Re: Scoping the Power Rails [8566B]
I'm not sure if this is the cause (probably) but it depends on how the 100 MHz reference interprets it. Can you connect to an external 10MHz source (possible from one of your other instruments internal reference0? Quoting Jinxie <paul666@...>:
Gentlemen,
Following advice here, I decided to first check the 10Mhz frequency of the reference oscillator to see if it had drifted and was rather surprised to see it come out on my frequency counter as 20Mhz. So only out by 10Mhz, then! I then connected it to my scope and got the trace shown below. Oddly enough, the ref oscillator warning on the screen went out when it was warmed up, so part of the analyzer at least didn't have a problem with this! The YTO unlock error message was still there, though.
Any suggestions? Could this weird ref trace be the cause of the YTO unlock?
Measured directly from the BNC at the rear of the analyzer on a 1:1 basis.
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Re: Scoping the Power Rails [8566B]
Gentlemen, Following advice here, I decided to first check the 10Mhz frequency of the reference oscillator to see if it had drifted and was rather surprised to see it come out on my frequency counter as 20Mhz. So only out by 10Mhz, then! I then connected it to my scope and got the trace shown below. Oddly enough, the ref oscillator warning on the screen went out when it was warmed up, so part of the analyzer at least didn't have a problem with this! The YTO unlock error message was still there, though. Any suggestions? Could this weird ref trace be the cause of the YTO unlock?  Measured directly from the BNC at the rear of the analyzer on a 1:1 basis.
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Re: Low EMI lighting for labs and work areas
few years ago- most
likely still true. the 40W LED 4 foot replacements for
fluorescent bulbs - (remove the ballast and wire to 120VAC)
generated horrible RF noise ( 50khz -to 50Mhz+). I took one
apart-they left off the line filters!!. Installing external
filter for the 4 bulbs solved the issue.....it is the switching
supply at the mains.
the company HYPERIKON did not care....IIRC the quote "we do not
care about anything except the light output. radiated RF noise
is not our concern."
so do beware
搁别苍é别
On 3/4/22 5:35 AM, Tommy wrote:
toggle quoted message
Show quoted text
A few years ago we decided to go with LED bulbs in the
household, I found that there was a significant difference in
RFI between models (20dB+, 1-30MHz) and no correlation
whatsoever to price/well known brands/unknown makes.
On 2022-03-04 14:16, Radu Bogdan Dicher wrote:
Hal,
I was just about to post on this - really interested?in
the conversation and solutions proposed/found!
?
I am currently using a couple of those LED fixtures
that replicate the format of fluorescent lights. As muy
bench is on one side of a low, grade level garage in
Southern California - therefore a lot of high hills and
mountains?all around - and that I do quite a bit of FM
tuner alignments?and such work - the reception?conditions
are terrible depending on what lights I turn on in the lab
and where my tuner or receiver?is. Effectively, because of
the lighting?situation, I am unable to use a radio on the
bench in any consistent way (I turned to streaming due to
that).?
?
And that may seem trivial, but except for FM
alignments, I also do a lot of audio or RF measurements
(some where the threshold for noise is critical) and I
wonder how much this garbage influences my readings.
Looking forward to some solutions and a feasible path
forward!
Radu.?
?
On Fri, Mar 4, 2022 at
4:59 AM Harold Foster < halfoster@...>
wrote:
All:
?
I'm in the process of moving and am thinking about
the design of my new lab/work area and am trying to
decide on the lighting.? In particular I would like to
minimize the effect of radiated noise from the lights
but also other factors such as the layout, CRI and color
temperature.? Does anyone have any recommendations or
experience they would share?? Thoughts so far are to
have 4400K in general and 4800-5000K lighting over the
task areas.? Having a high CRI is a plus but not
strictly necessary.? The lowest noise solution would be
custom LED arrays with a linear power supply - fairly
straightforward to do but expensive.? Currently I am
using 54W HO T-5 fluorescent fixtures in 4400K but they
are fairly noisy in emissions so I would love to find
alternatives.
?
TIA,
?
Hal
|
On Fri, Mar 4, 2022 at 10:31 AM, Attilio wrote:
I would like to point out that in the 200CD manual the diagram shows the diodes CR1 and CR2 connected incorrectly, ie with reversed polarity. I don't know if any corrected versions of the scheme have been published.
That's really interesting. I went back to my files and I see that I have 2 different manuals for the 200CD-605. The '65 manual, HP part #200CD-903, has the diodes backwards, as you said, but the '66 manual, HP #200CD-904, has those corrected. The manual I had been looking at was the later one. Seems like a pretty rookie mistake for HP.
