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It was never a question of "not being sure" what mode
I was in, but rather one of "being sure" and being wrong.

It is simply very tiring to have to keep toggling back
and forth in the modes. It reminds me of working with
ed... which is what vi is: ed with a screen interface.

Given the choice between using vi or ed, I would rather
just use ed.

Most companies are very concerned about software that
exists beyond what their IT departments have installed
for every user. So, if they have installed vi, they
often won't allow a foreign editor, even if it is installed
in user space.

When I am repairing crashed systems, I am root and I can do
whatever I want. It has never made sense to me to use a
badly broken system to fix itself, so I use a "live" disk,
and my live disks always have the tools I will need, and
one of them is always jove.

If forced to use vi by the paucity of tools, or by force,
I will use vi. I fully understand it, but still hate it.

For me using vi is like pounding nails in my head. Sure
I could do that, but why would I want to?

-Chuck Harris



Mark Wendt wrote:

Hi all,

today the relais and NiMh batteries arrived.

Although the relais were the Pin-through-hole type, by bending the pins 90 degrees and shorten them a bit the relay was a perfect fit.
The good news: step-1 was successfully, now both channels have the same attenuation steps, so the next is rebuilding the battery and ordering the replacement LCD.

I read somewhere about a non standard replacement screen, somebody used a (cheaper, slightly smaller) screen from a different Tek model??
Before ordering the original I will look for that article first.

Some pictures about today's progress are here: /g/TekScopes/album?id=41029

un saludo,

Leo

On 04/04/2018 04:29 PM, cmjones01 wrote:

On Wed, Apr 4, 2018 at 09:28 am, Chuck Harris wrote:

The thing that turned me off vi was the way you had
to flip-flop between modes. I found that through a
typing error, or forgetfulness, I could easily get
into command mode, and completely destroy several
hours of work by touch typing text into the command
mode window.

Remember, vi is a modal editor. It has two modes: "beep a lot" and "delete everything". These are not mutually exclusive.

I'm a fairly basic vi user. I can drive it, but sometimes I'll step on a landmine and have to type esc:q! and start over.

Chris

Chuckle.? Yeah, vi has it's landmines for the casual user, but it's still a pretty powerful editor with all you can do in it.? The command syntax can get a little arcane but the things you can do with the commands are basically limited by your imagination and how well you know regexp.

Mark

On 04/04/2018 12:28 PM, Chuck Harris wrote:

I used to love it when a customer would insist that
I use vi at their shop. Since I was paid by the hour,
it would easily add a few thousand bucks to the cost
of the job by slowing me down.

The thing that turned me off vi was the way you had
to flip-flop between modes. I found that through a
typing error, or forgetfulness, I could easily get
into command mode, and completely destroy several
hours of work by touch typing text into the command
mode window.

I have never found it all difficult to find a copy
of jove (a light weight emacs clone) for any system
I have ever worked on... including windows.

-Chuck Harris

Strange they would force you to use their text editor to do your programming.? All the places I ever worked where we programmed for Unix we were allowed to use our editor of choice.? Be that as it may, jove is a good editor too.? But it runs into the same issue as emacs (or xemacs) when trying to repair a broken system.? It's generally loaded on a partition that doesn't get mounted in single user mode, or there may be problems with that partition during boot.? If the system boots to single user mode, vi is always available while other editors may not be.? If you're not sure what mode you are in, hitting the esc key a couple of times will get you back to the vi mode.? As a sysadmin, vi is part of your basic toolbox.

Mark

I suspect that 99% of members know this already - could be it's in their DNA - but for the remaining 1% of us who have this issue and have failed to find anything related via google, here it is:

I got two P6006 probes to go with some old 'scopes I've fixed. Chose them because they are 'of the period' and will match to the 47pF input capacitance of said 'scopes - only they didn't, in fact neither of them would adjust at all.

This style of probe is compensated by unlocking a ferrule at the 'cable' end and rotating the probe body. Took me a while to figure out how the thing was meant to work because unscrewing the body completely left me with two parts that couldn't possibly change the capacitance of anything relevant! Long story short, there is a third part that had become detached and was retained in the probe body, sitting there all innocent and looking like it was supposed to be just where it was when I peered down the hole.

This part is the tubular 'moving' plate of the capacitor, concentric with the probe's resistor and common with the cable inner conductor.
Normally it should be screwed on to the plastic end of the cable termination assembly. Use a suitable screw - M5 works, just - to reach down the barrel and grab onto the thread and pull the tube out, fasten it back on the end of the cable assembly, reassemble and bingo - a working probe.

Seems to me a small blob of something to lock the thread would be no bad thing but care would be needed to keep it away from the connection to the cable inner which is a bit of copper wire (perhaps a resistor lead?) half sunk into the plastic thread such that the tube's thread cuts into it as you screw it together, I don't know if there was supposed to be anything?

