Date   
Re: Curve Tracer Adapers

Brent Watson <brentleew2003@...>
 

Thanks Brad,Well done.  I'll print that and put in my "Projects To Do" file
I look forward to projects like that.Brent

On Wednesday, July 19, 2017, 6:09:42 PM PDT, Brad Thompson brad.thompson@... [TekScopes] <TekScopes@...> wrote:

 


On 7/19/2017 8:15 PM, Tom Jobe tomjobe@... [TekScopes] wrote:
Hi Brent,
I see that you did not get an answer about the 'push buttons' on the
sides of curve tracer adapters such as the 013-0098-0x.
Hello--

Dunno whether this might prove helpful or merely thought-provoking, but
here's a fixture I used with a Tek 575 for vacuum-tube evaluation (within
the 575's test-voltage limits):

http://www.edn.com/design/test-and-measurement/4389419/Old-dog-newer-trick

...Scroll to the bottom of...

https://www.flickr.com/photos/aa1ip_pix/

...For a schematic. I designed a patch panel that plugs into the 575's DUT
(device under test) binding posts via flying leads. I used ExpressPCB's
miniboard
service to fabricate the patch panel.

Using some surplus two-piece wiring blocks, I configured a jumper kludge
that
routed signals to and from the tube socket. External sources supply heater
and screen voltages-- investigate your collection of "wall warts" for likely
heater-voltage sources. Always verify that the source is delivering
something
close to the tube's specified heater voltage.

For screen voltage, you can use a variable-output current-limited bench
supply
capable of delivering 50- 150 volts, or a power-over-ethernet (POE)
supply that
delivers 48 VDC. Use an external potentiometer to set the needed screen
voltage.

Limitations: this approach works best when you need to evaluate and
match a group
of tubes of the same type. The 575's relatively low upper
collector-voltage limit (200 V)
restricts applications to receiving tubes.

Parasitic oscillations due to the relatively long leads connecting the
tube's elements
may manifest as fuzzy areas on displayed traces. If necessary, adding
ferrite beads
or low-value (10-100 Ohm) carbon-composition resistors in series with
the grid
and plate leads at the tube socket will help suppress the parasitics.

Finally, note that most receiving tubes' published specifications state
a maximum control-grid voltage of zero volts POSITIVE. Make sure that
the curve-tracer's base-voltage step polarity is always negative-going
with zero
positive-voltage offset. Accidentally running the control-grid positive
with plate current set at a high level leads to an impressive fireworks
display as
the grid overheats<g>.

73--

Brad AA1IP



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

Re: Curve Tracer Adapers

Brent Watson <brentleew2003@...>
 

Thanks Tom, that was very helpful, and thank you also Chuck. 
Now I see the purpose of the push-buttons. I guess they could help. I see what you mean about their value testing in quantity.
I don't have anything yet. Just using banana jacks, leads and alligator clips on my 7ct1n.
I thought there might be some literature on them somewhere but a little trial and error will work too.

My 576 is still in Santa Ana, Ca.  Where I purchased it, and I'm in the SF bay area.  My travel plans to San Diego changed so I have to figure how to get the 576 up here. Maybe there's a Tek fan coming this way. I would be happy to contribute fuel costs and a steak dinner if you were.

brentleew2003@...

Brent

On Wednesday, July 19, 2017, 5:15:43 PM PDT, Tom Jobe tomjobe@... [TekScopes] <TekScopes@...> wrote:

