Date   
Re: SPC fails on TDS7404

Erkka Sointula
 

Hi Stan,

My TDS7404 has the same problem.
It has a special IC with a x-tal, Lithium battery and memory built in.
When the battery goes empty then also some cal values in the memory.
Based on some experts the only way to get it back is send it to Tek. Price ?

I have 8GHz high end Anritsu VNA with the same problem\circuit and it does not even boot up.

Your TEK might still be good for your own use. Check just the amplitude levels and freq response. They might be good enough.

br Erkka

Re: Most desirable Tektronix scope of them all?

Craig Sawyers <c.sawyers@...>
 

As far as rarity goes, how about the 567+6R1?
Ah - I'd forgotten about Tek's foray into early digital stuff. The peak of that madness was in 1970
with the R240 (and a whole bunch of related stuff) program control unit which interfaced with a
punched tape reader and a disc memory.

Prices in 1970 were:

R240 - $4400
Punched tape reader $1375
Disc memory $7200 (less than 1M-bit - or about 125kByte, storage, consuming 190W of electrical power)

And on top of that the 568 oscilloscope and programmable plugins.

Or you could just buy the S-3130, which had a 568, 230 digital unit, 240 program control unit, 250
program unit, 3S6 programmable sampling unit, 3T6 programmable sampling sweep, two S3 sampling heads,
Type R116 programmable pulse generator, disc memory, punched tape reader, four programmable power
supplies, two probe choppers, and a few bits and bobs, all fitted into two full-height 19" racks.
$46,700 or $750,000 in today's money.

Ultra rare - personally I've never seen any elements of that system for sale.

Craig

Re: Most desirable Tektronix scope of them all?

Craig Sawyers <c.sawyers@...>
 

For coolness, a 400 MHz 7844 dual beam oscilloscope with P7 blue phosphor and a green CRT filter
is
out of this world. Especially when running it as an oscilloscope and spectrum analyzer
simultaneously!

Agreed. Two independent oscilloscopes in one chassis, sharing a dual gun, dual deflection system
CRT. The only proviso is to make a note of the switch settings once you get the trace(s) you want.
There are 128 possible switch settings for vertical and horizontal mode (2^8) divided by two because
you have to have at least one vertical and one horizontal button pushed to get a trace. Not
counting the choices in the multi trace and multi timebase plugin settings.

Powerful, wonderful, cryptic!

And yes, why are you not surprised I have one...

Craig

Re: Most desirable Tektronix scope of them all?

Dave Seiter
 

As far as rarity goes, how about the 507, 517A or 567+6R1?  (I don't consider the 519 rare)
As far as usefullness, 547, 7603 (large display), 7844 (two in one), 7704A (gets the most usage)
-Dave From: "nicolas.sog@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Sunday, September 17, 2017 9:56 AM
Subject: [TekScopes] Most desirable Tektronix scope of them all?

  Pretty much it... I´m interested in knowing your choice and why.


400 series included.


Thank you!




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[Non-text portions of this message have been removed]

Re: 465M Blows Fuse for +32V UnReg

 

This is where I would look next. If I did not have a current limited
source to replace the +32 volt unregulated supply which would allow
measurements of the voltages in the regulator while the inverter is
limited to low and non-destructive level of power, then I would test
the various transistors pulling them if necessary and test the various
other parts.

Usually anything I pull gets socket pins installed but that is up to
you.

On Sat, 16 Sep 2017 23:58:21 -0400, you wrote:

...

The clue is entirely in the collector of Q548 being positive.
When your oscillator is running, and is the correct voltage,
the oscillation drives the emitter negative. When the voltage
regulator circuit, comprised of Q556 and Q552 thinks the HV
is too high (negative), it drives the emitter of Q548 negative,
which causes Q552 to spend more time turned off, which in turn
causes the HV to reduce. When the voltage regulator thinks
the HV is too low, it causes Q548 to go more positive, which
causes Q552 to stay on longer, putting more energy into the
transformer, and making the HV increase.

Your regulator thinks that the HV is kaput, and is not being
generated, and as such is dumping maximum current into Q552,
and the transformer, which is why it is hot, and is blowing
the fuse.

So, your task is to find out why.

I suggest that you look at the collector/base of Q544/548.

I have seen this problem before, and what was going on, is
C543 was leaky, and was dragging the resistor divider made up
of the 20M and the 320K to gnd, which is what you see if the
HV is too low. This turned the regulator on full, and poof
went the fuse.

