Date   

Re: jobs from hell

 

Reducing the incandescent lamp voltage has a huge effect on life which
is inversely proportional to the 16th power of the voltage. Most
(all?) of the 7000 mainframes have adjustable lamp voltage and I just
leave it set to minimum.

On Wed, 17 Jul 2013 15:48:13 +1000, Don Black
<donald_black@...> wrote:

I wonder if reducing the lamp voltage slightly to increase their life
would be worthwhile? Perhaps a silicon diode in series with their supply
would give about 0.7 volts drop and improve life (a diode would give a
constant drop however many lamps were lit where a resistor would depend
on load).

Don Black.

On 17-Jul-13 3:38 PM, David wrote:

On Tue, 16 Jul 2013 17:50:00 -0600, David DiGiacomo
<daviddigiacomo@... <mailto:daviddigiacomo%40gmail.com>> wrote:

Was it the pushbutton switches which they kept in later plug-ins or
the relays? I imagine those relays were expensive which would be
another reason to get rid of them.
I'm not sure what you are saying, but the white relays were used in
the 7A13 for a long time after the 7A12 was gone.
The 7A13 "pull for x10 Vc" function would require another x10 switched
input attenuator to implement without relays.

I am just suggesting that Tektronix made more effort to stop using the
relays than to stop using the pushbuttons. I remember seeing a price
list somewhere showing that Tektronix was OEMing the relays for a
price in the $50 range until alternative products became available.
After a certain time, it seems like the 7A13 was the only product
using them.

Also, there are lots of other plugins (and mainframes) where changing
the lamps is no fun at all. Soldering incandescent lamps just seems
like a bad idea.
I think the only problem is easy access which as has been pointed out,
is a major problem in many cases. My 7A12 needs new bulbs installed.

The on flakey pushbutton switch that I need to repair is on my 7T11A.


Reviving Tek Equipment After 20 Years In Storage...What to Do and Look For?

too_many_tools
 

I have received a number of Tektronix oscilloscopes and logic analyzers that have been stored unpowered for over 20 years.

I have yet to apply power to them.

What preparation if any should I do to them before applying power?

Afterwards, what possible problems should I look for in them after the long storage period?

Thanks


Re: jobs from hell

Don Black <donald_black@...>
 

I wonder if reducing the lamp voltage slightly to increase their life would be worthwhile? Perhaps a silicon diode in series with their supply would give about 0.7 volts drop and improve life (a diode would give a constant drop however many lamps were lit where a resistor would depend on load).

Don Black.

On 17-Jul-13 3:38 PM, David wrote:
 

On Tue, 16 Jul 2013 17:50:00 -0600, David DiGiacomo
<daviddigiacomo@...> wrote:

>> Was it the pushbutton switches which they kept in later plug-ins or
>> the relays? I imagine those relays were expensive which would be
>> another reason to get rid of them.
>
>I'm not sure what you are saying, but the white relays were used in
>the 7A13 for a long time after the 7A12 was gone.

The 7A13 "pull for x10 Vc" function would require another x10 switched
input attenuator to implement without relays.

I am just suggesting that Tektronix made more effort to stop using the
relays than to stop using the pushbuttons. I remember seeing a price
list somewhere showing that Tektronix was OEMing the relays for a
price in the $50 range until alternative products became available.
After a certain time, it seems like the 7A13 was the only product
using them.

>Also, there are lots of other plugins (and mainframes) where changing
>the lamps is no fun at all. Soldering incandescent lamps just seems
>like a bad idea.

I think the only problem is easy access which as has been pointed out,
is a major problem in many cases. My 7A12 needs new bulbs installed.

The on flakey pushbutton switch that I need to repair is on my 7T11A.



Re: 453

Alain B
 

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Many thanks folks, for all those really fine comments.
Very prolific group, great !
Regards
Alain




Le 17.07.2013 00:39, Ed Breya a �crit :
If there is only one layer of plastic material in front of the CRT face, it should be made of lexan (polycarbonate - soft, but tough), not acrylic (hard, but brittle), since it serves as an implosion shield. This has been dicussed a lot here, so the archives have plenty of good info on materials and techniques.

BTW I recently junked out some old HP CRTs, and found that they had an extra layer of glass glued to the face with rubbery goop, just like TV CRTs and laminated automotive windshield safety glass. I don't know if that's the case with all HP ones. I don't think Tek ever used that method. I think on the Tek CRTs that have the jug sections frit sealed together, the flat faceplates are made of tempered glass for strength, but they can shatter and implode, so need protection up front. I think the all-glass CRTs are regular glass (with slightly convex faceplate for strength), so same issues either way.

