Date   

Re: What is the fairest way to distribute scarce Tek resources

Dave Seiter
 

I've got to admit, it annoys me to be the first to respond to an item on CL and be told "you were first, but we decided to give "it" to someone else...
-Dave

On Tuesday, June 4, 2019, 10:57:02 AM PDT, ArtekManuals <manuals@artekmanuals.com> wrote:

 "Life is not fair" nor was it ever intended to be.

If one has an overreaching need to be first in line then  it is their
responsibility to research and subscribe to whatever email service is
fastest and have it ring their phone at 3AM in the morning.

Dave
ArtekManuals

On 6/4/2019 12:40 PM, Dennis Tillman W7PF wrote:
Often when a member says they have some Tek scope/instrument/plugin/part/etc
that they no longer need or want the next person who happens to logon is the
lucky individual who grabs it.

On occasion I have been the first to reply and benefited from this. More
often than not I see the email long after the item has been spoken for.

This happens often enough to all of us that we would benefit from finding an
alternative way to share our combined resources.

 

I would like suggestions on what is a fairer way to distribute Tek related
things to TekScopes members.

This affects all of us. It should not depend on chance.

 

Dennis Tillman W7PF




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


Re: How can we set up a Parts Wanted list on Groups.io

ArtekManuals <manuals@...>
 

MY experience is they post to group with "NEED LEFT HANDED GONZO-PLATZ FOR A 800Z-SUPER SCOPE" . Lots of those in archive and has seemed to work in the past, so not sure what the problem is ????  Sounds like  "millennial thinking" is creeping into the process ?

Or as one my mentors in industry suggested when I was complaining about lack of support in the factory... "Dave ...show me where in your job description it says your job is easy ...now if you cant run with the big dogs ...stay on the porch"

Dave
NR1DX
manuals@artekmanuals.com

On 6/4/2019 12:45 PM, Dennis Tillman W7PF wrote:
At the Seaside OR ham swap meet last Saturday one of the TekScopes members
asked if there was a way to list some Tek parts he was looking for on
TekScopes.

Of course there really isn't one at the moment but if we could set one up
what would it look like and how would it work?

If we can work out something "simple" maybe we can get Groups.io to
implement it for us.


Does anyone know how other groups handle this?


Dennis Tillman W7PF



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


Re: How can we set up a Parts Wanted list on Groups.io

Vince Vielhaber
 

Every group on groups.io has a database to use. Perhaps we can make use of that.

Vince.

On 06/04/2019 12:45 PM, Dennis Tillman W7PF wrote:
At the Seaside OR ham swap meet last Saturday one of the TekScopes members
asked if there was a way to list some Tek parts he was looking for on
TekScopes.

Of course there really isn't one at the moment but if we could set one up
what would it look like and how would it work?

If we can work out something "simple" maybe we can get Groups.io to
implement it for us.



Does anyone know how other groups handle this?



Dennis Tillman W7PF



Re: What is the fairest way to distribute scarce Tek resources

ArtekManuals <manuals@...>
 

"Life is not fair" nor was it ever intended to be.

If one has an overreaching need to be first in line then  it is their responsibility to research and subscribe to whatever email service is fastest and have it ring their phone at 3AM in the morning.

Dave
ArtekManuals

On 6/4/2019 12:40 PM, Dennis Tillman W7PF wrote:
Often when a member says they have some Tek scope/instrument/plugin/part/etc
that they no longer need or want the next person who happens to logon is the
lucky individual who grabs it.

On occasion I have been the first to reply and benefited from this. More
often than not I see the email long after the item has been spoken for.

This happens often enough to all of us that we would benefit from finding an
alternative way to share our combined resources.


I would like suggestions on what is a fairer way to distribute Tek related
things to TekScopes members.

This affects all of us. It should not depend on chance.


Dennis Tillman W7PF



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


Re: How can we set up a Parts Wanted list on Groups.io

Dave Seiter
 

Maybe a simple spreadsheet or multi column doc that's writable by all?  Seems to me I've seen something like that in the past in another forum/group.
-Dave

On Tuesday, June 4, 2019, 9:46:13 AM PDT, Dennis Tillman W7PF <dennis@ridesoft.com> wrote:

At the Seaside OR ham swap meet last Saturday one of the TekScopes members
asked if there was a way to list some Tek parts he was looking for on
TekScopes.