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Re: HP 8341B RF sweeper has reduced output
They are very small about 1/8” in diameter, back when i repaired this kind of stuff I ordered them from a watchmaker supply store (frei, borrel) they were used as sprocket gaskets on rolex watches but other companies might have them too?
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On Mar 4, 2022, at 10:15, Jim Adney via groups.io <jadney@...> wrote:
?McMaster-Carr is a good source for O-rings, but if these are really small, a better source might be? Apple Rubber,?.
Note that you have to choose a size AND an elastomer. The latter can be difficult to decide, but the right material may last longer and work better.
|
Hello everybody,
I would like to point out that in the 200CD manual the diagram shows the diodes CR1 and CR2 connected incorrectly, ie with reversed polarity. I don't know if any corrected versions of the scheme have been published.
-- Cheers
??? Attilio
|
Re: HP 8341B RF sweeper has reduced output
McMaster-Carr is a good source for O-rings, but if these are really small, a better source might be? Apple Rubber,?.
Note that you have to choose a size AND an elastomer. The latter can be difficult to decide, but the right material may last longer and work better.
|
On Thu, Mar 3, 2022 at 06:40 PM, H Kapa wrote:
Hi Jim Adney,
I have a 200CD Ser.605- working on my bench and a few days ago in the middle of another repair my 200CD signal failed,?
In time there I decided to check carefully, the DC voltages were present, but fluctuating in relation to the earth, result R40 of 15K / 10W open, I replaced it with an equivalent but with must the improvised fixing and nothing like the original.
?
So, I ask if you don't have an R40 to supply?
I pulled out my 200CD-605 manual and my box of salvaged parts. In the schematic I find R40 to be 10 kOhm, 10 watt, wirewound, by Lectrohm. I sincerely doubt if there's anything special about this one; anything you can come up with should work as well, but note that it should be TEN kOhm, not 15. I have one which you would be welcome to for the shipping, but I don't think you need it. The Manual Change pages in the back of my manual say that R40 was changed in 605-65305 and above. It gives a different HP part number, but doesn't say if the resistance value changed, but some of the other changes specify a value change, so this looks like it might be just a supplier change. If your R40 looks original and your serial number is 65305 or above, you should probably stick with 15 kOhm. BUT, I sincerely doubt if R40 is the source of your problems. I don't think there should normally be any significant current thru it. It sets the DC ground for the power supply, but I can't find any other DC ground connection anywhere else in the schematic. It looks like its only function might be to limit the inrush charging current into C14. Once C14 is charged, the only current thru R40 would be the 120 Hz ripple current thru C40, and perhaps this applies a bit of AC to the grid circuits of V2 & V4, as negative feedback to null out any 120 Hz component in the output. Do you have a correct 200CD-605 manual and schematic? I think the first thing you should do would be to check all the voltages called out on the schematic. I also recommend that you check continuity thru the two incandescent bulbs. I recommend removing the bulbs and soldering the press fit connections on the sockets. I've had those go resistive. I have a box of NOS bulbs if you need them, but you probably don't. I've never needed to replace one. One thing that would burn out R40 would be a shorted C14. If that happened, CR1 & CR2 may also have burned out. Those are listed as 1N2359s, but could probably be replaced by 1N4007s. If CR1 & CR2 are dead, that would certainly explain your totally dead 200CD.
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Re: HP 8341B RF sweeper has reduced output
Thanks for the info,
In this case, by my mistake, the resistance R40 is 10K, but it doesn't change your information.
The goal is to obtain the original HP resistance according to the photo
Best Regards?
H Capela?
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Re: Low EMI lighting for labs and work areas
It sounds like almost worth putting together a list of "known low emission" LED fixtures for others to refer to when selecting their bench lights.? I am aware this will be very market-dependent, but maybe, then, a few lists?... Sounds like a big project, but any list starts with one entry and by the time there's two, it's a list! :) Radu.?
On Fri, Mar 4, 2022 at 5:35 AM Tommy < tommy@...> wrote:
A few years ago we decided to go with LED bulbs in the household, I found that there was a significant difference in RFI between models (20dB+, 1-30MHz) and no correlation whatsoever to price/well known brands/unknown makes.
On 2022-03-04 14:16, Radu Bogdan Dicher wrote:
Hal,
I was just about to post on this - really interested?in the conversation and solutions proposed/found!
?
I am currently using a couple of those LED fixtures that replicate the format of fluorescent lights. As muy bench is on one side of a low, grade level garage in Southern California - therefore a lot of high hills and mountains?all around - and that I do quite a bit of FM tuner alignments?and such work - the reception?conditions are terrible depending on what lights I turn on in the lab and where my tuner or receiver?is. Effectively, because of the lighting?situation, I am unable to use a radio on the bench in any consistent way (I turned to streaming due to that).?
