Date   
Re: Wanted cabinet for 2465B with DMM

Dale Chayes
 

Having recently bought a refurbished 2465BDV (which I am very happy with) I am curious what this cabinet looks like.

Can you provide a link to a picture, drawing, etc?

Thanks,
-Dale

On Sep 8, 2018, at 16:31 , Manuel Maseda <mmaseda@...> wrote:

Looking for the large blue metal cabinet that goes on 2465 series scopes with the DMM option. Must be in very good or better condition.

Manuel W4SSB



067-0587-01 Calibrator Fixture

Tomas Alori
 

Hi, I got my hands on one of these. I noticed two things on the gain mode (grid).

A) The separation between the lines decreases when increasing the repetition speed. I dont understand why this would happen and pretty much defeats the purpose of this mode.

B) The lines are kind of dirty, particularly the center line. It looks very thick when untriggered, almost double the size than the others. If I trigger on the lines and 'zoom in' I can see some spikes on the lines, looks like overshoot.

Any thoughts on this? Thanks!!

Re: 067-0587-01 Calibrator Fixture

Craig Sawyers <c.sawyers@...>
 

What scope?

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Tomas Alori
Sent: 08 September 2018 23:28
To: TekScopes@groups.io
Subject: [TekScopes] 067-0587-01 Calibrator Fixture

Hi, I got my hands on one of these. I noticed two things on the gain mode (grid).

A) The separation between the lines decreases when increasing the repetition speed. I dont
understand why this would happen and pretty much defeats the purpose of this mode.

B) The lines are kind of dirty, particularly the center line. It looks very thick when untriggered,
almost
double the size than the others. If I trigger on the lines and 'zoom in' I can see some spikes on
the
lines, looks like overshoot.

Any thoughts on this? Thanks!!

Re: 067-0587-01 Calibrator Fixture

Harvey White
 

On Sat, 08 Sep 2018 15:28:14 -0700, you wrote:

Hi, I got my hands on one of these. I noticed two things on the gain mode (grid).

A) The separation between the lines decreases when increasing the repetition speed. I dont understand why this would happen and pretty much defeats the purpose of this mode.
Don't think I noticed this, it may be a bandwidth limit.


B) The lines are kind of dirty, particularly the center line. It looks very thick when untriggered, almost double the size than the others. If I trigger on the lines and 'zoom in' I can see some spikes on the lines, looks like overshoot.
The center line is supposed to be brighter, to identify it. You're
supposed to center it on the screen.

I did notice some fuzzyness on the waveforms. It was due to ringing
on the switching input to the main frame, if you trigger it just
right.

Harvey



Any thoughts on this? Thanks!!


Re: 067-0587-01 Calibrator Fixture

Tomas Alori
 

It's a 7704A mainframe.

I just realized that lines look alright on all repetition rates except 1MHz (fastest). At fastest speed the center line pretty much doubles in size.

Here is what it looks like when I trigger at medium repetition speed: https://i.imgur.com/K53nTaM.jpg

Re: 067-0587-01 Calibrator Fixture

Harvey White
 

On Sat, 08 Sep 2018 18:06:32 -0700, you wrote:

It's a 7704A mainframe.

I just realized that lines look alright on all repetition rates except 1MHz (fastest). At fastest speed the center line pretty much doubles in size.

Here is what it looks like when I trigger at medium repetition speed: https://i.imgur.com/K53nTaM.jpg
I see the same switching transients on a 7904, using the same
standardizer as you have.

Not so sure that it is a problem.

You are, of course, not supposed to sync on the switching rate.

Harvey




Re: 067-0587-01 Calibrator Fixture

Tomas Alori
 

Good to know, seems to be correct then.

Any ideas about the decreasing separation of lines when I increase repetition rate?

Thanks!

Re: 7K series - Conceptual question - What's the 3rd most useful plugin

Scott McGrath
 

I think the vote for least useful plug in needs to be for the 7M13, which allowed you to place text on the screen.

The 7M11 - may be a close second as its a dual 75 ns delay line which uses the scope only for power

Content by Scott
Typos by Siri

Re: 067-0587-01 Calibrator Fixture

Harvey White
 

On Sat, 08 Sep 2018 18:33:13 -0700, you wrote:

Good to know, seems to be correct then.

Any ideas about the decreasing separation of lines when I increase repetition rate?
This does not happen on mine. Try triggering on the switching
frequency and see if you have a change in observable rise time.

