Date   

Re: 7B85 mod GD

Don Black <donald_black@...>
 

That's significant, I hope everyone's OK.

Don Black.

On 24-May-13 2:27 PM, Jerry Barr wrote:
 
ow just had a 5-6 earthquake in northern cal
 
Jerry KJ6NTL
From: Dennis Tillman
To: TekScopes@...
Sent: Thursday, May 23, 2013 8:19 PM
Subject: RE: [TekScopes] 7B85 mod GD
 
Hi Craig,

I may have the companion plugin! I have a 7B80 Mod GB, serial number
B042313.

Looking at the front panel of my 7B80 it appears to be normal except for the
TIME/DIV range. The only sweep speeds it has go from 10uSec/Div (slowest) to
5nSec/Div. So it can't sweep slower than 10uSec/Div compared to an ordinary
7B80 which can go as slow as 5Sec/Div. Also, the regular 7B80's fastest
speed is 10nSec/Div so the GB version has one faster sweep speed.

Dennis

-----Original Message-----
From: Craig Sawyers, Sent: Thursday, May 23, 2013 1:26 AM
Subject: [TekScopes] 7B85 mod GD

Hi all
Title says it all. Serial number B096537. Anyone have any clue as to what
Mod GD actually is?
Craig



Re: 7B85 mod GD

Jerry Barr
 

ow just had a 5-6 earthquake in northern cal
 
Jerry KJ6NTL

From: Dennis Tillman
To: TekScopes@...
Sent: Thursday, May 23, 2013 8:19 PM
Subject: RE: [TekScopes] 7B85 mod GD
 
Hi Craig,

I may have the companion plugin! I have a 7B80 Mod GB, serial number
B042313.

Looking at the front panel of my 7B80 it appears to be normal except for the
TIME/DIV range. The only sweep speeds it has go from 10uSec/Div (slowest) to
5nSec/Div. So it can't sweep slower than 10uSec/Div compared to an ordinary
7B80 which can go as slow as 5Sec/Div. Also, the regular 7B80's fastest
speed is 10nSec/Div so the GB version has one faster sweep speed.

Dennis

-----Original Message-----
From: Craig Sawyers, Sent: Thursday, May 23, 2013 1:26 AM
Subject: [TekScopes] 7B85 mod GD

Hi all
Title says it all. Serial number B096537. Anyone have any clue as to what
Mod GD actually is?
Craig


Re: 7B85 mod GD

 

Hi Craig,

I may have the companion plugin! I have a 7B80 Mod GB, serial number
B042313.

Looking at the front panel of my 7B80 it appears to be normal except for the
TIME/DIV range. The only sweep speeds it has go from 10uSec/Div (slowest) to
5nSec/Div. So it can't sweep slower than 10uSec/Div compared to an ordinary
7B80 which can go as slow as 5Sec/Div. Also, the regular 7B80's fastest
speed is 10nSec/Div so the GB version has one faster sweep speed.

Dennis

-----Original Message-----
From: Craig Sawyers, Sent: Thursday, May 23, 2013 1:26 AM
Subject: [TekScopes] 7B85 mod GD

Hi all
Title says it all. Serial number B096537. Anyone have any clue as to what
Mod GD actually is?
Craig


Re: 7B85 mod GD

d.seiter@...
 

Any obvious extra parts/wires/etc?

-Dave



From: "Craig Sawyers"
To: TekScopes@...
Sent: Thursday, May 23, 2013 2:31:23 AM
Subject: RE: [TekScopes] 7B85 mod GD

 

No – definitely GD. Ie not a 0 with a bit missing – a very clear and unambiguous G.

 

Craig

 

From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Dave Daniel
Sent: 23 May 2013 09:38
To: TekScopes@...
Subject: Re: [TekScopes] 7B85 mod GD

 



Are you sure it is not "0D" ?

DaveD

On 5/23/2013 2:25 AM, Craig Sawyers wrote:

 

Hi all

Title says it all. Serial number B096537. Anyone have any clue as to what
Mod GD actually is?

Craig






Re: What are the uses for dual gun scopes like 7844?

 

The 7844 is two entirely independent oscilloscopes sharing one CRT and the
possibilities are limited by your imagination, not by the instrument.

