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Re: 1N21 etc

Craig Sawyers
 

Is the LO power level (1 mW) you have quoted a 'maximum' or a 'recommended
operating' level? Possibly the latter, I suspect- maybe based on
optimising
noise figure.
I think that hits it on the head - the noise figure and VSWR both go through
minima at 1mW local oscillator drive. The characteristic curves go up to
4mW - so presumably the thermal damage threshold is somwhat above that,
although a figure isn't quoted. 4mW would be about 8mA at 0.5V diode drop
(both rms) - and is about what GR's stated 1V drive into 250 ohms would
produce.

So that all kind of hangs together now.

Cheers

Craig
Re: 1N21 etc

Dave Brown
 

Craig

Is the LO power level (1 mW) you have quoted a 'maximum' or a 'recommended
operating' level? Possibly the latter, I suspect- maybe based on optimising
noise figure.

Dave Brown

----- Original Message -----
From: "Craig Sawyers" <c.sawyers@...>
To: "TekScopes" <TekScopes@...>
Sent: Tuesday, July 06, 2004 8:25 PM
Subject: [TekScopes] 1N21 etc


Thanks to Benoit and Vladimir, I have quite a lot of information now on
the
1N21 and 1N23 series of diodes.

There is a good amount of information on this site
, along with loads of
other interesting information about step recovery diodes (snap-off diodes
in
Tek-speak) and other microwave and high frequency components.

But here is an interesting thing - the 1N21 and 1N23 series have a
burn-out
threshold quoted in ergs - which is a unit of energy, not power. In fact
it
is a small number - between 2 and 5 (1 erg = 10^-7 Joules). Now the local
oscillator power for these mixer diodes is quoted at 1mW (in other words
10^-3 Joules/second) - so how do these figures stack up?

Or is the 2 - 5 ergs a statement of the static damage threshold? Since
they
have a point-contact junction capacitance of about 1pF or less, 2 ergs
implies a static discharge of less than 450V or so to zap the diode. That
would seem reasonable, and would explain why very early diodes were
supplied
in lead tubes (radiation hardening too?), and later ones in conductive
packets (like a few I have from Microwave Associates). It also implies
that
they ought to be handled on an antistatic bench.

The other problem is that the NTE equivalent to the 1N21 series is the
NTE112, which is actually a schottky diode (and not physically compatible,
BTW - it is wire ended) - and they state that the forward voltage drop of
0.55V at 10mA is measured with a 300us pulse length at 2% duty cycle -
implying that there is also a power damage threshold at the few mW level -
which I haven't seen quoted elsewhere. Or it could just be intended to
reduce Joule heating of the junction, which effects the forward drop. It
also doesn't quite stack up with the set-up that GR suggest using their
unit
oscillators as the Local Oscillator - and they shove out 400mW into 50
ohms.
In fact they state that 1V ought to be adequate as a local oscillator
level - and since the 874MR includes a 250 ohm series resistor indicates
at
least several mA of drive current, up to 16mA at higher drive levels.

Any further thoughts folks?

Craig





Yahoo! Groups Links
1N21 etc

Craig Sawyers
 

Thanks to Benoit and Vladimir, I have quite a lot of information now on the
1N21 and 1N23 series of diodes.

There is a good amount of information on this site
, along with loads of
other interesting information about step recovery diodes (snap-off diodes in
Tek-speak) and other microwave and high frequency components.

But here is an interesting thing - the 1N21 and 1N23 series have a burn-out
threshold quoted in ergs - which is a unit of energy, not power. In fact it
is a small number - between 2 and 5 (1 erg = 10^-7 Joules). Now the local
oscillator power for these mixer diodes is quoted at 1mW (in other words
10^-3 Joules/second) - so how do these figures stack up?

Or is the 2 - 5 ergs a statement of the static damage threshold? Since they
have a point-contact junction capacitance of about 1pF or less, 2 ergs
implies a static discharge of less than 450V or so to zap the diode. That
would seem reasonable, and would explain why very early diodes were supplied
in lead tubes (radiation hardening too?), and later ones in conductive
packets (like a few I have from Microwave Associates). It also implies that
they ought to be handled on an antistatic bench.

