Date   

Re: 2465B - Weak Readout Intensity

 

Congratulations!!!

On Tuesday, February 4, 2020, 03:58:52 PM CST, flanneltuba@gmail.com <flanneltuba@gmail.com> wrote:

The replacement CRT arrived yesterday afternoon, so I promptly sequestered myself out in my unheated shop (in a drafty barn) in 30 degree weather to swap in the new tube. Before I could even think of installing it, I had the very frustrating task of straightening all the bent deflector pins on the neck of the tube, which had been badly bent due to shabby packing for its long trip from Israel. (Who was it on this thread that said something like, every time I order parts from Israel, I've regretted it?) So I spent the first 35 chilly minutes very carefully bending back the bent neck pins. Some of these are fairly stiff and made me cringe as I applied fairly strong mechanical pressure to them to straighten them. I did wear safety glasses and gloves in the event of catastrophic glass failure, all the while praying I would not create a metal-glass leak. Luck was with me, and the only detectable real damage was minor cratering of the glass at the base of the heavier pins.

So with that accomplished, I slid in the new (used replacement) CRT. Some tips on technique are due here which you won't find in the manual, which I had to learn the hard way: Because of the delicate pins on the neck of the tube, "sliding" the tube into the chassis must be done in a thoughtful and deliberate manner or you risk bending one or more of these pins if they contact the sleeve as it is being inserted. Two ways to mitigate this possibility are, 1) turn the scope onto its right side, so that as the tube travels into the sleeve, the inevitable pull of gravity on the neck of the tube will cause the neck to slide along its =side= where there are no pin connectors, or 2) set the chassis onto its back side and lower the tube into the sleeve from the top using your best Milton Bradly "Operation" game skills to avoid letting the neck pins hit the sides. It's helpful to position the chassis on the edge of the bench such that the back of the CRT sleeve is accessible from the the underside so you can support the tube in its final centimeter or so of descent, since your ability to grasp the front of the tube will be lost as it enters the chassis at the top. This second technique has the added advantage that the four corner support wedges sit nicely in place during the descent, which they aren't so happy to do in the first.

Ok, cutting to the chase! With the new tube mounted and all connectors in place, (with more Milton Bradly maneuvers required for the deflector connections), I fired it up. The new CRT came to life with a beautifully bright and clear display that would happily allow the intensity to go all the way up to full brightness.

SUCCESS!

Chuck Harris nailed it on the first reply on this thread.

Being that my hands were now quite frozen, (remember, I'm doing all this in a 36 degree barn) I decided to leave the rest of the alignment and intensity calibrations for another day.

Speaking of calibrations, one poster noted that after a CRT replacement a full calibration would be necessary. That doesn't seem quite right to me, but this is where my knowledge turns to conjecture. Obviously I will need to conduct all the CRT related adjustments, but my question for the group is, what other post CRT replacement calibrations are truly and absolutely necessary?

- Scott


Re: TDS3000B USB floppy emulator

Tom B
 

Hello Holger,

From what I have learned, the Gotek emulators are all similar but have different firmware.  The TDS3000 series use a 26 pin interface, so the cable is a bit different from the 420A.

Did you have to change the firmware on the Gotek?

I put a new floppy drive in my TDS3044B and it tells me it has invalid media.  The same disks work fine in my TDS3012B.  So, maybe I have another problem with the floppy interface.

Tom Bryan
N3AJA

On 2/4/2020 3:56 AM, Holger Lübben wrote:
Hi!

I've added a Gotek Floppy Emulator to my 420A a while ago.

A short description of the process can be found on Tekwiki:

https://urldefense.com/v3/__http://w140.com/tekwiki/wiki/TDS420__;!!KfGNmQmE!wN8Ltk3TxbwRZaIyPOH8iaFED41B21Z34RFv2O27dT43TyJkg7ks5iwLiVK3$

The exact model number of the emulator was very important and it was also a little bit difficult to find the right jumper settings.

Holger


Re: 2465B - Weak Readout Intensity

Chuck Harris <cfharris@...>
 

Really, the answer is yes.

The new CRT will certainly have different gain for its deflection
plates, its control grid will have a different curve to match.

