开云体育

Thanks Emanuele for your extensive coverage for cleaning the pots of
an 475. I'm sure more people appreciate this nice stor, because it is
one of the most common failure's in 465, and 475 scopes, probably the
best scope line ever build by Tektronix.

Fred de Vries, Holland

--- In TekScopes@y..., Michael Dunn <mdunn@c...> wrote:

547 (my workhorse bench scope), 549, the enormous 555 scoposaurus,

575

Do you know how the 555 differs from that other monster, the

556?

I would love to have a 556. They are both massive double beam machines
but there are quite a few differences. The 556 is in one piece while
the 555 is quite a bit larger and has a separate power supply. The 555
has 4 plugins, 2 vertical and 2 special timebases while the 556 has
built in timebases. The 555 has twin distributed amplifiers and lumped
delay lines while I'm pretty sure the 556 has 549 type vertical amps
with a coaxial line and a pair of 8608s. They're different enough to
make them both desirable but unfortunately not many 556s made it down
here.

and many plugins including a homebrew spectrum analyzer built into

an

old plugin caracass

Please tell us something about your spectrum analyzer!

It's based on the unit described in QST in 1999 by Wes Hayward and
another fellow whose name escapes me. Wes (W7ZOI) has a website with
pictures of various versions including an early shot of mine before I
found an attenuator for it. You can probably find it by doing a
search. It goes up to 80 MHz and has 5 KHz resolution at its best. I
had to design an interface to the Tek plugin specification which works
quite well even if I say so myself.

Morris

--- In TekScopes@y..., dhuster@p... wrote:

Bill,

Don't play with the gain. Both channels are affected the same way,
and that pretty much says that the problem is in the vertical

output amplifier. First thing to check is the collector load
resistors
that

go from the board up to the terminal post. If they're the beige,
rectangular, silicone-covered resistors, they may be your problem.
They're double-counterwound, inductance-cancelling resistors and a
common problem is that one of the two internal parallel windings
opens up, increasing the resistor value by a factor of two. Those
were Tek-made parts and Tek quit making them (they were very
troubleshome) and started using outsourced parts. If one or both

of

those resistors have an open winding, they'll be inductive, the

gain

will be 'way low and the pulse response will be a HUGE ringing.

Dean

Dean, thanks for your quick response. I m not sure which collector
load resistors you are speaking of but you mention them going from
the video output amp board to the terminal assy. so I assume you mean
the two 18 ohm resistors which couple the next to last output stages
(Q4478 & Q4468) to the final output stage drivers. These appear to be
OEM and measure 18 ohms as they should.

If you are referring to the collector resistors of the final stage,
they are 430 ohm wire wounds at 7 watts. The final coupling resistors
to the vertical plates are indeed TEK home grown which consist of a
200 ohm resister paralleled with a .3uh choke winding. These have
almost no DC resistance for obvious reasons. BTW, there are two
different versions of the TEK video output amplifier and I have the
discreet component version as you can probably tell by now.

As you suggested, I am looking at component values but haven't found
anything suspicious yet. Your help is appreciated.

Bill

Bill,

Don't play with the gain. Both channels are affected the same way,
and that pretty much says that the problem is in the vertical output
amplifier. First thing to check is the collector load resistors that
go from the board up to the terminal post. If they're the beige,
rectangular, silicone-covered resistors, they may be your problem.
They're double-counterwound, inductance-cancelling resistors and a
common problem is that one of the two internal parallel windings
opens up, increasing the resistor value by a factor of two. Those
were Tek-made parts and Tek quit making them (they were very
troubleshome) and started using outsourced parts. If one or both of
those resistors have an open winding, they'll be inductive, the gain
will be 'way low and the pulse response will be a HUGE ringing.

Dean

Hello, I just discovered this group and look forward to
participating.
Right now I can use some technical help, though.

I am wrestling with a TEK 465 in the 32xxx serial # range that seems
to work fine in all areas except vertical position display. Both
channels have the same symptom, that is they have what seems to be an
accurate display when the vertical position is centered, but when the
position control for either channel is moved to either the top or
bottom of the screen, the trace only goes as far as the next to last
graticule and the signal gets compressed in amplitude until it
disappears altogether. I have been spending most of my troubeshooting
time in the vertical amplifier module because it appears that at
least one stage may be driving into cutoff or just the oposite (too
low gain) because the voltages on the vertical deflection plates do
not show the movement that the manual indicates. I have not yet tried
adjusting the gain pot because I need to find a signal source
compatible with the manual procedure on this. The manual gives you
the process but not much theory to allow for deviation.

