开云体育

Very useful info.

There's an error on page 78. An extra digit (4) has been added to
the 4 digit example of the 162k resistor. It should be 1623 not
16234.

--- In TekScopes@..., Jerry Massengale <jmassen418@...>
wrote:

Bravo! Thank You!
?
jerry

--- On Wed, 9/24/08, TekScopes@...

<TekScopes@...> wrote:

From: TekScopes@... <TekScopes@...>
Subject: [TekScopes] New file uploaded to TekScopes
To: TekScopes@...
Date: Wednesday, September 24, 2008, 1:50 PM







Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the TekScopes
group.

File : /SMD_codes.pdf
Uploaded by : udtmang <mwallace9@cfl. rr.com>
Description : smd part code nomenclature

You can access this file at the URL:
. yahoo.com/ group/TekScopes/ files/SMD_ codes.pdf

To learn more about file sharing for your group, please visit:
. yahoo.com/ l/us/yahoo/ groups/original/ members/web/

index.htmlfiles

Regards,

udtmang <mwallace9@cfl. rr.com>

On Thu, 25 Sep 2008, Howard Ashcraft wrote:

I have restored a SG5030 (bad electrolytic smd caps). It works
perfectly if allowed to run for about 5 minutes. If it has been
sitting cold for a few days, however, it will show various errors on
start up (all lock errors) that will disappear if the self-test is run
after a 5 minute warmup. I assume that this is related to the
oscillator being cold. Do others have this behavior or is it
relatively normal. Since it works fine when warm (and should be warm
when used), I'm not terribly concerned, but am interested if others
see this as well.

Having no own experience with this model I can't give you specific advice.
However, this kind of error is usually easy found. You need a hairdryer
and a can of coolant spray. Warm the machine gently with the hairdryer
until it runs good and carefully cool suspect parts with the coolant.
You'll find the temperature sensitive part quickly with this method.

Grü?e aus Hohenlohe,

Martin Jangowski

| Martin Jangowski E-Mail: Martin@...|
| Netzwerke und Multimedia |
| Voice: +49 7946/3723 Fax: +49 7946/940791 |
| Snail Mail: Von-Olnhausen Str. 4 74626 Bretzfeld Germany |

[Non-text portions of this message have been removed]

I have restored a SG5030 (bad electrolytic smd caps). It works
perfectly if allowed to run for about 5 minutes. If it has been
sitting cold for a few days, however, it will show various errors on
start up (all lock errors) that will disappear if the self-test is run
after a 5 minute warmup. I assume that this is related to the
oscillator being cold. Do others have this behavior or is it
relatively normal. Since it works fine when warm (and should be warm
when used), I'm not terribly concerned, but am interested if others
see this as well.

Regards,

Howard

Hello Jose,



In the 1986 Tek Catalog, for the 7912AD, Option 13 says the TV Scan is
changed to 625 lines at 50 Hz. I also consulted the 1974 Catalog and it
says Option 13 for the R7912 is TV scan is 625 lines at 50 Hz, too.



Stan



_____

From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of Jose V. Gavila
Sent: Friday, September 19, 2008 10:26 AM
To: TekScopes@...
Subject: [TekScopes] Option 13 in an R7912?



Hello!

Today I have received my last Tek toy, an R7912 mainframe :-). It has a
label in the plug-in compartment base which says 'Option 13'. I wonder if
someone know what does it mean.

Thanks!

JOSE
-------------------------------------------------
73 EB5AGV - JOSE V. GAVILA
IM99sm La Canyada - Valencia (SPAIN)

Hi,

Who sells the matching sockets that fit the P6137 scope probes?
What is the description and part number? I intend to solder these into a pcb at the nodes where I need to make measurements but must cannot use the probe ground lead.

Many thanks, 73, W6MIK, Dave

Bravo! Thank You!
?
jerry

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the TekScopes
group.

