Re: Switching power supplies
My take on this after replacing thousands of surface mount electrolytic capacitors is replace them all when you get a new to you device that is more than ten or so years old.
Switchers are harder on
By
Glenn Little
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#155600
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11801 calibrator rise time
I think I figured out why the calibrator rise time measurement doesn't read to spec. I warmed up the 11810 for about 40 minutes to do the Enhanced Accuracy adjustments. That seemed to go fine except
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Reginald Beardsley
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#155599
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Re: Switching power supplies
Replace Rifa mains interference suppression delayed action smoke generators on sight; if there is any sign of cracking in the transparent case, don't even turn it on.
Where there are tantalum beads
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Tom Gardner
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#155598
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Re: Switching power supplies
Tough question.
Yes, switching supplies are inherently harder on
components than linear, but they also use much better
parts. And they are more likely to be designed using
math, rather than rules of
By
Chuck Harris <cfharris@...>
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#155597
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Switching power supplies
I have a few questions about power supplies and would like some opinions. Are switching powers supplies inherently harder on components than linear power supplies? If you picked up a 70's-80's
By
Brendan
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#155596
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Re: Repairability of SD-24, SD-30 & SD-32 sampling heads
Hi Reginald,
It is in the archives:
/g/TekScopes/topic/7659008#141241
Enjoy.
Egge Siert
By
Egge Siert
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#155595
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Re: Impedance matching question
Because there is a mismatch between the high plate resistance of the output pentodes or tetrodes
(about 4.5k-ohms in push pull) and the loudspeaker. The impedance transformation goes as the square
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Craig Sawyers <c.sawyers@...>
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#155593
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Re: 11801 is reassembled, up and running :-)
Gentlemen... have a look here:
/g/TekScopes/message/155394?p=,,,20,0,0,0::Created,,egge+siert,20,2,0,30465052
Albert
By
Albert Otten
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#155592
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Re: Impedance matching question
Through the tube era and the discrete solid state era professional balanced audio lines in radio and recording studios were also impedance matched at 600 ohms (earlier 500 ohms) because they were
By
Dale H. Cook
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#155591
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Re: 11801 is reassembled, up and running :-)
The user manual I quoted has a revision date of May 1989. The August 1988 service manual states the calibrator is < 35 ps. The February 1989 revision page states the same rise time.
As I noted
By
Reginald Beardsley
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#155590
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Re: Impedance matching question
Thanks Craig... so, if I were to summarize what you wrote, at such short
distances, there's really no opportunity for a reflected signal to go out
of phase with the incident signal?
In watching the
By
David Berlind
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#155589
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Re: 11801 is reassembled, up and running :-)
They must have changed the cal output circuitry on the later models.
By
Bob Koller <testtech@...>
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#155588
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Re: Impedance matching question
It is to do with the frequency range. As soon as the length of
By
Craig Sawyers <c.sawyers@...>
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#155587
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Re: 11801 is reassembled, up and running :-)
Attachments are not allowed here Reg. Via the website you can create a new Album in the Photos section and put your picture(s) there. If you do so, it's handy for "us" if you insert a link to the
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Albert Otten
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#155586
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Re: Impedance matching question
That was a decent video, thank you. It doesn't seem like he had problems
with the terminators themselves. In fact, he uses them to address
mismatches. I'd be curious to know (from anyone who knows)
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David Berlind
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#155585
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Re: 11801 is reassembled, up and running :-)
Thanks. It will be a while before I take it apart again, but I'll make a note in my service manual.
Fortunately, most of my HP gear lists the parts in the manuals, so those will be easier to
By
Reginald Beardsley
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#155584
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Re: 11801 is reassembled, up and running :-)
I may have to take part of that back.
In my F/W EPROM collection I don't have 11801 but there is a note saying that 11801 can also use 11801A F/W
which I have and it uses both types. I now begin to
By
zenith5106
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#155583
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Re: 11801 is reassembled, up and running :-)
27C010 and 27C512
/H?kan
By
zenith5106
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#155582
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Re: Repairability of SD-24, SD-30 & SD-32 sampling heads
Far as I know he still works at a university in Portugal -he's been there for some years and is well known in scientific and amateur (especially EME) circles.
73
Dave, ZL3FJ
By
Dave Brown
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#155581
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Re: 11801 is reassembled, up and running :-)
11801 User manual p 42.
"The signal from the calibrator output us a 250 mV square wave with a rise time of approximately 20 ps and a period of approximately 10 microseconds."
After I did the
By
Reginald Beardsley
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#155580
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