An excellent use for a Dual Beam scope is to display two totally different
domains at once. Here are a few interesting things the 7844 is capable of
(there are many more):
1) Simultaneous Frequency Domain and Time Domain: Put a 7L5 or a 7L12
Spectrum Analyzer in the center two slots and an ordinary vertical plugin
and time base in the outer two slots and monitor a signals waveform and
spectrum at the same time
2) Simultaneous Real Time and Sampling Time display: Put a 7S11 and 7T11 in
the center two slots and an ordinary vertical plugin and time base in the
outer slots to view fast edges with the sampling plugins and long
time-constant aberrations with the real time plugins.
3) Simultaneous Data Domain and Time Domain analysis: Insert the 7D01 Logic
Analyzer in the center two slots and an ordinary vertical plugin and time
base in the outer slots. The logic analyzer allows you to specify complex
trigger situations based on the state of 16 channels. The 7D01 trigger
output signal can then be used to trigger the time base to examine one or
two actual circuit waveforms at the precise moment specified by the trigger
signal.
4) Simultaneous display of X-Y signals and Y-T signals. This allows you to
tune a signal for zero beat while monitoring the signal in real time.
5) Use the 7F10 Optical to Electrical Converter plugin with an ordinary
timebase to monitor the optical pulse shape of a laser diode while
simultaneously monitoring the spectra of the light output using the 7J20
Rapid Scan (optical) Spectrometer.
6) Use two 7CT1N curve tracers simultaneously. Configure the first one to
display the characteristic curves of a PNP power transistor, and configure
the 2nd one to display the complimentary NPN power transistor of the pair.
Align the curves up so the load lines intersect at 0 Volts and 0 Current to
observe the actual Class B Amplifier load line the pair will operate at in
the final amplifier output stage.
7) 7CT1N transistor curve tracer with any vertical amplifier in a horizontal
slot to show a transistor curve family; A vertical amplifier in the
remaining vertical slot and a vertical amplifier in the remaining horizontal
slot showing the amplifier's transfer curve in XY mode.

I could keep going and going...

Dennis

-----Original Message-----
From: cheater00, Sent: Thursday, May 23, 2013 2:08 PM

Hi guys,
Deviating from the usual SEM chat, I have been wondering what the uses are
for scopes with dual guns like the 7844. I understand it's great for seeing
two traces with signals faster than or comparable to the chopper frequency.
But is that all? Are there other things such a scope can do that a single
gun scope, or two single gun scopes, just cannot?

Cheers,
D.


Re: 2465 wrong front cover

 

Hi,

This is clearly not an emergency. Take your time and find the correct item. Someone else may need the one you have.


Jerry Massengale



-----Original Message-----
From: machineguy59
To: TekScopes
Sent: Thu, May 23, 2013 5:35 pm
Subject: [TekScopes] 2465 wrong front cover

 
My 2565 needs a front cover. I need one with the older style latches but haven't been able to find one. So I bought one with the clips that fit a smooth sided fron panel.

So here is my question, should I:
1. Cut the bumps off the front bezel so the new style cover will fit? This defaces the bezel but will still look pretty good if I am careful.
2. Buy a replacement bezel with smooth sides to fit this cover? Its a clean solution but it costs more and makes my 2465 somewhat a "Frankenstein" with parts from other generations.
3. Hold out for an old style cover IF I CAN FIND ONE? I can use this cover in the meantime and "trade up" if I don't use option 1 above.

What do others do to preserve their quality scopes?


Re: 2465 wrong front cover

kim.herron@sbcglobal.net
 

Hi There!
 

My 2565 needs a front cover. I need one with the older style latches but haven't been able to find one. So I bought one with the clips that fit a smooth sided fron panel.

So here is my question, should I:
1. Cut the bumps off the front bezel so the new style cover will fit? This defaces the bezel but will still look pretty good if I am careful.
2. Buy a replacement bezel with smooth sides to fit this cover? Its a clean solution but it costs more and makes my 2465 somewhat a "Frankenstein" with parts from other generations.
3. Hold out for an old style cover IF I CAN FIND ONE? I can use this cover in the meantime and "trade up" if I don't use option 1 above.

What do others do to preserve their quality scopes?