Hi Brent,
I see that you did not get an answer about the 'push buttons' on the
sides of curve tracer adapters such as the 013-0098-0x.
I don't know much about the push buttons and their purpose, but here are
a few thoughts about it all.
The push buttons are spring loaded so you can put a wire in the adjacent
hole (on the top side of the fixture) to get a fairly direct connection
to the C,B or E sockets on the curve tracer.
These adapters often come with a bent "U" shaped jumper wire that will
short any two adjacent holes (C to B on either side, or E to E across
the bottom).
This original bent wire jumper is made of 1/16"/1.5mm wire.
There is a little bit of additional confusion that depends on which dash
number your adapter is, as the -00 adapter is marked E-E on the two
bottom wire holes and the later -01 and -02 adapters are marked E on the
left side hole and a have a yellow dot on the right side wire hole. In
addition the -00 and -01 adapters have six pins that plug into your
curve tracer, whereas the -02 only has five pins.
All of the E test part sockets on the adapter seem to be connected
together and to the left socket on the curve tracer on the -01 and -02,
but on the -00 the E part test sockets seem to not be connected together
in the test fixture, but have the sixth pin for separate connections to
the curve tracer's sockets.
I don't understand all of this as the 576 curve tracer has both E
sockets connected together internally using the normal settings for
something like a transistor or diode.
The FET version of this same adapter (013-0099-0x has the test sockets
marked DGS instead of CBE, but it's probably wired about the same
internally.
I don't find this style of test adapter that be all that useful, and you
might consider Chuck Harris' excellent idea of some banana plugs,
alligator clips and short wires for general use at very low cost.
I have lots of test adapters for my Tektronix curve tracers, but they
seem to be more of a convenience for doing lots of testing which
hobbyists like us might not do that much of.
tom jobe...



On 7/18/2017 11:51 AM, brentleew2003@... [TekScopes] wrote:

I want to purchase an adapter for my 576 I recently purchased, but I'm
not sure what the difference between the Transistor, FET or
combination version is. A couple of questions- 1. Are the 013-0098-00,
013-0098-01 and 013-0098-02, wired differently, or is it just
labeling. 2. Is the bar at top front for emitter/source grounding or
separating the two sides, and finally what are the pushbuttons on the
sides for. I have not seen documentation for these as yet. Thanks and
Cheers,
Brent





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



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

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


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

Yahoo Groups Links





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

Re: Curve Tracer Adapers

Brad Thompson <brad.thompson@...>
 

On 7/19/2017 8:15 PM, Tom Jobe tomjobe@... [TekScopes] wrote:
Hi Brent,
I see that you did not get an answer about the 'push buttons' on the
sides of curve tracer adapters such as the 013-0098-0x.
Hello--

Dunno whether this might prove helpful or merely thought-provoking, but
here's a fixture I used with a Tek 575 for vacuum-tube evaluation (within
the 575's test-voltage limits):

http://www.edn.com/design/test-and-measurement/4389419/Old-dog-newer-trick

...Scroll to the bottom of...

https://www.flickr.com/photos/aa1ip_pix/

...For a schematic. I designed a patch panel that plugs into the 575's DUT
(device under test) binding posts via flying leads. I used ExpressPCB's miniboard
service to fabricate the patch panel.

Using some surplus two-piece wiring blocks, I configured a jumper kludge that
routed signals to and from the tube socket. External sources supply heater
and screen voltages-- investigate your collection of "wall warts" for likely
heater-voltage sources. Always verify that the source is delivering something
close to the tube's specified heater voltage.

For screen voltage, you can use a variable-output current-limited bench supply
capable of delivering 50- 150 volts, or a power-over-ethernet (POE) supply that
delivers 48 VDC. Use an external potentiometer to set the needed screen voltage.

Limitations: this approach works best when you need to evaluate and match a group
of tubes of the same type. The 575's relatively low upper collector-voltage limit (200 V)
restricts applications to receiving tubes.

Parasitic oscillations due to the relatively long leads connecting the tube's elements
may manifest as fuzzy areas on displayed traces. If necessary, adding ferrite beads
or low-value (10-100 Ohm) carbon-composition resistors in series with the grid
and plate leads at the tube socket will help suppress the parasitics.