The geometry plates will be a little different.

Tilt, and Y axis rotation will certainly be different.

And, the transient response is going to be different, because the
vertical deflection plates are really a lumped transmission line.

The manual says full calibration if you replace a major assembly...
the CRT applies.

That stuff said, you might be able to satisfy your own needs by
doing the CRT calibration, and the rotations.

The pots for vertical gain and centering, and Hx1, Hx10, and H-center
could be done without additional test equipment.

Worth a try... most won't notice the transient response... until
they get to the high frequencies.

-Chuck Harris



flanneltuba@gmail.com wrote:

The replacement CRT arrived yesterday afternoon, so I promptly sequestered myself out in my unheated shop (in a drafty barn) in 30 degree weather to swap in the new tube. Before I could even think of installing it, I had the very frustrating task of straightening all the bent deflector pins on the neck of the tube, which had been badly bent due to shabby packing for its long trip from Israel. (Who was it on this thread that said something like, every time I order parts from Israel, I've regretted it?) So I spent the first 35 chilly minutes very carefully bending back the bent neck pins. Some of these are fairly stiff and made me cringe as I applied fairly strong mechanical pressure to them to straighten them. I did wear safety glasses and gloves in the event of catastrophic glass failure, all the while praying I would not create a metal-glass leak. Luck was with me, and the only detectable real damage was minor cratering of the glass at the base of the heavier pins.

So with that accomplished, I slid in the new (used replacement) CRT. Some tips on technique are due here which you won't find in the manual, which I had to learn the hard way: Because of the delicate pins on the neck of the tube, "sliding" the tube into the chassis must be done in a thoughtful and deliberate manner or you risk bending one or more of these pins if they contact the sleeve as it is being inserted. Two ways to mitigate this possibility are, 1) turn the scope onto its right side, so that as the tube travels into the sleeve, the inevitable pull of gravity on the neck of the tube will cause the neck to slide along its =side= where there are no pin connectors, or 2) set the chassis onto its back side and lower the tube into the sleeve from the top using your best Milton Bradly "Operation" game skills to avoid letting the neck pins hit the sides. It's helpful to position the chassis on the edge of the bench such that the back of the CRT sleeve is accessible from the the underside so you can support the tube in its final centimeter or so of descent, since your ability to grasp the front of the tube will be lost as it enters the chassis at the top. This second technique has the added advantage that the four corner support wedges sit nicely in place during the descent, which they aren't so happy to do in the first.

Ok, cutting to the chase! With the new tube mounted and all connectors in place, (with more Milton Bradly maneuvers required for the deflector connections), I fired it up. The new CRT came to life with a beautifully bright and clear display that would happily allow the intensity to go all the way up to full brightness.

SUCCESS!

Chuck Harris nailed it on the first reply on this thread.

Being that my hands were now quite frozen, (remember, I'm doing all this in a 36 degree barn) I decided to leave the rest of the alignment and intensity calibrations for another day.

Speaking of calibrations, one poster noted that after a CRT replacement a full calibration would be necessary. That doesn't seem quite right to me, but this is where my knowledge turns to conjecture. Obviously I will need to conduct all the CRT related adjustments, but my question for the group is, what other post CRT replacement calibrations are truly and absolutely necessary?

- Scott




Re: 7000 horizontal plugins cheap

Martin Whybrow
 

Just what I'm after, unfortunately about 3,000 miles away from me.


Switch retainers for 7000 series plug ins

Martin Whybrow
 

I've just acquired a 7854 scope for a nice price; the 7B15 timebase module that was included has a pushed-in switch (S90) which I have found to be due to a broken plastic catch that should be holding the switch onto the PCB. Is there a source for these, other than from a scrap plug in?


Re: Push-push switch repair (need some theory of operation)

EJP
 

Thanks Dennis and Ke-Fong, I have ordered and will attempt this repair next week.

EJP


Re: 2465B - Weak Readout Intensity

flanneltuba@...
 