It almost sounds as if there's a frequency limit coming into play
here.

Have you another 7000 series mainframe you can try this in? How about
swapping this to a horizontal slot and putting a horizontal sweep
plugin into the vertical slot?



Harvey


Thanks!


Tek 7603 Followed Me Home

bobh@joba.com
 

I have seen this Tek 7603 scope sitting on the table at the Tek Country store for at least three years.  I have tried to power it up and twist some knobs several times over the years with no response.  They have been asking $35 for it and I noticed today there are about 5-6 price stickers stacked up under the current one.

I have been thinking a 7603 would fit into my ensemble if I clear space for it by giving another scope to the Tek Museum.   So, I asked if they would take $25 for it and they did.  So, here it sits with the covers off and the power supply hanging out the back.  It doesn't do nut-tin when powered up.

The main fuse, the fuse on the regulator board and the one on the power supply board above the caps are good. I checked the power supply voltages on the regulator board with the following results:

Volt        VDC      VAC
130       114          11
50            44           5
5            4.396       0.25
15           13.2        1.4
-15         -13.17      1.3
-50          -44          4.8

Unregulated Voltages

50           66            0.16
-50        -52              13
15           24              0.04
-15       -24               0.1
5           12.4             0.05

Seems to be discrepancies between the ripple on the corresponding regulated and unregulated supplies which I don't understand.

The 130 volt supply is partly made up from the 50 volt supply and the voltage on the emitter of Q850 should add about 40 volts but I measure 10.8 volts DC there.  Maybe I see it now, if the 50v supply is at 44 volts there is no way the emitter of Q850 can get to 40 v.

I appreciate any ideas from folks especially those who have been thru a 7603 before.  Haven't had a chance to research the archive but will do that before doing more troubleshooting.  I can't take another scope to the Tek Museum until I know we can bring this one back to service.

Bob.

Re: Tek 7603 Followed Me Home

Chuck Harris
 

What plugins do you have installed?

Without plugins, you might get the green power lamp to
light... assuming it isn't burned out.

-Chuck Harris

Robert Hay wrote:

I have seen this Tek 7603 scope sitting on the table at the Tek Country store for at
least three years. I have tried to power it up and twist some knobs several times
over the years with no response. They have been asking $35 for it and I noticed
today there are about 5-6 price stickers stacked up under the current one.

I have been thinking a 7603 would fit into my ensemble if I clear space for it by
giving another scope to the Tek Museum. So, I asked if they would take $25 for it
and they did. So, here it sits with the covers off and the power supply hanging out
the back. It doesn't do nut-tin when powered up.

The main fuse, the fuse on the regulator board and the one on the power supply board
above the caps are good. I checked the power supply voltages on the regulator board
with the following results:

Volt VDC VAC
130 114 11
50 44 5
5 4.396 0.25
15 13.2 1.4
-15 -13.17 1.3
-50 -44 4.8

Unregulated Voltages

50 66 0.16
-50 -52 13
15 24 0.04
-15 -24 0.1
5 12.4 0.05

Seems to be discrepancies between the ripple on the corresponding regulated and
unregulated supplies which I don't understand.

The 130 volt supply is partly made up from the 50 volt supply and the voltage on the
emitter of Q850 should add about 40 volts but I measure 10.8 volts DC there. Maybe I
see it now, if the 50v supply is at 44 volts there is no way the emitter of Q850 can
get to 40 v.

I appreciate any ideas from folks especially those who have been thru a 7603 before.
Haven't had a chance to research the archive but will do that before doing more
troubleshooting. I can't take another scope to the Tek Museum until I know we can
bring this one back to service.

Bob.






Re: Tek 7603 Followed Me Home

bobh@joba.com
 

So far no plugins and the light isn't lit.  I'll check it.

Bob.

On 9/8/2018 7:43 PM, Robert Hay wrote:
I have seen this Tek 7603 scope sitting on the table at the Tek Country store for at least three years.  I have tried to power it up and twist some knobs several times over the years with no response.  They have been asking $35 for it and I noticed today there are about 5-6 price stickers stacked up under the current one.

I have been thinking a 7603 would fit into my ensemble if I clear space for it by giving another scope to the Tek Museum.   So, I asked if they would take $25 for it and they did.  So, here it sits with the covers off and the power supply hanging out the back.  It doesn't do nut-tin when powered up.

