Date   
11801 and other 1180XX Sampling Scopes.

Egge Siert
 

Hi Reginald and others,

I looked at ended eBay Auctions and assume the 11801 you bought is the one which auction ended on March the 7th.

As far as I know all 11801 and 11802 (the Monochrooms) Models have a Fast Rise Calibrator (with the Gold Plated APC 3.5mm Female Connector) build in. This is the same Pulser as used in (one half of) the SD-24 and the 067-1338-XX Calibration Step Generator. Some early CSA803's also have it.

With respect to the CSA's. B's are never produced and all types have a Color Display. Color 11801's exist in the A,B and C variety.

Sometimes you can be lucky. There are 067-1338-XX'a and SD-24's with a Calculated Risetime of 11/12ps. Nice to see their Pulse on a SD-30/32. Intriging is the fact that for the "slow" Heads an 067-1338-XX is used for evaluating their Risetime (see SD Service Manuals), but not for the SD-32 (and I assume also for the SD-30).

Greetings,

Egge Siert

Re: Front panel knob removal on 2225 (or 2xxx series)?

Roy Morgan
 

Inspired by watch repair methods:

A couple pieces of hacksaw blade, de-toothed and shaped on a grinding wheel, then bent into short armed L shape, could make a fine pair of levers to get the knobs free. Apply pressure equally on both sides, with the tips well in toward the shaft/center of the knob. Fabric or even paper towel layered under the pivot point prevents panel damage.

Roy

On Feb 23, 2019, at 6:21 PM, Chuck Harris <cfharris@...> wrote:

It isn't that you need to make the knob expand, it is
simply a matter of warming the plastic a little so it
isn't quite so brittle.

You must, I repeat must, pull the knob straight off of the
shaft. I recently started using a pair of fine pointed
needle nosed pliers. I pull the knob up to clear the panel,
then stick the points to the knob's skirt's outer edges
and pry up gently. They come off very easily.
Roy Morgan
K1LKY since 1958
k1lky68@...

Re: Front panel knob removal on 2225 (or 2xxx series)?

Colin Herbert
 

From my experience with hacksaw blades, I think that any attempt at bending
them will result in breakage. Then again, if the metal was annealed before
bending..., but wouldn't that defeat the object?
How about a couple of similar-sized hex-keys used in the same way?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Roy
Morgan
Sent: 17 March 2019 17:23
To: TekScopes@groups.io
Subject: Re: [TekScopes] Front panel knob removal on 2225 (or 2xxx series)?

Inspired by watch repair methods:

A couple pieces of hacksaw blade, de-toothed and shaped on a grinding wheel,
then bent into short armed L shape, could make a fine pair of levers to get
the knobs free. Apply pressure equally on both sides, with the tips well in
toward the shaft/center of the knob. Fabric or even paper towel layered
under the pivot point prevents panel damage.

Roy

On Feb 23, 2019, at 6:21 PM, Chuck Harris <cfharris@...> wrote:

It isn't that you need to make the knob expand, it is
simply a matter of warming the plastic a little so it
isn't quite so brittle.

You must, I repeat must, pull the knob straight off of the
shaft. I recently started using a pair of fine pointed
needle nosed pliers. I pull the knob up to clear the panel,
then stick the points to the knob's skirt's outer edges
and pry up gently. They come off very easily.
Roy Morgan
K1LKY since 1958
k1lky68@...

Re: Front panel knob removal on 2225 (or 2xxx series)?

Chuck Harris
 

Cheap hacksaw blades are hardened steel, through-and-through...
and break easily.

More expensive hacksaw blades are bi-metal, and as such have
hardened teeth, and a less hard, more flexible back.

Bimetal blades bend without breaking, which is the point behind their
use.

Either type can be bent without breaking if you apply a torch.

Regardless, a pair of needle nosed pliers does a dandy job of
removing snap on tektronix knobs. Use them as a prying tool,
not a gripping tool. Position them so that their points are
straddle the pot's shaft, and are under the skirt of the knob.
Lever up carefully, and the knob will pop right off.

-Chuck Harris

Colin Herbert via Groups.Io wrote:

From my experience with hacksaw blades, I think that any attempt at bending
them will result in breakage. Then again, if the metal was annealed before
bending..., but wouldn't that defeat the object?
How about a couple of similar-sized hex-keys used in the same way?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Roy
Morgan
Sent: 17 March 2019 17:23
To: TekScopes@groups.io
Subject: Re: [TekScopes] Front panel knob removal on 2225 (or 2xxx series)?

