Date   

Re: Critical of Tektronix (was Tek 570 curve-tracer)

Dave Wise
 

Yes, I save the aspirin trick for the tough ones.

Thanks,
Dave Wise

-----Original Message-----
From: Gary Allsebrook [mailto:regman10@comcast.net]
Sent: Thursday, December 02, 2004 10:55 AM
To: David Wise; scoper796; TekScopes@yahoogroups.com
Subject: RE: [TekScopes] Re: Critical of Tektronix (was Tek 570 curve-tracer)


Simply tinning the wire is usually a good varnish remover also. I use liquid rosin flux as an enhancer.


Subject: Re: Re: Electrical safety - was Nuvistor type 8058 + New tube tester

Brooke Clarke
 

Hi Stefan:

The US mains electrical system for delivering electricity to single family homes uses a transformer that converts the local distribution A.C. voltage from say 4,000 volts to 220 VAC. The secondary of this transformer is center tapped and 3 wires are run to the dwelling unit. The third wire MUST be grounded. The purpose of this is to protect against the problem of a primary to secondary short in the transformer, which would otherwise supply 4,000 VAC to the dwelling. The dwelling wiring can either be for 220 VAC or for 110 VAC. It's good practice to try and balance the 110 VAC loads.

Have Fun,

Brooke Clarke, N6GCE
--
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com



Date: Thu, 02 Dec 2004 09:00:03 +0100
From: "Stefan Trethan" <stefan_trethan@gmx.at>
Subject: Re: Re: Electrical safety - was Nuvistor type 8058 + New tube tester

On Wed, 1 Dec 2004 16:07:13 -0800, Gary Allsebrook <regman10@comcast.net>
wrote:



According to the Tektronix book "Biophysical Measurements", published in
1970, 10-20mA is in the "cannot let go", 60Hz, arm to arm, shock current
chart; 100mA - 3A, ventricular fibrillation and probable death.

It doesn't take a lot of current surprisingly.
That might well be. But the thing is that 200mA ground fault protectors
don't work because
there are no 200mA flowing in normal situation arm-to-arm (small point of
contact on one side).
Luckily by far not all encounters are deadly, just potentially deadly, if
that wasn't the case
i wouldn't be typing here. (And probably some of you too). I wonder if
110V is as dangerous,
i mean if one would use a transformer with grounded center tap you would
only have 55V to earth
at all times, which is not more than the 50V considered safe.
Tht might be an option for you US guys, is that done in labs? why not? I
know it wouldn't work
with 3-ph but for single ph situation?


Re: Critical of Tektronix (was Tek 570 curve-tracer)

regman10
 

Simply tinning the wire is usually a good varnish remover also. I use liquid
rosin flux as an enhancer.


Re: Nuvistor type 8058 + New tube tester

Denton, Adam (Exchange)
 

--- In TekScopes@yahoogroups.com, "Craig Sawyers" <c.sawyers@t...>
wrote:
=============================================
INSTRUCTION SHEET
TYPE 874-FBL BIAS INSERTION UNIT
Lengthy non-sequitor replies like this I find really annoying, far
more so than "off topic" threads. Why not remain silent if you've
nothing to add?

JMHO.

Adam


Re: Critical of Tektronix (was Tek 570 curve-tracer)

Dave Wise
 

From: scoper796 [mailto:tekscopes@telus.net]
[snip]
Yes, I know whereof you speak. In fact, I stopped buying 3A6 plug-
[snip]
little tiny wire is accessible, but I have had no luck getting the
varnish off it and soldering it. But that would work. I have bypassed
Sorry if it's been mentioned before, but aspirin is a pretty
good varnish remover. It's the acid. Lay the wire on an
aspirin tablet, hold your breath, and heat with a soldering iron.
The varnish should disappear quickly. Now wash off the acid
residue, and you're ready to tin the wire.