Of course there really isn't one at the moment but if we could set one up
what would it look like and how would it work?

If we can work out something "simple" maybe we can get Groups.io to
implement it for us.



Does anyone know how other groups handle this?



Dennis Tillman W7PF


Re: What is the fairest way to distribute scarce Tek resources

Dave Seiter
 

I doubt there is a truly "fair" way of doing it, as all methods will ultimately rely on either who's first, who has the best story, or who has the most money/desire.  One of the freecycle-type orgs suggest waiting for multiple requests to come in and then pick the request with the most need or best story.  Sounds noble, but I've been burned by what I thought was a good choice in the past- it's honestly hard to tell, and can come down to who can make up the best sob story, while you're probably missing the individual who it would benefit the most (yeah, I was a bit bitter about it!)  There are folks who appear to sit on Craigslist (free and otherwise) all day waiting for good items to show up.  When I use CL, I've found that waiting actually helps because 3/4 of the people who reply don't respond when contacted; but of course we don't have flakes in our group!
On the other hand, when you're giving things away, sometimes you're just happy to get rid of it!  Still no takers on my chassis, and we have our annual dumpster weekend coming up this week...  
-Dave

On Tuesday, June 4, 2019, 9:41:25 AM PDT, Dennis Tillman W7PF <dennis@ridesoft.com> wrote:

Often when a member says they have some Tek scope/instrument/plugin/part/etc
that they no longer need or want the next person who happens to logon is the
lucky individual who grabs it.

On occasion I have been the first to reply and benefited from this. More
often than not I see the email long after the item has been spoken for.

This happens often enough to all of us that we would benefit from finding an
alternative way to share our combined resources.



I would like suggestions on what is a fairer way to distribute Tek related
things to TekScopes members.

This affects all of us. It should not depend on chance.



Dennis Tillman W7PF


Re: What is the fairest way to distribute scarce Tek resources

Daniel Koller
 

Hi all,  One could argue that the best way to share these resources is "the market" and let "market forces" be the arbitrator of supply and demand.  The best example of this we have now is probably e-bay.
   On the other hand, I hate e-bay.  The greedy bastards keep taking more and more of the cut and it's contaminated by bogus posts of Tek 453 oscilloscopes for $1000 that don't really exist, etc.   So, is there third party software that would allow us to set up our own auction site?  That could be kind of fun.   A small cut could be taken to support Tekscopes.
   But another observation:   We're all getting older, and there are not that many young people getting into electronics quite the way we did.  There is going to be more surplus test and measurement equipment coming as more of us pare down our collections.   I suspect supply will at least match demand (supply going down because the equipment also ages and leaves the realm of the functioning).
  Dan

On Tuesday, June 4, 2019, 12:41:24 PM EDT, Dennis Tillman W7PF <dennis@ridesoft.com> wrote:

Often when a member says they have some Tek scope/instrument/plugin/part/etc
that they no longer need or want the next person who happens to logon is the
lucky individual who grabs it.

On occasion I have been the first to reply and benefited from this. More
often than not I see the email long after the item has been spoken for.

This happens often enough to all of us that we would benefit from finding an
alternative way to share our combined resources.



I would like suggestions on what is a fairer way to distribute Tek related
things to TekScopes members.

This affects all of us. It should not depend on chance.



Dennis Tillman W7PF


PG506 ISSUES Need some experienced minds!