Ed

--- In TekScopes@..., Alain B <alain.betemps@...> wrote:
Thank for help,

I will look for colored plexiglass to take place and add contrast.
Regards
Alain



Le 16.07.2013 16:14, Cliff White a �crit :
My 466 has a veeeery fine metal mesh over the screen, it's listed as an
option to cut down on radiation/interference. FWIW it was an Army scope.


Respectfully,
Cliff White, W5CNW
w5cnw@... <mailto:w5cnw@...>
On 07/16/2013 09:11 AM, Paul Amaranth wrote:

I think the glare shield was a fine metal mesh; I have one like that
on a 422.

I made a glare filter using smoke plexiglass that popped into place
on my 453. I'm thinking it might be nice to make another one using
clear plexiglass and a colored gell to get a blue filter. I might
do that for a 454 that's in my queue.

I think it's very rare to fine an oem filter; most of them seem to
have gotten lost by now.

On Tue, Jul 16, 2013 at 05:34:54AM -0000, betounn wrote:
Hello Folks,

What the best way to replace blue plastic CRT shield on a 453, mine
is missing.
Thank for help.
Regards
Alain
--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... <mailto:paul%40AuroraGrp.Com> | Unix & Windows




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

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Re: jobs from hell

 

On Tue, 16 Jul 2013 17:50:00 -0600, David DiGiacomo
<daviddigiacomo@...> wrote:

Was it the pushbutton switches which they kept in later plug-ins or
the relays? I imagine those relays were expensive which would be
another reason to get rid of them.
I'm not sure what you are saying, but the white relays were used in
the 7A13 for a long time after the 7A12 was gone.
The 7A13 "pull for x10 Vc" function would require another x10 switched
input attenuator to implement without relays.

I am just suggesting that Tektronix made more effort to stop using the
relays than to stop using the pushbuttons. I remember seeing a price
list somewhere showing that Tektronix was OEMing the relays for a
price in the $50 range until alternative products became available.
After a certain time, it seems like the 7A13 was the only product
using them.

Also, there are lots of other plugins (and mainframes) where changing
the lamps is no fun at all. Soldering incandescent lamps just seems
like a bad idea.
I think the only problem is easy access which as has been pointed out,
is a major problem in many cases. My 7A12 needs new bulbs installed.

The on flakey pushbutton switch that I need to repair is on my 7T11A.


2465 missing Ch1

mosaicmerc
 

Hi All:
I just got in my 'parts' scope, it's missing Ch1 and the little pushbuttons on the 10X mag and trigger slope are broken off flush...but function if I use a toothpick in the holes. Cost $150 incl shipping.

Thing is...the calibration is fine, CH2,3,4 work just fine.
I feel kinda hard pressed to scrap it for parts now. I can easily mold replacement push buttons from epoxy or hot glue.

I was wondering if anyone had a CH1 they cared to part with so i can make this scope a backup rather than a parts unit.


Re: ?'s on 7B92 7B92A

hpxref
 






 >have a 7B92 ser# B031627. This unit loses stable trigger as it warms up. If I put a heat gun near the tunnel diodes the trigger will die completely in a very short time. I was trying to locate a manual download so I could look into the problem and get part #'s for the TD's. Found plenty of info on the 7B92A but nothing on the 7B92. Was the 7B92 short lived and an improved version took it's place? It is also curious that the model # on the pull is 7B92 but the side covers are marked for the 7B92A?? This cover shows jumper positions P760 >and P761 to select delayed or delaying sweep which I do not find on the PC boards. Bob

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

Advice given to calibrate is sound.  Same thing with my 7B92 when I got it.
ReCal  fixed that issue completely.  Tunnel diodes do drift
Wish I had the A model , though

John Byers


What is a 670-7942?

Doug
 

I found 3 small boards in my junk pile marked A70 670-7942-
The only standard chip on it is a MM74C165, date code R8307
the rest is a hybrid and multi pin connectors.
Anyone know what this is from? I can post a photo if necessary.

Doug


Tek scope logo for handles

Michael A. Terrell
 

There was a recent mention of the logo inserts for scope handles. I just saw this listing for them on Ebay: My standard disclaimer applies: I've never listed anything for sale on Ebay. :)

$8 includes shipping, and he has some of the blue ones. Tek part # 334-8202-00 and others.


http://www.ebay.com/itm/161063288987


Re: Do multi-colour CRTs exist? + other ideas on identifying graphs

John Rehwinkel <jrehwin@...>
 

Penetrons are super cool. I wonder what one would buy to get this? It doesn't seem like any products using those have been recorded.
Okay, managed to find the manual while sorting stuff during a house move.