If anyone has seen this before or has any suggestions, I would
appreciate hearing it. BTW, I am using a 453 to troubleshoot which
has an intermittent high voltage supply. That will be the next
project. Thanks in advance, good to have found this group.

Bill Wollam

Hello,
I just found out about this group and decided to join. I've got an
interesting collection of Tek scopes and other stuff, consisting of
three RM561As, a 551, a 181A time mark generator, a 106 square wave
generator, about 12 plugins, HP 523DR (tube frequency counter!), two
HP122ARs (HP tube scope), North Atlantic Phase Angle Voltmeter, Fluke
Differential Voltmeter, Kepco Power Supply, Waveforms
Oscillator/voltmeter, 4 radios, 2 TVs (tube, one color, one B/W), an
organ (Estey, 1961), Sherwood AM/FM tuner, Dynaco PAS-2, home made
tube amp. I have a few other pieces of test equipment that are
solid-state. Not looking so much to increase the size of my
collection, more interested in keeping it all working and sharing
ideas and stories with others.

George

At 7:00 AM +0000 2001/4/10, morriso2002@... wrote:

547 (my workhorse bench scope), 549, the enormous 555 scoposaurus, 575

Do you know how the 555 differs from that other monster, the 556?

and many plugins including a homebrew spectrum analyzer built into an
old plugin caracass and a Japanese commercial transistor testing

Please tell us something about your spectrum analyzer!

by it at the age of about 10. A few years later I saw my first Tek - a
549 with a 1A4 plugin - and it was a really mind blowing experience

At least 2 of us here have 549/1A4 combos! Yes, a nice piece of equipment...

Michael Dunn, listboss :-)

When I recently joined this group, I read alot of the old posts. I
saw in one the mention that Freon-TF, used to clean fans, wasn't
available anymore.

Where I work, they use something called "Freon TF" to clean sensors
on check-sorting equipment. The product says that "Freon is a
trademark of DuPont ... Contents: Trichlorotrifluoroethane".

Is this the same stuff you're talking about or is it a substitute.

If anyone is interested, I can give specifics on where to get it.

-Jim

Welcome aboard, Morris. I'm just a novice collector, and only have one scope (a late 535A, Scopemobile, and a few plugins). But, it's in almost mint condition and I have all the probes, cords, and manuals, even the little mini-manual under the popup hood on the top of the scope. The scope is a joy to use and works perfectly. Truly a tribute to good engineering and design. I like it because it's older than I am and is also the type of stuff that put America in space in the 60's. Think about it. We went to the moon over 30 years ago. Pocket calculators were just a dream. Amazing.

I digress...Enjoy the group and keep warm with your tubes!

Chris Beck
West Bend, Wisconsin.

TekScopes@... wrote:

I'm very pleased to have found this group as I am a great lover and
collector of vacuum tube Tek scopes here in Melbourne Australia. My
collection includes examples of the 310A, 502, 524AD, 529, 533A, 535A,
547 (my workhorse bench scope), 549, the enormous 555 scoposaurus, 575
and many plugins including a homebrew spectrum analyzer built into an
old plugin caracass and a Japanese commercial transistor testing
plugin built into a Tek blank. I also have a number of other
manufacturers' scopes as well, and sundry other pieces of Tek
equipment and manuals.

My interests include restoration and using these wonderful machines. I
can remember the first time I saw an oscilloscope and being fascinated
by it at the age of about 10. A few years later I saw my first Tek - a
549 with a 1A4 plugin ???- and it was a really mind blowing experience
compared to the sorts of scopes experimenters had access to in the
1960s. Now I'm very happy to be able to own some of these
instruments and fully understand their workings.

I hope I will be able to contribute to the discussions here, both in
the way of helping others and learning along the way.

Cheers,

Morris Odell

__________________________________________________________________
Get your own FREE, personal Netscape Webmail account today at

I'm very pleased to have found this group as I am a great lover and
collector of vacuum tube Tek scopes here in Melbourne Australia. My
collection includes examples of the 310A, 502, 524AD, 529, 533A, 535A,
547 (my workhorse bench scope), 549, the enormous 555 scoposaurus, 575
and many plugins including a homebrew spectrum analyzer built into an
old plugin caracass and a Japanese commercial transistor testing
plugin built into a Tek blank. I also have a number of other
manufacturers' scopes as well, and sundry other pieces of Tek
equipment and manuals.