Mlynch001
 

All:

I have a PG506 s/n >B0400000. It was plugged into my TM506 and working, then all the sudden, it quit, along with blowing a fuse on the 506. I was just in the process of familiarization with the entire unit, but the PG506 seemed to work normally up to that point. This was many months ago, so the details are foggy. After this event, the display quit and the high amplitude section quit. The display will occasionally generate random characters when the function switch is moved between ranges and the variable is switched in and out. I will say this up front, I am NOT any sort of EE or experienced technician, just a novice/hobbyist level technician. That being said, I followed the manual and found that the voltages on the +5V (5.065V @ F65), +16V, -16V (33.005 V between test points), -72V and +120V rails are normal. Output resistance was good per the performance check procedure. 9V was missing, which I traced to VR210, which was "open", Replaced with a standard 9.1V .5W zener diode. I understand, this is originally a temp compensated diode, I will get a suitable temp compensated item ordered and installed later, at least I have a 9V rail at the moment. The standard amplitude pulse is 1kHz, on the money, however, the amplitudes are off, both going into a 1M ohm and a 50 Ohm load and the signal amplitude "disappears" ( goes to almost "0") when the amplitude control is placed in the 20,50 or 100V Range. when switched to "DC" mode, the results are similar. Measured on my 2440 scope in the 1M range, the voltages are as follows .1V = .7040V, .2V = .2380V, .5V = .5920V, 1.0V = .6560V, 2V = 2.481V, 5V = 5.920V and 10V = 6.806V. 20,50 and 100V ranges do not indicate any appreciable voltage. One thing that stands out is that the .1, 1 and 10V ranges are all LOW, while the other ranges are slightly high? So I assume it is something to do with a divider section? Similar results with a recently calibrated TDS360, and my 465B so all these scopes cannot be wrong. The "Fast Rise" section appears to be very good, nice sharp square wave, with good edges (not very concerned with rise time at the moment).. Pulse amplitude control is functional. Trigger + Out is good. When I put the thing into "High Amplitude" mode, it all goes to crap. There is not a square wave and their is very little voltage, mostly a really noisy signal that looks like a ramp or a sawtooth DC signal with a bunch of noise over top of the signal. This signal measures a constant and approximate -7.5V DC, regardless of switch positions or amplitude control settings. There never is a 100V rail that I can find. One thing that I notice is that when switching to the High Amplitude mode, the voltage at F30 drops like a rock from about 22V down to about 10.5V. I am "assuming" this is from excess load from the high amplitude section??? I don't allow it to stay like that very long , but F30 has never blown. The "Service Manual" is very sparse with trouble shooting information. I suppose that they don't intend for hayseeds like me to be working on these things? Looking for some sage advice. Please feel free to ask questions and make suggestions. I'm going out to make more measurements.

--
Michael Lynch
Dardanelle, AR


How can we set up a Parts Wanted list on Groups.io

 

At the Seaside OR ham swap meet last Saturday one of the TekScopes members
asked if there was a way to list some Tek parts he was looking for on
TekScopes.

Of course there really isn't one at the moment but if we could set one up
what would it look like and how would it work?

If we can work out something "simple" maybe we can get Groups.io to
implement it for us.



Does anyone know how other groups handle this?



Dennis Tillman W7PF


What is the fairest way to distribute scarce Tek resources

 

Often when a member says they have some Tek scope/instrument/plugin/part/etc
that they no longer need or want the next person who happens to logon is the
lucky individual who grabs it.

On occasion I have been the first to reply and benefited from this. More
often than not I see the email long after the item has been spoken for.

This happens often enough to all of us that we would benefit from finding an
alternative way to share our combined resources.



I would like suggestions on what is a fairer way to distribute Tek related
things to TekScopes members.

This affects all of us. It should not depend on chance.



Dennis Tillman W7PF


Back cover 2445a

Fred Schumacher
 

Hi All,
To finish my 2445a, I am looking for a back cover, including the two feet and associated screws.
Maybe there is somebody out there in europe, as I am living in the Netherlands, having a scrap 2445a with these parts in good shape. Let me know.
Thanks in advance,
Fred Schumacher


Re: Chassis for free

David Berlind
 

Yes! Thank you David and Dennis for stepping up with offers to help! I'm
very much looking forward to dropping that chip into my 7603. I'll let
you know how it works out.

On Tue, Jun 4, 2019 at 3:33 AM Dave Seiter <d.seiter@att.net> wrote:

Hi Dennis,
I already sent David a chip.
-Dave
On Monday, June 3, 2019, 10:00:54 PM PDT, Dennis Tillman W7PF <
dennis@ridesoft.com> wrote:

Hi David,
I have one. It is obviously going to be a different date code but that is
not important
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David
Berlind
Sent: Thursday, May 30, 2019 3:22 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Chassis for free

Before these go into the trash heap, I am looking for a chip that goes
into the PCB at the back of slot 1 on a 7603 chassis with the marking:

155 0022 00
733 542 USA

I would greatly appreciate it if anyone is willing to spare that chip.

