Date   

7854 Service info

Max Vaughan
 

I am looking to either borrow, rent or buy a 7854 service manual. I am also
looking to add more
memory to it as well and am looking to find what options were available for
this scope.

The only thing that seems to be wrong with this scope is that the focus
control for the
intensity knob goes to very bright after the first couple of tick marks, not
sure if this
is normal or not. The focus seems to be tied in with this. I can get a nice
clean trace.
But have to constantly change and adjust intensity as I change sweep speeds.

A few years back I acquired some plug in circuit boards for various Tek
equipment.
Not sure what they are, but some of the parts on them might be of use to
someone.
Will compile of list of the part numbers and board numbers and post them.

I also have a bunch of assorted small screws used in Tek stuff. (2 lbs.) if
any one
is in need of some original miniature screws. Variouse lengths.

You can contact me off list at max@horizonps.com


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7904 wanted for parts - problem with my scope..

Mike D.
 

Dear Colleagues,

I have two questions:

My 7904 "focus control" is not fully functional. When the pot is
swung through about 75% of its travel the trace reaches a point of
almost perfect focus but any further travel does nothing. Is it as
simple as a faulty pot? Any ideas for troubleshooting?

I am searching for another 7904 that I can use to salvage parts
from. If anyone has a dead one laying around please drop me an email
at DrD@2020.com

Regards,

Mike, K4MMR
DrD@2020.com
Charlottesville, VA 22901


looking for SC503

eboytoronto
 

I am looking for a broken SC503 oscilloscope with a good high voltage
section. I do not need the tube or any case parts etc.


Can anybody help ?

Sincere regards,


John Barnes


Re: 7A26 problem

Doug Hale <doughale@...>
 

Sorry Don,
I don 't have a 7A12 or Manual. There is one on eBay right now (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&;item=1743215996)
but $30 seams a little high however one sold for 39.99 and one one didn't sell for 14.99 (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&;item=1740382396)
Again, there are venders on this list, and on the web.

Sorry again,
Doug


Don Black wrote:

Hi Doug,
I've been trying to get a schematic for a 7A12 plugin without
success. Would you have a copy of this that I could impose on you to scan for
me please.
Thanks (fingers crossed), Don
Black.

Doug Hale wrote:


Craig,
I have the scematic in front of me now and I don't see how only one
channel could be effected by the 20Mhz BW limiter. The BW limiter is in
the final stage after the two channels are mixed and just before the
backplane. This stage consists of two differental common base stages.
One w/o BW limiting (Q820&840) and one w/ a low-pass BW limiting
filter(Q860&880). The switch controls the base bias voltage which
enables/disables one or the other(+11.5 OFF/+9.8 ON).
Since both channels are mixed with summing resisters (R802, 804,
810/812, 814, 810) at the input to this stage, I don't think this is the
problem area. It is probably the channel amplifier itself.
If you wish, I can scan the schemos for you tonight but it would be
well worth it for you while to aquire a manual - they are availible from
other members of this list, from ebay, and from venders on the web.

Doug Hale

Craig Sawyers wrote:


Hi folks

I've a 7A26 with a problem (just discovered). The 20MHz bandwidth switch
only works on one of the channels of the plug-in. The other channel is
permanently 20MHz.

Yes - I've just spent a cheerful half hour wondering where my signal
was.....

I don't have a manual for the 7A26, so any pointers from anyone with a
schematic would be most welcome.

Cheers

Craig



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Re: 7A26 problem

Doug Hale <doughale@...>
 

Craig,
I have the scematic in front of me now and I don't see how only one channel could be effected by the 20Mhz BW limiter. The BW limiter is in the final stage after the two channels are mixed and just before the backplane. This stage consists of two differental common base stages. One w/o BW limiting (Q820&840) and one w/ a low-pass BW limiting filter(Q860&880). The switch controls the base bias voltage which enables/disables one or the other(+11.5 OFF/+9.8 ON).
Since both channels are mixed with summing resisters (R802, 804, 810/812, 814, 810) at the input to this stage, I don't think this is the problem area. It is probably the channel amplifier itself.
If you wish, I can scan the schemos for you tonight but it would be well worth it for you while to aquire a manual - they are availible from other members of this list, from ebay, and from venders on the web.

Doug Hale

Craig Sawyers wrote:

Hi folks

I've a 7A26 with a problem (just discovered). The 20MHz bandwidth switch
only works on one of the channels of the plug-in. The other channel is
permanently 20MHz.

Yes - I've just spent a cheerful half hour wondering where my signal
was.....

I don't have a manual for the 7A26, so any pointers from anyone with a
schematic would be most welcome.

Cheers

Craig



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Needed: Schematic and/or any info for 335

Michael <m_d_d@...>
 

Hi all,

A friend of mine is trying to repair a Sony/Tektronix type 335 scope. He
has no schematics, no info at all, but has narrowed the problem down to
the
sweep gen / horiz section.

Problem is no horiz deflection unless in x-y mode.

Can anyone assist with schematics or any useful info at all?

