Date   

Re: I don’t see my posts

Richard Knoppow
 

So you see this one? If you see my reply but not your original check to make sure the server at groups i.o. is set to echo your own posts. Most mail reflectors can be set either way.  Some mail readers have a similar setting. Check also your spam folder. Your messages ARE getting through.

On 7/9/2020 5:32 PM, stephen.nabet wrote:
Hi,

I’ve written 3 or 4 posts, some of which are kind of important and to me because I’m asking for advice and help, but I still don’t see any of them. What is going on?

Regards,

Sent from my 9.7-inch iPad Pro
Stephen S. Nabet
stephen.nabet@...

--
Richard Knoppow
dickburk@...
WB6KBL


Re: Frequencies and voltages required to calibrate a 2400-series scope?

Stephen
 

I think I could be of some help. Although far from being a metrology professional, I do calibrate all of my scopes (currently 8) using mostly the required equipment stated in the manuals if I have them. But sometimes I don’t. Results are more than acceptable, I think. I get Time Base accuracies up to >= 0.1/02%


Re: Tektronix 2230

Bert Haskins
 

On 7/9/2020 12:40 AM, Saroj Pradhan wrote:
Hi leo

For the fan I did mistake, I soldered the wire in reverse order. I soldered
the wire in correct order and it worked with external supply.
As Bert suggested the problem might be associated with high voltage
transformer and he was pretty sure about this. I decided to dismantle T906
which was the only component that was not tested in preregulator
section.There were many exposed copper spots in the primary winding.
Rewound the transformer, put in the circuit and power on the scope(with
limiter bulb). Same situation. This time the bulb flashes little dimmer
than it was before and the fan spins for the moment when the light is on.
Power on led and 'A trigger' led flash.
I am quite reluctant to power on the scope without limiter bulb.
By the way how can I measure inrush current. Any idea?
Tkanks.

What wattage limiter bulb are you using?

I would  not expect a 2230 power supply to even start with less than a 150 or 2-- watt bulb.

  Bert

What


On Sat, Jul 4, 2020, 10:23 AM Saroj Pradhan via groups.io <sarojman.Pradhan=
gmail.com@groups.io> wrote:

Hi Bert
OK it means in my case t906.
Do you have the schematic for 2230 so that we can confirm the transformer.
Thanks.


On Sat, Jul 4, 2020, 9:12 AM Bert Haskins <bhaskins@...> wrote:

On 7/3/2020 9:50 PM, Saroj Pradhan wrote:
Hi Bert
Thanks for your concern and suggestion.

But it operates normally with external power supply (in my case I
used
38v
dc across tp950 and tp940).

Saroj
No, I mean the HV supply, the one that runs off the input AC and
supplies the +40V.

Shorted turns make it draw too much current.



On Sat, Jul 4, 2020, 1:28 AM Bert Haskins <bhaskins@...>
wrote:
On 7/2/2020 8:51 PM, Saroj Pradhan wrote:
Hi Leo
No worry. It happens.
Sure I will check the component.
I confirmed that the scope is still working with external supply.
But before going further I want share with you my experience during
the
testing of scope with limiter bulb.
1. That day you suggested to put on the scope without limiter bulb.
And
you know the outcome.
2.It seems that even with shorted q9070
I could hear the same high pitch(with limiter bulb lighting)
3 changed q9070 and put on the scope(with limiter bulb). This time I
had
flashing light and there was power led at front panel also flashing.
And I
could hear the pitch at the same frequency as of bulb or led flashing.
Put off the scope. Again put on the scope with same result. Third
time
when I put on the scope q9070 damaged again. Any logic behind this?
Thanks.
Saroj
First, let me say that I have several 223x family scopes and had very
few problems with them.

I did have a 2215A that uses a similar power supply that gave me fits
until I finally figured out that the high voltage transformer had
shorted windings.

I proved this to myself by doing a ringing test after removing the
transformer.

Good luck,

Bert







Re: Technician in Need

Vince Vielhaber
 

I figured TS meant Tek Scope. But no model number or any details so who knows for sure what he meant.

Vince.

On 07/09/2020 11:03 PM, David C. Partridge wrote:
TS? What is that? Where on the planet are you?