Finally, note that most receiving tubes' published specifications state
a maximum control-grid voltage of zero volts POSITIVE. Make sure that
the curve-tracer's base-voltage step polarity is always negative-going with zero
positive-voltage offset. Accidentally running the control-grid positive
with plate current set at a high level leads to an impressive fireworks display as
the grid overheats<g>.

73--

Brad AA1IP

Re: Scope face focus anomaly

 

I was a Field Eng for Tek when the 465 was announced.A common complaint from customers was poor focus, esp when compared to the 453, which was its predecessor.This overlooks the fact that the 465 had a much bigger display.

The focus is impacted by an expansion mesh inside the CRT, which was there to improve the geometry.
This is a dome-shaped mesh which the electron beam must pass thru on its way to the phosphor.When the beam goes through it, it fans out a little, much like squirting a garden hose through a window screen.
Do you want a display which is big, or do you want it sharp & crisp ?
 HankC, Boston WA1HOS

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

Re: Curve Tracer Adapers

Tom Jobe <tomjobe@...>
 

Hi Brent,
I see that you did not get an answer about the 'push buttons' on the
sides of curve tracer adapters such as the 013-0098-0x.
I don't know much about the push buttons and their purpose, but here are
a few thoughts about it all.
The push buttons are spring loaded so you can put a wire in the adjacent
hole (on the top side of the fixture) to get a fairly direct connection
to the C,B or E sockets on the curve tracer.
These adapters often come with a bent "U" shaped jumper wire that will
short any two adjacent holes (C to B on either side, or E to E across
the bottom).
This original bent wire jumper is made of 1/16"/1.5mm wire.
There is a little bit of additional confusion that depends on which dash
number your adapter is, as the -00 adapter is marked E-E on the two
bottom wire holes and the later -01 and -02 adapters are marked E on the
left side hole and a have a yellow dot on the right side wire hole. In
addition the -00 and -01 adapters have six pins that plug into your
curve tracer, whereas the -02 only has five pins.
All of the E test part sockets on the adapter seem to be connected
together and to the left socket on the curve tracer on the -01 and -02,
but on the -00 the E part test sockets seem to not be connected together
in the test fixture, but have the sixth pin for separate connections to
the curve tracer's sockets.
I don't understand all of this as the 576 curve tracer has both E
sockets connected together internally using the normal settings for
something like a transistor or diode.
The FET version of this same adapter (013-0099-0x has the test sockets
marked DGS instead of CBE, but it's probably wired about the same
internally.
I don't find this style of test adapter that be all that useful, and you
might consider Chuck Harris' excellent idea of some banana plugs,
alligator clips and short wires for general use at very low cost.
I have lots of test adapters for my Tektronix curve tracers, but they
seem to be more of a convenience for doing lots of testing which
hobbyists like us might not do that much of.
tom jobe...



On 7/18/2017 11:51 AM, brentleew2003@... [TekScopes] wrote:

I want to purchase an adapter for my 576 I recently purchased, but I'm
not sure what the difference between the Transistor, FET or
combination version is. A couple of questions- 1. Are the 013-0098-00,
013-0098-01 and 013-0098-02, wired differently, or is it just
labeling. 2. Is the bar at top front for emitter/source grounding or
separating the two sides, and finally what are the pushbuttons on the
sides for. I have not seen documentation for these as yet. Thanks and
Cheers,
Brent

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



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

Re: CRT Tube (in good shape) for Tek464 / Tek466

 

Re: Experience with AliExpress for connectors

Jerry Massengale <jmassen418@...>
 

I only ordered one thing from them and was not happy


On Wed, Jul 19, 2017 at 10:01 AM, 'David C. Partridge'
@perdrix [TekScopes] <TekScopes@...> wrote:



I want to buy two Lemo connectors FGJ.2B.306.CLLD72Z

Problem is that Lemo want GBP19.24 each plus tax at 20% and have an MOV of
GBP100 plus tax (or a surcharge of GBP25 plus tax) with shipping on top.

