Date   

Re: Help with 2712 Spectrum Analiser

Marcus - PP5MS
 

Hi everyone,

I would like to thank everyone who kindly gave me information and advice on how to proceed with the repair.

I downloaded the service manual and will start the work with a good visual inspection, changing the battery and checking the power supply.

Certainly I will publishing here the progress and I hope to have the 2712 fully functional soon.

Marcus - PP5MS


Re: Backlash/Play in the Delta Time Position Control on a 2236

 

Raymond,

I just bought one I saw on eBay that wasn't ridiculously priced (though, I suspect, it might have been the only one I saw, as I can't find any listings now). Maybe I should have been more careful, but I doubt that the eBay listing showed the full title page, so I couldn't have known what printing I was getting. TekWiki only seems to have the later printings. I should put a note in my printed copy that it doesn't match the unit.

I've seen the discussions of Tek SNs. It makes my head hurt. It did reveal, however, a half-memory about one of my dad's scopes (the 2213): what I recall is that he bought that scope essentially as soon as they were available, and the SN (B010299) confirms that memory. Not that I'm impressed by low model numbers, but any time I can have a pre-adolescent memory confirmed I'm happy.

-- Jeff Dutky


Re: Comments from Peter Keller on the 500 Series Scopes

Shaun M
 

Folks,

Best of the Season to everyone,

Just as a counterpoise to John's message, I have a big stable of old TEK CRT gear waiting to be restore and I am just about to retire from my day job (Materials Eng). I am relatively young (Apollo kid) so that I never encountered Tek CRT gear in my day job, but recognized the pedigree when I saw it.

Film cameras, well there is a specialty. I still shoot MF B&W and do my own developing. In fact I can claim some little expertise in chemistry and scanning, with taming high contrast films like TechPan and ATP 1.1 to produce wonderful prints.

So it will be over someday, but not today.

Shaun M

-----Original Message-----
From: TekScopes@groups.io <TekScopes@groups.io> On Behalf Of John Williams
Sent: Wednesday, December 23, 2020 20:54
To: TekScopes@groups.io
Subject: Re: [TekScopes] Comments from Peter Keller on the 500 Series Scopes

Hello and happy holidays to you all.

I have to agree with Peter that interest in 500 series scopes is declining. But I also have to say of course it is. Most of us who would have used them are also declining. Just like interest in other things that have been replaced by new technology such as collecting film cameras, mechanical toys and stamps. Even the crt color tv and computer monitors are gone. Remember DEC and Data General? Not only are the companies gone, but the entire minicomputer industry is history.

However there has been a lot of good interest in the old scopes since I started collecting them. Peter's book is just one example. Vintage Tek, Tekwiki, and the Tek museum all came to be since then. I would say that few people in the industry would ever consider using a tube scope, most don't even know that they exist. I often wonder what my wife will do with all this stuff once I am gone.

As far as the ones I have, I lost count a long time ago. Here is the link to my pictures, please count them for me.

https://na01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fphotos.app.goo.gl%2Frv7WNBPM61PsdLpj7&;data=04%7C01%7C%7C69c51ac937724a58c6d608d8a7bf90cd%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637443788513925330%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&amp;sdata=MdXB2FyzRTqq1JhWTmBSHLjYU5ym0Qe2nfMIKWJ60rU%3D&amp;reserved=0


Tek for time

stevenhorii
 

I did not think this belonged in any of the current threads. Besides Tek scopes, I also restore and mess about with time and frequency stuff. I use mostly quartz frequency standards and my favorites are the mil-spec ones from Frequency Electronics and the older high-stability ones made by Tracor/Sulzer. In fact, my reason for this posting is that I am looking for a particular Tracor/Sulzer frequency standard - a quartz model 2.5B or (preferably) a model 2.5C. I suspect that at least some members of this group have an interest in time and frequency stuff or may know other electronics folks who do. I have a pair of Tektronix 7L5 spectrum analyzers both with (I think - have to check) the L1 input module and one with the Option 25 tracking generator. Also a 7L14. I have not used these in years nor have I recently powered them up. I'd swap all three for a Tracor/Sulzer Model 2.5C that has an intact dewar inside the case and has all three outputs working. I do not need the power supply - I have plenty of those. I know there is a model 2.5 on eBay, but it is the early version and I have one of those (still a remarkably stable quartz oscillator and still working after what - 40 years?). I have repaired a few of these; usually one of the output amplifier stages after the divider stage quits and only one or two outputs work. Harder to fix is if the oven temperature control goes - if it's just the oven controller, that's not too bad, but it's hard to get to, and recalibrating the oven needs a precision thermometer of the platinum type (like the HP one). Yes, I use GPS as well. I have a couple of quartz standards and one rubidium standard that are disciplined by GPS. So they are pretty much like cesium clock precision. Anyone who has the Tracor/Sulzer I am looking for or knows of someone who does and is interested in the swap or sale, let me know off-list (sonodocsch at gmail dot com). Merry Christmas and Happy New Year to all of the group!