-Chuck Harris

Re: Most desirable Tektronix scope of them all?

 

I have to pick the 2232 also. Besides what you said, it also has an
usually sharp digital storage display even compared to a modern DSO.

On Sun, 17 Sep 2017 13:24:44 -0400, you wrote:

I will pick the 2232.

It offers both a full function digital and analog scope in one package.
Has honest to goodness knobs and buttons to select most-needed settings.
Has a complete old Tek style service manual.
Most parts are still obtainable, few really hard to get parts.
I bought a few of mine for 'parts' scopes and have had little need to
use them for that purpose.

I am now up to four digital only scopes and I still find that I go back
to the 2232 for many things.
I use my 7K scopes less and less as they are just too hard to toss
around today ( I'm in my mid 80s).

- Bert

Re: Most desirable Tektronix scope of them all?

 

The first Tektronix oscilloscope I owned if I exclude my 545A clone is
a 2247A which shares many of the measurement capabilities of the 2236.
It makes all of its voltage measurements through a C trigger so while
it cannot measure AC, it can measure DC, peak, and peak-to-peak up to
its full bandwidth.

On 17 Sep 2017 18:59:23 +0000, you wrote:

"Love of my life" is 2236. 2236 was first scope I touch from Tek in 1989 and I love it from first look. Now have 7904, 7904A, 7704A, 7603, some 24xx, some 4xx but always first choice for work is 2236. It is very useful with dmm when check ripples with ac on channel 1. It is most used mode on it on my bench. Do all to find this scope for repair and to bring it back to life. It is the unit that can't be scraped for me. It is easy for repair and think that can live many years.

Re: Most desirable Tektronix scope of them all?

sittners
 

There are certainly a varied assortment of "favorites" in this group.
The collection here includes a 7104, 7704,7603, 2465B, 2445, 2247A, 485,
314 and a TDS210. The 2247A is the workhorse because the "smart cursor"
feature is so convenient. The 2465B is the second most used and the
TDS210 sees duty when dealing with slow digital signals. I guess it's to
be said that they all are my favorites, depending upon the application.

Phil


On 9/17/2017 4:00 PM, 'Morris Odell' vilgotch@... [TekScopes]
wrote:

I have a reasonable collection of Tek scopes including a working 519,
a 555
and a few 7000 series but to my mind there is only one contender for
greatness and that's the 547 with a 1A4 plugin. I know it's big and power
hungry but it's been my bench scope for years and never missed a beat for
the kind of work I do. I just hope I can find someone to keep it immortal
after I'm gone...

Morris

__________________________________________________________
5a. Most desirable Tektronix scope of them all?
Posted by: nicolas.sog@... nicolas.sog
Date: Sun Sep 17, 2017 9:56 am ((PDT))

Pretty much it... I´m interested in knowing your choice and why.

400 series included.

Thank you!




[Non-text portions of this message have been removed]

Re: Most desirable Tektronix scope of them all?

The Guy
 

Great answers so far... I just wish I had a like button ;)

Re: Most desirable Tektronix scope of them all?

Richard Solomon
 

For general all around usage the 475A can't be beat.

73, Dick, W1KSZ

On Sep 17, 2017 4:25 PM, "'Brian J. Henry' bhenry@... [TekScopes]" <
TekScopes@...> wrote:



This is a fun topic! There simply can't be just one....

My all time favorite Tektronix scope for field service is the compact,
rugged 100 MHz 2337 that I bought new in 1980 and still use regularly. It
is light weight, easy to use and has delta time and a dmm (like the 465B
DM44) which can be very helpful when troubleshooting.

For general bench work, I like looking at the 60 MHz 5440's big CRT with a
5B44 dual time base in the right slot, a 5CT1N curve tracer in the center
slot, and a 5A48 dual trace amplifier in the left slot.

For flexibility, the 100 MHz 2232 has the benefit of being both an analog
and a digital scope with the optional (and useful) capability of
transferring stored waveforms into a computer.

All three with blue CRT filters!

For coolness, a 400 MHz 7844 dual beam oscilloscope with P7 blue phosphor
and a green CRT filter is out of this world. Especially when running it as
an oscilloscope and spectrum analyzer simultaneously!

For cuteness, it would have to be a 5 MHz 323 oscilloscope with a blue CRT
filter piggy backed with either a 1401A spectrum analyzer or a rare 1501
time domain reflectometer.