Inspired by watch repair methods:

A couple pieces of hacksaw blade, de-toothed and shaped on a grinding wheel,
then bent into short armed L shape, could make a fine pair of levers to get
the knobs free. Apply pressure equally on both sides, with the tips well in
toward the shaft/center of the knob. Fabric or even paper towel layered
under the pivot point prevents panel damage.

Roy

On Feb 23, 2019, at 6:21 PM, Chuck Harris <cfharris@...> wrote:

It isn't that you need to make the knob expand, it is
simply a matter of warming the plastic a little so it
isn't quite so brittle.

You must, I repeat must, pull the knob straight off of the
shaft. I recently started using a pair of fine pointed
needle nosed pliers. I pull the knob up to clear the panel,
then stick the points to the knob's skirt's outer edges
and pry up gently. They come off very easily.
Roy Morgan
K1LKY since 1958
k1lky68@...











Re: 577 Curve tracer ringing CRT and noisy step generator

Rick Doersch
 

The looping you are showing on the pictures with transistor curves are normal for all 577 and all other analog curve tracers. They increase as you decrease drive and increase vert sensitivity. Here is a post that talks about the reasons for it. The reason you don't see it on the fast setting of generator is it makes 2 steps per half wave of collector supply. One on rising side of of wave then trace is blanked and another on the falling part of wave.

https://groups.io/g/TekScopes/message/152053?p=,,,20,0,0,0::relevance,,577+looping,20,2,0,27803072

Re: 475 with no Display and no HV

SuddenLink
 

Hi Reed,

I received the NTE539 a few days ago and pulled out the existing HV trippler these evening. It is going to be a tight fit but it looks I can squeeze the new trippler in it’s place. The question is, what do I do with the Focus tab on the NTE539. I am thinking that it gets clipped off and covered with a glob of silicon seal.

I am going to hold off until I hear back from you.

Thank you.

Ripley

Sent from Mail for Windows 10

From: Reed Dickinson
Sent: Tuesday, March 5, 2019 3:11 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 475 with no Display and no HV

Hi:
See answers in red below.
On Tuesday, March 5, 2019, 11:55:54 AM PST, Jim Olson <v_12eng@...> wrote:

I'm curious where the Museum is located it sounds interesting to me too I'm in the SF bay area.

Jim O

On March 5, 2019 at 4:55 AM SuddenLink <bob.ripley@... mailto:bob.ripley@... > wrote:


    Hi Reed,

    Yes sir working at the Radio Museum is a lot of fun and hard work at the same time but now that I am retired it is a great place to volunteer a few days a week.

    Between the NTE539 and NTE538 which one would you recommend for the Tektronix 475?
The NTE539 is the most suitable but if you get a 538 you need to connect the D lead to the LOW wire and connect both to ground.  Using the 539 connect LOW to ground, leave the FOCUS terminal open and connect the cap from the transformer to the IN terminal,  Either the 538 or the 539 MUST have a ,01uF, 5KV or 10KV cap between the transformer and the IN terminal.  NOt installing the cap will fry the multiplier in seconds.
Reed

    Ripley

    The words are mine but this iPad does what it will with them.

        > > On Mar 5, 2019, at 12:08 AM, Reed Dickinson <reed714@... mailto:reed714@... > wrote:

        Hi Ripley:
        Wiring in a NTE538 is a little different than wiring in an NTE539. When you get your 3Xer write ma back and I will detail how to do it.
        Your antique radio setup sounds most interesting. I would probably be helping you out at that facility if it were on the left coast.
        Reed
        On Monday, March 4, 2019, 4:43:02 PM PST, SuddenLink <bob.ripley@... mailto:bob.ripley@... > wrote:

        Hello Reed,

        You just have been reading my mind. I was wondering how to handle the HV lead out to the CRT. What about the Focus Tap on the module. I am guessing that is left unterminated and highly insulated from anything around it.

        Our plan is to repair the scope so that we can sell it. The Museum of Radio and Technology is a nonprofit all volunteer organization. We don’t charge for admission so our revenue sources are from cash donations, sales from our gift shop , small grants, and the three swap meet/auctions that we host every year.

        Museum of Radio and Technology

        I will keep everyone posted as I bring this repair to completion.