Dave Wise


Re: Critical of Tektronix (was Tek 570 curve-tracer)

scoper796 <tekscopes@...>
 

Hi John,

Yes, I know whereof you speak. In fact, I stopped buying 3A6 plug-
ins, even thogh it is the best amp for the 560 series, because it is
impossible to find out if they are broken before purchase. And of
course I don't know of any source for replacements. I think they are
made of the same material as the disappearing crt clamps.

As far as repairing them go, I have the following to offer. The
little tiny wire is accessible, but I have had no luck getting the
varnish off it and soldering it. But that would work. I have bypassed
the peaking coils altogether, and that worked, but I didn't measure
the frequency response afterwards.

I would disagree that this is a mistake on Tektronics part. I know
they had no idea this equipment would still be in-use 40 years or so
after production. Even so, I have a 555 that is indestructible and I
am sure will work fine for another 40 years.

Good luck.

Larry Christopher



--- In TekScopes@yahoogroups.com, "John Doran" <johnd@e...> wrote:
Howdy!



That German fellow's comments reminded me that, while I love

Tektronix and regard them highly, they have indeed done some
seriously
bone-headed things over the years.



For example, in the 3A1 and 3A6 plug-in amplifiers for the 560
series


Critical of Tektronix (was Tek 570 curve-tracer)

John Doran <johnd@...>
 

Howdy!



That German fellow's comments reminded me that, while I love

Tektronix and regard them highly, they have indeed done some seriously
bone-headed things over the years.



For example, in the 3A1 and 3A6 plug-in amplifiers for the 560 series
oscilloscopes, Tek had big, heavy rubber-covered resistors connected
directly to the fragile little terminals of plastic coil forms, with no
intermediate tie-points. I have one of each plug-in, and in each of
them the terminals have been snapped right off...



What was Tek thinking? ...Were they thinking?



I have not yet attempted to repair this damage; it looks tough.



-John


TDR plug-ins for 564 scopes

Tim Phillips <t.phillips@...>
 

Hi, All;
I notice on the cover of the TDR Measurement Concepts book
(up for auction you-know-where)
there are a couple of plug-ins, seemingly for the 564, that I
don't recognise. Were there special TDR plug-ins equivalent to
the 1S2 for this system?
regards
Tim P.


Re: Electrical safety - was Nuvistor type 8058 + New tube tester

Ahlbrecht, Andreas <ahlbra@...>
 

I think that specialized test equipment that deals with high power or high
voltage is intended for being used by trained people. If such equipment is
used by people 'not in the know', then they are in potential danger. That's
everyday life. Take a chain saw for example. A chain saw usually has one or
more facilities which are useless for sawing but solely deal with safety. (A
shield that prevents the operator from coming in contact with the chain for
example.) But still, you wouldn't let your three years old son use the saw,
right? Why wouldn't you? Because he doesn't know anything about the very
dangers involved and even if you would explain, he would not fully
understand. Common sense!!!

OTOH things of everyday life commonly taken for being safe can expose great
dangers. In our living room we have a light chain (correct term for 'many
bulbs on a string'?) which is sort of wound around our cupboard. Yesterday I
found one of my sons (one year old) standing in front of the cupboard,
playing with the bulbs. He was about to stick one of the bulbs into his
mouth. As I saw this I immediately pulled him away. My wife was astonished
until I explained her that the bulbs, although low voltage types, are not
mains insulated. I explained further what could have happened to our son if
he had bitten the bulb into pieces, replacing the bulb with his
tongue....... Much, VERY much more dangerous than a tube tester which is
being used by a trained person.

Just my two cents.

Andi


Re: Electrical safety - was Nuvistor type 8058 + New tube tester

stefan_trethan
 

On Wed, 1 Dec 2004 16:07:13 -0800, Gary Allsebrook <regman10@comcast.net> wrote:


According to the Tektronix book "Biophysical Measurements", published in
1970, 10-20mA is in the "cannot let go", 60Hz, arm to arm, shock current
chart; 100mA - 3A, ventricular fibrillation and probable death.