I just sold a 2465A scope to a gentleman in OK.  He has what you need and you have what he needs to fit his scope.  I'm sure that he would do a swap as soon as the scope arrives to his address.  Let me know what you think.  I'm sure that Glenn would just as soon have the right piece to fit his scope.  I looked for what you have for about 10 years and never ran across it.

Thanks!!
-- 
Kim Herron W8ZV
1-616-677-3706


DSA 601a / DSA602a

Leonard
 

I finally did a local pickup of the DSA601a and the DSA602a that I purchased on ebay a month ago.

http://www.ebay.com/itm/181111721101?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_233wt_1200

http://www.ebay.com/itm/181108740753?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649#ht_233wt_1200

I bought the 601a for spare parts. The 602a had 3 plugins and booted up and droped into the cursor screen so I think it's probably ok. I'll test it more in a week. The 601a only had one plugin and it displayed a test step with ?????? I'll be able to test it further in a week. I'm completely happy even if the 602a is the only working one. I was lucky as they were a local pickup so there was no freight involved. I can't imagine what it takes to ship these huge beasts. More to follow. I plan on doing a few video's of the working model if I end up with one. This has always been my dream scope.
Leonard


2465 wrong front cover

 

My 2565 needs a front cover. I need one with the older style latches but haven't been able to find one. So I bought one with the clips that fit a smooth sided fron panel.

So here is my question, should I:
1. Cut the bumps off the front bezel so the new style cover will fit? This defaces the bezel but will still look pretty good if I am careful.
2. Buy a replacement bezel with smooth sides to fit this cover? Its a clean solution but it costs more and makes my 2465 somewhat a "Frankenstein" with parts from other generations.
3. Hold out for an old style cover IF I CAN FIND ONE? I can use this cover in the meantime and "trade up" if I don't use option 1 above.

What do others do to preserve their quality scopes?


Re: What are the uses for dual gun scopes like 7844?

Craig Sawyers <c.sawyers@...>
 

You can also display the same signal at two different sweep speeds at the
same time.

Craig
Ah - I forgot I also uploaded an example of that
http://xa.yimg.com/kq/groups/2191247/sn/248405899/name/7844.jpg

Craig


Re: What are the uses for dual gun scopes like 7844?

Craig Sawyers <c.sawyers@...>
 

But is that all? Are there other things such a scope can do that a single
gun
scope, or two single gun scopes, just cannot?
This http://xa.yimg.com/kq/groups/2191247/sn/485471627/name/7844-2.jpg for
one

Note that these are two completely different signals, one displayed at at
20u/div and the other at 2ns/div

You can also display the same signal at two different sweep speeds at the
same time.

Craig


Re: What are the uses for dual gun scopes like 7844?

 

Two things come to mind:

1. You can display two very different sweep rates without the slower
sweep making the faster sweep too dim to see. A single beam
instrument needs horizontal CHOP mode to do the same thing which as
you point out, may cause display artifacts.

2. You can make a single shot photograph of two asynchronous but
related signals without using CHOP mode.

On Thu, 23 May 2013 23:08:24 +0200, "cheater00 ."
<cheater00@gmail.com> wrote:

Hi guys,
Deviating from the usual SEM chat, I have been wondering what the uses
are for scopes with dual guns like the 7844.

I understand it's great for seeing two traces with signals faster than
or comparable to the chopper frequency.

But is that all? Are there other things such a scope can do that a
single gun scope, or two single gun scopes, just cannot?

Cheers,
D.


What are the uses for dual gun scopes like 7844?

 

Hi guys,
Deviating from the usual SEM chat, I have been wondering what the uses
are for scopes with dual guns like the 7844.

I understand it's great for seeing two traces with signals faster than
or comparable to the chopper frequency.

But is that all? Are there other things such a scope can do that a
single gun scope, or two single gun scopes, just cannot?

Cheers,
D.


Re: 576 Curve Tracer HV Transformer - Group Buy

dc_rawding
 

Ross,

I will put you on the list. Once we are satisfied with the quality, I will contact you.

I will continue to update this thread as things progress.

Dave

--- In TekScopes@yahoogroups.com, "Ross Wellington" <wellington@...> wrote:

Hi,

I'm in. I could use a spare for when mine fails.

Hi-Rel could also make them too, I would imagine.