Adrian

On Thu, Apr 5, 2018 at 03:50 Lukus <lukusaurelius@...> wrote:

On Tuesday, I picked up a 2213A. While testing it, I noticed that the
trace does not fill the whole display regardless of position settings. I
tried messing around with the controls to see if I could fix it without
opening the scope, but I had no luck doing that. Today, I opened up the
scope (the cover won't come off all the way, but it comes off enough for me
to access the boards) so I could calibrate it. However, when I powered it
on, I found that a signal was displayed even when the trace was set to
ground. Adding to the confusion, the trace jumped between filling the
display and being too short; I couldn't figure out what triggers it.

Hi Lukus,

It sounds like the jumping might be a stuck or glitchy beam finder switch,
or you might have a power supply issue. Both are quite common in a scope of
this age.

Read this doc <
>, and get
a copy of the service manual. If you’re not familiar with how to operate a
scope, read through the operations manual.

Start by hooking a probe up to the calibrator, and see if you can get the
scope to show a good signal.
Work all the switches and pots and knobs several times, sometimes that’s
enough to clean the corrosion off the contacts.

Do you have a decent multimeter you could use to check the supply voltages?

Can someone help me work through calibrating this scope and getting it to

work properly?
By the way, this is my first ever oscilloscope.

Congrats on your first scope, nothing like a fixer upper to start with ;).

If you want more information and/or details, please let me know; I would
be happy to provide them.

See if the service manual doesn’t get you started on diagnosing what’s up,

if you get stuck it’s probably most expedient to post a video of how the
scope’s behaving.

Good luck,
Siggi

Hi guys,



I put the Gerbers and development files in the Files section. And photos of
the completed board in the Photos section.

I used OSH Park an got 3 boards for cheap. The Gerber files are all zipped
up and ready to go and work perfect at OSH Park. If you have a favorite PCB
house, you might need to create them using the supplied DipTrace development
files.

Happy new DC508 Displays!

Steve

On Tuesday, I picked up a 2213A. While testing it, I noticed that the trace does not fill the whole display regardless of position settings. I tried messing around with the controls to see if I could fix it without opening the scope, but I had no luck doing that. Today, I opened up the scope (the cover won't come off all the way, but it comes off enough for me to access the boards) so I could calibrate it. However, when I powered it on, I found that a signal was displayed even when the trace was set to ground. Adding to the confusion, the trace jumped between filling the display and being too short; I couldn't figure out what triggers it. Can someone help me work through calibrating this scope and getting it to work properly?
By the way, this is my first ever oscilloscope.
If you want more information and/or details, please let me know; I would be happy to provide them.

If you would quote some of the message you were responding
to, others could figure out what you were talking about.

-Chuck Harris

zoldanmirco via Groups.Io wrote:

I stand corrected.

-Chuck Harris

ADas via Groups.Io wrote:

Hi Jeff,
If you are referring to strips of bare IC socket pins I have used them. They have one quality I like in certain circumstances: since there is no plastic holder you still have access to the PC board under the IC so you can look at which way the lands go as they pass under the IC. It can be impossible to do this in many cases where conventional plastic IC sockets hide what is under them.

Dennis Tillman W7PF

Two things about this one. I would like to replace the batteries with something more modern to get more time and quicker charging. Not sure about what it out there to do it though. The originals look like sub D cells and they are in a sort of holder but wired together as far as I can tell. But that is not the current issue, that is more of a backburner thing, including possible modifications to the charging circuitry and maybe even making it so it can charge and run at the same time. Limitations of the AC power supply might preclude that though.

The issue right now it the intensity. This is the second 422 I've had and neither one of them goes all that bright, This one is a bit worse, to the point where it is hard to see the trace at higher sweep speeds. The other one that was a bit better was not an AC/DC model but that should make no difference. If it had to do with the power supply something else noticeable would happen, deflection variations etc.

Looking at the circuit, the negative side of the HV is shunt regulated with a GV4-S1400 which obviously means 1,400 volts. It feed G1, with the cathode dropped resistively to get a relative negative voltage from GI to K.

The cathode current is limited by the resistance, 1,400 volts across 6.2 megohms, which should be 225uA+, this by the entire accelerating voltage, provided none of the current is diverted should result in 1.3 mW at the phosphor. Would that be enough ? I should think so, Tektronix would not be prone to make a mistake in that regard.

In the other 422 the intensity control worked up to about halfway and then stopped. That was all she had and it was independent of sweep speed, darker at higher speeds. This one is not only darker than that, the intensity control seems to work in reverse when it is much past halfway. Since the intensity control is a rheostat, I am having trouble fathoming just how this can happen.

Could some of the beam current be diverted to the blanking grid ? And, since it is fed by relatively low impedances, how would I tell ?

I don't believe it likely that any significant current is diverted to the next grid as it is the focus grid and that should cause some sort of abberation there.

What are the odds of a weak CRT here ? What do you think ?