The replacement CRT arrived yesterday afternoon, so I promptly sequestered myself out in my unheated shop (in a drafty barn) in 30 degree weather to swap in the new tube. Before I could even think of installing it, I had the very frustrating task of straightening all the bent deflector pins on the neck of the tube, which had been badly bent due to shabby packing for its long trip from Israel. (Who was it on this thread that said something like, every time I order parts from Israel, I've regretted it?) So I spent the first 35 chilly minutes very carefully bending back the bent neck pins. Some of these are fairly stiff and made me cringe as I applied fairly strong mechanical pressure to them to straighten them. I did wear safety glasses and gloves in the event of catastrophic glass failure, all the while praying I would not create a metal-glass leak. Luck was with me, and the only detectable real damage was minor cratering of the glass at the base of the heavier pins.

So with that accomplished, I slid in the new (used replacement) CRT. Some tips on technique are due here which you won't find in the manual, which I had to learn the hard way: Because of the delicate pins on the neck of the tube, "sliding" the tube into the chassis must be done in a thoughtful and deliberate manner or you risk bending one or more of these pins if they contact the sleeve as it is being inserted. Two ways to mitigate this possibility are, 1) turn the scope onto its right side, so that as the tube travels into the sleeve, the inevitable pull of gravity on the neck of the tube will cause the neck to slide along its =side= where there are no pin connectors, or 2) set the chassis onto its back side and lower the tube into the sleeve from the top using your best Milton Bradly "Operation" game skills to avoid letting the neck pins hit the sides. It's helpful to position the chassis on the edge of the bench such that the back of the CRT sleeve is accessible from the the underside so you can support the tube in its final centimeter or so of descent, since your ability to grasp the front of the tube will be lost as it enters the chassis at the top. This second technique has the added advantage that the four corner support wedges sit nicely in place during the descent, which they aren't so happy to do in the first.

Ok, cutting to the chase! With the new tube mounted and all connectors in place, (with more Milton Bradly maneuvers required for the deflector connections), I fired it up. The new CRT came to life with a beautifully bright and clear display that would happily allow the intensity to go all the way up to full brightness.

SUCCESS!

Chuck Harris nailed it on the first reply on this thread.

Being that my hands were now quite frozen, (remember, I'm doing all this in a 36 degree barn) I decided to leave the rest of the alignment and intensity calibrations for another day.

Speaking of calibrations, one poster noted that after a CRT replacement a full calibration would be necessary. That doesn't seem quite right to me, but this is where my knowledge turns to conjecture. Obviously I will need to conduct all the CRT related adjustments, but my question for the group is, what other post CRT replacement calibrations are truly and absolutely necessary?

- Scott


7000 horizontal plugins cheap

ron roetzer
 

7B50 primarily working. there is a problem with the readout at sweeps 5uS and faster, reads 1000x faster that is 5uS reads as 5nS amnd 50nS reads as 50pS.

7B50a again primarily working, the display mode switch will not latch in timebase mode. If you hold the switch in it works properly.

I would like $10 each or offer a trade, local pickup only in central Mass. Fitchburg to be exact.

Please contact me off list if interested at ron_roetzer <at> comcast <dot> net


Re: 2465B - Weak Readout Intensity

Eric
 

The Tube in my 576 displayed a similar behavior. Though no read out on the
576. It was confirmed by others here as a high hour / weak tube.

On Mon, Feb 3, 2020, 5:04 PM <flanneltuba@gmail.com> wrote:

Really both the Readout and the Display intensities are weak. With the
Display, that is, the sweeping trace, it is quite readable in normal light
but maxes out at merely "readable"; as for the Readout, at its brightest
level it is almost unreadable in normal room light. The Readout intensity
control behaves as follows: In the Off, or center position of the control,
there is of course no readout shown at all. As the Readout intensity pot is
advanced either CW or CCW, it begins to display the Readout information,
and achieves its brightest point at roughly 50% of the control's travel.
Turning the Readout intensity control any further from this point does not
increase the intensity, rather causes the Readout characters to become
increasingly unfocused to the point of unreadability at the full CW or CCW
stops.

As for the Display intensity control, it behaves in much the same fashion
as the Readout control, where it will achieve peak intensity at about 50%
of the control travel, and begin to lose focus (though not as badly as the
Readout) through the reaming 50% of the range. It never gets to that point
where the travelling trace begins for form a brightness corona from being
turned all the way up, as normally functioning scopes tend to do.