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of davethetechman via groups.io
Sent: 08 July 2020 21:13
To: TekScopes@groups.io
Subject: [TekScopes] Technician in Need

Hi, looking for a technician to help me repair my dad's TS.
Please PM if you know one.



Re: Tektronix 465 No Trace, No Dot

Stephen
 

Thank you very much for answering.
I didn’t know ripple could have such a drastic effect..
Will do.

PS: I ended up making a new thread though.


Re: Restoring 545b

@0culus
 

I have been working on a 585A and an assortment of plugins. I cleaned up the Type CA plugin's dirty (exposed) controls with carefully applied deoxit. It definitely helped. You have to be really careful not to make a mess with these canned products since they typically are full blast or nothing.

Sean


Re: Tek 465 Turns on, No Dot, No Trace

Stephen
 

On Thu, Jul 9, 2020 at 03:48 PM, Tom Miller wrote:


Ok, first, check the fuse F1419. If blown, check C1419 for short.
Thanks for answering.
Yes. I didn’t mention it, but I have already. Fuse is fine.


Second, get the supplies working correctly. I suspect C1552 5000uF and
C1562 3000uF as being low capacity. Confirm by looking at the ripple on
the +5 and -8 test points.
Yep, will do tomorrow. 5:15AM over here.

A little searching the archives for 465 and 475 power supply tips would
help you.
Indeed, thanks.

You didn't mention the serial number so this is for the late model s/n
>250000 scopes.
I wished I knew it myself. It was apparently scraped. However, boards are dated 1971 and Dutch names on stickers, so I suspect an early model made in Holland.

Bottom line is my bet is on the old power supply caps.
That would do that just with a few volts off? Hmmm.., 🤔


Re: Cleaning TM500 module pushbutton switches

 

Over the years, the best method I have found for the
TM500 pushbutton switches is to spray a small bit of de-oxit into the rear open end,
and let it flood down to the front shaft (very important). hold the unhit so the opne back is UP, and the
shaft is DOWN.

once it has penetrated, cycle the switch rapidly a few times, this will also *free up the switch **
**shaft, and locking mechanism,* as well as clean the contacts.  a second flush is usually NOT required, and
if solvent based, would make the *shaft bind at the front*. many problems are shaft friction related, and not bad contacts, so this method fixes both nicely.

almost all the the switches are silver plated, so de-oxit is really the magic answer for aged contacts.

this method has restored switches I thought were totally useless, so I really recommend it.
all the best,
walter

--
Walter Shawlee 2
Sphere Research Corp. 3394 Sunnyside Rd.
West Kelowna, BC, V1Z 2V4 CANADA
Phone: +1 (250-769-1834 -:- http://www.sphere.bc.ca
+We're all in one boat, no matter how it looks to you. (WS2)
+All you need is love. (John Lennon)
+But, that doesn't mean other things don't come in handy. (WS2)
+Nature is trying very hard to make us succeed, but nature does not depend on us.
We are not the only experiment. (R. Buckminster Fuller)


Re: Technician in Need

 

TS? What is that? Where on the planet are you?

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of davethetechman via groups.io
Sent: 08 July 2020 21:13
To: TekScopes@groups.io
Subject: [TekScopes] Technician in Need

Hi, looking for a technician to help me repair my dad's TS.
Please PM if you know one.


Re: Tek 465 Turns on, No Dot, No Trace

 

Ok, first, check the fuse F1419. If blown, check C1419 for short.

Second, get the supplies working correctly. I suspect C1552 5000uF and C1562 3000uF as being low capacity. Confirm by looking at the ripple on the +5 and -8 test points.

You can use the next higher standard value and a higher voltage for replacements. Be careful removing the old caps as there is track on both sides of the board.  Radial lead caps work fine but you need to put some jumpers tieing the three ground points together for the can caps.

A little searching the archives for 465 and 475 power supply tips would help you.

You didn't mention the serial number so this is for the late model s/n
250000 scopes.
Bottom line is my bet is on the old power supply caps.

