work
on. It is packed full of boards and cables that most don't
have.
I've pretty much decided to sell these rather than attempt to repair myself or hire
the work out. Still I keep thinking about making a stab at the repairs. I don't know
why but I feel a little guilty not fixing it. I'm prone to overthinking decisions a
bit...

Dropbox of images;
https://www.dropbox.com/sh/ul4i0xnaakb01gf/AADPNQDCigzyeN9vELEndWNJa?dl=0
I've added three new images since first sharing the link. IMG_5796 A5 board and
IMG_5803 main board. and IMG_5784 beam finder output.

I have a couple donor 2445 that have the coupling lever and A and B SEC/DIV knobs.

Can anyone tell me the steps to replace the CH 2 coupling lever? Would I just need to
remove the front bezel? See IMG_5756.jpg.

Anything special to know or gotchas to replace those knobs?

Is there a test point where I can measure the current voltage of the settings backup
battery.

I have the service manual. I saw in a video there is a test point where you can
easily measure several voltages, but I can't find the chart of voltages and
tolerances for it in the manual.

Thanks, - Jeff






AM700

 

Hi Folks!

Recently I acquired an AM700 crt type in working condition with firmware V1.0.
I searced in group messages for any advice but find very little.
Most of topic learn about leaking smd capacitors wich I plan to check and replace.
Another issue is I would upgrade firmware to last version, service manual tell about floppy disc set but nothing find on the net.
Have anyone an image of this floppy?

Best Regards
Juri

The eBay microfiche winner

 

Who won the "Tektronix Microfiche Library HUGE service manuals programming schematics probes" auction (eBay item number: 123893461525)?
What do they intend to do with it?

Dennis Tillman W7PF



--
Dennis Tillman W7PF
TekScopes Moderator

Re: The eBay microfiche sale

Chuck Harris
 

The problem with breaking the scan up during scanning is that
there is a melange of different sizes on each sheet. Most
pages will be 8-1/2 x 11, but some will be 8-1/2 x 48 or more.

A program like unpaper can set up masks using the large contrast
difference between the borders and the paper. But to do so while
scanning would take too much time. Later, after the job is scanned
would be safer, as you could fix mistakes that would be immortalized
by the scanning software.

There are better scanners... but most work to a slightly higher
resolution than the fiche is capable of displaying.

-Chuck Harris

A Rhodes wrote:

I looked at commercially available microfiche scanners. They have surprisingly low resolution! It is much better using even a 6400 dpi scanner.

Certainly it is feasible to scan an entire microfiche, post process, and then crop it up to 98 times. But I think it is feasible to do all that essentially automatically and save a 98 page PDF as the final output with the user input limited to providing a file name.

The hardest part would be getting the scanner driver to automatically recognize the 98 individual fields of the microfiche.

-Tony



Re: The eBay microfiche sale

John Ferguson
 

Sounds like a Deep Learning project.  Tensorflow. If only there were more time, and fewer things to do.

On 9/9/19 9:45 PM, A Rhodes wrote:
I looked at commercially available microfiche scanners. They have surprisingly low resolution! It is much better using even a 6400 dpi scanner.

Certainly it is feasible to scan an entire microfiche, post process, and then crop it up to 98 times. But I think it is feasible to do all that essentially automatically and save a 98 page PDF as the final output with the user input limited to providing a file name.

The hardest part would be getting the scanner driver to automatically recognize the 98 individual fields of the microfiche.

-Tony


Re: Need Help Troubleshooting Tektronix PS280

daven9ooq <daven9ooq@...>
 

Hi Everyone, Much to my amazement I got the Master side working! Dont know what I did, had the board kut from last week to check for hairline cracks, didn't find any, must have had a dodgey connection somewhere.
The master side is working now ,had to adjust the min. Volts for 0 was slightly negative, also the max volts was wide open showing just over 41volts adjusted it for 31volts.
I'm getting a nice smooth adjustment on the master voltage control from 0-31 volts, I'm not out of the woods yet, still need to check under load, and the ripple, but first need to get the slave side working, as well as the metering.
More good news , I have the load resistors I ordered, 2) -12 ohm 200 watt variable ,IIRC 15ohm  fixed 200watt  2ohm 100 watt., and one other I forget the value off hand.
Should be much easier to troubleshoot now, but still would like a better understanding of whats going on.
Now that one side is working  should be easy to check the other side to see what's going on.
Although it's questionable weather I need further help, I would like to gain a better understanding of how to follow signals through transistors and op amps and such .
I only got as far as ELE 101 introductory to electronics in college and that was quite some time ago before my 2 strokes, although I'm mostly self taught , since the early 60's.
I am a hobbiest!
Many thanks again! Dave n9ooq