Steve Horii


Re: Comments from Peter Keller on the 500 Series Scopes

Dave Seiter
 

My first Tek scope was a working 502 I picked up at the Foothill fleamarket in about '79.  I had a Heathkit or Eico previously, and the 502 was so much better!  I spent endless hours just playing around with it, and used it to troubleshoot the early Commodore computers I built from dumpster parts. (It was a real testament to it's design that it could just barely trigger at the PCs frequencies (1MHz CLK), more or less!)  
Of the 80 or so scopes I have, the 500 series are:
502 (still have it!)R502511A514AD519 (3, including a 519 scopemobile)535 (I think- it's an old basket case)541545547 (2)RM547RM35A549551555575 (2- not scopes, but the same style & quality)
I love the narrow traces, the intuitive layout and the overall quality.  I have seen a few for sale locally in the past two years, but nothing I "needed".  One was a 536 for $20, but I was out of room at the time, and didn't need an XY scope.  Another was a 535 w/lots of plugins, but it had lived in a damp environment for years- there was a white corrosion film covering everything. As I was weighing my options, someone else snagged it.
-Dave

On Wednesday, December 23, 2020, 11:47:27 AM PST, Dennis Tillman W7pF <dennis@ridesoft.com> wrote:
Peter was disappointed that there didn't seem to be much interest in the 500
series of oscilloscopes. I thought it might be nice if Peter heard from how
many TekScopes members have 500 series scopes and what you like most about
your favorite model.


Re: Comments from Peter Keller on the 500 Series Scopes

John Williams
 

Hello and happy holidays to you all.

I have to agree with Peter that interest in 500 series scopes is declining. But I also have to say of course it is. Most of us who would have used them are also declining. Just like interest in other things that have been replaced by new technology such as collecting film cameras, mechanical toys and stamps. Even the crt color tv and computer monitors are gone. Remember DEC and Data General? Not only are the companies gone, but the entire minicomputer industry is history.

However there has been a lot of good interest in the old scopes since I started collecting them. Peter’s book is just one example. Vintage Tek, Tekwiki, and the Tek museum all came to be since then. I would say that few people in the industry would ever consider using a tube scope, most don’t even know that they exist. I often wonder what my wife will do with all this stuff once I am gone.

As far as the ones I have, I lost count a long time ago. Here is the link to my pictures, please count them for me.

https://photos.app.goo.gl/rv7WNBPM61PsdLpj7


Re: Backlash/Play in the Delta Time Position Control on a 2236

Ed Breya
 

OK, so it is the little pot on top. Regardless of which manual and part numbers are right, one thing that I recall is that pot is very flimsy (mechanically) for its application. A heavy handed user could over-torque it and bend or break it off the board, unless it has some kind of friction release over-run protection. With the number of part changes over the product life, I'm guessing there may have been two problems - one with having inadequate setting resolution, and possibly another needing mechanical changes for pot durability.

Ed


Re: Comments from Peter Keller on the 500 Series Scopes

snapdiode
 

I have a 547 with many plugins like the Type O, 1A1, 1A2, 1A5, 1A7, four 1S1's with accessories like P6032, Type 281 ans 282, four 1S2's.

I have a 531 but it is in pitiful condition, it was used by a cigar smoker before and it is coated in tar inside and out.

A 567 with 6R1A and a complement of sampling heads like S-1, S-2, S-3, S-4, S-52, S-6 and S-42.

And a box of stuff like those little epoxy bead 10mA tunnel diodes and Tek matched Nuvistors.

I also have a Type 132 power supply.


Re: Tek Prototype?

Ed Breya
 

I'd guess it was just some Tek employee's ham radio project. Equipment cabinets and chassis make good platforms for projects. An insider would have had access to blank, unused end plates, mechanical parts, and same vintage ceramic strips and components. There's not much point in using it for anything but the same - a cabinet, possibly a usable power supply or transformer, and some of the parts, depending on possible project needs. The rest is junk, or maybe all of it is junk, if you don't need a project box or parts. I always save old carcass boxes that can be resurrected for other uses.

Even if it was an actual Tek-built prototype or in-house equipment for something, there's no use for it anyway.

Ed


Re: Tek Prototype?

John Gord
 

Oops,
FT-241
--John Gord

On Wed, Dec 23, 2020 at 04:58 PM, John Gord wrote:


The crystal in the unit is an FT-242 "channel" crystal. Those had a strange
flex-mode crystal resonator (not the usual shear-mode). I think the 3-digit
channel crystals had a fundamental frequency equal to the marked frequency
divided by 72, or in this case 27.2MHz/72= 377.778kHz.
--John Gord

On Wed, Dec 23, 2020 at 03:42 PM, Phillip Potter wrote:


I was just gifted a Tek device and have almost no idea what it could be. I
have posted a few pictures of it (along with a gifted 310) linked here:

https://groups.io/g/TekScopes/album?id=258522

If you'd be willing to look at this and tell me what it is, I would
appreciate
your doing so. Thank you.

