Date   

1L20 Spectrum Analyzer

Andrew Campbell <service@...>
 

Hi,

I am looking for a manual for a Tektronix 1L20 Spectrum Analyzer plug-in. I
believe it is used with the 555 Scope?

Regards,

Andrew


Re: 475 hor.jitter

dhuster@...
 

Rich, the 465, 465B, 475, 475A, 464, 466 and 468 had identical fan
modules. And by the way, this has nothing to do with bearing noise,
but if you have a fan that has a dead spot and won't always start up
and you don't know whether to blame the motor or the driver chip,
just put the motor on the dead spot and then pull the driver chip and
reinstall it "backwards". It has a symmetrical pinout, and if one of
the transistors in the driver chip is bad, you'll have moved it to a
different spot in the switching sequence, the motor will no longer be
on a dead spot with the reversed chip and will probably start up when
power is applied. If the dead spot is still in the same place, then
you can blame the motor.

And Rich, the 475 has had several reliability mods over it's life,
and if you have a lower serial number, it may need some of them.
The -8v P/S should have a new rectifier that's much larger than the
others (i.e., it's NOT a 152-0488-00) and will be laying down rather
than standing up in order to clear the case.

There's also a bluish 1% resistor (with the scope upside-down as you
look on the main board with the front panel facing you, it's along
the left edge maybe 2 or 3 inches from the front) that overheats,
turns brownish and changes value, goofing up the timebases. If
there's a black resistor in that spot, the mod has already been
made. Otherwise, it needs replaced with a higher-power resistor.

And the one mod that may concern you most is down near the hole where
the horizontal deflection plate leads go down to the jug. An
unmodified scope has a silver-colored, axial-lead, tantalum, 1000µF
capacitor just to the front of the hole. If it's there, get rid of
it, for it's underrated in voltage and will cause a jittering
problem. A modified scope usually has a physically-larger, black
aluminum electrolytic with a higher voltage rating installed in it's
place.

Dean


475 hor.jitter

richg_1998@...
 

I recently picked up a 475 that has intermittent horizontal jitter and
a noisy fan. Does anyone have any ideas about the jitter? The fan
looks like it could be a challenge to replace. I am shopping around
for a manual and I have had the case open to clean around the hv area,
though it was very clean inside. Thank you.

Richg


Re: 7A16P vs. 7704A

Stan or Patricia Griffiths <w7ni@...>
 

Hey, its perfectly OK to disagree with me, but in this case, you are also
disagreeing with Tektronix since it is in the Tek microfiche where I read
about the power supply problem. Yes, I suspect Tek probably assumes power
hungry plugins will be used along with the 7A16P. There probably will be no
overload with only two plugins installed in a 4 hole mainframe, for example.

I did not know about the front panel lockout since I have never tried to power
up my 7A16P in a 7K mainframe. Interesting . . .

Stan
w7ni@easystreet.com

dd@adobe.com wrote:

I hate to disagree with Stan, but my experience with 7A16Ps is that if you
install them in a non-programmable mainframe, they power up OK, but the
front panel is locked out. From looking at the schematic, it appears
possible to force them to local mode, but I haven't tried that yet.

I didn't see any way to reduce the +5V loading, but in my experience, that
is not an issue. (Maybe if you put 2 of them in one mainframe along with
some other +5V hungry plugins?)

BTW, the 7A16P is used with the 7612D as well as the 7912s.

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Re: 7704A Repair and modules. 7B53 in faster frames

 

--- In TekScopes@y..., dd@a... wrote:

(Still.. it's fun to see the readout say, "500 pSec" on the -92s -
and realize it's even true within 3-5% !!
Most of them will give a solid trigger on a 1GHz signal - a tribute
to the
power of tunnel diodes.

... but the 7B92A SN B070000&up has no tunnel diodes anymore.


Jorgen
dj0ud


Tek 2230 GPIB OPT 10 or RS232 options

vincent coppola
 

Hi,
Would the person that responded back to my message
concerning the communication options for the TEK 2230
please respond again. I can't seem to find your
message.
Thank you,
Vince

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Re: 7A16P vs. 7704A

dd@...
 

I hate to disagree with Stan, but my experience with 7A16Ps is that if you
install them in a non-programmable mainframe, they power up OK, but the
front panel is locked out. From looking at the schematic, it appears
possible to force them to local mode, but I haven't tried that yet.

I didn't see any way to reduce the +5V loading, but in my experience, that
is not an issue. (Maybe if you put 2 of them in one mainframe along with
some other +5V hungry plugins?)

BTW, the 7A16P is used with the 7612D as well as the 7912s.


Re: Tektronix Parts.

Michael <mdd@...>
 

Thanks all, for your replies to my question...

Kind regards,
:)
Michael


Re: Tektronix Parts.

Michael <mdd@...>
 

Thanks all, for your replies to my question...