Re: The eBay microfiche sale

A Rhodes
 

I looked at commercially available microfiche scanners. They have surprisingly low resolution! It is much better using even a 6400 dpi scanner.

Certainly it is feasible to scan an entire microfiche, post process, and then crop it up to 98 times. But I think it is feasible to do all that essentially automatically and save a 98 page PDF as the final output with the user input limited to providing a file name.

The hardest part would be getting the scanner driver to automatically recognize the 98 individual fields of the microfiche.

-Tony

Re: The eBay microfiche sale

Chuck Harris
 

Which is why I suggested renting a scanner that does
full sheet scans, going through the entire collection
at the maximum scan rate, and then crowd sourcing the
extraction, indexing, and protecting against license
violations. Doing that while you are scanning just
slows the process down needlessly.

All of the software you need to break up the full page
scans into individual sheets, and to convert the individual
sheets to pdf files is available for free in the open
source linux world. There are members here that can hold
the group's hands in doing the crowd sourced end of the
job.

Virtually every large company in the world has already
done this, the hardware is available.

-Chuck Harris

A Rhodes wrote:

Yes, it is hard or impossible to crown-source the scanning when it can be done only in one location at specified times of the day.

It would be wonderful to be able to send out a batch of microfiches to many individuals who are willing and able to use standardized techniques to do a nearly automated process of scanning and conversion.

Unfortunately thre
Is likely a very small pool of people with the time, and scanner with high enough resolution, and software capable of doing the image processing and saving in the appropriate format. The pool may be so small that it is effectively the same as the people able to go to Beaverton to do the work on the museum's hardware.

-Tony



Re: The eBay microfiche sale

John Griessen
 

On 9/9/19 6:47 PM, A Rhodes wrote:
Unfortunately thre
Is likely a very small pool of people with the time, and scanner with high enough resolution,
The Epson v300 and related series of printer products are very capable for small batch, though not automatic...

It's just that crowd-sourcing is kinda foreign to 70++ year olds...

Re: The eBay microfiche sale

John Griessen
 

On 9/9/19 6:47 PM, A Rhodes wrote:
Unfortunately thre
Is likely a very small pool of people with the time, and scanner with high enough resolution,
The Epson v300 and related series pf printer products are very capable...

Re: The eBay microfiche sale

A Rhodes
 

Yes, it is hard or impossible to crown-source the scanning when it can be done only in one location at specified times of the day.

It would be wonderful to be able to send out a batch of microfiches to many individuals who are willing and able to use standardized techniques to do a nearly automated process of scanning and conversion.

Unfortunately thre
Is likely a very small pool of people with the time, and scanner with high enough resolution, and software capable of doing the image processing and saving in the appropriate format. The pool may be so small that it is effectively the same as the people able to go to Beaverton to do the work on the museum's hardware.

-Tony

Re: 535A CRT in a 575 - clever trick?

ditter2
 

Tek had an option to the 577 that substituted a CRT with a 10 x 10 graticule. The ertical gain adjustment has enough range to handle either CRT.

Substituting CRTs in curve tracers is relatively easy, as BW is not a concern. The maximum BW either deflection system handles is less than 300 Hz, so swapping vertical and horizontal should work, but you do need to make sure the vertical amp has enough voltage swing to handle the deflection. w/o a CRT data sheet, you can determine the required swing by studying the schematics of the vertical and horizontal amps of the scope from which the CRT you plan to use comes from. Tek publishes waveforms at various points in the circuit for troubleshooting purposes. Look at the pk-pk voltages of the amplifiers output, and be sure to check the input conditions. The horizontal is usually the full sweep, but the vertical may be a pulse from ground to a peak level, which only uses half of the CRT dynamic range.

Steve