Each is a work of art in its own unique and special way.

Brian Henry



[Non-text portions of this message have been removed]

Re: Most desirable Tektronix scope of them all?

Brian J. Henry
 

This is a fun topic! There simply can't be just one....

My all time favorite Tektronix scope for field service is the compact, rugged 100 MHz 2337 that I bought new in 1980 and still use regularly. It is light weight, easy to use and has delta time and a dmm (like the 465B DM44) which can be very helpful when troubleshooting.

For general bench work, I like looking at the 60 MHz 5440's big CRT with a 5B44 dual time base in the right slot, a 5CT1N curve tracer in the center slot, and a 5A48 dual trace amplifier in the left slot.

For flexibility, the 100 MHz 2232 has the benefit of being both an analog and a digital scope with the optional (and useful) capability of transferring stored waveforms into a computer.

All three with blue CRT filters!

For coolness, a 400 MHz 7844 dual beam oscilloscope with P7 blue phosphor and a green CRT filter is out of this world. Especially when running it as an oscilloscope and spectrum analyzer simultaneously!

For cuteness, it would have to be a 5 MHz 323 oscilloscope with a blue CRT filter piggy backed with either a 1401A spectrum analyzer or a rare 1501 time domain reflectometer.

Each is a work of art in its own unique and special way.

Brian Henry

Re: OT: need info on CPS-131N HVPS

Ed Breya
 

I rigged up a temporary remote control setup, fired up the HVPS, and it seems to work just fine, with smooth operation from near zero to -50 kV, no sweat. This was with no load, but I assume it will be fine up to the rating. One thing I noticed was that on power-down, as the control system goes down, the apparent output can shoot way up momentarily - if the metering signal is true - I saw up to 94 kV. Again, this is with no external load, only the internal feedback divider. If this is anything near right, then there should be no problem overdriving it a little to reach 60 kV at less current. I'd like to be able to hit that number for some specific testing.

For now, it will go on the shelf for later use someday.

Thought I'd ask ask one last time if anyone has heard of this company or product.

Ed

Re: Most desirable Tektronix scope of them all?

Morris Odell
 

I have a reasonable collection of Tek scopes including a working 519, a 555 and a few 7000 series but to my mind there is only one contender for greatness and that's the 547 with a 1A4 plugin. I know it's big and power hungry but it's been my bench scope for years and never missed a beat for the kind of work I do. I just hope I can find someone to keep it immortal after I'm gone...

Morris

________________________________________________________________________
5a. Most desirable Tektronix scope of them all?
Posted by: nicolas.sog@... nicolas.sog
Date: Sun Sep 17, 2017 9:56 am ((PDT))

Pretty much it... I´m interested in knowing your choice and why.


400 series included.


Thank you!

Re: Most desirable Tektronix scope of them all?

mosaicmerc
 

That would HAVE to be the one I have...2465A.

8))

Re: Most desirable Tektronix scope of them all?

Craig Sawyers <c.sawyers@...>
 

the slightly mad 7912AD. If you've got one (or more) of those then you're probably a collector
at least as much as a user!
I've the next one up - the 7912HB (for High Bandwidth). If you search photos for 7912HB you'll see the
pics I took of mine back in 2005.

Craig

Re: Most desirable Tektronix scope of them all?

Tom Brown
 

Oh, for collectability?


A 555 with a P7 CRT, matched serial number power supply and "A" series timebases. And, just for good measure, a MOD101D (60/400 cycle operation). Only a very very few of those made... I think only 20 of the later iteration...


Tom

Re: Most desirable Tektronix scope of them all?

Tom Brown
 

Well, it would depend on the exact criteria for "best"....


For "most pleasing to use and operate", for me it would be the 555, no question.


For "most versatile", it would be the 7934. 500 mc, high speed multi-mode storage and the range of 7000 series plug-in units is hard to beat.


And, as someone else said, for "fastest there is", it would be a 7104.


If I could only have one, it would probably have to be the 7934. It's just TOO versatile...


One thing it would NOT be is anything without a real CRT! :-)


Tom

Re: Most desirable Tektronix scope of them all?

Harvey White
 

On 17 Sep 2017 16:56:40 +0000, you wrote:

Pretty much it... I�m interested in knowing your choice and why.