The main fuse, the fuse on the regulator board and the one on the power supply board above the caps are good. I checked the power supply voltages on the regulator board with the following results:

Volt        VDC      VAC
130       114          11
50            44           5
5            4.396       0.25
15           13.2        1.4
-15         -13.17      1.3
-50          -44          4.8

Unregulated Voltages

50           66            0.16
-50        -52              13
15           24              0.04
-15       -24               0.1
5           12.4             0.05

Seems to be discrepancies between the ripple on the corresponding regulated and unregulated supplies which I don't understand.

The 130 volt supply is partly made up from the 50 volt supply and the voltage on the emitter of Q850 should add about 40 volts but I measure 10.8 volts DC there.  Maybe I see it now, if the 50v supply is at 44 volts there is no way the emitter of Q850 can get to 40 v.

I appreciate any ideas from folks especially those who have been thru a 7603 before.  Haven't had a chance to research the archive but will do that before doing more troubleshooting.  I can't take another scope to the Tek Museum until I know we can bring this one back to service.

Bob.





Re: Tek 7603 Followed Me Home

Dave Daniel
 

This is obvious, but make sure that the fuse is installed and of the correct rating.

DaveD

On 9/9/2018 9:22 AM, Robert Hay wrote:
So far no plugins and the light isn't lit.  I'll check it.

Bob.


On 9/8/2018 7:43 PM, Robert Hay wrote:
I have seen this Tek 7603 scope sitting on the table at the Tek Country store for at least three years.  I have tried to power it up and twist some knobs several times over the years with no response.  They have been asking $35 for it and I noticed today there are about 5-6 price stickers stacked up under the current one.

I have been thinking a 7603 would fit into my ensemble if I clear space for it by giving another scope to the Tek Museum. So, I asked if they would take $25 for it and they did.  So, here it sits with the covers off and the power supply hanging out the back.  It doesn't do nut-tin when powered up.

The main fuse, the fuse on the regulator board and the one on the power supply board above the caps are good. I checked the power supply voltages on the regulator board with the following results:

Volt        VDC      VAC
130       114          11
50            44           5
5            4.396       0.25
15           13.2        1.4
-15         -13.17      1.3
-50          -44          4.8

Unregulated Voltages

50           66            0.16
-50        -52              13
15           24              0.04
-15       -24               0.1
5           12.4             0.05

Seems to be discrepancies between the ripple on the corresponding regulated and unregulated supplies which I don't understand.

The 130 volt supply is partly made up from the 50 volt supply and the voltage on the emitter of Q850 should add about 40 volts but I measure 10.8 volts DC there.  Maybe I see it now, if the 50v supply is at 44 volts there is no way the emitter of Q850 can get to 40 v.

I appreciate any ideas from folks especially those who have been thru a 7603 before.  Haven't had a chance to research the archive but will do that before doing more troubleshooting.  I can't take another scope to the Tek Museum until I know we can bring this one back to service.

Bob.






Re: Tek 7603 Followed Me Home

Chuck Harris
 

No plugins, and the scope will do nothing.
The little green lights burn out all of the
time.

The manual tells you everything you need to
know about power supply diagnosis. It is
expecting that you will make DC measurements
with a DVM, and ripple measurements with another
scope, set to LINE trigger, and sweep at 5ms/div.

In this mode, ripple will be stationary.

The really high frequency glitches on the power
can be ignored, but the 60Hz and 120Hz ripple
are important, as are the general noise level.

The unregulated outputs are not critical as
to value, but do need to be close. They are
not especially critical as to ripple, expect
high values. Their purpose is to feed regulators.

They will vary greatly depending on your mains
voltage, and the mains setting of the scope.

The 7603 has a linear power supply. All of the
regulators are referenced to the -50V regulated
supply. You show it way off, everything else will
be off proportionately. Fix it first. Don't just
adjust it, fix it.

-Chuck Harris

Robert Hay wrote:

So far no plugins and the light isn't lit. I'll check it.

Bob.


On 9/8/2018 7:43 PM, Robert Hay wrote:
I have seen this Tek 7603 scope sitting on the table at the Tek Country store for
at least three years. I have tried to power it up and twist some knobs several
times over the years with no response. They have been asking $35 for it and I
noticed today there are about 5-6 price stickers stacked up under the current one.