File : /SMD_codes.pdf
Uploaded by : udtmang <mwallace9@...>
Description : smd part code nomenclature

You can access this file at the URL:


To learn more about file sharing for your group, please visit:


Regards,

udtmang <mwallace9@...>

Hello,

This email message is a notification to let you know that
a file has been uploaded to the Files area of the TekScopes
group.

File : /DiffOscMeasurements.pdf
Uploaded by : udtmang <mwallace9@...>
Description : A Primer on Differential Measurements,

You can access this file at the URL:


To learn more about file sharing for your group, please visit:


Regards,

udtmang <mwallace9@...>

I am not familiar with the 7623 (BAMA is slow downloading today) but my 7633
and 7603 use the same IC part 155-0022-00 for the vertical and horizontal
amp switch so I tested by substitution.



My problem was not in the channel switch IC but in one horizontal amplifier
resistor R563. It gave a similar problem but with a horizontal shift and
dance plus slight right hand sweep compression. I posted last month in
response to someone else working on a 76 series.



I attempted to deduce the internal circuit of 155-0022-00 by a series of DC
measurements but was not satisfied with my efforts as I could not accurately
calculate the output voltages from the current summation. Maybe you will do
better and if so I would like to see your equivalent circuit.



Robert Furniss

RobertFurniss@...



650 504 1468 cel

_____

From: TekScopes@... [mailto:TekScopes@...] On Behalf
Of fuzzbrain01
Sent: Tuesday, September 23, 2008 7:38 PM
To: TekScopes@...
Subject: [TekScopes] 7623A readout problem



I have a 7623A which has developed an unusual problem. Perhaps
someone in the group has dealt with this before?

I have 7A18 and 7A26 vertical plug-ins, and a 7B53A timebase plug-in.
The traces for each vertical channel are visible and operating
normally. When I turn on the readout, I can see the expected
characters; however, the position of each vertical channel's amplitude
readout moves with the vertical centering adjustment for that channel.
The readout for the timebase seems to move with channel 1 of the
selected (right or left) vertical plug-in. When I put a sine wave on
one channel, the readout for that channel has an added vertical offset
that corresponds to the AC component of the sine wave input. It's as
if it were dancing! If I use the variable adjustment on the timebase,
I can "zero-beat" the vertical offset error of the character.

I checked the low and high voltage power supplies, which were all
within tolerances. I cleaned the contacts of the plug-in connectors
on the main interface board, and re-seated the plug-ins in the
mainframe. I swapped the vertical plug-ins, and tried a different
timebase plug-in. Still the same problem.

The symptoms seemed to indicate a problem with vertical channel
switching in the mainframe. I read through the theory of operation
for the readout system, and looked through the schematics. I
concentrated on the A4 Vertical Interface board. Using another
'scope, I checked the waveform at the base of Q2390 (X/Y inhibit). I
found normal voltage levels, and pulses of the correct amplitude that
appeared in small groups, that I took to be the character slots.
Checking the emitter and base of Q2390, I also found correct voltage
levels (per the blue voltages given in the manual's schematic). I
noticed that the X/Y Inhibit line also goes to pin 6 of the Vertical
Channel Switch IC, U2340.

Does anyone have a cross-reference or data sheet for 155-0022-00,
U2340? Without knowing what's inside, it's difficult to know what to
expect on the output pins.

Or perhaps I'm on the wrong track. Has anyone seen this before? What
should I look for?

Thanks for your help.

I have a 7623A which has developed an unusual problem. Perhaps
someone in the group has dealt with this before?

When you say "developed", do you mean that this is a problem that has not
occurred before with this particular mainframe?

Craig

I have a 496 SA s/n b010424 that was converted into a hangar queen
at some point in its life.

It has a mix of modules pulled from five different units. Very
organized module changers worked on this unit, and left notes
on color coded tags...

I have worked my way through the unit to the point that I have
occasional error 58's (I need to go through the cal sequence).

If the phase lock control module is installed the digital storage
option fails to operate. If the phase lock module is activated
it hangs the data bus and the unit displays garbage on the display
and ceases to respond to the controls.

I do have a set of card extenders and a 1230 logic analyzer and
enjoy a good mystery, however I am not sure that I wish to spend
a couple of weeks chasing this problem.