My interests include restoration and using these wonderful machines. I
can remember the first time I saw an oscilloscope and being fascinated
by it at the age of about 10. A few years later I saw my first Tek - a
549 with a 1A4 plugin - and it was a really mind blowing experience
compared to the sorts of scopes experimenters had access to in the
1960s. Now I'm very happy to be able to own some of these
instruments and fully understand their workings.

I hope I will be able to contribute to the discussions here, both in
the way of helping others and learning along the way.

Cheers,

Morris Odell

At 5:07 PM +0000 2001/4/08, Doug wrote:

Hi,
my name is Doug and I am looking for a User Manual and Service manual
for a Tek 454 Scope. I had seen a source on the web but can't seem
to find it now. Does anyone know were I might find these manuals?
I understand tek is very expensive for printed versions of the manual

Don't forget to monitor eBay!


-----------------------------------------------------------------
Michael Dunn | Surround Sound Decoder & Stereo Enhancer
Cantares | Self-Amplified Speakers, Test Equipment
74 George St. | Ambisonic Surround Sound CDs and Recording
Waterloo, Ont. | (519) 744-9395 (fax: 744-7129)
N2J 1K7 | mdunn@...
Canada |
-----------------------------------------------------------------

You may also want to look at www.big-list.com under "manual
dealers". I have had good luck finding manuals from several entries
in this list.

Jim

Hi Doug,

I doubt you could get that manual from Tek at any price these days. Anyway,
if you go to the following URL, you can find a list of companies and people
who can supply you with copies of Tek manuals:

<> Click on the Tek reference section and keep looking
around. You will find the list you are looking for.

Stan
w7ni@...

Doug wrote:

Try this one. Bill



Doug wrote:

Hi,
my name is Doug and I am looking for a User Manual and Service manual
for a Tek 454 Scope. I had seen a source on the web but can't seem
to find it now. Does anyone know were I might find these manuals?
I understand tek is very expensive for printed versions of the manual

Thanks
DOug


Yahoo! Groups Sponsor

[E*TRADE. It's your money]

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



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

Hi,
my name is Doug and I am looking for a User Manual and Service manual
for a Tek 454 Scope. I had seen a source on the web but can't seem
to find it now. Does anyone know were I might find these manuals?
I understand tek is very expensive for printed versions of the manual

Thanks
DOug

Hi All

My old faithful 7904 has started to have a little problem with the display.

It will run for hours or days with no problem. Then it will start to drift
the display up and down, this is the trace/s and readouts as well. Note this
is not on oscillation up and down. It will shift up for awhile, then drop
down lower then it should be for awhile. I am talking about a 1/2 CM or so.
Everything is always on screen, it just gets annoying after awhile.

I found I can turn off the readouts and it will stop. Turn the readouts back
on, and it will be fine again for a few hours or days.

Any ideas what might be going on and where to start looking before I tear
into it.



Thanks,
Don

BTW Hi Mark Gurries glad to see you on the list.

Eventually I have got it!
The entire story is reported at

I want to thank you once again the group for the support and in
particular Mr. Fred de Vries who helped significantly.
Until next time, ciao.

Hi Michael,

Thanks for the rundown on the 7S14/5S14. I knew the 5S has come before the 7S and
that they had similar specifications, but since I have never seen a 7S version, I
did not know they were THAT similar!

Stan
w7ni@...

Michael Dunn wrote:

Hi,

there is a 6CZ5 and a 2AS-15 in the regulation loop of the Tek 555
heater supply voltage. The 2AS-15 is probably the one you mean.
Quoting from the 555 manual:

I hope this helps.

Laurent Lamesch

Yep. That's just what I needed. Thanks much!

-- John Rehwinkel

I need someone to refresh my memory. The old Tek scopes with
the separate power supplies (555 and similar) had an unusual
filament voltage regulator that operated with a saturable core
reactor. Part of the feedback circuit involved a tube that (I
think) was very sensitive to its filament voltage. I have a
clear mental image of the tube, it was a glass octal type with
a horizontal filament and a cylindrical plate around it. I'm
looking for the type number of this tube. Anybody know offhand
or have a manual with this info? Otherwise, I'll probably have
to wait 'til the next hamfest and see if one of the Tek manual
vendors will let me have a peek.

-- Thanks,
John Rehwinkel KG4L
spam@...