I have probed the signal transition through this adjustment range from
every point in the circuit from the DAC signal and hold op amps, through to
the Display Sequencer and then the Z-Axis Amplifier and HV circuit, and
have observed that the levels at all points follow the full range of change
in the front panel Readout intensity control, from Off through Full without
any noticeable deviations through this range. Hence, the arrival at the
conclusion that the CRT may be at fault.

I already have the original CRT removed in anticipation of the arrival of
the replacement. When the replacement arrives, I'll pop it in and the
verdict should be obvious. Either I have a weak CRT, or I have a whole lot
more head scratching to do! I tool a number of pictures, which I intend on
posting when I can free up some time...perhaps this weekend.




464 for parts only

vaclav_sal
 

Was purfectly working scope until the delayed sweep switch broke internally.
The friction part just broke off.
There is a post somewhere how to fix it.
No time to do it and got a new one anyway.

LOCAL pickup only
NO SHIPPING
Houston / Cypress TX


Re: TDS3000B USB floppy emulator

Holger Lübben
 

Hi!

I've added a Gotek Floppy Emulator to my 420A a while ago.

A short description of the process can be found on Tekwiki:

http://w140.com/tekwiki/wiki/TDS420

The exact model number of the emulator was very important and it was also a little bit difficult to find the right jumper settings.

Holger


Re: Please send me your list of broken 7K plugins

momemeca
 

Hello Dennis,
Thank you for replying but ... I cannot find an attachment :-)
Perhaps the "system" stripped it?
What was the format of the file?

Cheers,

Rick

On 4 Feb 2020, at 08:40, Dennis Tillman W7PF <dennis@ridesoft.com> wrote:

Hi Rick,
Attached is my list.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of momemeca
Sent: Sunday, February 02, 2020 4:21 AM
To: TekScopes@groups.io
Subject: [TekScopes] Please send me your list of broken 7K plugins

Hello Dennis,
Greetings from the beautiful Mornington Peninsula, near Melbourne,
Australia.
I am Physicist and professional Electrical / Electronics / Mechatronics
Engineer working at The Australian Synchrotron where I work mainly on
accelerator control systems.
My love affair with all Tektronix equipment of old began with the 500 series
oscilloscopes at college and university in the UK (late 70s) and,
subsequently, in my early professional years in Oz (early 80s onwards).
I have been a keen collector and restorer for some 35 years now and have,
mainly, series 500 CROs (~6), associated plug-ins (~12), accessories (misc)
and series 7000 (4), associated plug-ins (~20).
Most of those are in current use in my lab as they are "cycled" into service
according to their functions and capabilities.
Apart from those I have a 2465B CRO and 2712 spectrum analyser in the lab
plus a contingent of Hewlett-Packard high precision instruments.
Why do I love these instruments? Well, my answer would certainly resonate
with that of many fellow contributors herein; it is the elegant design of
Textronix's bygone years, their clever manipulation and application of
foundation electrical and electronics theories and use of the latest devices
of the day. Not to mention the sheer accessibility and gorgeous mechanical
build.
I genuinely feel that I am doing my bit to contribute to the survival of
these old gems and, one day, pass them on to a new generation of
appreciative "fan-a-tics".
Now that I have started to plan towards my impending retirement, I will have
more free time to devote my free time to working on restoration, repairs and
calibration (and perhaps even writing articles on same for our excellent
TEK-WiKi).
We are not as blessed, here in Oz, with the availability of vintage
Tektronix (or other USA equipment) as compared to the USA. Therefore, I am
constantly on the internet searching for affordable instruments.
Unfortunately, freight charges tend to be a prohibitive kill-joy!
If I am Lucky enough to benefit from your generosity I would be more than
happy to provide components of your "Essay" list.

On another note - I was saddened to read of Barrie Gilbert's passing. A
huge loss, indeed, to the world of analogue design.

Cheers,

Rick
Mornington Peninsula, Victoria, Australia.