At least one was produced, because I had one. It had a largish (16" diagonal or so) square CRT. It came as two large heavy boxes. One was the control gear, which accepted coarse and fine X and Y inputs, along with a color input.
Turns out it was a CPS 8001 21" beam penetration monitor. Not many references to it in the literature, but found a mention of it here:

http://www.computer.org/csdl/mags/co/1973/03/01641679.pdf

Scroll down 3 pages to page 54, it's at the bottom of the 3rd column.

I'm guessing the color input was like a "hue" input, just a voltage
selecting from the gamut? E.g. 0V = Red, 15V = Green, inbetween is a
mix?
It had a 2-bit TTL input, to select red, orange, yellow, or green. It also had a "color busy" output to indicate it was switching colors. This was accomplished by having one bit select the anode voltage (which varied +/- 2kV), and the other select the cathode voltage (which varied +/- 1.25kV).

The manual doesn't state which CRT was used, other than it's a 21" diagonal unit, with P22 red and P22 green phosphors. 72 degree, magnetic focus and deflection. However, the stated "picture size" is 12 x 12 inches.

This was linked by a fat umbilical containing wires, coax, and fiber optics
Wait.. fiber optics???
From the manual, page 30-31, § 5.3.2.4 "Ground Level Driver Board and Video Transmitter":

"Next, a buffer is provided for each of the Color Bit control signals coming from the Display Section. These buffered control signals are then fed to the two High Voltage Switches to select the output state of each Switch. A buffered driver circuit is provided to switch a LED On or Off corresponding to the state of the Unblank signal. The light output from this LED is carried by a light pipe to the Unblank circuitry in the Gun Box. Lastly, an amplifier and driver circuit, called the Video Transmitter, is provided to drive two LED's whose light outputs change from no output to full brightness as the Video Input Signal goes from 0V to a maximum +1V. The light output from these LED's is conducted by a light pipe to a light sensor on the Cathode Driver Card in the Gun Box. Again, the use of light pipes provides high voltage isolation between Unblank and Video circuitry on the Ground Level Driver Board, which is near ground potential, and the Grid and Cathode Driver circuitry in the Gun Box, whish is at the potential of the High Voltage, Adjustable DC Power Supply."

to the display unit, which contained the deflection amplifiers, switchable high-voltage power supply, and of course the penetron CRT itself. Alas, I do not recall who made it or what it was called. There is a chance I still have the manual for it somewhere, but it would take some time for me to find it.
As you see, I did manage to find the manual. Turns out I have two copies. The schematics are in poor shape, as they were reproduced by some process that didn't age well. Additionally, they're incomplete - the manual states "Also included, for reference, are a complete set of schematics for all uncast circuit boards in the Model 8001 Monitor and a Recommended Spare Parts List." I assume that "uncast" here means boards that aren't potted. The recommended spares list is pretty extensive, which seems to imply the design didn't have good margins and tended to fry transistors on a regular basis.

- John


Re: digital guy, lost in analog space, need help with 561B

John Griessen
 

http://elektrotanya.com/tektronix_type-561b_oscilloscope_instruction_sch.pdf/download.html

Has a non-mil manual for 561B.

I looked at it and there's a little more on turn-on/check out for the uninitiated:

561b frame:
ASTIGMATISM centered
FOCUS centered
CRT cathode selector (rear panel) NORM

time base:
magnifier OFF


Re: jobs from hell

David DiGiacomo
 

Was it the pushbutton switches which they kept in later plug-ins or
the relays? I imagine those relays were expensive which would be
another reason to get rid of them.
I'm not sure what you are saying, but the white relays were used in
the 7A13 for a long time after the 7A12 was gone.

Also, there are lots of other plugins (and mainframes) where changing
the lamps is no fun at all. Soldering incandescent lamps just seems
like a bad idea.


Re: Questions re 575- cap replacement, fan

Ed Breya
 

The original/common trade-name for that is Oilite - there's lots of info available. When reusing the bearings it's best to solvent flush, then saturate them with fresh oil - vacuum impregnation can do it thoroughly - or at least soak them for a while, and of course, refill the oil reservoir.