Thank you!



--
Dennis Tillman W7PF
TekScopes Moderator







Re: 7A13 relay substitution report

Craig Sawyers <c.sawyers@...>
 

Hi Fabio and Tom,
Tek made relays are notoriously bad. This is because the "expert" Tek hired to design, manage, and
produce them was not an expert after all.
Dennis Tillman W7PF
That is very interesting Dennis, and is information I did not know about those relays.

Personally I have only had one fail totally as a result of an O/C coil - a particularly small one in
a 7A11 probe head. But fortunately that was when Deane Kidd was alive and active, and of course he had
one in his basement trove.

The dreaded contact problem can only be properly cured by carefully dremelling off the lid along the
plastic weld line, clean the contacts with alcohol and paper, and then either reattach the lid or just
leave it off entirely.

Craig


Re: Chassis for free

Dave Seiter
 

Hi Dennis,
I already sent David a chip.
-Dave

On Monday, June 3, 2019, 10:00:54 PM PDT, Dennis Tillman W7PF <dennis@ridesoft.com> wrote:

Hi David,
I have one. It is obviously going to be a different date code but that is not important
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David Berlind
Sent: Thursday, May 30, 2019 3:22 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Chassis for free

Before these go into the trash heap, I am looking for a chip that goes into the PCB at the back of slot 1 on a 7603 chassis with the marking:

155 0022 00
733 542 USA

I would greatly appreciate it if anyone is willing to spare that chip.

Thank you!



--
Dennis Tillman W7PF
TekScopes Moderator


Re: 7A13 relay substitution report

 

Hi Fabio and Tom,
Tek made relays are notoriously bad. This is because the "expert" Tek hired to design, manage, and produce them was not an expert after all.

I have experienced the exact same thing you did with the rotors on your 7A13 trim capacitors on one of my 7A22 plugins. The rotors just fall out of the variable capacitors without any apparent explanation. More than half the rotors fell out of one 7A22 I owned. I was stunned to see something like this happening so quickly that I couldn’t pick up the pieces fast enough. It was very strange how it happened to so many capacitors almost all at once. I don't think Tek made these capacitors however.

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of tomford717@gmail.com
Sent: Saturday, June 01, 2019 8:18 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7A13 relay substitution report

Hi Fabio,

I'm going through the same 7A13 repair as you are. My Tek relays are failing and three rotors have fallen out of the air-variable input tuning caps.

I chose the Fujitsu NA12W-K as my replacement relay and decided to replace them all. The Fujitsu is rated at 220 VDC and has good specs at 100MHz. I made a pcb adapter board to simplify the wiring. Only two different pcb patterns were needed to satisfy all of the Tek relay pin-outs.

I included an SMT full wave bridge on the pcb to convert the Fujitsu relays to non-polarity coil types. I've replaced all relays and the four input attenuator variable caps. The DC offset and gain calibration has gone well. I am partially done with the RF cal and so far, the 3dB BW has been good to 100MHz using a 50 Ohm source.

My concern now is BW performance when the input attenuators are in operation. I have taken capacitance measurements of the Tek, Fujitsu, and Omron G6K relays. They all measure about the same when separate. When I mount the Fujitsu relay to the adapter board, the capacitance between the armature to the open contact jumps from 0.3pF to about 1.7pF. The pcb adapter adds roughly 1.3pF to all four inter-electrode points I've measured. I'm using a DE-5000 LCR meter @100KHz. I have pics of my progress so far if anyone has an interest.

Thanks,
Tom Ford




--
Dennis Tillman W7PF
TekScopes Moderator


Re: Chassis for free

 

Hi David,
I have one. It is obviously going to be a different date code but that is not important
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of David Berlind
Sent: Thursday, May 30, 2019 3:22 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Chassis for free

Before these go into the trash heap, I am looking for a chip that goes into the PCB at the back of slot 1 on a 7603 chassis with the marking:

155 0022 00
733 542 USA

I would greatly appreciate it if anyone is willing to spare that chip.