On 2 Feb 2020, at 11:23, Dennis Tillman W7PF <dennis@ridesoft.com> wrote:

I have quite a few 7000 plugins in need of repair and I don't have the
time to do it.
I have two goals in mind: 1) be sure each plugin goes where it will do
the most good;
2) Learn how to become a better troubleshooter from your suggestions
and skills.

THEY ARE IN PERFECT CONDITION
They are complete - all parts are there. Nothing is broken.
All knobs, switches, push buttons, levers, etc work.
All the knobs are present. There are no bent shafts, etc.
Last summer I tested every one. I spent about an hour checking everything.
If I encountered a problem with it I wrote down what the problem was.
I then guessed what might be causing it and looked at that section of
the circuitry.
If I found nothing unusual or out of the ordinary I set it aside for
something to do when I had more time.

These are not parts mules.
DON'T ASK FOR A LIST UNLESS YOU INTEND TO REPAIR THEM.
If you find debugging hardware challenging then there might be
something you can use in my list of plugins.
If you would like my list email me off list at dennis at ridesoft dot com.
The SUBJECT of your email should be" Send me your list of broken 7K
plugins".
Otherwise your email might be lost in all the other stuff I get.

ESSAY QUESTIONS: I am very interested in learning more about you and
how you go about troubleshooting 7K plugins.
It is likely I will get more requests than I have plugins. In that
case your answers to these questions will help me choose who to give them
to:
Which 7K MFs and plugins do you have now?
What do you use them for?
What have you repaired in the past?
Why tools, instruments, hardware, documentation, education, skills,
strategies, checklists, and anything else do you have that makes it
more likely that you will be able to find the problems in these or any
7K plugins?
Which plugin you want and why?
What will you use it for when you fix it?
What is the most interesting thing you have ever used a 7K oscilloscope
for?
How bad do you want this plugin?
If you have pictures of you lab include them in your email.

THE BAD NEWS: There is no free lunch
These will cost $20 to $25 in USPS postage to ship to anywhere in the US.
Nobody makes boxes the right size to send a single plugin in.
They do make boxes that are the perfect size for two plugins.
These are the boxes I bought. If you find two plugins on my list the
postage goes up to $30 to $35 which is less per plugin.

Dennis Tillman W7pF



--
Dennis Tillman W7PF
TekScopes Moderator



Re: TDS3000B USB floppy emulator

 

On-topic:  My own experience with 720K 3.5 inch disks is entirely with a
Toshiba T1000 laptop computer (running DOS 2.x) that I think I purchased
around 1988.  The T1000 had/has a single 720K 3.5 inch drive, and while
it worked fine (read/write/format) with any 3.5 inch disk labeled as
"DD" (720K), it was totally unusable with any floppy labeled as "HD"
(1.44M). It would not even format an brand-new unformatted HD floppy as
a 720K disk, which surprised me.  I still have the T1000 (stored away
somewhere in a box), along with a bunch of DD 720K 3.5 inch disks.  When
I last used the T1000 (early 1990's) the DD (720K) disks had become
pretty much unobtanium; I kept all the 720K disks that I had when I
subsequently "retired" the T1000 because I figured the T1000 would be
unusable without them.  I seem to also remember that reading or writing
any 720K disk on other computer(s) with a HD (1.44M) disk drive was
"iffy" at best.

Off-topic: if anyone has managed to retrofit a T1000 with a HD drive and
is willing to share the info with me as to how it went, please contact
me directly (_not_ thru the Tekscopes user group) to share the info, at
<mdinolfo> <at> <erols> <dot> <com>.

Mike Dinolfo N4MWP

On 2/3/20 1:14 PM, John Ferguson via Groups.Io wrote:
David,

This may not be that illuminating, but my memory from the time these
disks were in daily use was that there were drive differences as well
as disk differences and that it was not at all certain that a
particular disk could be read in nay drive.  Their were different
coating formulations, ED, DD, and HD.  I suspect that the DD (Double
Density) forumulation worked at 720 KB and the HD at something like
1.4 MByte.

I'm pretty sure that an HD disk will not work on a DDdrive for example.




Re: 2465B - Weak Readout Intensity

flanneltuba@...
 