The other problem is that the NTE equivalent to the 1N21 series is the
NTE112, which is actually a schottky diode (and not physically compatible,
BTW - it is wire ended) - and they state that the forward voltage drop of
0.55V at 10mA is measured with a 300us pulse length at 2% duty cycle -
implying that there is also a power damage threshold at the few mW level -
which I haven't seen quoted elsewhere. Or it could just be intended to
reduce Joule heating of the junction, which effects the forward drop. It
also doesn't quite stack up with the set-up that GR suggest using their unit
oscillators as the Local Oscillator - and they shove out 400mW into 50 ohms.
In fact they state that 1V ought to be adequate as a local oscillator
level - and since the 874MR includes a 250 ohm series resistor indicates at
least several mA of drive current, up to 16mA at higher drive levels.

Any further thoughts folks?

Craig
Re: Tek 2213A - Power Supply Problems - UPDATE4

vintageaudio2004
 

Hi Dave,

Thanks for your input. I will get back to the scope this week, I was
out for the past few days.

Sorry for the late reply, will keep the group posted of any new
developments as I run some more tests involving what you are
suggesting.

Alex

--- In TekScopes@..., Dave Ashby <dashby@q...> wrote:
Hi Alex,

I would guess the transformer itself is okay, because when you run
it with
no secondaries connected to the PCB and just your test load
(rectifier,
capacitor & bulb) the inverter was drawing a low current.

It is when you reconnected the secondaries to the board - "Next I
proceeded
to connect all the secondaries (one by one) to the PC board with
some short
jumper wires. At first I connected all the secondaries, but still
left the service
jumpers open (just the ones for the +/-8.6, 5, 30, and 100V. The
others I had
previously disconnected I left in the circuit, including the CRT
filaments, HV
Multiplier, and deflection circuit feeds)" - that you started
seeing the high
current.

So, even though the service jumpers are open, there might be
something on
the PCB that is loading one or more of the secondaries. So with
the service
jumpers open and the secondaries disconnected, I would check the
resistance
between the pads on the board in every possible combination - e.g.
there might
be a short between a 5V connection and an 8V connection. I'd check
from
each pad to every other pad that the transformer secondaries go to.

The other possibility is that the problem is in the area of the CRT
filaments, HV
Multiplier, or deflection circuit feeds. It might be worthwhile
repeating the test
with each of these disconnected, to see if one of these is causing
most of the
500mA current draw.

Apologies if you've already tried these ideas. I had fixed a PSU
in a 2230 which
is very similar, and although I found quite a few components blown
in the
pre-regulator and primary side of the inverter, I did get it
going. But there were
no faults on the secondary side of the inverter, whereas in your
case, I guess
there is. Hope you fix it in the end!

David Ashby

==========================================================
Re: Tektronix 2101 Pulse Generator - for the Ages

Denis Cobley
 

Hi Matt
This Horz hybrid problem was mostly with the early 2445/2465 (155-0241-00
or -01).
The later scopes had an improved chip 155-0241-02 which was much more
reliable.
Keep in mind that tab is at 5V potential and not ground so if it shorts to
the case you can damage the power supply or blow the 5V fuse on the board.
Any 2400 analogue scope with an -02 chip can be a donor to get it going
again.
Most 24XXB scopes failed with a bad Vertical Channel switch (vertical
compression at top & bottom of screen or bandwidth rolloff at about 230MHz
or lower.

Regards
Denis Cobley

----- Original Message -----
From: "matt" <ml_potter@...>
To: "Ashton Brown" <ashton@...>
Cc: <TekScopes@...>
Sent: Tuesday, July 06, 2004 12:54 PM
Subject: Re: [TekScopes] Tektronix 2101 Pulse Generator - for the Ages


Ashton,
If memory serves me correct the 2467B micro channel
plate scope has a common problem of the horizontal amp
chip overheating and the trace disappearing after a
few minutes. If you have one of the few remaining
working 2467B units, you are lucky. If I remember,
the chip is U200 with a bolt tab extending from notch
end. Tektronix quite supporting this IC with about
three years left on their service agreements for these
scopes and therefore offered a trade in plan toward a
TDS series scope. Any how I got about another two
years of service out of the scope by attaching a
heatsink on top of the horizontal IC made from about
1"x2" with some fins that was about 3/32" thick
aluminum stock. I also used the existing stud to
mount the spacer on.