Thank you!



--
Dennis Tillman W7PF
TekScopes Moderator


Re: Weird(?) behaviour in tek 492BP power distribution - Please help

d.schilling.net@...
 

Just an observation: It seemed to work until you worked on the front panel.
-David


Re: 7B92A time-base plug-in odd behaviour

Albert Otten
 

Hi Colin,

I hardly use my 7B92A and I had to play with it some time to re-familiarize myself with how it operates. That must be difficult when the 7B92A is faulty and new to you. Here are some "features" that might or might not help you.
- In Normal sweep mode (locked knobs) the displayed sweep actually is generated as delayed sweep, not as delaying sweep.
- The upper readout is for the delaying sweep, the lower readout is for the delayed sweep. Note how the readout jumps from lower to upper when from Normal sweep you pull the Time/Div knob.
- The delaying sweep goes up to 10 ns/div even when the knob is at a faster position. (Just try the previous remark at 1 ns/div).
- I have VAR set for Delayed sweep. So VAR also affets the sweep rate in Normal sweep mode. VAR can reduce sweep speed and at the same time reduces sweep length (like you seemed to notice).
- ALT mode is set by pulling the Time/Div knob *and* setting Trace Sep not fully ccw. Is that wheat you meant by ALT? Then 2 traces are displayed. The upper (delaying, with intensified zone) trace intensity is controlled by the 7B92A Intensity(!) and probably invisible when you set that Intensity fully ccw previously. The lower (delayed) trace listens to the mainframe Intensity.
- If you turn the transparent skirt in ALT mode then you change the delaying time/div. This will shift the delayed t race (unless Delay Time Multiplier is fully ccw). Is that what you observed?
- The trigger light is on during the delayed sweep (in Normal sweep mode) or during the delaying sweep mode (in all not-Normal modes). This can easily be recognized at a very slow time/div and even slower trigger signal.

Altogether I have the impression the your delaying sweep is working and displayed in non-Normal modes but that the delayed sweep is interrupted somewhere. I guess that the delayed sweep generator itself is working correctly since otherwise triggering would be blocked I think. It's difficult to follow in the schematics when triggering is blocked and given free again. The same holds for (un)blanking signals.

Albert

On Mon, Jun 3, 2019 at 06:42 PM, Colin Herbert wrote:


Hi,
In continuation of this, when the scope is turned on and the CRT has warmed
up, all I see is a vertical line (or a spot) on the left of the screen,
corresponding to the Y input. The "TRIG'D" light is illuminated, but there is
no horizontal sweep. If I pull out the "TIME/DIV" knob to show the "ALT"
time-base display, I get a sweep but this is not altered by the "TIME/DIV"
knob, but _is_ altered by the transparent skirt. Again, the "TRIG'D" light is
illuminated. After some warm-up period, a horizontal sweep with the "TIME/DIV"
knobs locked can be seen, but it is unstable and doesn't always travel the
entire width of the display. What _does_ sometimes have an effect on the
horizontal sweep is the "VARIABLE" knob, but this also alters the width of the
sweep; is this supposed to happen? If I use "NORM" triggering mode with no Y
input, the sweep is blanked as you would expect.
I realise that there are jumpers on the boards to alter the "TIME/DIV"
selector from delaying sweep to delayed sweep and for compatibility with
different mainframes. As far as I can tell, these are set for variable
delaying sweep and for 7400, 7600 and 7700 mainframes (mine is a 7623A). I am
wondering if S800 has a problem (it is difficult to access without removing a
few things, or if the switch associated with the "VARIABLE" knob is faulty. I
have ascertained that switch S490 is _not_ causing any of these problems (by
wiggling it when the time-base is connected using a rigid extender - the
time-base doesn't seem to work with either of my flexible extenders and I'm
sure that they're good) .
I am also thinking that the time-base cam switches might benefit from
cleaning, but as I said before, there are around 50 of them and that sounds
like a big job, unless someone can tell me where I might try first.
I have cleaned the PCB edge-contacts which connect to the mainframe with no
improvement (although some blue stuff came off some of the contacts) and I
have tried another time-base plug-in (my 7B53A) which works fine.
Head-scratching time....