I saw this page on AliExpress:

<https://www.aliexpress.com/item/LEMO-connector-FGJ-2B-2-
3-4-5-6-7-8-10-12-1
4-16-18/32802964953.html?spm=2114.search0104.8.60.UYHEap>

Offering them at a lower price than Lemo and seemingly offering small
orders
and free shipping.

Are they OK to deal with or would I be throwing my money down a black hole?

Dave



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

Re: 11402 in tick mode

Vince Vielhaber
 

There is life in it again. At some point the fan was replaced. When they put it back together they pinched the leads between the fan body and the chassis, hard enough to go right thru the insulation. Fixed that, powered it up again and away it went.

Thanks for the ideas!
Vince - hoping yahoo posts this in a reasonable period of time...

On 07/19/2017 04:54 PM, Artek Manuals manuals@... [TekScopes] wrote:
Also check all the cables are seated properly at the connectors a Switch
mode supply without a load due to a loose connector might go into tick
mode as well
Dave
manuals@...

On 7/19/2017 4:31 PM, Vince Vielhaber vev@... [TekScopes] wrote:


I just had an 11402 shipped to me that worked before it was shipped. It
was packed well and there was no damage to the box. It just doesn't
work. The power supply is in tick mode - I can hear it. I can't smell
any signs of a loss of magic smoke. Any suggestions where to look?

Thanks!
Vince - hoping yahoo posts this in a reasonable period of time...
--
Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/
http://www.metalworkingfun.com

Interesting Tek Training stuff avaiable

 

Trying to re-arrange my lab, I found all kinds of Tek bits crammed into every available space on shelves. Here's what I found that I'd like to be rid of:

1. Tek QuickStart 2232/2224 Digitizing Oscilloscope Training Package. Big blue plastic box with VHS tape, two manuals, and a battery operated training board. Looks complete.

2. Tek QuickStart 11402A/11403 Digitizing Osciloscope Training Package. Big blue plastic box with 2 books, and line powered training board, place for a tape, but none in it.

3. The 11201A Digitizing Oscilloscope. Large mint binder with operating, service (no schematics) and parts info.


4. 11A52 Two Channel Amplifier operation manual.


5. 11A71 Amplifier, tagged good, 11A72 amplifier tagged bad, no details.


I no longer have any 11K gear, so this all should go. email me with any offers, for part or all to: walter2 -at- sphere.bc.ca off list, let's not annoy everybody. The TP's are bulky, so keep that in mind for shipping. LOTS of 7K plug ins too, way too many to ever use, welcome to stop by and browse if you are visiting here in BC. Still tons of free goodies left over from the last stuff day.



all the best,
walter

sphere research corp.

http://www.sphere.bc.ca/test/index.html

Re: 11402 in tick mode

ArtekManuals
 

Also check all the cables are seated properly at the connectors a Switch
mode supply without a load due to a loose connector might go into tick
mode as well
Dave
manuals@...

On 7/19/2017 4:31 PM, Vince Vielhaber vev@... [TekScopes] wrote:


I just had an 11402 shipped to me that worked before it was shipped. It
was packed well and there was no damage to the box. It just doesn't
work. The power supply is in tick mode - I can hear it. I can't smell
any signs of a loss of magic smoke. Any suggestions where to look?

Thanks!
Vince - hoping yahoo posts this in a reasonable period of time...
--
Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/
http://www.metalworkingfun.com

--
Dave
Manuals@...
www.ArtekManuals.com

Re: 11402 in tick mode

ArtekManuals
 

Vince
1) Electrolytics and tants in the power supply
2) Even though it was boxed well you want to pull the covers (going to
have to do that anyway). Possible something was "jarred loose" in
transit (an errant screw that was floating around to begin with) and is
now shorting internally
Dave
manuals@...

