Re: Circular Polarisation in Waveguide
HP used to sell a 3D SW package for simulating E-M fields that looked pretty nice
but was hugely expensive (>$30,000). Can you tell us more about this HFSS please?
Thanks,
-John -=-=-=- From Agilent web site: "15 June 2001 High-Frequency Structure Simulator (HFSS) is no longer available for purchase from Agilent EEsof EDA. Ansoft Corporation has purchased the rights to Agilent's HFSS technology and is now the only source of HFSS for purchase." Anasoft HFSS web page: <> Dave
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Re: Scope Tube Rejuvenation...
Hi Mark,
If you check the archives here, and at TekScopes, you will find
several articles where I detailed the process using a CR-70. The
CR-7000 is the same, only better.
In the book that came with the CR-7000, there is a detailed discussion
of the process. There are also several papers on Sencore's website.
And, in the test book, you will see settings for several generic scope
tubes, such as the 5UP1. All scope tubes are basically the same.
The Sencore CR-70, and CR-7000 have a universal CRT adapter available.
Essentially, it is a bunch of micro grabber clips connected to the
Sencore's test cable. The heater is obvious, the cathode, too. The
control grid is the first electrode after the cathode, and the focus
grid is next in line. The gain test uses the cathode, control grid, and
the next anode in the line to run the gun as a triode.
The Sencore does its rejuvenation using the control grid as the anode
and draws much higher than normal current out of the cathode. To aid
in that process, the heater voltage is raised 50% over normal.
In case you are worried, the control grid on a CRT is nothing like the
grid on a triode. It is a metal cup with a hole in its center for the
beam to pass through.
Beware! HP heaters often use non-standard voltages, such as 4.8V.
-Chuck Harris
Mark wrote:
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Hello all...
I have been a member here for awhile, but haven't had anything to say
constructive to any of the topics discussed, even though I use a large
number of HP instruments in my work. As such I kinda sit back and learn from you folks. Several posts have made me able to maintain my
HP instruments...Thank you!
A recent discussion centered around the ability to rejuvenate scope
tubes in the 141T. I searched the files and found several related
posts. However, I wasn't able to find anything that talked about the
actual procedure to do the rejuvenation. When I left the general
service business I took along with me a Sencore CR7000 CRT tester and
rejuvenator, which I assume would work for this operation since
mention was made of a Sencore CR-70.
I do restoration of vintage audio equipment and I run across scope
tubes, in several of the high end tuners and audio monitors, that
clients' send in for restoration. Most, if not all, are very weak.
These units have the small, 2 and 3 inch CRTs. Could anyone here lay out the procedure for rejuvenating an actual
scope tube. I do have several tech sheets for the tubes involved.
I would really appreciate a lesson on how to accomplish this feat.
Thanks folks...
Mark
Absolute Sound Labs
email: wilsonm@...
Yahoo! Groups Links
|
Scope Tube Rejuvenation...
Hello all...
I have been a member here for awhile, but haven't had anything to say
constructive to any of the topics discussed, even though I use a large
number of HP instruments in my work. As such I kinda sit back and
learn from you folks. Several posts have made me able to maintain my
HP instruments...Thank you!
A recent discussion centered around the ability to rejuvenate scope
tubes in the 141T. I searched the files and found several related
posts. However, I wasn't able to find anything that talked about the
actual procedure to do the rejuvenation. When I left the general
service business I took along with me a Sencore CR7000 CRT tester and
rejuvenator, which I assume would work for this operation since
mention was made of a Sencore CR-70.
I do restoration of vintage audio equipment and I run across scope
tubes, in several of the high end tuners and audio monitors, that
clients' send in for restoration. Most, if not all, are very weak.
These units have the small, 2 and 3 inch CRTs.
Could anyone here lay out the procedure for rejuvenating an actual
scope tube. I do have several tech sheets for the tubes involved.
I would really appreciate a lesson on how to accomplish this feat.
Thanks folks...