Any suggestions on common failures on this unit?

Does anyone have have a reasonably priced spare available?

Jim, n8qoh

Many thanks to the Tektronix forum and for all of the terrific help
received from the members.

The 465 scope is now fixed. Capacitor C1419 was shorted to ground.
Once the capacitor and fuse were replaced, the scope was back to normal.

A series of pictures are posted in photo album 465 - HV Bad Cap C1419,
linked below:


Some confusion occurred due to different schematic versions of the HV
section. Newer 465 scopes (S/N B289565 and above ) use two 22 uFd
caps in parallel (C1419 and 1418):


Older 465 scopes (S/N B289564 and below) have a single 47 uFd
capacitor (C1419). Older models do not have a capacitor named C1418.


The voltage to fuse F1419 is around 24.4 to 24.9 volts. The schematic
is labeled +15 unregulated. While technically correct, that's a bit
misleading because the normal voltage is listed as 24.4 volts. Since
C1419 is rated at 25 volts, capacitor C1419 operates at the brink of
destruction.


Kemet's Tantalum Dipped / Radial - Polar capacitor specifications were
researched. This document is posted in the links section as Tantalum
Replacement Caps and also listed here:


On page 61 (the first page of this document), a table lists all of the
capacitors available with various voltage ratings.

This document shows that the highest voltage rating available for a 47
uFd capacitor is 35 volts. But, 22 uFd capacitors are rated as high
as 50 volts (and are less expensive).

It is speculated that newer 465 scopes use two 22 uFd capacitors in
parallel with a higher voltage rating to overcome frequent failures of
the 25 volt, 47 uFd capacitors.


The shorted C1419 capacitor in my scope was replaced with a Kemet 47
uFd tantulum capacitor rated for 35 volts. It seems to work fine and
cost $5.76 from Mouser Electronics. The fuse cost $0.28, so six were
purchased (just in case).

Of particular interest, notice the steep voltage derating curve of
tantalum capacitors based on temperature. A tantalum capacitor rated
for 25 volts at 85 degrees C is only rated for 16.5 volts at 125
degrees C! With an input voltage approaching 25 volts, C1419 is at
high risk of failure, especially if the fan is not doing a good job.
Since the old Tektronix scopes are full of Tantalum capacitors, a high
temperature excursion could be quite costly, if not catastrophic. So,
careful consideration is highly recommended when choosing a fan
replacement.

A great trouble-shooting tip is to disconnect Q1418 by unplugging
connector P1400. This enables Q1418 (under the A9 board) to be tested
without removal and also allows continuity checks from fuse F1419 down
through the transformer primary winding. If the demand side of F1419
is shorted to ground with P1400 disconnected, you can bet C1419 is bad.

Capacitor C1419 is located at the corner of the A9 board under the
high voltage shield.


Once the shield is removed, be careful poking around those high
voltage caps! The good news is that board A9 does not have to be
removed. C1419 is easily removed and replaced from the top side of
the circuit board using a low wattage soldering iron and a bit of care.

I am very pleased to have my old 465 scope going again. Again many
thanks to the Tektronix forum. Having the guidance of such
experienced members was a big help and made this project a lot of fun!

Ron

My 7704A does the same thing. I thought it was normal until I got a
R7704 where the readout characters stay put no matter what the
vertical position controls do (It's the first thing I checked on the
scope). I have 7A26's, 7B70 and a 7B71. I also tried cleaning the
connectors in the 7704A but didn't get an improvement. The power
supplies looked ok to me too. I'm also curious if anyone else has any
ideas.

Cheers,
Neil

I have a 7623A which has developed an unusual problem. Perhaps
someone in the group has dealt with this before?