Kind regards,
:)
Michael


Re: Tektronix Parts.

Phil (VA3UX) <phil@...>
 

At 12:56 AM 5/23/2001 -0400, you wrote:
At 9:00 AM +1000 2001/5/23, Michael wrote:



I would ask again that anyone who wishes to can place a URL link
to their site in the LINKS section of the TekScopes Yahoo site.
Also, people who have parts etc to sell, but DON'T have a web site,
can send me a message. I will summarize all the information
somewhere on the site, and clearly note where it is!
I have the start of a Tek interest site :

www.vaxxine.com/phil/

Phil Turcotte
Grimsby, Ont.


Michael


-----------------------------------------------------------------
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@cantares.on.ca
Canada | http://www.cantares.on.ca/
-----------------------------------------------------------------

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Re: Tektronix Parts.

Michael Dunn <mdunn@...>
 

At 9:00 AM +1000 2001/5/23, Michael wrote:
It seems that it might be a nice idea if there was a list of these people or
organisations, either posted semi-regularly to the list, or on a web site
somewhere.

Does this list have a "parent" website? Or is there a list of relevant
sites somewhere? I have unfortunately lost my old "bookmarks" list as well,
but I know that some of the list's contributors have "Tek" sites, which I
have visited...

I would ask again that anyone who wishes to can place a URL link to their site in the LINKS section of the TekScopes Yahoo site. Also, people who have parts etc to sell, but DON'T have a web site, can send me a message. I will summarize all the information somewhere on the site, and clearly note where it is!

Michael


-----------------------------------------------------------------
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@cantares.on.ca
Canada | http://www.cantares.on.ca/
-----------------------------------------------------------------


Re: 7704A Repair and modules.

Stan or Patricia Griffiths <w7ni@...>
 

Hi Bob,

There is some possible incompatibility using the 7A16P in a normal 7K
mainframe such as the 7704A. The 7A16P was specifically made to be used with
the 7912AD digitizer and is programmable (that's what the "P" on 7A16P
means). Anyway, I have read a note that says the additional circuitry for
implementing programmability in the 7A16P may overload one or more of the
7704A's power supplies causing some unpredictable results in all the other
circuits powered by them. You might try it with caution. You might get
lucky and not cause any permanent damage and it might even work for you.

There is probably a way to disable some of that extra circuitry in the 7A16P
without damaging it as a nonprogrammable amplifier and reducing the power
supply load to an acceptable level. I have not looked into that yet. Future
project . . .

Stan
w7ni@easystreet.com

Bob H. wrote:

Good Evening

I have a 7704A mainframe that is in need of repair. I turned it on
this morning after not having been powered up for about 2 years. The
trace was moving around erratically. Then I heard a sizzling sound
(never a good sound) and immediately turned it off but not before a
whisp of smoke emerged from the bottom of the scope.

I live in the Atlanta metro area and would like to find a company or
individual who is able to repair it.

Also I am in need of a horizontal sweep module. I'm not sure what
model I am looking for. This scope will be primarily used for audio
frequency applications. Any hints or suggestions would be very
helpful.

The modules I have are 2 7A26 and 1 7A16P that is also in need of
repair.

Any help would be greatly appreciated.

Thanks

Bob

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Re: 7704A Repair and modules.

Stan or Patricia Griffiths <w7ni@...>
 

As I recall, the reason Tek would not recommend a 7B53 as a timebase for a
7704 is that it will not sweep fast enough to take full advantage of the
7704's 200 MHz bandpass. Other than that, I believe it will work just fine.
An even simpler, and probably cheaper, timebase would be a 7B50 or 7B50A with
does not have the delayed sweep feature. You could even use a 7B51 that is
normally used with a 7B50 to provide delayed sweep but can be used as a simple
timebase without a 7B50. I only suggest the 7B50, 7B50A, and 7B51 because
they might be more available and cheaper than the 7B53/A alternatives. There
was also an earlier version of the 7B53 called the 7B52 which would work as
well . . .

I really need to get on with finishing my second book . . .

Stan
w7ni@easystreet.com

dd@adobe.com wrote:

I have a 7704A mainframe that is in need of repair...

Also I am in need of a horizontal sweep module.
For mostly audio frequencies a 7B53(A) would be the right choice for
the time base plug in.
The 7B53/7B53A is not recommended for use in the 7704/7704A. I don't
remember why, but I think it was a good reason. The original poster needs
to find a 7B70+7B71, 7B80+7B85, or 7B92/7B92A.

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Tektronix Parts.

Michael <mdd@...>
 

Hi all, :)

A couple of times recently there have been mentions of people who hold some
stocks of Tek parts for sale for replacements. (e.g. pots, transistors,
tubes etc).

After a recent rebuild (hopefully the last) of this computer, I have
unfortunately lost the message/s containing this information, and I may need
some parts for a friend's 454.