It doesn't take a lot of current surprisingly.
That might well be. But the thing is that 200mA ground fault protectors don't work because
there are no 200mA flowing in normal situation arm-to-arm (small point of contact on one side).
Luckily by far not all encounters are deadly, just potentially deadly, if that wasn't the case
i wouldn't be typing here. (And probably some of you too). I wonder if 110V is as dangerous,
i mean if one would use a transformer with grounded center tap you would only have 55V to earth
at all times, which is not more than the 50V considered safe.
Tht might be an option for you US guys, is that done in labs? why not? I know it wouldn't work
with 3-ph but for single ph situation?


ST


Re: Nuvistor type 8058 + New tube tester

John Miles <jmiles@...>
 

What a hideous design - especially the "basic"
version! It's
not portable, it undoubtledly has safety deficiencies as you note, it's
incredibly ugly, and worst of all it requires mutilating a
classic piece
of
vintage test equipment.

That's a pretty neat hack, actually. He claims it does not permanently
damage the Cardmatic (which I seriously doubt lives up to contemporary UL or
CE safety standards even without a large metal box wired to it).

Personally, I'd be tempted to build a self-contained unit with its own bank
of sockets using high-voltage IGBTs or a similar technology to do the
switching, but for his purposes and those of his customers it sounds like he
has arrived at a good working solution.

Maybe someday Ralph Nader's successors will manage to bubble-wrap the world,
perhaps with help from some of the others in this thread. I hope I've
already electrocuted myself by then.

-- john KE5FX


Re: Tek 570 curve tracer

Dave Brown <tractorb@...>
 

Tks Fred- I downloaded all six of the pdfs anyway. Just over 4.6 Megs all up.
Cheers
DaveB, NZ

----- Original Message -----
From: "Fred Olsen" <fwolsen@wi.rr.com>
To: <TekScopes@yahoogroups.com>
Sent: Thursday, December 02, 2004 12:46 PM
Subject: Re: [TekScopes] Tek 570 curve tracer



I found the rock.
http://www.jogis-roehrenbude.de/Roehren-Geschichtliches/Roe-Pruefer/Curve-Tracer/TEC-570/TEC-570.htm

This guy sure is critical of Tektronix. Don't know what his problem is
and given our international membership I'll make no further editorial
comment.

Here it is in English, sort of. Google's translation is no worse than
the babbling fish.
http://translate.google.com/translate?hl=en&sl=de&u=http://www.jogis-roehrenbude.de/Roehren-Geschichtliches/Roe-Pruefer/Curve-Tracer/TEC-570/TEC-570.htm&prev=/search%3Fq%3Dtek%2B570%2Btracer%26hl%3Den%26lr%3D%26sa%3DG

David, it looks like he has most or all of the manual. I didn't open
all of the PDFs to find out. Bottom of the page.

Fred
--
<><
--
Outgoing checked by eTrust EZ AV



------------------------ Yahoo! Groups

Yahoo! Groups Links









--
No virus found in this incoming message.
Checked by AVG Anti-Virus.
Version: 7.0.289 / Virus Database: 265.4.4 - Release Date: 30/11/2004



--
No virus found in this outgoing message.
Checked by AVG Anti-Virus.
Version: 7.0.289 / Virus Database: 265.4.4 - Release Date: 30/11/2004


Re: Electrical safety - was Nuvistor type 8058 + New tube tester

regman10
 

According to the Tektronix book "Biophysical Measurements", published in
1970, 10-20mA is in the "cannot let go", 60Hz, arm to arm, shock current
chart; 100mA - 3A, ventricular fibrillation and probable death.

It doesn't take a lot of current surprisingly.

15uA can cause defib if through a catheter, or blood contact. This is why
pacemakers run very well on batteries - it takes very little current to pace
the heart.