400 series included.
Small, portable, and cute: 200 series
Portable, rugged, and useful: 465/468/475/485 depending on bandwidth
needed
Lab scope allaround: 7904/7904A

Digital and affordable, TDS-540A
Digital with older CRT and more portable 2430A and up

1) I've always liked the 200 series, cute, battery operated, and
small.
2) I have two 468's, 100 Mhz bandwidth (465) with 10 Mhz digital
backpack (very useful for digital scope and low rep rate), decent
scopes.
3) 500 mhz 7000 series, highest without being specialized, reliable,
needs plugins but will do almost anything with the right plugin
4) I have one, 500 Mhz, 4 channel. Was affordable for me at the time.
There's better ones, but I've never played with them. Possibly one of
the last of the repairable scopes.
5) I have a 2430A, well behaved and portable, not the most wonderful
with the triggering modes, but still a worthwhile scope. The higher
bandwidth digitals are likely better, but have hard to find custom
IC's that often break... 2465?

Harvey







Thank you!





Re: Tek 7K Extenders for Robert Dixon?

Robert Dixon
 

Hi John,

Yes, I do want to order a 7000 extender kit.

I don't understand why the email address didn't come through.
Please use the following:
robert_j_dixon@...

Robert Dixon

On 18 Sep 2017, at 06:07, John Griessen @jgriessen [TekScopes] <TekScopes@...> wrote:

On 09/17/2017 10:15 AM, 'James R. Bartlett' james.r.bart@... [TekScopes] wrote:
Hi John,

Yes please. Will be a useful addition to my 7104 and 7904 stable.

Shipping to Brisbane, Australia.

Regards,

Robert Dixon
There was not a working email address for Robert Dixon. Does Robert Dixon
want an extender kit?

--
John Griessen -- building field gear for biologists
Ecosensory Austin TX ecosensory.com

[Non-text portions of this message have been removed]

Re: 465M Blows Fuse for +32V UnReg

Harvey White
 

On Sun, 17 Sep 2017 13:34:47 -0400 (EDT), you wrote:

Thanks for the response, Harvey. I'm hoping that Chuck's explanation of the positive voltages is the cue here. If not, I'll keep looking.
He's looking at the schematic, has the manual, and has likely fixed
one; and I'm patching things together from what you've said. He's
more accurate on this than I can be.

Harvey



Thanks,
Barry - N4BUQ

----- Original Message -----
From: "Harvey White madyn@... [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Saturday, September 16, 2017 9:51:02 PM
Subject: Re: [TekScopes] 465M Blows Fuse for +32V UnReg

On Sat, 16 Sep 2017 22:28:01 -0400 (EDT), you wrote:

Switching gears just a bit on this.
Guessing a few things, but perhaps this'll help.

I got the replacement for Q552 but still getting too much current through
F558. If I replace the fuse with an ammeter and gradually bring the line
voltage up, at a certain point (somewhere under 40 volts or so), the
current through the ammeter jumps rather rapidly and then will continue to
increas the more I increase the line voltage. Q552 is getting hot so
that's where the current's going. If I remove Q552, I can increase the
line voltage to full voltage with no ill effect seen (other than, of
course, no HV).
Sounds as if Q552 is not being turned off.

Thinking it could be leaking VR552 and VR553 and since it was rather
convenient, I unsoldered the flying connection between those to zeners but
the problem persists.
If that's the only source of base current, then disconnecting them
removes (in theory) all base drive. Is there another connection to
the base? How about a resistor from base to ground (minimizes the
effect of base current leakage).

I'm beginning to wonder if the transformer itself is the problem. As soon
as the circuit starts to oscillate, Q552 begins drawing excessive current
and I'm not sure where the base voltage is coming from. I've checked all
the diodes and all seem good. I checked the resistance across the primary
windings (both pins 4/5 and 3/6) and I'm seeing almost zero resistance.
Does that make sense? Shouldn't there be some small resistance in those
windings? Is that in indication of a shorted winding(s)?
It might be, but you're considering reactance at high frequencies, not
just resistance.

Another thing I find odd is the waveform at TP59 is all positive. The
diagram shows that as an oscillating negative voltage and the schematic
shows there should be -0.8V at the collector of Q548. Is it possible the
problem is in/around Q548/Q544? I need to test the voltages in/around
those so that could very well be the problem.
If this is a source of the base current for Q552, then the transistor
is being turned on too much. It's a thought.

Harvey


Thanks for listening to this tirade...

Barry - N4BUQ