?
And that may seem trivial, but except for FM alignments, I also do a lot of audio or RF measurements (some where the threshold for noise is critical) and I wonder how much this garbage influences my readings. Looking forward to some solutions and a feasible path forward!
Radu.?
?
On Fri, Mar 4, 2022 at 4:59 AM Harold Foster < halfoster@...> wrote:
All:
?
I'm in the process of moving and am thinking about the design of my new lab/work area and am trying to decide on the lighting.? In particular I would like to minimize the effect of radiated noise from the lights but also other factors such as the layout, CRI and color temperature.? Does anyone have any recommendations or experience they would share?? Thoughts so far are to have 4400K in general and 4800-5000K lighting over the task areas.? Having a high CRI is a plus but not strictly necessary.? The lowest noise solution would be custom LED arrays with a linear power supply - fairly straightforward to do but expensive.? Currently I am using 54W HO T-5 fluorescent fixtures in 4400K but they are fairly noisy in emissions so I would love to find alternatives.
?
TIA,
?
Hal
|
Re: Low EMI lighting for labs and work areas
FWIW, here's another possibility. I use 12V LED strips, powered directly from the 12V side of my solar power system. I have only fairly light loads on that side of the system, and with 940AH of storage, I can run them a very long time even when the panels are covered in snow. No switching, pure DC by the time it gets into the house. However, not everyone will have the 12VDC distribution infrastructure that I've built up over the years.
Steve Hendrix
|
Re: Low EMI lighting for labs and work areas
A few years ago we decided to go with LED bulbs in the household, I found that there was a significant difference in RFI between models (20dB+, 1-30MHz) and no correlation whatsoever to price/well known brands/unknown makes.
toggle quoted message
Show quoted text
On 2022-03-04 14:16, Radu Bogdan Dicher wrote:
Hal,
I was just about to post on this - really interested?in the conversation and solutions proposed/found!
?
I am currently using a couple of those LED fixtures that replicate the format of fluorescent lights. As muy bench is on one side of a low, grade level garage in Southern California - therefore a lot of high hills and mountains?all around - and that I do quite a bit of FM tuner alignments?and such work - the reception?conditions are terrible depending on what lights I turn on in the lab and where my tuner or receiver?is. Effectively, because of the lighting?situation, I am unable to use a radio on the bench in any consistent way (I turned to streaming due to that).?
?
And that may seem trivial, but except for FM alignments, I also do a lot of audio or RF measurements (some where the threshold for noise is critical) and I wonder how much this garbage influences my readings. Looking forward to some solutions and a feasible path forward!
Radu.?
?
On Fri, Mar 4, 2022 at 4:59 AM Harold Foster < halfoster@...> wrote:
All:
?
I'm in the process of moving and am thinking about the design of my new lab/work area and am trying to decide on the lighting.? In particular I would like to minimize the effect of radiated noise from the lights but also other factors such as the layout, CRI and color temperature.? Does anyone have any recommendations or experience they would share?? Thoughts so far are to have 4400K in general and 4800-5000K lighting over the task areas.? Having a high CRI is a plus but not strictly necessary.? The lowest noise solution would be custom LED arrays with a linear power supply - fairly straightforward to do but expensive.? Currently I am using 54W HO T-5 fluorescent fixtures in 4400K but they are fairly noisy in emissions so I would love to find alternatives.
?
TIA,
?
Hal
|
Re: Low EMI lighting for labs and work areas
Currently I am thinking the same as Jon - research the high quality LED options and go with the DIY linear solution for the close-in task work.? Of course, "research the high quality LED options" is very easy to say, but the doing could prove to be somewhat bothersome...
Hal
|
Re: Low EMI lighting for labs and work areas
Hal, I was just about to post on this - really interested?in the conversation and solutions proposed/found!
I am currently using a couple of those LED fixtures that replicate the format of fluorescent lights. As muy bench is on one side of a low, grade level garage in Southern California - therefore a lot of high hills and mountains?all around - and that I do quite a bit of FM tuner alignments?and such work - the reception?conditions are terrible depending on what lights I turn on in the lab and where my tuner or receiver?is. Effectively, because of the lighting?situation, I am unable to use a radio on the bench in any consistent way (I turned to streaming due to that).?
And that may seem trivial, but except for FM alignments, I also do a lot of audio or RF measurements (some where the threshold for noise is critical) and I wonder how much this garbage influences my readings. Looking forward to some solutions and a feasible path forward! Radu.?
