Date   
Re: Tek 2465 Problem

Panos
 

Τhank you both for the detailed answers.
@John
To Be sure that I will do it as an exercise in my bench! Your way remind me my school days. :-)

@Harvey
No, I measured these out of circuit, after first I measured low ohm resistance in circuit. :-|
I like also very much the way you think to resolve the problem.

Re: TM500 / 5000 Extenders

Harvey White
 

SeeedStudio will do 10 cm by 10 cm (maximum) boards for 4.90 for a lot of 10.  HASL, Silk screen both sides, PTH, dual layer.  Your choice of solder mask colors.  6 mil min trace, etc...

With DHL shipping (few dollars more than cheapest), the boards come to about $3.00 each if that's the only lot you order. Ordering the maximum number of designs (to get the $4.90) gives you $1.00 a board for 5 board designs of 10 boards each, and they can handle paneling as long as (for the discount) you stay under the 10cm by 10cm.  Design must be the same, though.

They're not the only people who do this, either, at that price.

Harvey

On 12/23/2019 11:09 AM, John Griessen wrote:
For anyone interested in making TM500 extenders from 0.16" pitch straddle connectors they may have or find,
this pcb layout is available as RS274-X data, and in pcb-rnd format:
https://www.ecosensory.com/tek/tek_tm_flex_pcb_top.jpg
https://www.ecosensory.com/tek/tek_tm_flex_pcb_bot.jpg

It fits in the low cost 10cm square board size available for about $50 for ten from China.
The connections from one side to other plated holes are just for strain reliefs, so it
could be made in a back yard etching pyrex pan also.



Tektronix ORS2488/ORS622 SDH/SONET Reference Receiver

Melvin Gleep
 

The subject item is obviously not an oscilloscope, so I hope that I am not being impertinent by placing my request here. I am hoping that with so much Tektronix enthusiasm shown here, someone may have worked with one of these at some time during their career.

I recently purchased this discontinued Tektronix SDH/SONET Reference Receiver http://w140.com/tekwiki/wiki/ORS2488 on EBay, and have been searching for a user manual. Tektronix support links go really nowhere, so I am hoping someone can provide me with access to a user guide, service manual, or anything related. I sent a request to Tektronix support, but they have thus far remained silent.

Thanks for any help!

Re: TM500 / 5000 Extenders

John Griessen
 

For anyone interested in making TM500 extenders from 0.16" pitch straddle connectors they may have or find,
this pcb layout is available as RS274-X data, and in pcb-rnd format:
https://www.ecosensory.com/tek/tek_tm_flex_pcb_top.jpg
https://www.ecosensory.com/tek/tek_tm_flex_pcb_bot.jpg

It fits in the low cost 10cm square board size available for about $50 for ten from China.
The connections from one side to other plated holes are just for strain reliefs, so it
could be made in a back yard etching pyrex pan also.

Re: tektronix 7S14 batteries and time base question

Chuck Harris
 

Hi John,

That has been my experience as well. I did a long stint
in a lab where we were doing IR spectroscopy, using lasers.

When I tried to make such a bias device, I ground both LED's
ends flat, and welded them together with crazy glue. I figured
that it would reduce reflections at the red I was using.

I couldn't get spit out of them... measured with a 200M input
impedance meter... I guessed the older LED's just weren't
bright enough.

Or, maybe the mechanism is not reciprocal?

-Chuck

John Griessen wrote:

On 12/22/19 11:30 PM, Chuck Harris wrote:
If I have been following correctly (always suspect), aren't
we using an LED illuminated by another LED to behave as a
photo diode, and produce the bias voltage for the switch?
One thing for sure from back when I worked with near IR LEDs and laser diodes
in a narrow beam system is that what absorbs IR or reflects or not is
not obvious from our visible light experience... So, the efficiency could be because
the incoming IR light "gets in" instead of reflecting. They are both designed only to
output, yet one is being used to receive...

Longer IR tends to go through more things that look black to us, and probably go
right through
the plastic of LED lamps without much refraction so angle and placement can be whatever.

Re: Tek 2235 Repair

Tony Fleming
 

My switch did not feel stuck or crunchy... it just does lot more than I
ever knew! But you know more about scopes than I do for sure.
Happy holidays!

On Sun, Dec 22, 2019 at 10:35 PM Oscar Anderson <oscar.anderson462@...>
wrote:

Little update:

Haven't had a lot of time to work on this, but I did look at the ripple on
the power supply rails. +/- 8.6V rails are each within 50mV, and the ripple
was something like 2mV peak to peak. Ripple on the 100V rail was something
like 100 mV peak to peak.