        Ripley

        Sent from Mail for Windows 10

        From: Reed Dickinson
        Sent: Monday, March 4, 2019 4:59 PM
        To: TekScopes@groups.io mailto:TekScopes@groups.io
        Subject: Re: [TekScopes] 475 with no Display and no HV

        Hi Ripley:
        Good show, a new 3X voltage multiplier will get your 475 back on the air. If you elect to get an ECG or NTS 538 or 539 you will have to splice the HV lead leaving the new tripler. I very carefully slip a piece of thick wall plastic tubing over where the splice will be, carefully solder the joint leaving NO sharp points, coat the entire joint with silicone and slip the tubing over the joint. I put a small tie wrap over each end to keep moisture out. The 538 or 539 will fit in the space the present tripler is in, you will need to drill two mounting holes for the retainer screws.
        Reed Dickinson
        On Monday, March 4, 2019, 1:40:15 PM PST, SuddenLink <bob.ripley@... mailto:bob.ripley@... > wrote:

        Hi Reed,

        Per your suggestion I disconnected the wire from the secondary of T1320 to the voltage tripler and powered up the scope. The waveform at TP1318 immediately snapped to 32 volts p-p at about 70Khz without any persuasion via the 1K resistor trick. I also checked the oscillator over at the junction of CR1329 an C1326. It measures 320 volts p-p so it looks like I need to order a voltage tripler module.

        Thank you so much for your help. Obviously, you know your way around these scopes.

        Ripley

        Sent from Mail for Windows 10

        From: SuddenLink
        Sent: Sunday, March 3, 2019 8:27 PM
        To: TekScopes@groups.io mailto:TekScopes@groups.io
        Subject: Re: [TekScopes] 475 with no Display and no HV

        Hello Again,

        I went back to the circuit around Q1306 and Q1308 this evening. The resistors are all within specs. C1305 was pulled and checked. It is also fine. C1304 is good and so is C1302.
        By the way I am checking the capacitors with a DE-5000 LCR meter. It was never let me down yet.

        The only component that I have not replaced or substituted is Q1306. It checks fine on my little Chinse component tester. For whatever that is worth.

        Enough for today.

        Ripley

        Sent from Mail for Windows 10

        From: Steph L
        Sent: Sunday, March 3, 2019 7:05 PM
        To: TekScopes@groups.io mailto:TekScopes@groups.io
        Subject: Re: [TekScopes] 475 with no Display and no HV

        Hi Ripley,
        How about C1305 0.1uF.
        If open, gain of Q1306 (and whole oscillator loop) will be lower and perhaps not enough to maintain oscillation? (Great suggestion from Don re 1K pull up touch on Q1318 base.)
        Steph

        PS. Still nubie here and unsure which "Reply" button to click on. I clicked on Ripley's "what the heck?" message "reply" button and see it has been inserted a few messages prior! That is really confusing. I'm in Melbourne Oz GMT +10 hrs. Is this the reason (i mean time difference guys and not quirky)


















    >



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Museum of Radio and Technology

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Re: 475 with no Display and no HV


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Tektronix DSA602 boot up problem

Sparky99
 

Hi everyone,

I've just added a DSA602 (with 32, 33 and 72 plugins) to my Tektronix collection - even though it's a different era the engineering that has gone into these machines seems a great tribute to some of the earlier models. The instrument itself is in fine cosmetic condition, however hangs on boot-up with the message "Comm test in progress". After looking at the service manual and some investigation, it seems that the problem is with the kernel of the executive processor, and that therefore the fault is likely with either the main CPU or associated memory cards. As this is still a bit vague I was just wondering if anyone has experience of solving this or similar problems before, or if there are any common causes of this fault?

Thanks for your help,

Re: 577 Curve tracer ringing CRT and noisy step generator

DW
 

A big thanks, that certainly answers the loops in the transistor trace in which there is nothing actually wrong with the instrument or transistor

Now that just leaves me with the spiking interference when I turn on the step generator

When set to repeat and the selector switch to off on the fixture and the collector at 0 volts a little spike appears on the right or left of the dot, it flickers at the rate the step rate is set at. If I push single I see the spike briefly appear and pushing it again the spike appears. My best assumption so far is I have a leaky IC or bad socket which I hope not. I bought some op amps which I will replace in hopes of fixing the noisy spiking step generator.

Re: Tektronix DSA602 boot up problem

 

Have you checked the memory backup batteries?

On 3/17/2019 4:47 PM, Sparky99 wrote:
Hi everyone,

I've just added a DSA602 (with 32, 33 and 72 plugins) to my Tektronix collection - even though it's a different era the engineering that has gone into these machines seems a great tribute to some of the earlier models. The instrument itself is in fine cosmetic condition, however hangs on boot-up with the message "Comm test in progress". After looking at the service manual and some investigation, it seems that the problem is with the kernel of the executive processor, and that therefore the fault is likely with either the main CPU or associated memory cards. As this is still a bit vague I was just wondering if anyone has experience of solving this or similar problems before, or if there are any common causes of this fault?