Maybe this will help someone, with their scope.

Later,
Matt Potter





__________________________________
Do you Yahoo!?
New and Improved Yahoo! Mail - 100MB free storage!





Yahoo! Groups Links
Filament voltage on SONY/TEK 336

 

Hi,

Does anybody know the correct filament voltage on a Sony / Tek 336 DSO ?

I am measuring only 0.7 volts, it seems low.

The CRT is part no. 154-0866-00, not list on sphere or Stan's website.

Thanks in advance,


John Barnes





________________________________________________________________
Sent via the WebMail system at aztec-net.com
Re: Tektronix 2101 Pulse Generator - for the Ages

 

Ashton,
If memory serves me correct the 2467B micro channel
plate scope has a common problem of the horizontal amp
chip overheating and the trace disappearing after a
few minutes. If you have one of the few remaining
working 2467B units, you are lucky. If I remember,
the chip is U200 with a bolt tab extending from notch
end. Tektronix quite supporting this IC with about
three years left on their service agreements for these
scopes and therefore offered a trade in plan toward a
TDS series scope. Any how I got about another two
years of service out of the scope by attaching a
heatsink on top of the horizontal IC made from about
1"x2" with some fins that was about 3/32" thick
aluminum stock. I also used the existing stud to
mount the spacer on.

Maybe this will help someone, with their scope.

Later,
Matt Potter





__________________________________
Do you Yahoo!?
New and Improved Yahoo! Mail - 100MB free storage!
Re: Scanned Tek manuals

 

Hi Ben - (I'll get the feet up for sale soon. I have to create a
decent web page explaining what they are...)

Miller is, I notice, selling a PDF scanned version of the "1982
Parts Catalog" for $20.00. You can peek at 1 page/chapter (16 pages
out of 400 or so) for free, to see if the quality sucks. It doesn't
suck IMO, much closer to "very good".

To me, a preview of scanned manuals is very important - having
bought a scanned manual that's nearly worthless - lacking the fine
details in the schematics such as traces and readable part numbers.

Miller's scan of that manual looks great to me. So, $20.00 buys a
usable PDF scan of a manual that, just today, in paper, sold for
$255 on eBay!

Good link, Ben - thanks.
-Howard




--- In TekScopes@..., Ben Clarke <benclarke@b...> wrote:
Hi All
A few weeks ago there was a thread about Tek manual scans on CD
and Dave
Miller's name came up as an example of best practice in this area.
Yesterday I decided that I needed one of Dave's offerings, I paid
him by
Paypal directly off his site, he made an ftp download available
within
minutes and I was using the information less than 1 hour later!
Some of the
items he has on offer are very rare and the quality of the example
I had
was of the very best.
I have no connection with Dave other than as a very satisfied
user, but if
you need Tektronix information you should check out his site at


Ben
Re: Tektronix 2101 Pulse Generator - for the Ages

Ashton Brown
 

The first-rate engineering knowledge of this group is awesome (that overused word), and some of the subtleties are clearly of the sort unlikely to appear in (even a) Tek manual - though perhaps in some of those -fiches and other special Notes which Stan refers to..

Wouldst there were an Angel about, willing to finance the methodical collecting, cross-sorting for model and symptom.. of a few hundred of these gems. We know already, that the New Tek has no slightest interest in such preservation. (I'd still like to imagine a 7104 working on command at 1 GHz *analog* in 2050. (Dunno about the longevity of a 2467B in that scheme of things, given the delegation of the deceased Tek semiconductor Fab to far lesser lights .?.)

I lack both the expertise and will, for such a compilation (and curve tracer) - but knowing when, say, recovery-time is mondo-Important? in an arcane application - would also escape my lore. I would however, contribute a few $ towards any such project as might arise.. before we're all dead. Just Because - these Are works of Art. Modern Modiglianis, at least. Y'know?