On 7/19/2017 4:31 PM, Vince Vielhaber vev@... [TekScopes] wrote:


I just had an 11402 shipped to me that worked before it was shipped. It
was packed well and there was no damage to the box. It just doesn't
work. The power supply is in tick mode - I can hear it. I can't smell
any signs of a loss of magic smoke. Any suggestions where to look?

Thanks!
Vince - hoping yahoo posts this in a reasonable period of time...
--
Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/
http://www.metalworkingfun.com

--
Dave
Manuals@...
www.ArtekManuals.com

11402 in tick mode

Vince Vielhaber
 

I just had an 11402 shipped to me that worked before it was shipped. It was packed well and there was no damage to the box. It just doesn't work. The power supply is in tick mode - I can hear it. I can't smell any signs of a loss of magic smoke. Any suggestions where to look?

Thanks!
Vince - hoping yahoo posts this in a reasonable period of time...
--
Michigan VHF Corp. http://www.nobucks.net/ http://www.CDupe.com/
http://www.metalworkingfun.com

Re: CRT Tube (in good shape) for Tek464 / Tek466

Fabio Trevisan
 

Hello Håkan,
Thanks for the tip on the CRT p/n replacement and the kit P/N.
My 464 is S/N B132xxx (don't recall the last digits right now) so I suppose
that either the 154-0749-00 or 154-0750-00 will serve.

My guess is that the 0749 is nothing else than a 0750 that wasn't good
enough to pass the 466 writing speed test.

I wonder what's in this kit... I can't refrain from thinking, even hoping,
that someone could have attempted to install a 466 CRT on my 464 and it may
be missing some retrofitting, and maybe that be the cause for the weak
trace and blooming.
But I doubt. All the symptoms for a worn-out cathode are there.
double-peaking, poor focus tracking (with Intensity), Intensity dependent
astigmatism... Everything that leads to conclusion that the cathode is
emitting from its outer ring, instead of from its sweet center spot.

KRgrds,

Fabio


2017-07-18 19:21 GMT-03:00 hahi@... [TekScopes] <
TekScopes@...>:



Please be aware that the 464 and 466 do not have the same CRT.
Actually they could use the same CRT if they are within the same S/N range
i.e either
below or above B080000. The recommended replacement for all 4x6 CRT's is
154-0750-00.
If the scope is below B080000 some minor modifications must be done. The
kit P/N is 050-0762-14.

/Håkan

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



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

Re: For sale UK Tek7854 plus plugins

chris_leyson@...
 

Hi guys, quick update scopes and plug-ins have all gone. Needed a quick sale.

Re: Scope face focus anomaly

Fabio Trevisan
 

Hello Gary,
The new ones, however, don't deliver the same pleasure and fun to use, and
they're not as interactive and intuitive to use (after some practice with
the old ones, of course).
A good reading that will help you understand better how these multitude of
electrodes play their magic inside the CRT is one of Tek's "Concepts
Series" books, on CRTs, that you can find on TekWiki website:

http://w140.com/tekwiki/images/6/62/062-0852-01.pdf

It has a very good explanation on how the voltages translate into electric
fields that divert the electron beam or "shape" it, by acting like
electrostatic lenses.

Rgrds,

Fabio

2017-07-19 9:17 GMT-03:00 Gary Robert Bosworth @grbosworth
[TekScopes] <TekScopes@...>:



Thank you Fabio. I am developing a list of things to look into. I know so
little about these old analog CRTs. The modern digital designs do not
suffer the headaches.

Gary

On Tue, Jul 18, 2017 at 9:59 PM, Fabio Trevisan fabio.tr3visan@...
[TekScopes] <TekScopes@...> wrote:



Hello Gary,
Not specifically related to your 7514, I want to share 2 of my last (and
pretty much all) experiences with my 464 (focus related)....
As you've seen from some of the other folks answers focus seem to be
influenced by quite a few of the inner elements (or, let's call them
intermediate anodes) that are not directly related to the focus electrode
itself.
My first experience was when my 464 was still recent on my hands and it
had
a nasty overall focus.
It wouldn't focus well over the entire screen.
It had, back then, a major vertical high freq response imbalance (too
much
high freq gain, or too low lo-freq gain, which was my main concern).
As the troubleshooting evolved I found an opened (burnt) resistor on the
vertical output amplifier's biasing.
As soon as I replaced the resistor, I noticed a great improvement in
focus
(after I readjusted a number of trimpots that were set wrong partially
compensating the bias imbalance).