Really both the Readout and the Display intensities are weak. With the Display, that is, the sweeping trace, it is quite readable in normal light but maxes out at merely "readable"; as for the Readout, at its brightest level it is almost unreadable in normal room light. The Readout intensity control behaves as follows: In the Off, or center position of the control, there is of course no readout shown at all. As the Readout intensity pot is advanced either CW or CCW, it begins to display the Readout information, and achieves its brightest point at roughly 50% of the control's travel. Turning the Readout intensity control any further from this point does not increase the intensity, rather causes the Readout characters to become increasingly unfocused to the point of unreadability at the full CW or CCW stops.

As for the Display intensity control, it behaves in much the same fashion as the Readout control, where it will achieve peak intensity at about 50% of the control travel, and begin to lose focus (though not as badly as the Readout) through the reaming 50% of the range. It never gets to that point where the travelling trace begins for form a brightness corona from being turned all the way up, as normally functioning scopes tend to do.

I have probed the signal transition through this adjustment range from every point in the circuit from the DAC signal and hold op amps, through to the Display Sequencer and then the Z-Axis Amplifier and HV circuit, and have observed that the levels at all points follow the full range of change in the front panel Readout intensity control, from Off through Full without any noticeable deviations through this range. Hence, the arrival at the conclusion that the CRT may be at fault.

I already have the original CRT removed in anticipation of the arrival of the replacement. When the replacement arrives, I'll pop it in and the verdict should be obvious. Either I have a weak CRT, or I have a whole lot more head scratching to do! I tool a number of pictures, which I intend on posting when I can free up some time...perhaps this weekend.


Re: Please send me your list of broken 7K plugins

 

Hi Rick,
Attached is my list.
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of momemeca
Sent: Sunday, February 02, 2020 4:21 AM
To: TekScopes@groups.io
Subject: [TekScopes] Please send me your list of broken 7K plugins

Hello Dennis,
Greetings from the beautiful Mornington Peninsula, near Melbourne,
Australia.
I am Physicist and professional Electrical / Electronics / Mechatronics
Engineer working at The Australian Synchrotron where I work mainly on
accelerator control systems.
My love affair with all Tektronix equipment of old began with the 500 series
oscilloscopes at college and university in the UK (late 70s) and,
subsequently, in my early professional years in Oz (early 80s onwards).
I have been a keen collector and restorer for some 35 years now and have,
mainly, series 500 CROs (~6), associated plug-ins (~12), accessories (misc)
and series 7000 (4), associated plug-ins (~20).
Most of those are in current use in my lab as they are "cycled" into service
according to their functions and capabilities.
Apart from those I have a 2465B CRO and 2712 spectrum analyser in the lab
plus a contingent of Hewlett-Packard high precision instruments.
Why do I love these instruments? Well, my answer would certainly resonate
with that of many fellow contributors herein; it is the elegant design of
Textronix's bygone years, their clever manipulation and application of
foundation electrical and electronics theories and use of the latest devices
of the day. Not to mention the sheer accessibility and gorgeous mechanical
build.
I genuinely feel that I am doing my bit to contribute to the survival of
these old gems and, one day, pass them on to a new generation of
appreciative "fan-a-tics".
Now that I have started to plan towards my impending retirement, I will have
more free time to devote my free time to working on restoration, repairs and
calibration (and perhaps even writing articles on same for our excellent
TEK-WiKi).
We are not as blessed, here in Oz, with the availability of vintage
Tektronix (or other USA equipment) as compared to the USA. Therefore, I am
constantly on the internet searching for affordable instruments.
Unfortunately, freight charges tend to be a prohibitive kill-joy!
If I am Lucky enough to benefit from your generosity I would be more than
happy to provide components of your "Essay" list.

On another note - I was saddened to read of Barrie Gilbert's passing. A
huge loss, indeed, to the world of analogue design.

Cheers,

Rick
Mornington Peninsula, Victoria, Australia.

On 2 Feb 2020, at 11:23, Dennis Tillman W7PF <dennis@ridesoft.com> wrote:

I have quite a few 7000 plugins in need of repair and I don't have the
time to do it.
I have two goals in mind: 1) be sure each plugin goes where it will do
the most good;
2) Learn how to become a better troubleshooter from your suggestions
and skills.