(I suspect the Smithsonian might well keep a unplugged 7104 on display.. but sans the knowledge base, strategic spares to maintain it. Post 2050.)

Just a thought,

Ashton


Miroslav Pokorni wrote:

Diodes 1N4152 and 1N4148 are replacements for 1N914 of lesser capabilities.
There is something in spec for 1N914 that was very difficult to match, I
think it was recovery time, and not very many applications did need that,
so -48 and -52 were registered.

In some other applications very low reverse current was required and
Tektronix used some of Fairchild's FD series diodes. I believe, the
application was voltage converter/rectifier for biasing CRT grids in 7904
scopes (part of high voltage power supply). I have been told that when those
FD diodes become leaky, circuit works poorly (at times erratically) and
replacing diodes with a modern high frequency rectifier does not do anything
for it, the only known cure is to get the original diodes. Tektronix was
selling those diodes 6 - 7 years ago at quite exorbitant price.

Regards

Miroslav Pokorni


----- Original Message -----
From: "D. Dufresne" <ddufresn@...>
To: <TekScopes@...>
Sent: Monday, July 05, 2004 8:30 AM
Subject: [TekScopes] Tektronix 2101 Pulse Generator



Tektronix 2101 Pulse Generator, serial number B040xxx, restricted
pulse width adjustment range

I purchased this pulse generator used in 1994 from Dumont Electronics
here in Montreal Quebec. It worked fine until last year. I could not
get any pulse with a larger width than 60 ns or so. Pulse duration
range switch did almost nothing, pulse duration variable control did
allow the pulse width to vary from 10 ns to about 60 ns.
Troubleshooting section in manual 070-1029-00, dated 1970 April, is
not very useful. Found CR182 to be defective, it conducted in both
directions in the diode test function of my multimeter. Removed from
circuit is measured about 300 ohms in both directions. Diode is
152-0322-00 a silicon Tektronix special, manufactured by or for them
or reworked or checked. So I looked at the parts list and found
another diode, CR335, with the same Tek part number that was changed
after serial number B040000 to a 152-0141-02 a 1N4152. And old
General Electric data book shows this diode to be similar to the
widely used 1N914. Replaced the diode with a 1N914 and the generator
works fine. Touched up the calibration, last cal in 1986, an the unit
is within specifications.

Daniel from Ville Saint-Laurent, QC, Canada.
Scanned Tek manuals

 

Hi All
A few weeks ago there was a thread about Tek manual scans on CD and Dave Miller's name came up as an example of best practice in this area.
Yesterday I decided that I needed one of Dave's offerings, I paid him by Paypal directly off his site, he made an ftp download available within minutes and I was using the information less than 1 hour later! Some of the items he has on offer are very rare and the quality of the example I had was of the very best.
I have no connection with Dave other than as a very satisfied user, but if you need Tektronix information you should check out his site at

Ben
Re: Diode question

Craig Sawyers
 

There is a little typo where you listed diode for 874MR, that should be
1N21B.
Thanks Miroslav - the Sylvania links were great! And you're right, the
874MR was specced as a 1N21B.

Cheers

Craig
Re: Tektronix 2101 Pulse Generator

 

Diodes 1N4152 and 1N4148 are replacements for 1N914 of lesser capabilities.
There is something in spec for 1N914 that was very difficult to match, I
think it was recovery time, and not very many applications did need that,
so -48 and -52 were registered.

In some other applications very low reverse current was required and
Tektronix used some of Fairchild's FD series diodes. I believe, the
application was voltage converter/rectifier for biasing CRT grids in 7904
scopes (part of high voltage power supply). I have been told that when those
FD diodes become leaky, circuit works poorly (at times erratically) and
replacing diodes with a modern high frequency rectifier does not do anything
for it, the only known cure is to get the original diodes. Tektronix was
selling those diodes 6 - 7 years ago at quite exorbitant price.