On 7/9/2020 4:58 PM, stephen.nabet wrote:
Hi,

I have this Tektronix 465 that I got a few days ago. I knew it had that issue, and I thought I could fix it. It turns out to be more difficult than I anticipated. Here’s the issue:

The scope turns on, the fan spins, the graticule illumination is working, when I inject a signal from my function generator, I can see the trigger light go on and off whenever I turn the knob. Everything seems to be working, except there is no trace or dot on the display, and the beam finder is also silent.
As per the troubleshooting steps in the manual, I’m checking the CRT circuit to the best of my ability.

I’ve checked Q1404 and R1404, and they are fine. I even replaced Q1404 just to be safe.
Voltages are not what I would expect: Base: 3.53V, Emiter: 2.95V, Collector: 2.97V

Voltages have been checked as well, and 2 of them are very low:
TP1536: dead on -55V
TP1548: 15.05V
TP1558: 4.74V (too low)
TP1568: -6.3V (way too low!)
TP1518: 111.2V

I can’t check the HV (-2450V) because I don’t have a High Voltage probe. My DVM will fry.

I could use some help...

--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: Tektronix 465 No Trace, No Dot

Paul Amaranth
 

Have you checked the ripple on the LV supplies? It must be within
the specs in the manual, somewhere around 10mv or less I think.

Don't even look at anything else until the power supplies are working
correctly (there may be a bad part loading down the supply somewhere,
but still, get the voltages and ripple where they are supposed to be,
then start looking at other stuff).

Paul

On Thu, Jul 09, 2020 at 11:39:00AM -0700, stephen.nabet wrote:
Hi,

First post here.
Instead of making a new post, I opted for reviving this one, since I practically have the same issue.
This Tek 465 I got recently turns on, but absolutely no trace. Beam finder not working either.
I followed the troubleshooting instructions in the manual, and I’m looking at the CRT schematic.

Here’s what I have found:

R1404 read fine
Q1404 C 2.97V, E 2.97V, B 3.53V
Q1408 E 2.97V, B 3.57V, C 3.6V

Now:
TP1536 is exactly -55V
TP1548 is 15.04V
TP1558 however, is 4.74V (too low)
TP1568 is also very low at -6.3V
TP1518 is around 111.3V

I cannot check HV -2450V, I don’t have a HV probe. My DVM will fry.

How did your issue end up?
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows


Re: Cleaning TM500 module pushbutton switches

Andy Warner
 

I use standard DeOxit D5 and it has worked great for every one of my TM500
modules.

Depending on the module in question, I try and be careful not to
accidentally spray any variable caps in the vicinity.

On Thu, Jul 9, 2020 at 8:05 PM W1PJE <@W1PJE> wrote:

Hi all,

Hopefully not way off topic:

I have some TM500 modules with sticky/intermittently responsive
pushbutton switches (the small square kind). What is the recommended
cleaning procedure - Deoxit from Caig, or something else?

Cheers, Phil



--
Andy


Technician in Need

abners96@...
 

Hi, looking for a technician to help me repair my dad's TS.
Please PM if you know one.


Re: Tektronix 465 No Trace, No Dot

Stephen
 

Hi,

First post here.
Instead of making a new post, I opted for reviving this one, since I practically have the same issue.
This Tek 465 I got recently turns on, but absolutely no trace. Beam finder not working either.
I followed the troubleshooting instructions in the manual, and I’m looking at the CRT schematic.

Here’s what I have found:

R1404 read fine
Q1404 C 2.97V, E 2.97V, B 3.53V
Q1408 E 2.97V, B 3.57V, C 3.6V

Now:
TP1536 is exactly -55V
TP1548 is 15.04V
TP1558 however, is 4.74V (too low)
TP1568 is also very low at -6.3V
TP1518 is around 111.3V

I cannot check HV -2450V, I don’t have a HV probe. My DVM will fry.

How did your issue end up?


Cleaning TM500 module pushbutton switches

W1PJE
 

Hi all,

Hopefully not way off topic:

I have some TM500 modules with sticky/intermittently responsive
pushbutton switches (the small square kind). What is the recommended
cleaning procedure - Deoxit from Caig, or something else?