THEY ARE IN PERFECT CONDITION
They are complete - all parts are there. Nothing is broken.
All knobs, switches, push buttons, levers, etc work.
All the knobs are present. There are no bent shafts, etc.
Last summer I tested every one. I spent about an hour checking everything.
If I encountered a problem with it I wrote down what the problem was.
I then guessed what might be causing it and looked at that section of
the circuitry.
If I found nothing unusual or out of the ordinary I set it aside for
something to do when I had more time.

These are not parts mules.
DON'T ASK FOR A LIST UNLESS YOU INTEND TO REPAIR THEM.
If you find debugging hardware challenging then there might be
something you can use in my list of plugins.
If you would like my list email me off list at dennis at ridesoft dot com.
The SUBJECT of your email should be" Send me your list of broken 7K
plugins".
Otherwise your email might be lost in all the other stuff I get.

ESSAY QUESTIONS: I am very interested in learning more about you and
how you go about troubleshooting 7K plugins.
It is likely I will get more requests than I have plugins. In that
case your answers to these questions will help me choose who to give them
to:
Which 7K MFs and plugins do you have now?
What do you use them for?
What have you repaired in the past?
Why tools, instruments, hardware, documentation, education, skills,
strategies, checklists, and anything else do you have that makes it
more likely that you will be able to find the problems in these or any
7K plugins?
Which plugin you want and why?
What will you use it for when you fix it?
What is the most interesting thing you have ever used a 7K oscilloscope
for?
How bad do you want this plugin?
If you have pictures of you lab include them in your email.

THE BAD NEWS: There is no free lunch
These will cost $20 to $25 in USPS postage to ship to anywhere in the US.
Nobody makes boxes the right size to send a single plugin in.
They do make boxes that are the perfect size for two plugins.
These are the boxes I bought. If you find two plugins on my list the
postage goes up to $30 to $35 which is less per plugin.

Dennis Tillman W7pF






--
Dennis Tillman W7PF
TekScopes Moderator


Re: 2465B - Weak Readout Intensity

satbeginner
 

I have been more or less following this thread, because I am a big fan of these 24xx scopes, but I am a bit puzzled by the title of the thread:

Is it just the readout that is weak, or are the traces weak/dim too?


Re: 2465B - Weak Readout Intensity

 

I would consider increasing the heater voltage as a test, and only as a test.  It does risk destroying the tube completely but it usually does increase electron output and can brighten a CRT.  So if an increased heater voltage corrects the dim display you have diagnosed the problem and can go ahead with CRT replacement in confidence.  .  But, as you, these instruments are too proud to suffer long term indignity.

On Monday, February 3, 2020, 09:35:01 AM CST, flanneltuba@gmail.com <flanneltuba@gmail.com> wrote:

I have to admit it is tempting to try bumping up the heater voltage and seeing if the tube will eek out a bit more brightness. Some part of me though can't bring myself to making such mods to a Tek scope of this particular pedigree. This old gal is too proud to stoop to a facelift! :) Another aspect that holds me back from this is knowing that this would really amount to a temporary fix. If the cathode is already spitting out its last gasps of electrons, forcing it to work harder surely will only bring desired results for limited amount of time. I would always be worrying that it would fizzle out at any moment. It also seems to me this technique would cause a considerable amount of extra heat to be generated in the tube, which feels bad somehow. I suppose if there were no surplus/used CRTs available at all, this would be a much more enticing path.

I recall using one of the old fashioned color TV CRT "restorers" on a Sony Trinitron sidewalk salvage back in my college days in the early 80's. It did the trick quite neatly as I recall. Never tried the grid-cathode arc technique. Sounds fun, but pretty chancy. Then there's the CRT neck whack... I'm just imagining the Wile E. Coyote comic moment standing there with that resigned look on his face, the imploding CRT in his hands in a halo of flying glass. We used to whack old hard disks that had developed "sticktion" in a similar fashion to the horror of any onlookers. Worked about 50% of the time.