Thanks,

Ross

_____

From: TekScopes@yahoogroups.com [mailto:TekScopes@yahoogroups.com] On Behalf
Of drawding@...
Sent: Wednesday, May 22, 2013 9:51 AM
To: TekScopes@yahoogroups.com
Subject: [TekScopes] 576 Curve Tracer HV Transformer - Group Buy




Hello,

I would like to get a count of how many would be interested in purchasing a
576 Curve Tracer HV Transformer.

I have located an American company that will make them for $225 each. I am
still working out a minimum order, but it will be in the range of 20 units.
The only thing they are waiting for is the inductance measurement so they
can set the air gap. They are concerned because they need to get it right
the first time to keep costs low.

I am working with another company that might be able to make them for a
little less.

Both would be made in the USA.

Are there 15-20 takers out there? I need two. Are there 18 others? I would
be glad to handle logistics.

Full disclosure: As of right now $225 per unit is my cost. This is ~ $50
over what I understand that Chuck would change. I am not looking to make
money on this deal. I have no affiliation with either company. I am just
trying to repair my 576 in a reasonable time frame and help out others with
the same issue. I would love to use Chuck's service, but I do not want to
wait.

Thanks,
Dave


Re: 576 Curve Tracer HV Transformer Rebuild

Michael A. Terrell
 

magnustoelle wrote:



Hello,

a nice exchange of good eng. thoughts here, thanks.

The flyback powers the entire TV in most sets. One of the windings
is monitored, and used to set the horizontal drive. That regulates all
the outputs. Has anyone considered the transformer cores from small
SMPS for computers? There are literally tons of scrap cores available
and in a multitude of sizes.
May I add a comment here. In most "modern-age" CRT-TVs, a separate Switched Mode Power Supply (quite commonly another flyback-converter) generates the low-supply voltages (5V, 3.3V etc.) plus stand-by voltage supply. This power supply was separate from the so-called "EHT" or extra high tension supply for the anode voltage.

This architecture was essential to achieve energy start compliance i.e. low power consumption in stand-by mode etc.

That is the same as the +5V standby output in a computer power supply. It's enough to power the remote controls & a low power microprocessor to read the pushbuttons on the TV set. Some SMPS simply used a resistor to make sure one side came up faster than the other. Usually in the megohm+ range. It lowered the efficiency slightly, and they were prone to failure. I found them open, often in dead video monitors. It makes more sense to have a second, low power source for control, than to try to use the high current supply at under 1% of the rated output.


The architecture is essential for the remote control that is so common these days. A supercap would work for weeks or longer, but those can be problematic as well.


Re: 576 Curve Tracer HV Transformer Rebuild

magnustoelle
 

Hello,

a nice exchange of good eng. thoughts here, thanks.

The flyback powers the entire TV in most sets. One of the windings
is monitored, and used to set the horizontal drive. That regulates all
the outputs. Has anyone considered the transformer cores from small
SMPS for computers? There are literally tons of scrap cores available
and in a multitude of sizes.
May I add a comment here. In most "modern-age" CRT-TVs, a separate Switched Mode Power Supply (quite commonly another flyback-converter) generates the low-supply voltages (5V, 3.3V etc.) plus stand-by voltage supply. This power supply was separate from the so-called "EHT" or extra high tension supply for the anode voltage.

This architecture was essential to achieve energy start compliance i.e. low power consumption in stand-by mode etc.

Cheers,

Magnus


Re: 576 Curve Tracer HV Transformer Rebuild

 

On Thu, 23 May 2013 13:54:47 -0400, "Michael A. Terrell"
<mike.terrell@earthlink.net> wrote:

David wrote:

How are television flyback supplies regulated? On an oscilloscope,
the cathode and acceleration voltages are tightly regulated because
they directly affect the horizontal and vertical calibration.
The flyback powers the entire TV in most sets. One of the windings
is monitored, and used to set the horizontal drive. That regulates all
the outputs. Has anyone considered the transformer cores from small
SMPS for computers? There are literally tons of scrap cores available
and in a multitude of sizes.
So they rely on cross regulation through the flyback transformer. I
thought maybe they had something trickier going on.

I have designed low voltage flyback switching power supplies that
worked that way but I doubt the cross regulation would be good enough
for accurate deflection in an oscilloscope CRT with a high winding
ratio where close coupling of the windings is not possible.