Mark
Absolute Sound Labs
email: wilsonm@...
|
Circular Polarisation in Waveguide
Lothar Ok guys this is not directly related to agilent t+m but im
banging my <br> head on the wall with this !<br>
Im looking for material on how to design and build a turnstile <br>
polarization converter, i googled up and down but cant find anything <br>
usefull , not even in the books i have.<br>
The problem i have requires me to design and build a 36GHz circular <br>
polarized horn antenna, the antenna needs to have two ports one for <br>
right and the other one for left turn polarization .<br>
any help would be appreciated <br> There are number of ways of doing this, but at 36GHz there's a rather more limited number of choices. Techniques such as the use of coax hybrids are definitely not usable, and the septum polariser becomes tricky to make above about 10GHz. My suggestion would be to split the problem: use an otho-mode-transducer to launch two orthogonal linearly polarised waves into a length of circular waveguide, and then delay one polarisation by 90degrees using a suitable polariser. I don't think there's a simple 'recipe' for a feed that I could recommend - frequency scaling of a waveguide component is often quite complex. However, the late Dick Turrin, W2IMU, (of Bell Labs) wrote an interesting paper describing such a system for amateur 10GHz EME back in the 1980s which might scale reasonably easily. That's on my ham radio web site: either <www.christopherbartramrfdesign.com/blaenffos/indexgw4dgu.html> or <www.blaenffos.org/indexgw4dgu.html> should get you there. There is a book: 'Waveguide Components for Antenna Feed Systems' by Uher, Bornemann & Rosenberg. (Artech House) which is very good, but rather expensive. ($200?) You may be able to find it in a library, though. In the UK, most university libraries allow public access, if you ask nicely... If you are doing waveguide design, I'd also strongly recommend that you try to get access to a 3D electromagnetic simulator such as HFSS. That can save considerable hair loss, although in my case that's less of a consideration than it used to be! BTW. Thanks for the ongoing observations, tips and transferred knowledge. I find your posts to this group very useful. There are some very bright contributors to the group, and it's on my daily 'must read' list! Best wishes Chris Bartram (actively playing 10GHz Moonbounce as GW4DGU)
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Re: Circular polarization antenna question
Septum feed is going to require some smart machining at 36GHz - the diameter of the waveguide is around 0.71 lambda - haven't done the sums for 36G, but at 10G thats just about 20mm. You'll also have to check out what the matching is to whatever reflector you're using (I'm assuming that this will be at the focus of a small dish?) CWST (circular waveguide septum transformer) and RWST (rectangular WST) feeds are optimum for f/d of around 0.4, and even then benefit from some cavity rings a la VE4MA (see W1GHZ work) or Chapparal (see W1GHZ or recent practical work by DL4MEA). To adapt to other dish f/d ratios flared horns work well on the front of the feed.
You would probably benefit by looking at W1GHZ's latest work, published at Microwave Update in PA 2 weeks ago - this will be on his website, or on the MUD2007 site.
Cheers,
Dave
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----- Original Message ---- From: J Forster <jfor@...> To: hp_agilent_equipment@... Sent: Sunday, 4 November, 2007 2:12:27 AM Subject: Re: [hp_agilent_equipment] Circular polarization antenna question Another lead from a local ham: For the guy looking for the circular pol horn info Try the W1GHZ on line microwave antenna book . org/antbook/ contents. htm His best bet is the Septum feed . org/antbook/ conf/SEPTUM. pdf I really don't want to register to join the Yahoo group so I'll be happy reading only. Best, -John lothar baier wrote: i dont have any of those books on hand, i never had much interest in antennas so i got a bunch of other books and periodicals but nothing on antenna stuff J Forster <jfor@...> wrote: Have you looked at some of the old standard books like Kraus or the Rad Lab series? I'd at least start there. Then perhaps the IEEE Antenna & Propagation (or whatever it is actually called) The web is fine for some things, but is not great on fundamental engineering. Also, Google has an academic research function. That might give you a lead. Best, -John microwaveengineer19 68 wrote: Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