Ed

--- In TekScopes@..., "Steve" <ditter2@...> wrote:

--- In TekScopes@..., "keithostertag" <keitho@> wrote:



Hi Steve-

Thanks for the tip! I wouldn't have known how to do that. I would have thought the lacquer thinner or other solvent might damage whatever that porous stuff in the bearings is made of.
The bearings are made of sintered bronze. Essentially this is bronze metal shavings which are compressed under high pressure until they partially fuse together, leaving gaps that provide porosity.

The reservoir for the oil is a washer shaped piece of felt. It is sealed inside the die cast zinc frame member that also contains the bearing. Neither will be damaged by lacquer thinner or acetone. However, the windings in the stator may be. Be sure to disassemble the motor and keep the solvent away from the other parts.

- Steve


Re: Questions re 575- cap replacement, fan

Craig Sawyers <c.sawyers@...>
 

With "modern" solid state designs from the late 1960s and 1970s, you need
to be careful not to put in a replacement cap with too *low* of ESR
because
the ripple current may be too high. In addition to stressing the cap
itself, this
can stress the rectifier circuit.
The impedance limiting is usually dominated by the effective secondary
impedance of the transformer - which is the case for high voltage tube
supples. That is what effectively throttles the charging current. The only
time you need to be a little careful is for low voltage high current designs
when the effective secondary impedance can be pretty low.

Craig


Re: digital guy, lost in analog space, need help with 561B

John Griessen
 

On 07/16/2013 05:40 PM, gndarnell wrote:
Can someone please tell me what basic settings I should be using to get something displayed on the screen? It's got a 3A6 dual
trace amplifier and a 3B4 time base.

http://w140.com/tekwiki/wiki/3B4

Set the pos knob in the middle,
time on 10 msec
trigger on auto,
trigger level in middle,
slope +
coupling DC source int

http://w140.com/tekwiki/wiki/File:3A6_1.JPG

volts/div at 1,
ch1 DC
pos in middle
mode ch1

and connect a probe so you can show the cal out signal from the back.

intensity knob down,

power on.

Then wiggle pos knobs,
incr intensity,
wiggle,
repeat.

If you see big brightness off screen or no bright green at all,
try pos knobs more, then shut off and
use the manual to debug low volt PS voltages.

http://www.ko4bb.com/Manuals/Tektronix/Tektronix_-_561/Tektronix_561B_Technical_Manual.pdf


Re: digital guy, lost in analog space, need help with 561B

Ed Breya
 

It sounds like you don't need it even if it works, so the proper settings and steps should be:

1. Unplug the power cord from the wall, and wrap it around the cord wraps, if available, or wad it up under the handle.

2. Disconnect the probe from the scope, and wad it up under the handle also.

3. Send an email to this group offering it free to anyone in your locale.

4. Wait for a response - it should only take a day or two to have it gone. If there are no takers, try the same on craigslist.

5. Be sure to notify wife of proper disposal, to get full credit for space allocation for a different item. If you stretch the truth a bit you can get extra credit, because not only did you get it working, but you got rid of it anyway, just to make her happy.

Ed

--- In TekScopes@..., "gndarnell" <gndarnell@...> wrote:

Hi,
Let me say up front that I am completely clueless in analog electronics, having forgotten all of what I learned in the one analog class I took in 1977 (and barely passed) that was required for my EE/CS degree. Anyway, in that class we used a Tek scope, and in the late 80's I saw a 561B for sale as college surplus and bought one on a whim. I know it worked at the time.
Many years have gone by with the scope untouched; it has always been stored in climate controlled environments and it's quite clean.

Now, to the point - my wife tells me to get it working or get rid of it. I'm trying to figure out if it even works or has a chance of working, or if I should just take it to the recycling area at the landfill.

No matter what combinations of settings I try, I cannot seem to get a trace on the screen. I do have a probe and have tried connecting it both to the calibrator output and to various other sources.

Can someone please tell me what basic settings I should be using to get something displayed on the screen? It's got a 3A6 dual trace amplifier and a 3B4 time base.

Thanks!
Greg


Re: digital guy, lost in analog space, need help with 561B

Michael A. Terrell
 

gndarnell wrote:

Hi,
Let me say up front that I am completely clueless in analog electronics, having forgotten all of what I learned in the one analog class I took in 1977 (and barely passed) that was required for my EE/CS degree. Anyway, in that class we used a Tek scope, and in the late 80's I saw a 561B for sale as college surplus and bought one on a whim. I know it worked at the time.
Many years have gone by with the scope untouched; it has always been stored in climate controlled environments and it's quite clean.