I plan to post better pics shortly, and when I do I will repost the link.

Thanks, and Merry Christmas.

Phil, N6OMM


Re: Tek Prototype?

John Gord
 

The crystal in the unit is an FT-242 "channel" crystal. Those had a strange flex-mode crystal resonator (not the usual shear-mode). I think the 3-digit channel crystals had a fundamental frequency equal to the marked frequency divided by 72, or in this case 27.2MHz/72= 377.778kHz.
--John Gord

On Wed, Dec 23, 2020 at 03:42 PM, Phillip Potter wrote:


I was just gifted a Tek device and have almost no idea what it could be. I
have posted a few pictures of it (along with a gifted 310) linked here:

https://groups.io/g/TekScopes/album?id=258522

If you'd be willing to look at this and tell me what it is, I would appreciate
your doing so. Thank you.

I plan to post better pics shortly, and when I do I will repost the link.

Thanks, and Merry Christmas.

Phil, N6OMM


Re: Help with 2712 Spectrum Analiser

WB6GHK
 

Hi Marcus,

The Tektronix 2712 spectrum analyzer is a very good unit and it is definitely worth your time to fix and keep. The 2712 is part of a family of compact spectrum analyzers (2710/11, 2714/15) made by Tektronix. There are service manuals readily available and collecting and reading them will give you good understanding of the units. The biggest issue will be BOTH troubleshooting and the cost of replacement parts. While all of the other suggestions provided will get you going in the right direction, I suggest you look for a failure of the following items in this order:

1. Intra-board cabling may not be correct, use the service manual to confirm cable routing. I believe the first page of schematics in the 2712 service manual has a drawing of the modules and the cabling. It is not uncommon for techs to troubleshoot a unit and then when they find it is not economical to repair they just hurriedly put the unit back together and it goes to scrap. Sometimes cable aren't connected, may be damaged (bent pins), missing, or connected to the wrong port or board.

2. The A21 100 MHz oscillator board may not be putting out the 100 MHz frequency needed by the 2712's subsystems, reflected in the error messages you posted. With a scope or frequency counter, check J110 (level unknown), and J130 / J140 (about -4 dBm for either) for frequency and output level. If there is no signal, or it is weak or distorted (check by 100 MHz or higher input scope), then you will need to replace the assembly or component level troubleshoot the board.

3. The A18 Input Attenuator module has the front panel input and the internal calibrator signal fed through a TO-5 can relay used as a switch into the first attenuation stage. Try cycling through the front panel Level steps to see if an input signal is displayed at any point. There are five attenuators where one of them could be damaged from an excessive input signal, typically from an accidental connection to a transmitter. Worse case is you can bypass the attenuator, or connect the calibrator signal directly to the RF Mixer low pass filter input for testing.

4. The A16 RF Mixer has internal and difficult to replace mixer diodes that can be easily damaged by a high level signal. If the attenuator is set to zero dBm attention, a high level signal can pass through the attenuator and can cause damage to the RF Mixer stage. While you can repair the mixer, some components are no longer available (think mixer diodes) but you may be able to substitute a different part that may or may not provide the same level of performance. You will need some good test equipment to trouble shoot the mixer, but at minimum a 100 MHz scope may work, along with a signal generator capable of -30 to 10 dBm and a frequency range of 100 - 500/1000 MHz. If you have equal or better equipment and time, study the service manual and the operation explanations and then start with good troubleshooting measurements.

Best of luck, keep us updated as you go. Paul/WB6GHK


Re: Tek Prototype?

Bob Albert
 

That is the range but there is no channel at just 27.2 MHz.  All channels are at 5 kHz points, such as 27.255.

On Wednesday, December 23, 2020, 04:08:06 PM PST, Phillip Potter <p.potter@sbcglobal.net> wrote:

Isn't 27Mhz Citizens Band?\

Phil

On 12/23/2020 4:01 PM, Raymond Domp Frank wrote:
On Thu, Dec 24, 2020 at 12:56 AM, Bob Albert wrote:

Is there a frequency determining element, such as a crystal?  Smacks of ham
radio.
I see at least three empty quartz crystal sockets and one 27.2 MHz quartz crystal ("Channel 272")

Raymond



Re: Tek Prototype?