Thanks for your help,



Re: Tektronix DSA602 boot up problem

TekTom
 

Pretty amazing machine for it's time. Been toying around with the idea of getting a Rigol for every day use, but I've not been able to bring myself to the point of dissing my DSA :)

The service manual indicates that the executive processor tries to communicate with the digitizer (IO Board I believe) and the display card via the back plane. If this communication attempt fails, it gets stuck at the "Comm test in progress" point of the startup sequence. I did have this error once when I upgraded the ROMs in my 602A. After much frustration, it turned out to be a mis-seated ROM chip (one leg had bent under the chip) on the display card. You may want to try to reseat these cards in the back plane.

Re: Tektronix DSA602 boot up problem

TekTom
 

Also, forgot to mention that there are testpoints and status LEDs on the display and digitizer IO board that can help to narrow down what may be the issue on either of these boards. Table 3-7 and 3-8 related to the display board and 3-11 and 3-12 to the digitizer IO. The binary test points helped me to recognize my ROM seating issue on the display board.

Storage CRTs fade with age ?

Tim Phillips
 

from Tim P (UK)
I have three 5000-series storage 'scopes where the store mode seems weak
and lacking 'bite' . I have done the 'fade positive' thing as recommended
in the manual, to clean out the dead ions (!), and been through the storage
setup, and it all works sort-of-OK, in that it stores and erases as it
should, but the stored trace / background has little contrast, and
increasing Intensity range just blooms the CRT. Is the CRT showing its age
? Affects all three instruments to different degree.
many thanks
Tim

Re: Storage CRTs fade with age ?

Chuck Harris
 

The fast storage mode had almost no contrast, even
straight from the factory. It is normal for them to
sport a comfortably bright background, with a ever so
slightly brighter trace. The difference between the
two is maybe 10%.

If I remember correctly, the trace can actually be more
visible when it is *darker* than the background on some
scope models.

The high contrast storage modes are variable persistence,
and bi-stable.

Also, you can quickly destroy the storage mesh by trying
to brighten up the beam in a fast storage mode. The manual
gives you a formulaic way of setting it. Follow it. Don't
just keep turning the intensity up in storage mode hoping
for more contrast. All you will succeed in doing is burning
the storage mesh.

As a guideline, the intensity adjustment in storage mode should
be the same as a somewhat dim to comfortably bright display
in non storage mode. I find that dim is usually best.

Anyone that actually did real work with storage CRT's dropped
them like hot potatoes, when digital storage scopes arrived
that met their speed needs.

In my not so humble opinion, the best thing that was ever done
with storage CRT's was the Tektronix 4010 family of bi-stable
storage plotting terminals. Yes, they were slow, but they gave
high resolution graphics plotting to the masses when it was
needed desperately.

-Chuck Harris

Tim Phillips wrote:

from Tim P (UK)
I have three 5000-series storage 'scopes where the store mode seems weak
and lacking 'bite' . I have done the 'fade positive' thing as recommended
in the manual, to clean out the dead ions (!), and been through the storage
setup, and it all works sort-of-OK, in that it stores and erases as it
should, but the stored trace / background has little contrast, and
increasing Intensity range just blooms the CRT. Is the CRT showing its age
? Affects all three instruments to different degree.
many thanks
Tim



Re: Tektronix DSA602 boot up problem

Sparky99
 

Thanks for the replies. I tested the batteries and found that the memory board one was reading almost 0V! Have just replaced, but unfortunately to no avail - still same error. Whilst doing this I also found that two of the board were in a different place on the backplane to that shown in the manual - although oddly the length of the cables suggests that this might have been done at the factory. I think both digitizer cards run on a different backplane. It was neither of these cards, and unsurprisingly therefore swapping the location of the other cards to that shown in the manual made no difference.

I've not had a chance to go through each card yet and reseat the ROM's etc. - this will be next on my list. I also took a look in the manual. Based on the LED's and also the front panel LED patters, the fault is supposed to be in the main CPU/memory cards. Thanks TekTom for your suggestion - I can also imagine that a fault in the display and/or digitizer IO boards might generate the fault seen - will check the test points.