Tektronix regulated the cathode supply directly and just used a
multiplier for the anode. Even then they often included temperature
compensation for the multiplier.

I will probably end up building a stepper controlled winding machine
if any of my oscilloscopes needs a replacement transformer and I can
not find a replacement. I have been able to get by winding
transformers by hand so far.


Re: Tek 475

Craig Sawyers <c.sawyers@...>
 

Thanks very much! I'll dig into it over the next few days, and let you
know.
Much appreciated. --M
Could also be a bridge. Both the Sprague twist-lock electrolytics and the
bridges are weak points in a 465/475.

Craig


Re: Tektronix R7844 Problem: can not set intensity and focus

 

On Thu, 23 May 2013 18:37:15 +0100, "Craig Sawyers"
<c.sawyers@tech-enterprise.com> wrote:

I have not used any of the Tektronix high voltage probes (P6013, P6013A,
P6015, P6015A) but they would require an adapter to use with a voltmeter.

The Fluke 40K-6 is inexpensive and easier to maintain. If you do a lot of
this
kind of work, then a Fluke 40K-20 would be better because it has a much
higher input resistance.
Horses for courses. The Tek P6013 and P6015(A) are high frequency, high
voltage probes that you connect to an oscilloscope. The Fluke 40K6 and
80K40 is only good for 100Hz maximum frequency (2% accuracy at DC, 5%
accuracy at 60Hz), and is intended for close to DC measurements using a DVM.

Craig
Cut the coat to fit the cloth. I think this question came up last
year when someone used one of the Tektronix high voltage probes for
this type of high voltage DC measurement on the CRT circuits. I do
not know what kind of meter they used or how they interfaced it but I
think just a 1.11 megohm shunt would work to bring the 10 megohm input
resistance of a multimeter down to 1 megohm. I would include a
trimmer to calibrate it.


Re: Tek 475

maximrice
 

Thanks very much! I'll dig into it over the next few days, and let you know. Much appreciated. --M

--- In TekScopes@yahoogroups.com, Artekmedia <manuals@...> wrote:

Bingo !

Time to start digging into that portion of the supply and find out why
that voltage is so low, With that much ripple likely one of the
electrolytic is dead

Dave


On 5/22/2013 9:53 PM, maximrice wrote:

CORRECTION! I double checked and the 105-160 V PS is only 10 V with
maybe a 1 volt ripple. Sorry I missed that. Otherwise the settings are
as you suggested. And my level of experience is pretty low -- but I'm
a fast learner! :>) --Maxim

--- In TekScopes@yahoogroups.com <mailto:TekScopes%40yahoogroups.com>,
Chris Jones <chris@> wrote:

It sounds like the timebase isn't running, or isn't triggering. How are
the timebase and trigger controls set? What's your level of experience
of driving analogue scopes? There are a lot of combinations of settings
that will result in what you describe. Make sure the 'A lock knobs'
horiz display button is pressed, and the AUTO trig mode is selected,
and
the timebase isn't set to 'X-Y' mode, the furthest anticlockwise
position. That should get you a line if everything's working as it
should.

Chris

On 22/05/2013 16:17, maximrice wrote:
1) I recently got it used and that's the way it arrived.
2) Yes, but turning it fully right brings the dot only near the
center.
3) Yes.
4) All look good except the 50V unregulated is about 68 volts.
Thanks! --Maxim

--- In TekScopes@yahoogroups.com
<mailto:TekScopes%40yahoogroups.com> <mailto:TekScopes%40yahoogroups.com>,
Artekmedia <manuals@> wrote:

We are all going to need more info

1) It was working before and suddenly died or you bought it used and
that is the way it arrived?
2) Does the horizontal position control move the dot left / right?
3) when you put a signal in does the dot become a vertical line?
4)Measure all the power supply voltages ...are they pretty much
spot on?

Dave



On 5/21/2013 7:36 PM, maximrice wrote:

My 475 has no line, just a dot for both channels. I would love to
repair it. I have a manual, but not experienced with
oscilloscopes.
Any suggestions out there? --M

--
Dave Henderson
Manuals@...
www.Artekmanuals.com
PO Box 175
Welch,MN 55089
651-269-4265

99781 - 99800 of 192851