Phillip Potter
 

Isn't 27Mhz Citizens Band?\

Phil

On 12/23/2020 4:01 PM, Raymond Domp Frank wrote:
On Thu, Dec 24, 2020 at 12:56 AM, Bob Albert wrote:

Is there a frequency determining element, such as a crystal?  Smacks of ham
radio.
I see at least three empty quartz crystal sockets and one 27.2 MHz quartz crystal ("Channel 272")

Raymond



Re: Tek Prototype?

Bob Albert
 

Channel 272 may not refer directly to frequency.  So it's crystal controlled.  It is very likely for the HF range.  If it is indeed 27.2 MHz perhaps that's a local oscillator frequency.
Bob

On Wednesday, December 23, 2020, 04:02:06 PM PST, Raymond Domp Frank <hewpatek@gmail.com> wrote:

On Thu, Dec 24, 2020 at 12:56 AM, Bob Albert wrote:


Is there a frequency determining element, such as a crystal?  Smacks of ham
radio.
I see at least three empty quartz crystal sockets and one 27.2 MHz quartz crystal ("Channel 272")

Raymond


Re: Tek Prototype?

 

On Thu, Dec 24, 2020 at 12:56 AM, Bob Albert wrote:


Is there a frequency determining element, such as a crystal?  Smacks of ham
radio.
I see at least three empty quartz crystal sockets and one 27.2 MHz quartz crystal ("Channel 272")

Raymond


Re: Backlash/Play in the Delta Time Position Control on a 2236

 

On Thu, Dec 24, 2020 at 12:09 AM, Jeff Dutky wrote:


Exactly right about which control I'm talking about, but I'm a bit confused
about the service manual. I have the same PN for the service manual that you
indicate, but I can't find R1618/1619, and the delta time position pot is
labeled R1617, and indicates that it is only a single 2.2K pot. It sounds like
we have the service manuals for each other's scopes (mine is a much later SN
than yours, B027035). My SM appears to be the first printing from MAR 83.
Jeff,
I don't know where you've got your manual from. I looked through my own PDF and 4 PDF's on TekWiki. They all show the double pot in dwg 10 (K2 area is difficult to read). R1618 and R1619 also are in dwg 10 just to the right of R1617 and both are listed in the parts list. Different copies may have been made from manually updated originals.

The setup for the pots is the standard way that's often used: The two pot's ends in parallel and the runners connected to a common point through separate resistors. The common point becomes the virtual "runner".

Your 2336 was made in Beaverton, USA, mine in the UK, as can be seen from the starting "2" in my SN. There is no straight relation between serial numbers in different regions. This has been brought up and complained about many times in this group. If non-USA production didn't start until a few years after (USA) introduction, regional "early" numbers would cross to US high numbers. Not really a way to tell though.

Raymond


Re: Tek Prototype?

Bob Albert
 

It's got a microphone input and an SO-239 in front, probably an output.  Several power tubes so it looks like a signal generator of high power or a transmitter/exciter.  Modulated but maybe AM or SSB.  Is there a frequency determining element, such as a crystal?  Smacks of ham radio.
Bob K6DDX

On Wednesday, December 23, 2020, 03:43:10 PM PST, Phillip Potter <p.potter@sbcglobal.net> wrote:

I was just gifted a Tek device and have almost no idea what it could be. I have posted a few pictures of it (along with a gifted 310) linked here:

https://groups.io/g/TekScopes/album?id=258522

If you'd be willing to look at this and tell me what it is, I would appreciate your doing so. Thank you.

I plan to post better pics shortly, and when I do I will repost the link.

Thanks, and Merry Christmas.

Phil, N6OMM


Re: Comments from Peter Keller on the 500 Series Scopes

Greg Muir
 

Have:

(2) Tek 502
(1) Tek 541A
(4) Tek 547
(1) Tek 549
(1) Tek 555
(1) Tek 575
(1) Tek 585 w/type 81 adapter (when required)

Plus a raft of plug-ins too numerous to mention at this time as well as scope carts for most of them.

Had a couple of 511s tucked away somewhere but I’ll be darned if I can locate them right now.

Obviously my legacy choice is the 547. For “blazing” speed (heh) I rely on the 585.

Was actually “raised” on a Tek 524 at the local television station when I was 14 years old back in the 60’s. Never saw the worth of looking at other manufacturers oscilloscopes after the experience of using a scope that performed so well. The crisp triggering really impressed me. But that was also in the era when other scope manufacturers were still using "sync" triggering a lot.

I guess you could say that first Tek experience was what started me on my Tek scope hobby of today.

Greg


Tek Prototype?

Phillip Potter
 

I was just gifted a Tek device and have almost no idea what it could be. I have posted a few pictures of it (along with a gifted 310) linked here:

https://groups.io/g/TekScopes/album?id=258522

If you'd be willing to look at this and tell me what it is, I would appreciate your doing so. Thank you.

I plan to post better pics shortly, and when I do I will repost the link.

Thanks, and Merry Christmas.

Phil, N6OMM

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