Re: 11801 diagnostic help

 

On Sat, Mar 16, 2019 at 04:45 PM, Reginald Beardsley wrote:

Hopefully with 11801 manuals in hand rather than manuals for later variants.
Seem to be a hard one to find. I scanned mine and you can find it here for some time:
www.hakanh.com/dl/temp/11801_Service.pdf
It is OCR'ed and bookmarked. Feel free to upload it to TekWiki.
/Håkan

Re: 11801 diagnostic help

Reginald Beardsley
 

Thank you!! I just bought the user manual, so I'll be scanning it when it arrives. There is a paper copy of the service manual on eBay for $35 which I will buy if the seller will verify it is the correct manual, though now that I have a confirmed part number I may go ahead.

But now that I have the correct manual I can at least identify the boards and while I'm at it copy the ROMS.

I found so many 11801C manuals online listed as 11801 it was ridiculous.

Have Fun!
Reg

--------------------------------------------

On Mon, 3/18/19, zenith5106 <hahi@...> wrote:

Subject: Re: [TekScopes] 11801 diagnostic help
To: TekScopes@groups.io
Date: Monday, March 18, 2019, 4:54 PM

On Sat, Mar 16, 2019 at 04:45 PM,
Reginald Beardsley wrote:

> Hopefully with 11801 manuals  in hand
rather than manuals for later variants.

Seem to be a hard one to find. I scanned mine
and you can find it here for some time:
www.hakanh.com/dl/temp/11801_Service.pdf
It is OCR'ed and bookmarked. Feel free to
upload it to TekWiki.
/Håkan

2467B No B Sweep

thespin@...
 

Hey All,

I've managed to find some time to play with my 2467B and have been trying to untangle whether the non-working CTT option (CT TEST 86 FAIL 02) has broken the B sweep or if the B sweep itself isn't working at all. Regardless of whether B "RUN AFT DLY" "TRIG AFT DLY" or "TRIG Delta DELAY" is selected, I see "MISSING B TRIG" on screen. I reckon "TRIG AFT DLY" shouldn't work at all since this is what's indicated isn't working by TEST 86 FAIL 02.

So here's what I observe. I get a stable trace using the A sweep. I pull the SEC/DIV knob, turn it one click to the right, and push it back in to switch to the B sweep. I then observe no trace at all, for any position of the holdoff knob, for any value of the DLY value on screen, and for any B trigger setting. This scope is pretty complex and I understand I might just not be using the B sweep correctly... but if indeed this is abnormal behavior, how can I tell if the CTT failure is causing this, or if it's something related to the A/B trigger hybrid, B sweep hybrid, or display sequencer IC? Or perhaps something totally unrelated? Does anyone have any experience with this behavior?

Re: 2467B No B Sweep

thespin@...
 

Okay following the video of w2aew (https://www.youtube.com/watch?v=54roz8IUoVI), I'm now a bit more confident I'm not goofing something up. Pulling the SEC/DIV knob doesn't result in an intensified region, and turning the knob doesn't result in a second trace. I think the B sweep is just out.

On Mon, Mar 18, 2019 at 09:05 PM, <thespin@...> wrote:


Hey All,

I've managed to find some time to play with my 2467B and have been trying to
untangle whether the non-working CTT option (CT TEST 86 FAIL 02) has broken
the B sweep or if the B sweep itself isn't working at all. Regardless of
whether B "RUN AFT DLY" "TRIG AFT DLY" or "TRIG Delta DELAY" is selected, I
see "MISSING B TRIG" on screen. I reckon "TRIG AFT DLY" shouldn't work at all
since this is what's indicated isn't working by TEST 86 FAIL 02.

So here's what I observe. I get a stable trace using the A sweep. I pull the
SEC/DIV knob, turn it one click to the right, and push it back in to switch to
the B sweep. I then observe no trace at all, for any position of the holdoff
knob, for any value of the DLY value on screen, and for any B trigger setting.
This scope is pretty complex and I understand I might just not be using the B
sweep correctly... but if indeed this is abnormal behavior, how can I tell if
the CTT failure is causing this, or if it's something related to the A/B
trigger hybrid, B sweep hybrid, or display sequencer IC? Or perhaps something
totally unrelated? Does anyone have any experience with this behavior?

Re: 222/224 Portable scope CRT pinout?

Jared Cabot
 

Does anyone have one of these they can pop the cover off and take a photo or two, or have the physical pinout of the CRT so I can match up the wires?

Re: 2467B No B Sweep

 

Is it possible the switch isn't operating when you pull the knob out?  There is a plastic piece between the knob and the switch that can be broken.