This is why leakage current in medical instruments is held to such a high
standard (UL544, IEC601).

The actual maximum acceptable limit for external arm to arm contact is 300uA
(at least it was in 1970).

The threshold of pain, incidentally, is 1mA.


Re: Nuvistor type 8058 + New tube tester

Craig Sawyers <c.sawyers@...>
 

I'm waiting
for you to post some bit of electronics trivia in response to one
of yours
or my posts on the electronic death trap :-).
<Grin!>

============================================================================
=============================================
INSTRUCTION SHEET
TYPE 874-FBL BIAS INSERTION UNIT



Figure l. Type 874-FBL Bias Insertion Unit.

SPECIFICATIONS
Current Rating: 2.5 A.
Voltage Rating: 400 V.
VSWR: Typically, Less than 1.25 from 300 MHz to 5 GHz.
Insertion Loss: Typically, Less than 0.4 dB from 300 MHz to 3 GHz, Less than
0.8 dB from 3 GHz to 5 GHz.
Dimensions: 4 3/8 by 3 7/8 in (ll5, 99 mm).
Weight: 6 1/2 oz (185 g).
U.S. Patent No. 2,548,457.

DESCRIPTION
The Type 874-FBL Bias Insertion Unit is a dc bias and isolation unit used to
bias devices installed in coaxial-1ine systems. It is particularly useful tn
measuring the immittance of semiconductor devices with a slotted line It is
fitted with locking GR874 connectors at both rf ports and 3 /4 -inch spaced
binding posts of the GR938 type at the dc input. See Figure l.

PRINCIPLES OF OPERATION
In the schematic diagram, Figure 2 , the inductor L2 and the capacitor C3
are designed to introduce the minimum discontinuity in the 50-ohm system
between the coaxial connectors at each end. Capacitor C3 dc isolates the
biasing system from devices connected to coaxial terminals "A", usually
signal generators or attenuators. The low-pass filter, L1/Cl/C2 prevents the
radio-frequency signals present in the coaxial line from passing out the
bias terminals. This filter has a cutoff frequency of about 1 MHz.

APPLICATIONS
Figure 2. Schimatic diagram for Type 874-FBL.
C1 = 3900 pF
C2 = 3000 pF
C3 = 4700 pF
L1 = 4.7 uH
L2 = 0.3 uH

The principal application of the Type 874-FBL Bias Insertion Unit is in the
biasing of semiconductor devices, in particular , in impedance measurements
in the frequency range 300 MHz to 5 GHz. Other applications include
construction of diode- or transistor- amplifier circuits in the coaxial
configuration and low, and high-frequency combining circuits.

SEMICONDUCTOR IMMITTANCE MEASUREMENTS WITH SLOTTED LINE OR DIRECTIONAL
COUPLER
The Type 874-FBL is usually installed at the generator end of an
immittance-measuring instrument, so that the small but observable
discontinuities of the bias unit are not introduced in the "unknown"
circuit. A typical configuration for two-terminal unknowns is shown in
Figure 3. For transistor biasing, another Bias Insertion Unit is employed at
the transistor as shown in Figure 4.

Figure 3. Use of the Type 874-FBL for immittance measurements on a
two-terminal unknown.

The require termination is:
l. A Type 874-W50BL, if scattering coefficients (reflection and transmission
coefficients), normalized to 50 ohms, are being measured.
2. A Type 874-D20L sliding short circuit, if y or z parameters are being
measured. In this case, an ideal open or short circuit is-required at the
transistor terminals. Because the finite loss in the Type 874-FBL is
aggravated if a voltage maximum appears at the choke within the unit, it is
sometimes necessary to use a line-stretcher (Type 874-LK10L) between the
Bias Insertion Unit and the transistor jig. This ensures that the open
circuit is of sufficiently high impedance and that the short circuit is of
sufficiently low impedance. The Type 874-LK10L and the Type 874-D20L are
adjusted together to obtain the final terminating impedance at the required
reference plane, while at the same time obtaining the highest VSWR. The
transistor test jigs recommended are the Types 1607-P41, -42, -43, -44
Transistor Mounts. These mounts are accessories for the Type 1607 Transfer
Function and Immittance Bridge that permit its use in measurements of
transistor parameters at frequencies up to 1.5 GHz. They accept over 30
commonly used transistor packages. These, and the Type 1607-P40 termination
kit, permit transistor measurements up to about 5 GHz, when used with
instruments such as the Type 900-LB Precision Slotted Line. Specific
procedures are given in the instruction sheets furnished with the mounts.