Lesson learnt (as I understood):
Focus is affected by inadequate balance between voltages of symmetrically
opposed electrodes, such as the vertical or horizontal plates, so, the
average of the varying voltages at the upper and lower plates must remain
constant and at a value that is correct in relation to the voltages of
the
preceding and next electrodes in the electron beam's path.
If the upper plate is at an average level of, say, 60V (example), and if
the lower is at 40 (average being 50) and if 50 is the right voltage for
the vert plates, overall the focus may be right, but as the trace moves
up
or down, the average between them doesn't remain constant and the focus
becomes modulated by the vertical signal.
A defect on the vertical amplifier that may be causing an imbalance of
such
top and bottom plates'voltages, may affect adversely the focus in the
up-down direction.

My second experience was after I dismantled the oscilloscope to replace
its
power supply caps and, in the process, I may have dislodged the
"geometry"
trimppt from its correct adjustment.
As I just powered up the scope after reassembly, the focus was once again
awful, but luckily I also noticed that waveforms were distorted (Sort of
pin-cushion distotyion).
As soon as I properly re-adjusted the geometry trimpot, focus improved
again back to what it was.

Brgrds,

Fabio

On Jul 18, 2017 11:12 PM, "Gary Robert Bosworth @grbosworth
[TekScopes]" <TekScopes@...> wrote:

Thanx Stephen. I will see if there is a shield adjustment. I know very
little about CRTs.

Gary

On Tue, Jul 18, 2017 at 2:56 PM, sbell@... [TekScopes] <
TekScopes@...> wrote:



The setting of the CRT's vertical shield voltage seems to have a
considerable effect on the ability to obtain a well focused spot. I am
not
familiar with the 7514 but if it has a adjustment for this voltage you
could try tweaking it to see if it results in improved focus.
On my 7834 I was unable to obtain a good spot with the shield voltage
adjustment procedure detailed in the manual so after going through the
complete CRT set-up procedure I had to further tweak the shield voltage
to
obtain best overall focus.

Stephen

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


--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247 <(310)%20317-2247> <(310)%20317-2247>
<(310)%20317-2247>

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




--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247 <(310)%20317-2247>

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


Re: Experience with AliExpress for connectors

 

ons. 19. jul. 2017 kl. 17.01 skrev 'David C. Partridge'
@perdrix [TekScopes] <TekScopes@...>:

I want to buy two Lemo connectors FGJ.2B.306.CLLD72Z

Problem is that Lemo want GBP19.24 each plus tax at 20% and have an MOV of
GBP100 plus tax (or a surcharge of GBP25 plus tax) with shipping on top.

I saw this page on AliExpress:

<
https://www.aliexpress.com/item/LEMO-connector-FGJ-2B-2-3-4-5-6-7-8-10-12-1
4-16-18/32802964953.html?spm=2114.search0104.8.60.UYHEap
<https://www.aliexpress.com/item/LEMO-connector-FGJ-2B-2-3-4-5-6-7-8-10-12-14-16-18/32802964953.html?spm=2114.search0104.8.60.UYHEap>
Offering them at a lower price than Lemo and seemingly offering small
orders
and free shipping.

Are they OK to deal with or would I be throwing my money down a black hole?