If it is a weak CRT I have a way to boost the filament voltage. It entails caps in series with resistors across the bridge, CR 849, to cause some limited voltage doubler action. The issues with that are that I absolutely don't want to do it if the CRT is not weak, and the obvious isolation required. (and space of course, I have no idea how cramped it is in there)

I have the CRT from the other 422, but it is shorter. I am not sure it will work, and I am not sure it is compatible completely when it comes to geometry etc. Actually I really don't want to replace the CRT anyway and if necessary will find other options. Perhaps only use it at slower speeds indoors. But it would be nice to have a bright enough trace to use it outdoors on batteries.

So the intensity problem comes first. Weak CRT ?

I have noticed both type of transistor sockets, I think I prefer the ones with no plastic around them after the 561 job. I stuck some transistors in and could not be sure they were seated properly, with the open type there is no doubt. I imagine they are not as easy to replace, simply because of the issue of holding them in place while soldering, but for general service when you know you can leave the replacement transistor in there you could must solder the pin to the,... ... socket ? The 1 pin socket ?

I have also seen those open sockets used for DIP ICs, not so sure I would like to install them, though it got done in some Heathkit stuff and them people aren't usually pros.

Hi Lop Pol,

Tek used both methods on their PC boards as well as soldering parts directly to the PC boards. I would suspect the decision of which method to use was based on numerous factors. For example:
* Sockets are less reliable than soldering directly to the board and parts can be dislodged due to a mechanical shock or get knocked out if they are in the way.
* Parts that are soldered in are harder to repair or troubleshoot but they can't be dislodged by a mechanical shock.
* The plastic transistor sockets can affect HF performance, but they can allow for hand selecting the optimum part during final calibration and testing.
* Cost and socket availability would be considerations as well.

Integrated Circuit sockets are another matter entirely. I don't recall the exact story but I believe it was Texas Instruments that attempted to get around the major patent for IC sockets. To do this the fingers in the TI sockets gripped the pins of the IC in such a way that the raw edges of the IC pins damaged the socket fingers. The result was a notoriously unreliable socket.

The transistor sockets I like the best are the pin-sockets that are inserted directly into the board. They have some kind of elastomer that holds a part's leads very tightly and they take up almost no room or additional height on the board.

Dennis Tillman W7PF

Hi Szabolcs,
Very nicely done and a great idea. Thanks for making it available to our members.
Dennis Tillman W7PF

I have a few Tek parts laying around, free to anyone that wants them. I will need to get reimbursed for shipping unless you stop by our shop in New Berlin, WI (Milwaukee). I have the following:

7L12 pull button on bottom to release the plugin from the mainframe.

670-3114-00 CIrcuit board and switch for a 7L13, this has a typical Tek barrel type rotary switch with a thin rod through the middle of the shaft which operates a pot on the back. The shaft is broken off at the front but he rest of it looks ok, probably suitable for parts.

0510-01/152-17. This is a RF module for a spectrum analyzer, don't remember which one but it was probably a 7L12, 7L13 or 7L18. It is non functional. Maybe repairable?

Terry Michaels

On Wed, Apr 4, 2018 at 09:28 am, Chuck Harris wrote:

The thing that turned me off vi was the way you had
to flip-flop between modes. I found that through a
typing error, or forgetfulness, I could easily get
into command mode, and completely destroy several
hours of work by touch typing text into the command
mode window.

Remember, vi is a modal editor. It has two modes: "beep a lot" and "delete everything". These are not mutually exclusive.

I'm a fairly basic vi user. I can drive it, but sometimes I'll step on a landmine and have to type esc:q! and start over.

Chris

Hi,

Since I had a 287 laying around I created the PCB for the FPU option for the Tekmate. This is a very simple converter board to convert the 2x20 pin header to a dip socket. You need a female 2x20 header, a DIP40 socket and 2 100nF ceramic decoupling capacitors, and a 287 FPU of course. It does speed up the FFT operation, not that it is any useful by today's standards, but still.

Here is how it looks like when installed: /g/TekScopes/photo/42207/0?p=Name,,,20,1,0,0
I have uploaded the Gerber files for it here: /g/TekScopes/files/Tekmate%20FPU%20option

I actually have 3 PCBs left, since the smallest number to manufacture was 5, but I think it is cheaper to order a batch from China than to mail it from here. The Gerbers are the copy of what i have uploaded to the PCB shop.

But if someone wants one, I can send it for the cost of the postage. May be worth inside the EU, definitely not economical overseas.

Szabolcs

I noticed on my spare parts 7633 the transistors are socketed directly into the boards. On my good unit they are set into plastic looking sockets that sit off of the board. Is that just some type of later revision?

I agree ideally for a scope of this vintage a recalibration with a fresh nvram installed is the only proper way to get the scope working to its absolute specs and keep it there.
But if the typical user doesn't have the timing generators, step generators etc for the recal, then a copy of the current cal data, is still worth something. If the scope is currently usable, then a copy of the nvram at least keeps it usable. An old NVRAM needs replacement anyway, even if the scope was recalibrated, as they are well and truly past their use by date, and data corruption an imminent threat.
The cal data copy procedure is pretty simple really, takes very little time, and the only equipment needed is a PC and ram reader.
With a copy of the cal data in a new NVRAM, when the opportunity comes up a recal can be performed.