I have been thinking a 7603 would fit into my ensemble if I clear space for it by
giving another scope to the Tek Museum. So, I asked if they would take $25 for it
and they did. So, here it sits with the covers off and the power supply hanging
out the back. It doesn't do nut-tin when powered up.

The main fuse, the fuse on the regulator board and the one on the power supply
board above the caps are good. I checked the power supply voltages on the regulator
board with the following results:

Volt VDC VAC
130 114 11
50 44 5
5 4.396 0.25
15 13.2 1.4
-15 -13.17 1.3
-50 -44 4.8

Unregulated Voltages

50 66 0.16
-50 -52 13
15 24 0.04
-15 -24 0.1
5 12.4 0.05

Seems to be discrepancies between the ripple on the corresponding regulated and
unregulated supplies which I don't understand.

The 130 volt supply is partly made up from the 50 volt supply and the voltage on
the emitter of Q850 should add about 40 volts but I measure 10.8 volts DC there.
Maybe I see it now, if the 50v supply is at 44 volts there is no way the emitter of
Q850 can get to 40 v.

I appreciate any ideas from folks especially those who have been thru a 7603
before. Haven't had a chance to research the archive but will do that before doing
more troubleshooting. I can't take another scope to the Tek Museum until I know we
can bring this one back to service.

Bob.








Re: Tek 7603 Followed Me Home

bobh@joba.com
 

Chuck & Dave,

The fuses are good.  The jumper for 120/240 is there but not connected on one end.  I think this is correct since the three position plug seems to also parallel the windings for 120v.

I had tried a 7A22 & a 7B50 but the 7B50 is probably bad so I replaced it with a 7B53A and I now have some lights on the plug-ins and graticle light.  No trace, but moving the trigger knob does cause the trigger light to flicker as expected.

I can't work on it again until this evening.  I'll re-check the voltages and check the ripple(s) with another scope.

Bob.

On 9/9/2018 7:36 AM, Chuck Harris wrote:
No plugins, and the scope will do nothing.
The little green lights burn out all of the
time.

The manual tells you everything you need to
know about power supply diagnosis. It is
expecting that you will make DC measurements
with a DVM, and ripple measurements with another
scope, set to LINE trigger, and sweep at 5ms/div.

In this mode, ripple will be stationary.

The really high frequency glitches on the power
can be ignored, but the 60Hz and 120Hz ripple
are important, as are the general noise level.

The unregulated outputs are not critical as
to value, but do need to be close. They are
not especially critical as to ripple, expect
high values. Their purpose is to feed regulators.

They will vary greatly depending on your mains
voltage, and the mains setting of the scope.

The 7603 has a linear power supply. All of the
regulators are referenced to the -50V regulated
supply. You show it way off, everything else will
be off proportionately. Fix it first. Don't just
adjust it, fix it.

-Chuck Harris

Robert Hay wrote:
So far no plugins and the light isn't lit. I'll check it.

Bob.


On 9/8/2018 7:43 PM, Robert Hay wrote:
I have seen this Tek 7603 scope sitting on the table at the Tek Country store for
at least three years. I have tried to power it up and twist some knobs several
times over the years with no response. They have been asking $35 for it and I
noticed today there are about 5-6 price stickers stacked up under the current one.

I have been thinking a 7603 would fit into my ensemble if I clear space for it by
giving another scope to the Tek Museum. So, I asked if they would take $25 for it
and they did. So, here it sits with the covers off and the power supply hanging
out the back. It doesn't do nut-tin when powered up.

The main fuse, the fuse on the regulator board and the one on the power supply
board above the caps are good. I checked the power supply voltages on the regulator
board with the following results:

Volt VDC VAC
130 114 11
50 44 5
5 4.396 0.25
15 13.2 1.4
-15 -13.17 1.3
-50 -44 4.8

Unregulated Voltages

50 66 0.16
-50 -52 13
15 24 0.04
-15 -24 0.1
5 12.4 0.05

Seems to be discrepancies between the ripple on the corresponding regulated and
unregulated supplies which I don't understand.

The 130 volt supply is partly made up from the 50 volt supply and the voltage on
the emitter of Q850 should add about 40 volts but I measure 10.8 volts DC there.
Maybe I see it now, if the 50v supply is at 44 volts there is no way the emitter of
Q850 can get to 40 v.