I do not believe this to be an issue with the beam find switch since it
feels fine (not crunchy or anything) and I've pushed and wiggled it enough
times that I would have expected any issues with it to become apparent.
Haven't checked the voltage on the deflection plates yet.




Re: Tek 576 Curve Tracer HV Transformer winding

Mlynch001
 

On Mon, Dec 23, 2019 at 08:40 AM, Eric wrote:


How is the transformer testing going? I find my self in need of 1 or 2 when
they are ready.

Eric
Eric,

Contact me Off List and I will ad you to the waiting list. I have some final details to work out as to some aspects of this product, but hoping to roll out the first ones near the end of February 2020.
mylnch002atgmaildotcom

I appreciate your interest.

Sincerely,

--
Michael Lynch
Dardanelle, AR

Re: Tek 576 Curve Tracer HV Transformer winding

Mlynch001
 

Magnus,

Thank you for your kind comments! I hope that you are having a wonderful Christmas Season in Bavaria. This project is in the prototype and testing stage, I have some details to work out, optimistically I am looking to roll out the first production units at the end of February. Forgoing any unforeseen problems, of course. More details to follow, but I do have a working prototype under test. I believe that this is something that has been needed for some time.

--
Michael Lynch
Dardanelle, AR

Re: Tek 576 Curve Tracer HV Transformer winding

Eric
 

How is the transformer testing going? I find my self in need of 1 or 2 when
they are ready.

Eric

On Sun, Dec 22, 2019, 9:16 AM magnustoelle via Groups.Io <magnustoelle=
yahoo.com@groups.io> wrote:

Good Day,
wow, what a nice surprise of a critical replacement part for the 576
lovers.
Very nice work from what I have seen, Michael!
Have a wonderful holiday time.
Greetings from Bavaria, Germany,
Magnus
Ed,


Yes, you are exactly right the plastic screw is a critical item with this
type of core and mounting method. My instructions will include those
important details with the finished product. This little tidbit of
information came to me while researching specifics for this product
construction. The reason that we did not use clips was that this would
have made the core effectively wider and may not have fit. This was also
cheaper to produce. I decided to use the existing center hole and plastic
screw as an alternative to the clips. Obviously, I had to drill a hole,
centered between the two existing holes to mount the new transformer from.
I can also provide a 3D printed "adapter" for those who do not wish to
drill another hole in their instrument. More to come very soon.

--
Michael Lynch
Dardanelle, AR








Re: TM500 / 5000 Extenders

dnmeeks
 

Thanks everyone for the endorsement! I am really happy they have been useful. I don't have any more parts for building more, though. My cost for parts is about $20-$25 for each extender, with a purchase of 20 boards.
I sort of felt like the market was saturated on these so I have been declining new orders.
If anyone wants to let me know they want one (or two), email me off-list. If I get enough requests I'll place an order.
Otherwise if anyone is in a bind I am happy to loan out mine.
Thanks
Dan

Re: tektronix 7S14 batteries and time base question

John Griessen
 

On 12/22/19 11:30 PM, Chuck Harris wrote:
If I have been following correctly (always suspect), aren't
we using an LED illuminated by another LED to behave as a
photo diode, and produce the bias voltage for the switch?
One thing for sure from back when I worked with near IR LEDs and laser diodes
in a narrow beam system is that what absorbs IR or reflects or not is
not obvious from our visible light experience... So, the efficiency could be because
the incoming IR light "gets in" instead of reflecting. They are both designed only to
output, yet one is being used to receive...

Longer IR tends to go through more things that look black to us, and probably go right through
the plastic of LED lamps without much refraction so angle and placement can be whatever.

Re: Tek 485 short sweep

Siggi
 

You can start by looking at the A-sweep output. Per the service manual “A
and B sweep generators each produce, upon receipt of a gate, a negative
going sweep of 1.0 V/div of horizontal excursion, starting at +13 V.”

If you have a correct idle DC level of 13V, and you have linear slope for
-12V or so, you can assume the sweep is OK.

On Mon, Dec 23, 2019 at 01:26 stephen white <sswhite@...> wrote:

How can we narrow this short sweep to the sweep circuit or to the
horizantal amp circuit ??? I am back at this problem child of mine again
and am trying to figure which board to chase around on...I have a few more
things to check per all the good inputs I have had here but seems like it
would a good thing to determine which board the problem is on..
Any thoughts on this??

Steve



Re: Tek 485 short sweep

stephen white
 

How can we narrow this short sweep to the sweep circuit or to the horizantal amp circuit ??? I am back at this problem child of mine again and am trying to figure which board to chase around on...I have a few more things to check per all the good inputs I have had here but seems like it would a good thing to determine which board the problem is on..
Any thoughts on this??