Figure 4. Type 874-FBL units used in measurements with a transistor mount.


Figure 5. Use of the Type 874-FBL with 1602-B UHF Admittance Meter.

WITH THE TYPE 1602 UHF ADMITTANCE METER
The Type 1602 is operated with the DET and GEN connections interchanged. The
conductance and susceptance standards are dc blocked with General Radio Type
874-KL Coaxial Coupling Capacitor units. The Type 874-FBL is connected to
the terminals labeled GEN at the rear of the instrument, as shown in Figure
5, but is actually in the detector circuit.

WITH AMPLIFIER OR OSCILLATOR CIRCUITS.
Experimental coaxial circuits involving semiconductor elements may be made
up with other GR874 components, with the Type 874-FBL employed for applying
bias to the elements.* The bias system in this case does not interact
significantly with the rf circuits. A typical configuration is shown in
Figure 6.

Figure 6. Typical coaxial test set-up in GR874 components that utilizes the
Type 874-FBL for rf transistor measurements.
TUNERS: Type 874-D20L adjustable stub in a Type 874-TL Tee
MOUNT: Types 1607-P1O1, -P102, -P111, -P401, -P41, -P42, -P43, or -P44

COMBINER
When combining a high radio -frequency signal and, say, an audio signal,
some isolation can be achieved with the Type 874-FBL because of the 4700-pF
blocking capacitor. A typical connection is shown in Figure 7. The reactance
of the 4700-pF capacitor is about 3500 ohms at 10 kHz.

Figure 7. Connection of the Type 874-FBL to permit combination of audio and
rf signals.

The complete line of GR874 coaxial air line elements and patch cords permit
easy assembly of coaxial systems utilizing the Type 874-FBL.

*Gelnovatch, V. and Hambleton, G. E., "l Gc Transistor Amplifier Stage Using
Linvill Technique", Proceedings of the IEEE, Vol. 52, No. lO, October 1964,
p. 1262.


GENERAL RADIO COMPANY
WEST CQNCORD, MASSACHUSETTS 01781
BOSTON $B!& (B NEW YORK $B!& (B PHILADELPHIA $B!& (B WASHINGTON, D.C.
$B!& (B SYRACUSE $B!& (B DALLAS $B!& (B SAN FRANCISCO $B!& (B LOS ANGELES
ORLANDO $B!& (B CLEVELAND $B!& (B TORONTO $B!& (B MONTREAL
Form 0874-0131-A April,1966
Printed in USA


Re: Nuvistor type 8058 + New tube tester

Michael Bender <Michael.Bender@...>
 

Craig Sawyers wrote:
Sure, it doesn't look like something that
you can buy
from Tek or Agilent, but it looks a lot like the gear that I and
many others
have made over the years at home. This add-on is clearly not for the
mass-market, so I'm not sure why everyone is making such a big
fuss over it.
That is exactly the point, though. We all make stuff for our own use that
looks a whole lot like that electric death bucket, and worse - but there is
a world of difference between that, and providing a piece of kit you
designed for sale and commercial gain. It matters not one jot the size of
the market - you legally can't sell a single unit that does not meet safety
standards. End of story, really.
I think we're straying from the topic of Tek scopes, Craig, and I'm waiting for you to post some bit of electronics trivia in response to one of yours or my posts on the electronic death trap :-).