TDS3000B USB floppy emulator

John Ferguson
 

David,

This may not be that illuminating, but my memory from the time these disks were in daily use was that there were drive differences as well as disk differences and that it was not at all certain that a particular disk could be read in nay drive.  Their were different coating formulations, ED, DD, and HD.  I suspect that the DD (Double Density) forumulation worked at 720 KB and the HD at something like 1.4 MByte.

I'm pretty sure that an HD disk will not work on a DDdrive for example.


Re: TDS3000B USB floppy emulator

David Kuhn
 

https://www.ebay.com/itm/GOTEK-26-Pins-1-44Mb-Floppy-To-USB-Disk-Emulators-For-Barudan-Embroidery-Machine/254448239852?hash=item3b3e4c04ec:g:knMAAOSwG5td7hXh


???? I wonder if this will work with our TDS3000s? It's not hard to keep
the floppy drives working, but 3.5" disks have not been made since 2012 and
even "brand new" ones out of the box have issues. They may work fine with
the scope, but then can not be accessed with a USB-FLOPPY drive (I have
several). I have to search through a box to find a few that work with both
drives. Come to think of it, even if you let the computer re-format the
floppy, they still do not work with the three USB-Floppy drives I have. I
was quite confused if the problem was the drives or the disks. The disks,
typically, all worked with the scope's drive. I can find 3 or 4 out each
box of 20 that work with both. I may install a real 3.5" drive in my main
bench computer, but its mother board doesn't support it. So I will need a
PCB or Floppy to SATA Emulator PCB.

I use GPIB to get screen shots in to my Word Documents rather quickly, so
it is not urgent except when down-grading the scope software in order to
update the scope bandwidth and then re-upgrading the scope software again.
I used to have a lot of setups on floppy for the scopes, but I now pull the
setups off and save them to the computer with OpenChoise Desktop.

It would be nice to a USB port in the front of the scope verses the floppy,
but it's not urgent. If you try one that works, please le us all know, I
would order three drives to update my three TDS3000 scopes.

Thanks kindly,

Dave

On Sat, Feb 1, 2020 at 10:15 PM Tom B <tbryan@nova.org> wrote:

Hello,

I looked at these. It looks like all are SD, not USB. I also need a 26
pin interface. HXC did have one USB emulator with a 26 pin interface
but it is USB type B. Not quite what I want.

I did find one on ebay for about $30US that looks like it will fit but
I don't know if it will function in the oscilloscope.

Tom



On 2/1/2020 8:03 PM, Geoffrey Smith wrote:
Have a look at
https://urldefense.com/v3/__http://hxc2001.free.fr/floppy_drive_emulator/__;!!KfGNmQmE!1spBXzicCsUJKw4KZxEE3pSMbfpGjM0Hm2JVHq4ESgwQLxm3yt0zLa67KhdX$

HXC may already have one or , from experience, seem happy to program one
for you.

-



Re: 2465B - Weak Readout Intensity

flanneltuba@...
 

I have to admit it is tempting to try bumping up the heater voltage and seeing if the tube will eek out a bit more brightness. Some part of me though can't bring myself to making such mods to a Tek scope of this particular pedigree. This old gal is too proud to stoop to a facelift! :) Another aspect that holds me back from this is knowing that this would really amount to a temporary fix. If the cathode is already spitting out its last gasps of electrons, forcing it to work harder surely will only bring desired results for limited amount of time. I would always be worrying that it would fizzle out at any moment. It also seems to me this technique would cause a considerable amount of extra heat to be generated in the tube, which feels bad somehow. I suppose if there were no surplus/used CRTs available at all, this would be a much more enticing path.

I recall using one of the old fashioned color TV CRT "restorers" on a Sony Trinitron sidewalk salvage back in my college days in the early 80's. It did the trick quite neatly as I recall. Never tried the grid-cathode arc technique. Sounds fun, but pretty chancy. Then there's the CRT neck whack... I'm just imagining the Wile E. Coyote comic moment standing there with that resigned look on his face, the imploding CRT in his hands in a halo of flying glass. We used to whack old hard disks that had developed "sticktion" in a similar fashion to the horror of any onlookers. Worked about 50% of the time.

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