It seems that it might be a nice idea if there was a list of these people or
organisations, either posted semi-regularly to the list, or on a web site
somewhere.

Does this list have a "parent" website? Or is there a list of relevant
sites somewhere? I have unfortunately lost my old "bookmarks" list as well,
but I know that some of the list's contributors have "Tek" sites, which I
have visited...

Can anyone help...?

Thanks in advance for any help, and regards,
:)
Michael


Tektronix 475 Oscilloscope - Position Pots

Andrew Campbell <service@...>
 

Hi All,

I am looking for two (2) Tektronix 475 Position Pots.

Tektronix Part Number 311-1411-00.

Regards,

Andrew Campbell

Calibration and Repair Network Pty. Limited
A.B.N 64 090 761 363
An ISO9001:2000 Quality Certified Company
Licence No. QCC 716
Bldg. T2A, Nirimba Education Precinct
Eastern Road (P.O. Box 147)
Quakers Hill NSW 2763
Australia
Ph: (02) 9853 3259
Fx: (02) 9853 3258
Email: service@candrnet.com.au
Web: www.candrnet.com.au


Re: 7704A Repair and modules. 7B53 in faster frames

dd@...
 

Seconded - before I acquired 7B87, later -92As via a package deal: a
7B53 in my 7854 (400 MHz nom) scope worked fine. At fastest sweeps,
with a known ~700 pS risetime pulse - yes, you can see some combo of
delay-line (absent or mismatched?) aberrations on trace start; IIRC
maybe an almost double-pulse clearly "not happening".
Yes, that's what I was talking about... I know it's written up in one of
the manuals or catalogs, but I can't seem to locate it at the moment.
I guess I'm just picky :-) On the other hand, 7B8xs are pretty cheap.

(Still.. it's fun to see the readout say, "500 pSec" on the -92s -
and realize it's even true within 3-5% !!
Most of them will give a solid trigger on a 1GHz signal - a tribute to the
power of tunnel diodes.


Re: 7704A Repair and modules. 7B53 in faster frames

ashtonb@...
 

--- In TekScopes@y..., dhuster@p... wrote:
There's not a darned thing wrong with using a 7B53A in a 7704 or
7704A. It's the 7B92/A that you can't easily use on lower
bandwidth
scopes only because they can't handle the faster sweeps. And
7B53A's
are so plentiful that they should be cheap. Having to come up with
and pay for a pair of 7B7x or 7B8x is a lot more difficult and
expensive -- and you'll need two service manuals instead of one.
And
the 7B53A leaves a horizontal compartment free for a counter or DMM.
Seconded - before I acquired 7B87, later -92As via a package deal: a
7B53 in my 7854 (400 MHz nom) scope worked fine. At fastest sweeps,
with a known ~700 pS risetime pulse - yes, you can see some combo of
delay-line (absent or mismatched?) aberrations on trace start; IIRC
maybe an almost double-pulse clearly "not happening". So all one
needs to remember is: Stay away from <10 nS/DIV - it isn't 'sposed
to be linear down there.. Audio is almost DC. And as Dean observes,
the built-in dual timebase gets you delayed sweep w/o wasting a
compartment.

(Still.. it's fun to see the readout say, "500 pSec" on the -92s -
and realize it's even true within 3-5% !! One gonzo ramp generator,
to use the technical term ;-) Maybe sometime I can steal a 7104 / 7B10
and see: "200 pSec/DIV" !! As Spock might say.. fascinating


Ashton


Tek 2230 CAL/Var Pot Broken

vincent coppola
 

The pot/switch for the CAL/VAR volts on Ch1 of my 2230
is disfunctional and there is no detent.
Manual says 311-2218-00 Tek part number, but it
describes it as an Allen bradley 10K pot with a
DPST,etc.
Sounds off the shelf but can't be sure until I dive
into it. According to the manual it sounds like a
MAJOR job. Does anyone really no if is a standard POT?

Help appreciated
Vince

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Re: 7704A Repair and modules.

dhuster@...
 

There's not a darned thing wrong with using a 7B53A in a 7704 or
7704A. It's the 7B92/A that you can't easily use on lower bandwidth
scopes only because they can't handle the faster sweeps. And 7B53A's
are so plentiful that they should be cheap. Having to come up with
and pay for a pair of 7B7x or 7B8x is a lot more difficult and
expensive -- and you'll need two service manuals instead of one. And
the 7B53A leaves a horizontal compartment free for a counter or DMM.


Re: 7704A Repair and modules.

dd@...
 

I have a 7704A mainframe that is in need of repair...

Also I am in need of a horizontal sweep module.
For mostly audio frequencies a 7B53(A) would be the right choice for
the time base plug in.
The 7B53/7B53A is not recommended for use in the 7704/7704A. I don't
remember why, but I think it was a good reason. The original poster needs
to find a 7B70+7B71, 7B80+7B85, or 7B92/7B92A.

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