Thanks and regards,
:)
Michael Dunn
(Australia)


7A26 problem

Craig Sawyers <c.sawyers@...>
 

Hi folks

I've a 7A26 with a problem (just discovered). The 20MHz bandwidth switch
only works on one of the channels of the plug-in. The other channel is
permanently 20MHz.

Yes - I've just spent a cheerful half hour wondering where my signal
was.....

I don't have a manual for the 7A26, so any pointers from anyone with a
schematic would be most welcome.

Cheers

Craig


7788 tubes and the 545B

excavatoree
 

Is there any circuit modification that I can make to a 545B to allow
the use of a more inexpensive and more readily available tube than
the 7788?


Re: 453A CRT HV Problem

Stan & Patricia Griffiths <w7ni@...>
 

This is more likely to be a problem with the door knob cap shorting than the
CRT. You can disconnect the CRT and see if just connecting the door knob
cap kills the high voltage. If not, then the door knob is probably good.
The last thing is the CRT itself and if connecting and disconnecting it
causes the HV to fail and come alive, then I would say it is probably the
CRT. Replacement door knobs for a 453A can be found. CRT's are much harder
to find.

Stan
w7ni@easystreet.com

----- Original Message -----
From: "zs5la" <cohenro@vodacom.co.za>
To: <TekScopes@yahoogroups.com>
Sent: Thursday, May 30, 2002 7:14 AM
Subject: [TekScopes] 453A CRT HV Problem


I wonder if any of you could help me out here. I have a 453A where
the HV section (12kV) does not seem to work. When I disconnect the
12kV from the big doorknob cap in the HV section to the CRT, then
everything seems to work, except no trace, and I can arc a nice spark
from the cap to the HV wire going to the CRT. When I connect the HV
wire back onto the cap then all fails. I can still hear the
transformer oscillating away at a high pitch, but no voltage. Could
the CRT be faulty from the anode side somehow shorting internally to
GND or am I missing something in the HV power supply section? The
resistance of the anode to pin 12 on the CRT is very high when
measuring with a Fluke ohmeter. Is it common for CRT's to fail like
this?

Thanks.



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Re: Which one?

Ray Menke <rndmenke@...>
 

On Thu, Jun 20, 2002 at 08:13:42AM -0000, PANOS29 wrote:

First of all i have to say i am into DIY audio electronics and also
radio amateur and the scope will be used for these two uses, mainly
audio though.
So I am about to buy something from the 466 465 475 kind of scope or
on the other hand a 7000 frame (7603),however, i was wondering if
these oldies are any good on measurement precision or should i go for
a new cheap scope?
I would look for a working 7603 type scope with a 7A22 high gain
differential amplifier. This is a very sensitive amplifier with
adjustable bandwidth up to 1 MHz. Sensitivity can be as good as 10 or
20 Microvolts per division. Also look for a 7A18 or 7A26 for your 60
or 100 Mhz needs. Hopefully you can find these with the proper probes,
as recommended by Tektronix. Be sure the scope is working. If you buy
on ebay, beware of the "I can't check this out because I'm not
technical" songs. This usually means it is broken! The 7B53A is a
good dual time base for this series scope, although you might be happy
with a 7B50.
What u propose between the 4XX and 7000, as both these choises are
about the same cost.
The plug-in scopes are easier to work on. (most of the time.) If you
are into audio, then you could use high gain diff amps, and perhaps
stumble on a jewel like an audio spectrum analyzer type 7L5. For
Amateur needs, a 7L12, or 7L13 (WORKING) would be ideal! (Spectrum
Analyzers)
Also about the 7603 read out option, can somebody explain if the read
outs have anything to do with actuall values measured , or these are
just readouts of the various settings?
The readouts show the knob settings, and warn you if they are not in the
detent or calibrated position. A digital multimeter (7D13) or a digital
counter uses the crt readout as a display, and I would use these if they
were available for a low price. The CRT readout of the dual time base delayed
sweep measurements can be quite accurate. Vertical Amplifiers and
probes are generally better than 3 percent accurate at frequencies about
20% of the rated bandwidth. Scope waveforms show waveshapes, overshoot,
risetimes, falltimes, pulse width, delay, etc...and you just can't get
that information any other way. A 7A13 Differential Comparator is good
at measuring power supply voltages and ripple. If you see one, get it,
but you will have to learn how to use it.
Moreover I would like some info for places who sell this kind of
equipment in Europe and mainly on line.
Be careful that what you buy is not broken! (especially on line).
Look for a photo of a working display, with waveforms being displayed,
not just the readout and a flat line. (I recently bought a 7603 that
has a crt readout and a trace...the problem is that I cannot adjust the
trace intensity, and it is very bright. I got what the seller showed,
but he didn't mention that there was no control of intensity. The
freight was more than the price of the mainframe, so I guess I'll just
have to find another one.)
--
Ray Menke


Re: Which one?

Morris Odell <morriso@...>
 

Hi all,

PANOS29 wrote:

So I am about to buy something from the 466 465 475 kind of scope or
on the other hand a 7000 frame (7603),however, i was wondering if
these oldies are any good on measurement precision or should i go for
a new cheap scope?
What u propose between the 4XX and 7000, as both these choises are
about the same cost.
Maybe I'm biased ( ;-) but I wouldnt dream of buying a "cheap" scope.
Firstly, a Tek of the 7603 of 460 series will probably be just as cheap, and
as far as quality is concerned, you really can't compare them. A warning
though, once you get your first Tek, you will become addicted and will never
want to use one of those plastic toys again.