Anyway, to beat this dead horse a bit more (and apologizes to the list in advance) - is it really illegal to sell something that doesn't meet safety standards? I can understand that it might not be a good idea in the event that your device kills someone and you get taken to court, but I've seen people selling lots of electronic gizmos over the years that are clearly homemade and clearly don't have a UL/CSA/CE/TUV/etc... certification sticker on them.

mike

--
----------------------------------------------------------------------------
Michael Bender E-Mail: Michael.Bender@sun.com
Sun Microsystems, Inc. Tel: 831-401-9510
14 Network Circle Tel: x.31807
Menlo Park, Ca. 94025
Mailstop: UMPK14-260 MD: VPN/IMAP

Never give up! Never surrender!

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


Re: Electrical safety - was Nuvistor type 8058 + New tube tester

stefan_trethan
 

On Wed, 1 Dec 2004 22:19:38 -0000, Jim Beacon <jim@g1jbg.co.uk> wrote:

Larry,

I can understand your feelings! I was working on my 564 today, trying to see why the 300V supply would not regulate, when I realised that my finger was within 0.25" of the (un-insulated) connections to the power connector...........

Jim.

You _must_ have a ground fault protector or a isolation transformer.
Remember that only ground fault protectors with a trip current of 30mA or
less are safe, the higher
current ones will not switch off even if you solidly touch hot and earth
(i know from experience... bad
experience). Many older houses still have 200mA protectors - replace them!
(now!).

isolation transformers are another option for the bench, not sure what's
better.

But both doesn't protect you if you touch both wires, and not earth.

A emergency cutoff switch is another MUST. Ideally you use a big
pushbutton switch that you regularly
use to power off the bench - this way it is the first thing that springs
to mind. It would not be wrong
to add a second switch which you can easily reach with your foot,
especially when working alone.

Get those safety features, and USE THEM! Never use another unprotected
outlet to "quickly check something".
I had to nudge a plug out of the socket with my foot once, 'cause both
hands were involuntarily "occupied" you might say. A potentiall lethal
experience i don't want to repeat, caused by working when tired and not
thinking. (never do that).
Before doing anything (powering up, touching something, ..) always think
"is that safe?". CHECK if you
have pulled the plug before touching the stuff, when working on "hot" gear
consider every move before executing it. Carefully inspect the unit and
observe every exposed spot that can carry high voltage.
Don't work tired or otherwise preoccupied, never haste.

take care.

ST


Re: Nuvistor type 8058 + New tube tester

Craig Sawyers <c.sawyers@...>
 

Sure, it doesn't look like something that
you can buy
from Tek or Agilent, but it looks a lot like the gear that I and
many others
have made over the years at home. This add-on is clearly not for the
mass-market, so I'm not sure why everyone is making such a big
fuss over it.
That is exactly the point, though. We all make stuff for our own use that
looks a whole lot like that electric death bucket, and worse - but there is
a world of difference between that, and providing a piece of kit you
designed for sale and commercial gain. It matters not one jot the size of
the market - you legally can't sell a single unit that does not meet safety
standards. End of story, really.

Craig


File - Posting Rules

TekScopes@...
 

Please edit any posts/replies to the list to
minimize quoted material to that required for continuity.

Please do not send personal replies to the list.
List replies go to the original sender by default.
If you want to also reply
to the list, use Reply-to-all (or whatever it's called in your
mailer), or manually add the TekScopes address. Do this if your
reply would be of interest to the list. Otherwise, just reply to the
sender.

Those congesting the list with with either of the above may have
posting rights revoked. Only by following these
simple rules will we have a "clean" archive.
They also reduce inbox clutter, make digests much nicer to read,
improve searches, and reduce the chance of having old messages deleted.