I appreciate any ideas from folks especially those who have been thru a 7603
before. Haven't had a chance to research the archive but will do that before doing
more troubleshooting. I can't take another scope to the Tek Museum until I know we
can bring this one back to service.

Bob.







Re: Tek 7603 Followed Me Home

John Griessen
 

On 9/9/18 10:11 AM, Robert Hay wrote:
I'll re-check the voltages
50 and -50 being actual 44 and -44 is the big clue.

Chuck was saying you probably have a very much changed component contributing
the the +44 and -44 regulated voltages, so some individual component volt level measurements are next to do.

Them both being the same 44V suggests some protection feature of the circuit is kicking in because some
filter caps are too leaky, but not shorted or open yet.
Look for bad caps there after the regulator.

The -52 for unregulated 50 is not likely enough headroom to regulate to 50V, so that is suspect also.
Look for bad caps there before the regulator.

7S12 Extender.

William Himbert
 

Hello Everyone:

I've recently purchased a nice 7S12 (with S-52 and S-6) from a seller, which worked fine when he had it but somehow in shipping (or slightly thereafter when I powered it up in my 7904) has acquired a strange problem affecting both the horizontal and vertical deflection. Is there anybody out there that would be able to sell or loan me a 7S12 internal card extender to assist in the diagnosis work when I am ready to get started? (I have to exhaust some basic testing first, along with building another mainframe extender as I only have one now.)

I searched the group for this kind of problem, and I only found one reference to someone who had a problem with both the horizontal and vertical deflection, but nobody responded to their call for help. Interestingly, the front panel SWEEP OUT seems to have a proper ramp (0-10V) and the horizontal card test points look like the right wave-forms according to the service manual, but on the scope screen I can only get 4 divisions of display maximum. All other plug-ins work in the same slots with no problem. At one point I improved the vertical a bit by re-seating all of the components on the vertical board, but then later while diagnosing the horizontal problem I lost most of the vertical deflection again, and the DC OFFSET no longer re-positions the beam up and down. Very odd!

Originally I was thinking that the only thing that could affect both the H and V deflection would be a power rail, but this seems unlikely so far as all of the internal voltages seem ok.

Regards,
Bill

Re: Tek 7603 Followed Me Home

Chuck Harris
 

My guess would be the -50V unregulated supply's
filter capacitor is no longer any good.

His VAC readings are certainly Vrms as read by his
DVM, so they are 2 x 1.4Vp-p, or in other words, he
has: 13Vrms x 2.8Vp-p/Vrms, or 36Vp-p ripple on a 50V
unregulated supply. No way that can work!

-Chuck Harris

John Griessen wrote:

On 9/9/18 10:11 AM, Robert Hay wrote:
I'll re-check the voltages
50 and -50 being actual 44 and -44 is the big clue.

Chuck was saying you probably have a very much changed component contributing
the the +44 and -44 regulated voltages, so some individual component volt level
measurements are next to do.

Them both being the same 44V suggests some protection feature of the circuit is
kicking in because some
filter caps are too leaky, but not shorted or open yet.
Look for bad caps there after the regulator.

The -52 for unregulated 50 is not likely enough headroom to regulate to 50V, so that
is suspect also.
Look for bad caps there before the regulator.



Re: 7S12 Extender.

Craig Sawyers <c.sawyers@...>
 

I've recently purchased a nice 7S12 (with S-52 and S-6) from a seller, which worked fine when he had
it
but somehow in shipping (or slightly thereafter when I powered it up in my 7904) has acquired a
strange problem affecting both the horizontal and vertical deflection. Is there anybody out there
that
would be able to sell or loan me a 7S12 internal card extender to assist in the diagnosis work when
I am
ready to get started? (I have to exhaust some basic testing first, along with building another
mainframe extender as I only have one now.)
I think you need to tell people where on the planet you are.

Craig

Re: Tek 7603 Followed Me Home

John Griessen
 

On 9/9/18 11:57 AM, Chuck Harris wrote:
His VAC readings are certainly Vrms as read by his
DVM, so they are 2 x 1.4Vp-p, or in other words, he
has: 13Vrms x 2.8Vp-p/Vrms, or 36Vp-p ripple on a 50V
unregulated supply. No way that can work!
Oh, yeah, missed that DVM VAC reading. Must be a little air capacitance in a dried out can!
Really suggests caps needing replacing.