On Fri, Mar 4, 2022 at 4:59 AM Harold Foster < halfoster@...> wrote: All:
?
I'm in the process of moving and am thinking about the design of my new lab/work area and am trying to decide on the lighting.? In particular I would like to minimize the effect of radiated noise from the lights but also other factors such as the layout, CRI and color temperature.? Does anyone have any recommendations or experience they would share?? Thoughts so far are to have 4400K in general and 4800-5000K lighting over the task areas.? Having a high CRI is a plus but not strictly necessary.? The lowest noise solution would be custom LED arrays with a linear power supply - fairly straightforward to do but expensive.? Currently I am using 54W HO T-5 fluorescent fixtures in 4400K but they are fairly noisy in emissions so I would love to find alternatives.
?
TIA,
?
Hal
|
Re: Low EMI lighting for labs and work areas
use high quality LED strip and EU not Chinese ballast compliance to EMI a nd safety
Fluorescent are arcs,and wideband RF and microwave noise emitting
Jon
|
Low EMI lighting for labs and work areas
All:
?
I'm in the process of moving and am thinking about the design of my new lab/work area and am trying to decide on the lighting.? In particular I would like to minimize the effect of radiated noise from the lights but also other factors such as the layout, CRI and color temperature.? Does anyone have any recommendations or experience they would share?? Thoughts so far are to have 4400K in general and 4800-5000K lighting over the task areas.? Having a high CRI is a plus but not strictly necessary.? The lowest noise solution would be custom LED arrays with a linear power supply - fairly straightforward to do but expensive.? Currently I am using 54W HO T-5 fluorescent fixtures in 4400K but they are fairly noisy in emissions so I would love to find alternatives.
?
TIA,
?
Hal
|
Re: HP 8341B RF sweeper has reduced output
I've had to replace 'O' rings in quite a few of these attenuators
over the years, in most cases because they had gone brittle and
disintegrated.
However, two days ago I decided to sort out an 83545A sweeper
plug-in which was showing signs of an intermittent attenuator
misfire and found 16 rings that had decided to revert to their
original liquid hydrocarbon form and presented as 16 dollops of
gooey black sludge.
After removing the chunks of it with cocktail sticks and discovering
IPA had no effect, using my ultrasonic cleaner for 3 minutes with a
10% solution of 'Crystal Simple? Green' cleaner the rods came up a
treat!
Either way, good luck and take your time - these things are a bit
fragile and somewhat fiddly to work on but eminently fixable!
Adrian
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Show quoted text
thanks to all who replied, i just watched a "rf attenuator
rebuild" video and ordered a "watch repair rubber o-ring
kit"..cause I didnt have tiny o-rings like that...seems some in
there should fit...will open the 8341B and check the attenuator
when i have these on hand and hopefully open/fix/close back up in
a single "repair session"...Ill posts results then...
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Re: HP 8341B RF sweeper has reduced output
I looked through my stash and I still have one new push rod with o-rings , I can send you this one free of charge if you email me your adress
?
Sent from for Windows
?
toggle quoted message
Show quoted text
thanks to all who replied, i just watched a "rf attenuator rebuild" video and ordered a "watch repair rubber o-ring kit"..cause I didnt have tiny o-rings like that...seems some in there should fit...will open the 8341B and check the attenuator when i have
these on hand and hopefully open/fix/close back up in a single "repair session"...Ill posts results then...
|
Re: HP 8341B RF sweeper has reduced output
Be cautious when removing the push rods not to break off the tips , ?you need a needle to push the tips over gently when pulling them out , the contacts actually have a slot that ends in a little hole you have to push the rods over to line
them up with the hole to pull them out
?
Sent from for Windows
?
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From: charlesterrebonne via groups.io
Sent: Thursday, March 3, 2022 10:40 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 8341B RF sweeper has reduced output
?
thanks to all who replied, i just watched a "rf attenuator rebuild" video and ordered a "watch repair rubber o-ring kit"..cause I didnt have tiny o-rings like that...seems some in there should fit...will open the 8341B and check the attenuator
when i have these on hand and hopefully open/fix/close back up in a single "repair session"...Ill posts results then...
|
Re: HP 8341B RF sweeper has reduced output
thanks to all who replied, i just watched a "rf attenuator rebuild" video and ordered a "watch repair rubber o-ring kit"..cause I didnt have tiny o-rings like that...seems some in there should fit...will open the 8341B and check the attenuator when i have these on hand and hopefully open/fix/close back up in a single "repair session"...Ill posts results then...
|
Jinxie
Attilio
H Kapa
Harold Foster
Froggie the Gremlin