Dave

hi david,
Pay with kredit card, then you are safe,youncan get an refund from you bank.
helge



------------------------------------
Posted by: "David C. Partridge" <@perdrix>
------------------------------------


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

Yahoo Groups Links



Experience with AliExpress for connectors

 

I want to buy two Lemo connectors FGJ.2B.306.CLLD72Z

Problem is that Lemo want GBP19.24 each plus tax at 20% and have an MOV of
GBP100 plus tax (or a surcharge of GBP25 plus tax) with shipping on top.

I saw this page on AliExpress:

<https://www.aliexpress.com/item/LEMO-connector-FGJ-2B-2-3-4-5-6-7-8-10-12-1
4-16-18/32802964953.html?spm=2114.search0104.8.60.UYHEap>

Offering them at a lower price than Lemo and seemingly offering small orders
and free shipping.

Are they OK to deal with or would I be throwing my money down a black hole?

Dave

Re: Scope face focus anomaly

Gary Robert Bosworth
 

Thank you Fabio. I am developing a list of things to look into. I know so
little about these old analog CRTs. The modern digital designs do not
suffer the headaches.

Gary

On Tue, Jul 18, 2017 at 9:59 PM, Fabio Trevisan fabio.tr3visan@...
[TekScopes] <TekScopes@...> wrote:



Hello Gary,
Not specifically related to your 7514, I want to share 2 of my last (and
pretty much all) experiences with my 464 (focus related)....
As you've seen from some of the other folks answers focus seem to be
influenced by quite a few of the inner elements (or, let's call them
intermediate anodes) that are not directly related to the focus electrode
itself.
My first experience was when my 464 was still recent on my hands and it had
a nasty overall focus.
It wouldn't focus well over the entire screen.
It had, back then, a major vertical high freq response imbalance (too much
high freq gain, or too low lo-freq gain, which was my main concern).
As the troubleshooting evolved I found an opened (burnt) resistor on the
vertical output amplifier's biasing.
As soon as I replaced the resistor, I noticed a great improvement in focus
(after I readjusted a number of trimpots that were set wrong partially
compensating the bias imbalance).

Lesson learnt (as I understood):
Focus is affected by inadequate balance between voltages of symmetrically
opposed electrodes, such as the vertical or horizontal plates, so, the
average of the varying voltages at the upper and lower plates must remain
constant and at a value that is correct in relation to the voltages of the
preceding and next electrodes in the electron beam's path.
If the upper plate is at an average level of, say, 60V (example), and if
the lower is at 40 (average being 50) and if 50 is the right voltage for
the vert plates, overall the focus may be right, but as the trace moves up
or down, the average between them doesn't remain constant and the focus
becomes modulated by the vertical signal.
A defect on the vertical amplifier that may be causing an imbalance of such
top and bottom plates'voltages, may affect adversely the focus in the
up-down direction.

My second experience was after I dismantled the oscilloscope to replace its
power supply caps and, in the process, I may have dislodged the "geometry"
trimppt from its correct adjustment.
As I just powered up the scope after reassembly, the focus was once again
awful, but luckily I also noticed that waveforms were distorted (Sort of
pin-cushion distotyion).
As soon as I properly re-adjusted the geometry trimpot, focus improved
again back to what it was.

Brgrds,

Fabio

On Jul 18, 2017 11:12 PM, "Gary Robert Bosworth @grbosworth
[TekScopes]" <TekScopes@...> wrote:

Thanx Stephen. I will see if there is a shield adjustment. I know very
little about CRTs.

Gary

On Tue, Jul 18, 2017 at 2:56 PM, sbell@... [TekScopes] <
TekScopes@...> wrote:



The setting of the CRT's vertical shield voltage seems to have a
considerable effect on the ability to obtain a well focused spot. I am
not
familiar with the 7514 but if it has a adjustment for this voltage you
could try tweaking it to see if it results in improved focus.
On my 7834 I was unable to obtain a good spot with the shield voltage
adjustment procedure detailed in the manual so after going through the
complete CRT set-up procedure I had to further tweak the shield voltage
to
obtain best overall focus.