If you do not wish to belong to TekScopes, you may
unsubscribe by sending an email to

TekScopes-unsubscribe@yahoogroups.com

You may also visit the Yahoo web site to modify your
subscriptions:

http://groups.yahoo.com/mygroups

Check out the files, links, and photos sections,
and remember, you can search the group's archives from its home page,
or when reading messages. The group's home is at:

http://groups.yahoo.com/group/TekScopes

Regards,
Michael Dunn
Listowner, TekScopes


Re: Electrical safety - was Nuvistor type 8058 + New tube tester

jim_beacon2000
 

Larry,

I can understand your feelings! I was working on my 564 today, trying to see why the 300V supply would not regulate, when I realised that my finger was within 0.25" of the (un-insulated) connections to the power connector...........

Jim.

----- Original Message -----
From: scoper796
To: TekScopes@yahoogroups.com
Sent: Wednesday, December 01, 2004 9:52 PM
Subject: [TekScopes] Re: Electrical safety - was Nuvistor type 8058 + New tube tester



The subject of safety is one that is always close to our minds. The
last electric shock I received was from the 15KV fly-swatter that I
inadvertently grabbed by the wires. I am telling you, I won't be
doing that again anytime soon. The reason I am sure that I have not
received any other shocks from appliances is the high level of safety
that comes with them today, like my insulated recip saw that allows
me to cut even live electrical cables safely. My tube tester has a
two-wire cord! Like xmas lights, and is about as safe.

But now that I am working on tube scopes daily, I try to remember
that these old boxes do not conform to many safety standards. The
line voltage is the most dangerous, because it is innocous. I often
find myself forgetting to pull the plug before moving or working on
one, and I shudder everytime I do it, as encounters with AC lines are
often fatal. DC, well, that may knock you across the room, but that's
probably all it will do. I usually replace the line cord it there is
one built-in, just to be on the safe side. Incidentally, I use
computer cords, which are often shielded and available cheap to cut
off the computer plug end.

I still won't touch HV, don't know why, I just feel I don't have the
proper tools to deal with it.

So keep one hand in your pocket, just like high school, and remember
not to touch anything where 'lectricity could be hiding.

Larry Christopher


--- In TekScopes@yahoogroups.com, Michael Bender
<Michael.Bender@s...> wrote:
> Craig Sawyers wrote:
> >>Well, then the regulations are unrealistic.
> >>You can't use the gear if you can't access the voltage.
> >
> > I for one wouldn't like to poke around with an exposed tip at
(say) 500V DC,
> > and find it difficult to imagine under what circumstances one
would wish to.
>





Yahoo! Groups Sponsor
ADVERTISEMENT





------------------------------------------------------------------------------
Yahoo! Groups Links

a.. To visit your group on the web, go to:
http://groups.yahoo.com/group/TekScopes/

b.. To unsubscribe from this group, send an email to:
TekScopes-unsubscribe@yahoogroups.com

c.. Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


Re: Nuvistor type 8058 + New tube tester

Michael Bender <Michael.Bender@...>
 

Craig Sawyers wrote:
I don't know, a tube tester is a specialized piece of equipment that is
meant to be used by trained operators who I would expect would have more
safety sense than members of the general public.
You need to read back through the thead to see where this discussion came
from - a really nasty tube-tester add-on.
I have been following the thread and had a look at the web site - grey metal homemade box and all! Sure, it doesn't look like something that you can buy from Tek or Agilent, but it looks a lot like the gear that I and many others have made over the years at home. This add-on is clearly not for the mass-market, so I'm not sure why everyone is making such a big fuss over it.

I still make coffee by pouring boiling water over coffee grounds :-).

mike

--
----------------------------------------------------------------------------
Michael Bender E-Mail: Michael.Bender@sun.com
Sun Microsystems, Inc. Tel: 831-401-9510
14 Network Circle Tel: x.31807
Menlo Park, Ca. 94025
Mailstop: UMPK14-260 MD: VPN/IMAP

Never give up! Never surrender!

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

177721 - 177740 of 188094