Cheers, Phil


New member with a currently-dead 2465

Vincent Mallet
 

Hi group,

I just joined TekScopes after hunting for info on how to go about
resurrecting a dead 2465 I acquired recently. I picked up electronics as a
hobby a little over a year ago and it has been a learning experience for
sure, and my new challenge is to see if I can do something about this
'scope :)

The 2465 powers on and a lot of lights light up and stay lit on the front
panel; the display stays absolutely blank (no hint of a beam anywhere no
matter the position of the intensity settings). No blinking TRIG'D light,
pressing A/B does nothing (actually, pressing any button doesn't change
anything).

I started getting familiar with the service manual and going through the
basic troubleshooting steps. The power supply measurements appear to be
within specs as per table 5-1; ripples _seem_ to be within spec but I'm not
sure I'm measuring them right with my DSO.

I moved on the troubleshooting steps until I reached the clock signal
coming to U2092-37 (TP505) where I get a flatline rather than a 5MHz
signal. I looked at the oscillator circuit on A5 and the test points at the
output of U2556B and U2468A are both flat lines too (instead of a 10MHz
square and 5MHz square). I do get a -5V on one side of R2553 and +5V on
R2549.

Question: how likely is it that the oscillator circuit has failed? Or could
there be an external factor preventing it from oscillating that I don't see?

My next step would be to pull the few components from the oscillating
circuit out so I can test them but I figured maybe I'd ask around if this
rang a bell first.

Thanks!

Vince.


Restoring 545b

Jayadamski728@...
 

Hi all, I am from London uk and I am restoring a 545b which I obtained from ebay for £30. It was in a bad state when I recieved it and had 7 vacuum tubes missing. I now have got it to the point where I get a dot on the screen from both A and B channels and it seems the vertical output is not working at all. I think a lot of the problems is with dirty contacts on the rotary switches ...
I was wondering what is the best way to clean these as I have tried to clean them with alcohol and cotton buds. Do you guys have a good way to clean them and get all the oxide off ?


My first scope, a Tektronix 11401 with option 2D extended memory and two 11A34 plugins and an 11A33 plugin.

 

The 11k series, and the elusive 11401. Almost all google searches result in low double digit number of results. The ones that do return a large number of results are mostly user manual sales. The 11401 and other 11000 series sadly has missing extended service technical documentation and I've only seen prototype pcb pictured. There are some cool 1980's 11000 series marketing materials from vintageTEK on youtube and single self test videos on youtube and that's about all I could find. No one seems to care about them largely and It seems to be almost forgotten. Outside of a handful of sites, and a tiny number of posts and pages from the likes of tekwiki, evvblog, groups.io/TekScopes, hakanh.com/dl/ and barrytech.com plus the wayback machine, the internet archive, and ArtekManuals. There is nothing. Compare that to a 453, or the 7854 you get millions and millions. I mostly resorted to scouring the old 1986, 1987, 1988 Tektronix product catalogs for my cross reference knowledge on the machines general capabilities, recommended probes for each plugin, plugin compatibility. Yeah yeah, read the manuals. easier said than done as I had to find them first. People talk about dreading working on their 11400 scopes. But a quoted service center tech said, "The 11400's are boring to fix; they're no fun to troubleshoot because the diagnostics finds the problems so quickly and easily." I'm sure it's mostly marketing but the 11400s were engineered from the ground up with self diagnostics in mind. They offer a very wide range of features and really is the pioneer of DSOs. (probably why they later code named it 'pioneer', if not ... wow that foresight)