Stephen




--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247 <(310)%20317-2247> <(310)%20317-2247>

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

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




--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247

Re: Scope face focus anomaly

Fabio Trevisan
 

Hello Gary,
Not specifically related to your 7514, I want to share 2 of my last (and
pretty much all) experiences with my 464 (focus related)....
As you've seen from some of the other folks answers focus seem to be
influenced by quite a few of the inner elements (or, let's call them
intermediate anodes) that are not directly related to the focus electrode
itself.
My first experience was when my 464 was still recent on my hands and it had
a nasty overall focus.
It wouldn't focus well over the entire screen.
It had, back then, a major vertical high freq response imbalance (too much
high freq gain, or too low lo-freq gain, which was my main concern).
As the troubleshooting evolved I found an opened (burnt) resistor on the
vertical output amplifier's biasing.
As soon as I replaced the resistor, I noticed a great improvement in focus
(after I readjusted a number of trimpots that were set wrong partially
compensating the bias imbalance).

Lesson learnt (as I understood):
Focus is affected by inadequate balance between voltages of symmetrically
opposed electrodes, such as the vertical or horizontal plates, so, the
average of the varying voltages at the upper and lower plates must remain
constant and at a value that is correct in relation to the voltages of the
preceding and next electrodes in the electron beam's path.
If the upper plate is at an average level of, say, 60V (example), and if
the lower is at 40 (average being 50) and if 50 is the right voltage for
the vert plates, overall the focus may be right, but as the trace moves up
or down, the average between them doesn't remain constant and the focus
becomes modulated by the vertical signal.
A defect on the vertical amplifier that may be causing an imbalance of such
top and bottom plates'voltages, may affect adversely the focus in the
up-down direction.

My second experience was after I dismantled the oscilloscope to replace its
power supply caps and, in the process, I may have dislodged the "geometry"
trimppt from its correct adjustment.
As I just powered up the scope after reassembly, the focus was once again
awful, but luckily I also noticed that waveforms were distorted (Sort of
pin-cushion distotyion).
As soon as I properly re-adjusted the geometry trimpot, focus improved
again back to what it was.

Brgrds,

Fabio

On Jul 18, 2017 11:12 PM, "Gary Robert Bosworth @grbosworth
[TekScopes]" <TekScopes@...> wrote:



Thanx Stephen. I will see if there is a shield adjustment. I know very
little about CRTs.

Gary


On Tue, Jul 18, 2017 at 2:56 PM, sbell@... [TekScopes] <
TekScopes@...> wrote:



The setting of the CRT's vertical shield voltage seems to have a
considerable effect on the ability to obtain a well focused spot. I am not
familiar with the 7514 but if it has a adjustment for this voltage you
could try tweaking it to see if it results in improved focus.
On my 7834 I was unable to obtain a good spot with the shield voltage
adjustment procedure detailed in the manual so after going through the
complete CRT set-up procedure I had to further tweak the shield voltage to
obtain best overall focus.

Stephen

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


--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247 <(310)%20317-2247>

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

Re: Scope face focus anomaly

Gary Robert Bosworth
 

Thanx Stephen. I will see if there is a shield adjustment. I know very
little about CRTs.

Gary


On Tue, Jul 18, 2017 at 2:56 PM, sbell@... [TekScopes] <
TekScopes@...> wrote:



The setting of the CRT's vertical shield voltage seems to have a
considerable effect on the ability to obtain a well focused spot. I am not
familiar with the 7514 but if it has a adjustment for this voltage you
could try tweaking it to see if it results in improved focus.
On my 7834 I was unable to obtain a good spot with the shield voltage
adjustment procedure detailed in the manual so after going through the
complete CRT set-up procedure I had to further tweak the shield voltage to
obtain best overall focus.

Stephen






--
Gary Robert Bosworth
@grbosworth
Tel: 310-317-2247


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