Steve

Re: tektronix 7S14 batteries and time base question

Chuck Harris
 

Hi Leon,

If I have been following correctly (always suspect), aren't
we using an LED illuminated by another LED to behave as a
photo diode, and produce the bias voltage for the switch?

If so, I would think that an LED of the same color as the
"bias" LED would work best, as they are both set up to deal
with the same physics of electron levels, and photon energy.

I haven't given a lot of thought to the physics involved,
maybe they are different mechanisms?

-Chuck Harris




Leon Robinson wrote:

Maybe better responsiveness at longer wavelengths?

Leon Robinson K5JLR

Political Correctness is a Political Disease.

Politicians and Diapers should be changed
often and for the same reasons.

On Sunday, December 22, 2019, 10:08:56 PM CST, Chuck Harris <cfharris@...> wrote:

Hi Miguel,

Why is that? I would think that the shorter wavelengths
with their higher photon energy would be better.

-Chuck Harris

Miguel Work wrote:
Best efficiency is obtained with long wavelength LEDs





Re: Tek 2465 Problem

Harvey White
 

If you measured them in circuit, there's other paths that can contribute to the 2K resistance.  I'd look to see what the voltage is, and look to see (given the secondary voltage) what the output ought to be.  What you want to see is the classic 120 Hz half sinewave displayed on an oscilloscope, and that would be with no capacitors in circuit.  If the ripple on the bulk supply is 60 Hz (or 50), then you may have a bad rectifier, and you'd expect to see the bulk supply reading low (assuming no other problems).  If the ripple is 120/100 Hz, then I think you're ok.  Most of the power rectifiers that I've seen tend to fail shorted, not open. Shorted would blow the primary fuse.

If the power supplies are within spec for both voltage and ripple, I'd be looking elsewhere.

Harvey

On 12/22/2019 4:55 PM, Panos wrote:
On Sun, Dec 22, 2019 at 04:31 PM, Panos wrote:

because they have very low in ohm resistance (about 130 ohm) when I measure
these with forward polarity. Conversely they have a complete cut.
Sorry I must to said forward 80 ohm and conversely 2 kohm.



Re: Tek 2235 Repair

Bob Albert
 

My guess it has to do with intensity control.  The beam finder bypasses that, I believe.  So maybe there is no unblanking gate or maybe the gate isn't getting to the CRT.
Bob

On Sunday, December 22, 2019, 08:35:29 PM PST, Oscar Anderson <oscar.anderson462@...> wrote:

Little update:

Haven't had a lot of time to work on this, but I did look at the ripple on the power supply rails. +/- 8.6V rails are each within 50mV, and the ripple was something like 2mV peak to peak. Ripple on the 100V rail was something like 100 mV peak to peak.

I do not believe this to be an issue with the beam find switch since it feels fine (not crunchy or anything) and I've pushed and wiggled it enough times that I would have expected any issues with it to become apparent. Haven't checked the voltage on the deflection plates yet.

Re: Tek 2235 Repair

Oscar Anderson
 

Little update:

Haven't had a lot of time to work on this, but I did look at the ripple on the power supply rails. +/- 8.6V rails are each within 50mV, and the ripple was something like 2mV peak to peak. Ripple on the 100V rail was something like 100 mV peak to peak.

I do not believe this to be an issue with the beam find switch since it feels fine (not crunchy or anything) and I've pushed and wiggled it enough times that I would have expected any issues with it to become apparent. Haven't checked the voltage on the deflection plates yet.

Re: tektronix 7S14 batteries and time base question

Leon Robinson
 

Maybe better responsiveness at longer wavelengths?

Leon Robinson    K5JLR

Political Correctness is a Political Disease.

Politicians and Diapers should be changed
often and for the same reasons.

On Sunday, December 22, 2019, 10:08:56 PM CST, Chuck Harris <cfharris@...> wrote:

Hi Miguel,

Why is that?  I would think that the shorter wavelengths
with their higher photon energy would be better.

-Chuck Harris

Miguel Work wrote:
Best efficiency is obtained with long wavelength LEDs

Re: tektronix 7S14 batteries and time base question

Chuck Harris
 

Hi Miguel,

Why is that? I would think that the shorter wavelengths
with their higher photon energy would be better.

-Chuck Harris

Miguel Work wrote:

Best efficiency is obtained with long wavelength LEDs

Re: 7K flexible extenders

John Griessen
 

On 12/22/19 5:12 PM, @Tek_HP wrote:
John,
I am interested to buy two extender kits, if you still have them. If so, how could I order?
I don't supply TM500 extenders anymore, and some parts for 7k flex extenders are out,
and I'm moving to Albuquerque, so nothing for 6 months. I'll start a waiting list.