Now, to the point - my wife tells me to get it working or get rid of it. I'm trying to figure out if it even works or has a chance of working, or if I should just take it to the recycling area at the landfill.

No matter what combinations of settings I try, I cannot seem to get a trace on the screen. I do have a probe and have tried connecting it both to the calibrator output and to various other sources.

Can someone please tell me what basic settings I should be using to get something displayed on the screen? It's got a 3A6 dual trace amplifier and a 3B4 time base.
Start here, and ask questions after a look at the manual. :)

http://w140.com/tekwiki/wiki/561


digital guy, lost in analog space, need help with 561B

gndarnell <gndarnell@...>
 

Hi,
Let me say up front that I am completely clueless in analog electronics, having forgotten all of what I learned in the one analog class I took in 1977 (and barely passed) that was required for my EE/CS degree. Anyway, in that class we used a Tek scope, and in the late 80's I saw a 561B for sale as college surplus and bought one on a whim. I know it worked at the time.
Many years have gone by with the scope untouched; it has always been stored in climate controlled environments and it's quite clean.

Now, to the point - my wife tells me to get it working or get rid of it. I'm trying to figure out if it even works or has a chance of working, or if I should just take it to the recycling area at the landfill.

No matter what combinations of settings I try, I cannot seem to get a trace on the screen. I do have a probe and have tried connecting it both to the calibrator output and to various other sources.

Can someone please tell me what basic settings I should be using to get something displayed on the screen? It's got a 3A6 dual trace amplifier and a 3B4 time base.

Thanks!
Greg


Re: 453

Ed Breya
 

If there is only one layer of plastic material in front of the CRT face, it should be made of lexan (polycarbonate - soft, but tough), not acrylic (hard, but brittle), since it serves as an implosion shield. This has been dicussed a lot here, so the archives have plenty of good info on materials and techniques.

BTW I recently junked out some old HP CRTs, and found that they had an extra layer of glass glued to the face with rubbery goop, just like TV CRTs and laminated automotive windshield safety glass. I don't know if that's the case with all HP ones. I don't think Tek ever used that method. I think on the Tek CRTs that have the jug sections frit sealed together, the flat faceplates are made of tempered glass for strength, but they can shatter and implode, so need protection up front. I think the all-glass CRTs are regular glass (with slightly convex faceplate for strength), so same issues either way.

Ed

--- In TekScopes@..., Alain B <alain.betemps@...> wrote:

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Thank for help,

I will look for colored plexiglass to take place and add contrast.
Regards
Alain



Le 16.07.2013 16:14, Cliff White a écrit :
My 466 has a veeeery fine metal mesh over the screen, it's listed as an
option to cut down on radiation/interference. FWIW it was an Army scope.


Respectfully,
Cliff White, W5CNW
w5cnw@... <mailto:w5cnw@...>
On 07/16/2013 09:11 AM, Paul Amaranth wrote:

I think the glare shield was a fine metal mesh; I have one like that
on a 422.

I made a glare filter using smoke plexiglass that popped into place
on my 453. I'm thinking it might be nice to make another one using
clear plexiglass and a colored gell to get a blue filter. I might
do that for a 454 that's in my queue.

I think it's very rare to fine an oem filter; most of them seem to
have gotten lost by now.

On Tue, Jul 16, 2013 at 05:34:54AM -0000, betounn wrote:
Hello Folks,

What the best way to replace blue plastic CRT shield on a 453, mine
is missing.
Thank for help.
Regards
Alain
--
Paul Amaranth, GCIH | Rochester MI, USA
Aurora Group, Inc. | Security, Systems & Software
paul@... <mailto:paul%40AuroraGrp.Com> | Unix & Windows

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Re: 453

PA4TIM
 

Mine http://www.pa4tim.nl/?p=3247
has a sort of mesh insert. I have a picture from a manual on that link
where they show how to change it.
Mine is from 1965 according components and pcb. Only miss the very
special mains connector and dustcover

John, that is a cute collection. I like this little scope. The right one
with the blue trace is cool.

Fred

Op dinsdag 16-07-2013 om 23:07 uur [tijdzone +0100], schreef John Sykes:


I've had several 453's and 454's with no screen cover (contrast
enhancer). I made a few using smoked plexiglass/ acrylic held in a
frame routed from bamboo flooring.

http://www.flickr.com/photos/jaybs/sets/72157630205984812/

John



--
John Sykes
Director, QUAM Technology

Tel/ Fax: (+44) 20 8660 4416
Mob: (+44) 7770 656 390
Email: John@...




98301 - 98320 of 194034