Measurment precision? Well that depends on calibration. The finest scope is
only as good as its calibration. I would think that a Tek scope originally
intended to be calibrated accurately to provide reproducible professional
performance should still be capable of superior performance even though it
was quite a bit older than a plastic modern toy scope.

As far as choosing between a 7000 and a 460 series, this depends on how much
you need the portability of the 460. They are both comparable in terms of
performance & technology. The 7603 is bulkier but has a bigger screen, takes
a wide renge of plugins and has on-screen display. The 465 is a classic
workhorse that you can take anywhere and run on batteries but has no plugin.


Also about the 7603 read out option, can somebody explain if the read
outs have anything to do with actuall values measured , or these are
just readouts of the various settings?
They are readouts of the control settings. I believe it is possible to have
measurement readings from cursors with certain plugins, (eg: time
measurements with a 7D15) but I have no experience of that.

Good luck.

Morris Odell


Which one?

PANOS29
 

Hello all!
This is Panos from athens, I recently thought of buying a used TEK
scope from surplus market.
Since its the first time for me to buy a scope, I would like to ask
some basic questions about scopes.

First of all i have to say i am into DIY audio electronics and also
radio amateur and the scope will be used for these two uses, mainly
audio though.
So I am about to buy something from the 466 465 475 kind of scope or
on the other hand a 7000 frame (7603),however, i was wondering if
these oldies are any good on measurement precision or should i go for
a new cheap scope?
What u propose between the 4XX and 7000, as both these choises are
about the same cost.
Also about the 7603 read out option, can somebody explain if the read
outs have anything to do with actuall values measured , or these are
just readouts of the various settings?
Moreover I would like some info for places who sell this kind of
equipment in Europe and mainly on line.
Sorry for the long post but i am a bit confused.

Best regards to all,

Panos


7912AD

kngtron
 

Looking for prints for the power supply only for the 7912AD. Pick up
2 from e-bay to use them for testing other tek modules instead of
building my own supplies. Thanks to the group for helping me with the
7854 problem !!!


Re: Need 465 B Sweep Cam Assy.

Stan & Patricia Griffiths <w7ni@...>
 

I don't have the part you need but you might try Deane Kidd
dektyr@teleport.com or the following web site:

http://www.sphere.bc.ca

Stan
w7ni@easystreet.com

----- Original Message -----
From: "cinerama84106" <cinerama84106@yahoo.com>
To: <TekScopes@yahoogroups.com>
Sent: Sunday, April 07, 2002 8:58 AM
Subject: [TekScopes] Need 465 B Sweep Cam Assy.


I'm looking for the B sweep cam assy for my 465 scope. Its part
number 105-0614-00. This is the cam assy that you pull out the sweep
knob for to use for delayed sweep
Thanks!
Mark Gulbrandsen
Salt Lake City, UT



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7704 power supplies...

nn2027299 <silvermoon.group@...>
 

Dear All,

I have a somewhat sick 7704 scope that is in need of a new power
transformer. I've hunted high and low for one of these and have
turned up with nothing! Has anyone got one lying around, or indeed
a complete PSU module, or even an old (dead) 7704 (with good PSU)!
Please, please have a rummage to see if you have one so that I can
restore this fine scope!
Cheers,
Ed.


new to group

kngtron
 

HI - I'm new to the group and here is my first question.
I'm looking for an expert with the 7854. Mine is giving
me problems when it is in both scope and stored mode.
I'm also looking for interfacing advice with the gpib
and for any software. -- thanks


Re: Wanted to buy: Tektronix publication: The XYZ's Of Using A SCOPE

david@...
 

I am searching for the following publication by Tektronix: "The
XYZ's of using a Scope, an Oscilloscope Primer." If you are not using
your copy I'd sure love to have it. Thanks for looking.
It's available online at:

http://www.tek.com/Measurement/App_Notes/XYZs/


David DiGiacomo


Re: Wanted to buy: Tektronix publication: The XYZ's Of Using A SCOPE

ROLYNN PRECHTL K7DFW
 

I am searching for the following publication by Tektronix: "The
XYZ's of using a Scope, an Oscilloscope Primer."
It's on the www for a free pdf download. Put the words in Google to find out
where it is.

K7DFW


Need transformers?

 

I have several Tektronix parts that people in this group might be able
to use:
1. Power Transformer - marked T-514 PB1; believed to be for a Tek 514
'scope.
2. Power Transformer - marked 120037; believed to be for a Tek 535
'scope
3. Saturable Reactor - Marked L517-SB1, 108053; believed to be in the
filament circuit of a Tek 517 'scope.
4. High Voltage Power Supply Module -- Marked Type 210B; believed to
be for a Tek 513 'scope.
Each item is $15 plus actual shipping costs. The transformers weigh
about 18 pounds, unpacked. All are unused and in good condition.
Contact me for further details at leedyt@aol.com

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