Why should anyone care about the 11k and largely the 11400? Do I have buyers remorse?
The Tektronix 11400s brought high expectations and new standards for what a digital scope is and what it could be. The 11k line brought to market advanced triggering, storage, full hardware and firmware program-ability, Live operation, high accuracy, high resolution, multiple channels, plugin modular-ity, 7k plugin compatibility, self calibration, self diagnostics and a freaking touch screen interface + many other features that all good DSOs have today. Going by today's standards almost all of those features are vital. If it were not for the 11k series and largely the 11400 line, i believe the Modern Digital Storage Oscilloscopes probably wouldn't be what they are today. I feel there is enough room for argument to say that the bench-top DSO would probably be nothing more than a pico pci-e card or a phone with a usb dongle if it were not for the 11400s. Why? Well first, everyone was watching Tektronix after the 7854, how could you not? With eyes on them, they had to do something bold, and I believe they did just that. The 11000 series was released in 1986, only 5 years before pico technology. The DSA600s released in 90. Talk about breathing room. If Tektronix didn't go where no scope designer went before, and released just another analogue scope with 500 buttons instead of 250, or a mediocre DSO with 250 buttons, the DSO wouldn't have progressed like it had so vigorously with the 11000s into what they are today. They wouldn't have had time to engineer the 11k line if they made a 500 button analogue or a 250 button DSO first, pico tech would have came out, and with the accessibility of the microprocessor ruling the world. I don't see how DSOs would have been relevant. The 11400 wasn't designed for today in 1982-1986, it was designed for today in 2020. All modern oscilloscopes should look to the 11ks and largely the 11400 for their grandscope. Sure 11ks only have 20 mega samples per second, but it's cousins the DSA600s with plugins like the 11A72 can get you to 500Mhz @ 2ghz sample rate. Truly mental for the 1990s. Anyway, just an afterthought I had floating in my brain, but maybe you can see how if it were not for machines like the 11400s which came out in a crucial time right before mass pc computers and pico technology the mighty DSO might just have become just another piece of software on a laptop or another apple dongle. I think we can almost all agree that this was for the better. The 11k series to me, is likened to zx spectrum, the bbc micro, or commadore 64 of oscilloscopes. The one that started it all. And if you ask why hasn't pico become more popular ? that i think is because established companies were already making DSOs before we were blessed with the pico. so much was already invested into what modern DSOs were to become. so there was no room for pico.

What are my plans with this machine? No... I don't have buyers remorse what makes you say that?
I got this largely for the 11k plugins it has in it, notably the differential comparator, also 2-4 channel amplifiers lol, the mostly working mainframe with Option 2D - Extended Memory is a bonus. My plan is to use this as my first scope, and fix it until I feel like i need breathing room and as i can easily upgrade into a DSA602a while still using the plugins, once i collect enough excess 11k plugins and probes, i plan to get a 11302a and have a very decent set of retro-ish scopes. Currently awaiting arrival. I will update this topic, post pictures, and I will be posting videos on youtube about this scope as this is almost nothing about it online. Im currently in research and developing a robot with multiple dual core 64 bit risc-v chips and fancy mechanical 3d printed parts.

Onto the now hopefully rose tinted machine itself.
I just picked up this Tektronix 11401 with Option 2D - Extended Memory, it came with two 11A34s and an 11A33 from ebay for 199, and 50 usd shipping. It came from a university who's upgrading. Overall seems decently kept for a machine built in 1986. I also swooped up a few P6134c, P6134 and P6135's probes. I also went over to ArtekManuals and bought the 4 volume manual set they offer. I believe that they have the 2 missing extended service manuals i cant find on the open internet. The machine passed almost all of its self tests with a single fault on the TimeBase Test with fault code G2121. There is also a penciled X by channel 2 on the far right 11A34, possible dead channel?. My initial thought without reading the manuals because they haven't arrived yet, is that the timebase G2121 fault is from that pencil'd x channel that could be dead as its marked with a x. lol.... honestly no clue, it's what i can tell from the photo and knowing nothing about the machine or really electronics engineering, im a software guy who just recently fell in love with the programming language of solder! The machine hasn't even shipped yet! Im typing this as I eagerly await my boat anchor. You and I will find out more when it arrives. in the mean time, i await the service manuals and i get to read the user manual :D !!! Wait who reads these anyway?


Time base for 7854: 7B85/80 or 7B92a

Martin Hodge
 

I have a newly acquired 7854 with one 7b85 time base. Is there any advantage to using a 7b85/7b80 pair over a single 7b92a in the right vertical slot?

Also I am looking for the reference card pocket thing (with cards) that goes on the top if anyone has a spare stored away. Contact me at mhodge[at]innocent(dot)com.


TM500 module pushbutton switch cleaning procedure

W1PJE
 

Hi all,

Hopefully not too off-topic:

I have multiple TM500 modules that have developed sticky / intermittent pushbutton switches (the square small ones). Is there a recommended cleaning procedure? I was going to do the standard use of Caig's DeOxit in a sparing manner, but perhaps there is a better way.

Thanks
Phil