I have 7A18 and 7A26 vertical plug-ins, and a 7B53A timebase plug-in.
The traces for each vertical channel are visible and operating
normally. When I turn on the readout, I can see the expected
characters; however, the position of each vertical channel's amplitude
readout moves with the vertical centering adjustment for that channel.
The readout for the timebase seems to move with channel 1 of the
selected (right or left) vertical plug-in. When I put a sine wave on
one channel, the readout for that channel has an added vertical offset
that corresponds to the AC component of the sine wave input. It's as
if it were dancing! If I use the variable adjustment on the timebase,
I can "zero-beat" the vertical offset error of the character.

I checked the low and high voltage power supplies, which were all
within tolerances. I cleaned the contacts of the plug-in connectors
on the main interface board, and re-seated the plug-ins in the
mainframe. I swapped the vertical plug-ins, and tried a different
timebase plug-in. Still the same problem.

The symptoms seemed to indicate a problem with vertical channel
switching in the mainframe. I read through the theory of operation
for the readout system, and looked through the schematics. I
concentrated on the A4 Vertical Interface board. Using another
'scope, I checked the waveform at the base of Q2390 (X/Y inhibit). I
found normal voltage levels, and pulses of the correct amplitude that
appeared in small groups, that I took to be the character slots.
Checking the emitter and base of Q2390, I also found correct voltage
levels (per the blue voltages given in the manual's schematic). I
noticed that the X/Y Inhibit line also goes to pin 6 of the Vertical
Channel Switch IC, U2340.

Does anyone have a cross-reference or data sheet for 155-0022-00,
U2340? Without knowing what's inside, it's difficult to know what to
expect on the output pins.

Or perhaps I'm on the wrong track. Has anyone seen this before? What
should I look for?

Thanks for your help.

--- In TekScopes@..., "David" <gavinator68@...> wrote:

I am in the market for a 556 in decent condition. They are just so
damn good looking!!! Anyone out here looking for a good (permanent)
home for your stagnant 556?

What is your location? They are around a hundred pounds... not fun to
ship!

BTW, I have one for sale in the Boston, MA area.

Also 2 non-working 547's (one an engineering prototype), a
basically-working 575, some carts, some working 360 gear, some
almost-working 300-series scopes, HP nixie freq counters, pair of
working RM564's, associated manuals, etc etc. Further info by email
on request, please make offers :)

I am in the market for a 556 in decent condition. They are just so
damn good looking!!! Anyone out here looking for a good (permanent)
home for your stagnant 556?

One more to add to the heap if it hasn't been mentioned already. I
watched as one of our top rework operators removed "chip" resistors,
caps, inductors. She would use two irons of equal tips, heat settings
by placing the two tips on each end of the component and with a gentle
pressure on each end, lift the chip off like you would do two handed
chopsticks. Use solder-wick to gently remove the extra solder on the
pad(s). Now put alittle new solder(paste if you have it) on one pad
only. Put your new component in position, heat, check position, then
solder the other end. That will anchor the part. Go back to the other
end and solder if needed. Practice on some scrap boards to get the
hang of it. The operation works just fine and you reduce the pad damage
and possible damage to the old component so you could ascess if it is
still good. Lower heat for small components, more for bigger or more
heat massive components.

Go For It!!....Norman

I was recently given a bunch of components from a 549 scope. What a
beautiful piece of engineering. I was inspired to create something to
help the bits live on. I built a 1 tube regenerative receiver for the
broadcast band. Very 1920's design, using parts from the 40's, 60's
and probably the 80's. It works a treat. See picture in the ve7it
photos section.

cheers
Lawrence Glaister VE7IT
Nanoose Bay BC, Canada

I just happened to think
Now that I no longer have 5 extra bodies around here, I don't really need to keep their tools either
I do have an extra Ungar / Weller 4624 Solder / de-solder station I could send to a new home
It does better on small leads and pads than on the larger pads
Not the best not the worst
Gauranteed ok
If interested contact me off net and I'll see if I have any extra tips and such and send pictures. Hopefully we can make a deal we can both live with.
Paul

Hi,

I remember hearing of a company that used long thorns from a local
bush to clear solder-filled PCB holes while heating the pad. They
don't wet or conduct much heat away but are unforgiving if you fall in
the bush :-)


Cheers - Joe G3LLV