Regards

Miroslav Pokorni

----- Original Message -----
From: "D. Dufresne" <ddufresn@...>
To: <TekScopes@...>
Sent: Monday, July 05, 2004 8:30 AM
Subject: [TekScopes] Tektronix 2101 Pulse Generator


Tektronix 2101 Pulse Generator, serial number B040xxx, restricted
pulse width adjustment range

I purchased this pulse generator used in 1994 from Dumont Electronics
here in Montreal Quebec. It worked fine until last year. I could not
get any pulse with a larger width than 60 ns or so. Pulse duration
range switch did almost nothing, pulse duration variable control did
allow the pulse width to vary from 10 ns to about 60 ns.
Troubleshooting section in manual 070-1029-00, dated 1970 April, is
not very useful. Found CR182 to be defective, it conducted in both
directions in the diode test function of my multimeter. Removed from
circuit is measured about 300 ohms in both directions. Diode is
152-0322-00 a silicon Tektronix special, manufactured by or for them
or reworked or checked. So I looked at the parts list and found
another diode, CR335, with the same Tek part number that was changed
after serial number B040000 to a 152-0141-02 a 1N4152. And old
General Electric data book shows this diode to be similar to the
widely used 1N914. Replaced the diode with a 1N914 and the generator
works fine. Touched up the calibration, last cal in 1986, an the unit
is within specifications.

Daniel from Ville Saint-Laurent, QC, Canada.
Re: Diode question

 

Hello Craig,

There is a little typo where you listed diode for 874MR, that should be
1N21B.

I have seen somewhere, and now I can not find those data sheets, that low
suffixes, A though D, were diodes for rectifiers while high suffixes, like
F, WE, WB etc., were diodes with lower noise figure, so I guess, mixer
diodes. I think that latter also were with higher threshold voltage. Sorry
that information is so vague, but there was a while since I looked at that.

There is a site which has scans of pages from Sylvania data manuals. There
is not much information on those pages, but seems to me better than what
Micro Semi does offer and certainly much better than what my memory can
provide.

1N21:

1N23:

Regards

Miroslav Pokorni

----- Original Message -----

From: "Craig Sawyers" <c.sawyers@...>
To: "TekScopes" <TekScopes@...>
Sent: Monday, July 05, 2004 4:13 AM
Subject: [TekScopes] Diode question


Hi all

This is really a GR question. There are a number of GR874 elements that
use
the 1N23 or 1N21 series diodes. From the 1968 catalogue these are:

874VQ voltmeter detector: 1N23B
874VR voltmeter rectifier: 1N23B
874MR mixer rectifier: 1N23B
874MRAL improved mixer rectifier 1N23C

Also, in the 1956 catalogue, the 874MR seems to use the 1N21B.

Now doing a quick check, the 1N23 was avaialable in (at least) A, B, C,
CR,
D, E, F and WE versions. I guess the question is partly to do with
interchangeablility, and partly out of curiosity. The AmericanMicroSemi
site has short form specs on these, but no information about
applicability.
Going through the series of letters indicates a progressive improvement in
specification (VSWR, noise figure, resistance tolerances, power handling
etc) - so is that all there is to it?

Anyone out there with a few ancient data books that they could have a look
in?

Thanks folks

Craig
Tektronix 2101 Pulse Generator

D. Dufresne
 

Tektronix 2101 Pulse Generator, serial number B040xxx, restricted
pulse width adjustment range

I purchased this pulse generator used in 1994 from Dumont Electronics
here in Montreal Quebec. It worked fine until last year. I could not
get any pulse with a larger width than 60 ns or so. Pulse duration
range switch did almost nothing, pulse duration variable control did
allow the pulse width to vary from 10 ns to about 60 ns.
Troubleshooting section in manual 070-1029-00, dated 1970 April, is
not very useful. Found CR182 to be defective, it conducted in both
directions in the diode test function of my multimeter. Removed from
circuit is measured about 300 ohms in both directions. Diode is
152-0322-00 a silicon Tektronix special, manufactured by or for them
or reworked or checked. So I looked at the parts list and found
another diode, CR335, with the same Tek part number that was changed
after serial number B040000 to a 152-0141-02 a 1N4152. And old
General Electric data book shows this diode to be similar to the
widely used 1N914. Replaced the diode with a 1N914 and the generator
works fine. Touched up the calibration, last cal in 1986, an the unit
is within specifications.