TIA, Colin.


Re: 453 HV Transformer Rewind SUCCESS

Dave Wise
 

[SUPPLEMENT 5 omitted because...]

SUPPLEMENT 6 2019-05-31

John Sykes unwound his transformer
and got the following turns counts which are accurate +/- 1 turn:

5-9-7 0T-543T-1101T
6-10 0T-583T

Reminder: I wound a layer, then a (insulated) retrace to the starting side, then the next layer, instead of winding back and forth. This reduces the winding capacitance, which reduces loss.


Re: 7B92A time-base plug-in odd behaviour

Colin Herbert
 

Hi,
In continuation of this, when the scope is turned on and the CRT has warmed up, all I see is a vertical line (or a spot) on the left of the screen, corresponding to the Y input. The "TRIG'D" light is illuminated, but there is no horizontal sweep. If I pull out the "TIME/DIV" knob to show the "ALT" time-base display, I get a sweep but this is not altered by the "TIME/DIV" knob, but _is_ altered by the transparent skirt. Again, the "TRIG'D" light is illuminated. After some warm-up period, a horizontal sweep with the "TIME/DIV" knobs locked can be seen, but it is unstable and doesn't always travel the entire width of the display. What _does_ sometimes have an effect on the horizontal sweep is the "VARIABLE" knob, but this also alters the width of the sweep; is this supposed to happen? If I use "NORM" triggering mode with no Y input, the sweep is blanked as you would expect.
I realise that there are jumpers on the boards to alter the "TIME/DIV" selector from delaying sweep to delayed sweep and for compatibility with different mainframes. As far as I can tell, these are set for variable delaying sweep and for 7400, 7600 and 7700 mainframes (mine is a 7623A). I am wondering if S800 has a problem (it is difficult to access without removing a few things, or if the switch associated with the "VARIABLE" knob is faulty. I have ascertained that switch S490 is _not_ causing any of these problems (by wiggling it when the time-base is connected using a rigid extender - the time-base doesn't seem to work with either of my flexible extenders and I'm sure that they're good) .
I am also thinking that the time-base cam switches might benefit from cleaning, but as I said before, there are around 50 of them and that sounds like a big job, unless someone can tell me where I might try first.
I have cleaned the PCB edge-contacts which connect to the mainframe with no improvement (although some blue stuff came off some of the contacts) and I have tried another time-base plug-in (my 7B53A) which works fine.
Head-scratching time....

TIA, Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Albert Otten
Sent: 30 May 2019 19:34
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7B92A time-base plug-in odd behaviour

Hi Colin,

When the sweep stops I would expect a blanked screen. You still see the signal at the start position of the sweep. This could perhaps mean that the sweep is running but that the sweep output to the horizontal amplifier is interrupted.
Is the screen blanked when you don't trigger the sweep(s)?
Perhaps you should choose the lowest possible sweep rate. If you then wiggle the time/knob and the sweep reappears, does it start then at the left side or does it start "random" at some horizontal position, as if the sweep was running normally but with sweep output interrupted? Maybe you can also recognize a still normally running sweep from the trigger light blinking.
(Just an idea. I have not encountered this problem.)

Albert



On Thu, May 30, 2019 at 07:01 PM, Colin Herbert wrote:


Has no-one any ideas about this? Surely it can't be that unusual a problem?
Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Colin
Herbert via Groups.Io
Sent: 24 May 2019 16:49
To: TekScopes@groups.io
Subject: Re: [TekScopes] 7B92A time-base plug-in odd behaviour

Not totally the case, Albert. As I said, the instability can be present after
warm-up and can be stopped or induced by "wiggling" the Time/Div knob.
Specifically, if the delaying or delayed time-base is showing (i.e. the
Time/Div knob is "IN") and the Time/Div knob is pushed in a little more
firmly, the time-base stops and a vertical line or dot (depending on the Y
input) at the left-hand side is shown.

Yes, It is the model with the "Alt Off" position on the Trace Sep knob; the
S/N is B096566.

Colin.


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