Daniel from Ville Saint-Laurent, QC, Canada.
Diode question

Craig Sawyers
 

Hi all

This is really a GR question. There are a number of GR874 elements that use
the 1N23 or 1N21 series diodes. From the 1968 catalogue these are:

874VQ voltmeter detector: 1N23B
874VR voltmeter rectifier: 1N23B
874MR mixer rectifier: 1N23B
874MRAL improved mixer rectifier 1N23C

Also, in the 1956 catalogue, the 874MR seems to use the 1N21B.

Now doing a quick check, the 1N23 was avaialable in (at least) A, B, C, CR,
D, E, F and WE versions. I guess the question is partly to do with
interchangeablility, and partly out of curiosity. The AmericanMicroSemi
site has short form specs on these, but no information about applicability.
Going through the series of letters indicates a progressive improvement in
specification (VSWR, noise figure, resistance tolerances, power handling
etc) - so is that all there is to it?

Anyone out there with a few ancient data books that they could have a look
in?

Thanks folks

Craig
Re: TDS350

Peter de Vroome
 

Hello Zenith5106,

thanks a lot for your help, the DC balance is as expected now...

best regards

Peter/the Netherlands




zenith5106 wrote:

--- In TekScopes@..., Peter de Vroome <p.devroome@a...>
wrote:
Dear Tektronix experts,

I have a Tek TDS350 with a DC balance problem in channel A, when I
turn
the attenuator the trace is hopping app. 1cm. Is this easy to
adjust by
a potmeter, or is it not possible for customers to adjust?

Channel B is ok..

Thanks for your advice

Peter
---------
Do an SPC (= self cal). Press Utility, on bottom/left menu select
Cal, select Signal Path. To start, select OK Compensate Signal Path.
It will take a couple of minutes and should take care of your balance
problem unless there is a hardware problem. Make sure the scope is
warmed up.
/Zenith, Sweden



Yahoo! Groups Links
Re: OT: Seeking manual (scan or paper) for USM-32

Dave & Lynn @ Artek Media
 

David

There is a manual of sorts out on the LOGSA site



Not much useful info though i it as near as I can tell, no schematics

Dave

At 08:07 PM 7/4/2004, David Wise wrote:
This little scope followed me home. Anyone got a manual?

Logsa doesn't, just a parts list. BAMA doesn't.



Thanks,

Dave Wise





Yahoo! Groups Links



Dave & Lynn Henderson
ArtekMedia
High Resolution Scans of Out-of-Print Technical Manuals
manuals@...
603-465-7891
OT: Seeking manual (scan or paper) for USM-32

 

This little scope followed me home. Anyone got a manual?
Logsa doesn't, just a parts list. BAMA doesn't.

Thanks,
Dave Wise
Re: Power supply problem on a Tek 2232

Denis Cobley
 

Hi Dominique
I would only use a TO220 package device as it's at mains potential and the
design is approved with only that style of device.
You can use any number of N channel FET's like the 6N60 or IRF820 (anything
rated at 6-8A 600 to 800V)

Regards
Denis Cobley

----- Original Message -----
From: "dvp8_fr" <cabinet.baumann@...>
To: <TekScopes@...>
Sent: Monday, July 05, 2004 5:26 AM
Subject: [TekScopes] Power supply problem on a Tek 2232


Hello,

I have problem to find a replacement of the power mosfet MTP6N56
(Q9070 on the schematic). Do you know if I could replace this TO220
mosfet by a more classical and easy to find BUZ80A for example ?
Thanks for your help,

Dominique





Yahoo! Groups Links
Ballantine 6126M Manuals Needed

Bernie Golchuk
 

Hi Everyone,

Would anyone have any manuals in pdf form for the Ballantine 6126M
Calibrator that they would like to share. Any help would be
appreciated.

Thank you,

Bernie
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