____________ _________ _________ _________ _________ __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around . yahoo.com Yahoo! Groups Links <!-- #ygrp-mkp{ border:1px solid #d8d8d8;font-family:Arial;margin:14px 0px;padding:0px 14px;} #ygrp-mkp hr{ border:1px solid #d8d8d8;} #ygrp-mkp #hd{ color:#628c2a;font-size:85%;font-weight:bold;line-height:122%;margin:10px 0px;} #ygrp-mkp #ads{ margin-bottom:10px;} #ygrp-mkp .ad{ padding:0 0;} #ygrp-mkp .ad a{ color:#0000ff;text-decoration:none;} --> <!-- #ygrp-sponsor #ygrp-lc{ font-family:Arial;} #ygrp-sponsor #ygrp-lc #hd{ margin:10px 0px;font-weight:bold;font-size:78%;line-height:122%;} #ygrp-sponsor #ygrp-lc .ad{ margin-bottom:10px;padding:0 0;} --> <!-- #ygrp-mlmsg {font-size:13px;font-family:arial, helvetica, clean, sans-serif;} #ygrp-mlmsg table {font-size:inherit;font:100%;} #ygrp-mlmsg select, input, textarea {font:99% arial, helvetica, clean, sans-serif;} #ygrp-mlmsg pre, code {font:115% monospace;} #ygrp-mlmsg * {line-height:1.22em;} #ygrp-text{ font-family:Georgia; } #ygrp-text p{ margin:0 0 1em 0;} #ygrp-tpmsgs{ font-family:Arial; clear:both;} #ygrp-vitnav{ padding-top:10px;font-family:Verdana;font-size:77%;margin:0;} #ygrp-vitnav a{ padding:0 1px;} #ygrp-actbar{ clear:both;margin:25px 0;white-space:nowrap;color:#666;text-align:right;} #ygrp-actbar .left{ float:left;white-space:nowrap;} .bld{font-weight:bold;} #ygrp-grft{ font-family:Verdana;font-size:77%;padding:15px 0;} #ygrp-ft{ font-family:verdana;font-size:77%;border-top:1px solid #666; padding:5px 0; } #ygrp-mlmsg #logo{ padding-bottom:10px;} #ygrp-vital{ background-color:#e0ecee;margin-bottom:20px;padding:2px 0 8px 8px;} #ygrp-vital #vithd{ font-size:77%;font-family:Verdana;font-weight:bold;color:#333;text-transform:uppercase;} #ygrp-vital ul{ padding:0;margin:2px 0;} #ygrp-vital ul li{ list-style-type:none;clear:both;border:1px solid #e0ecee; } #ygrp-vital ul li .ct{ font-weight:bold;color:#ff7900;float:right;width:2em;text-align:right;padding-right:.5em;} #ygrp-vital ul li .cat{ font-weight:bold;} #ygrp-vital a{ text-decoration:none;} #ygrp-vital a:hover{ text-decoration:underline;} #ygrp-sponsor #hd{ color:#999;font-size:77%;} #ygrp-sponsor #ov{ padding:6px 13px;background-color:#e0ecee;margin-bottom:20px;} #ygrp-sponsor #ov ul{ padding:0 0 0 8px;margin:0;} #ygrp-sponsor #ov li{ list-style-type:square;padding:6px 0;font-size:77%;} #ygrp-sponsor #ov li a{ text-decoration:none;font-size:130%;} #ygrp-sponsor #nc{ background-color:#eee;margin-bottom:20px;padding:0 8px;} #ygrp-sponsor .ad{ padding:8px 0;} #ygrp-sponsor .ad #hd1{ font-family:Arial;font-weight:bold;color:#628c2a;font-size:100%;line-height:122%;} #ygrp-sponsor .ad a{ text-decoration:none;} #ygrp-sponsor .ad a:hover{ text-decoration:underline;} #ygrp-sponsor .ad p{ margin:0;} o{font-size:0;} .MsoNormal{ margin:0 0 0 0;} #ygrp-text tt{ font-size:120%;} blockquote{margin:0 0 0 4px;} .replbq{margin:4;} -->
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Re: 419A Chopper Replacement
deane kidd who has tektronix parts might have the neon bulbs you need
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Show quoted text
----- Original Message -----
From: Harvey White
To: hp_agilent_equipment@...
Sent: Saturday, November 03, 2007 9:07 PM
Subject: Re: [hp_agilent_equipment] Re: 419A Chopper Replacement
On Sat, 03 Nov 2007 15:22:26 -0500, you wrote:
>I don't know about the alignment. My experience was with the opto-chopper in
>the 410C. Mine was replaced as a unit by the company cal lab.
>
>There are only a very few wire pigtail Ne's made. I think there was a means of
>ID'ing which is in there by looking very carefully at the glass pinch area.
>There is something stamped into the glass as I remember. You might ask someone
>like BulbDirect that specializes in lamps.
I remember NE2-D and NE2-J as well as the NE2; different wattages,
IIRC.
Harvey
>
>Best,
>-John
>
>
>
>Christian A Weagle wrote:
>
>> --- In hp_agilent_equipment@..., J Forster <jfor@...> wrote:
>> >
>> > Many Ne bulbs have minute amounts of radioactive material in them to
>> > stabilize the firing point. As the radioactive emission rate decays, the
>> > bulbs become erratic. Put in new bulbs, if you can.
>>
>> That was my first impulse; however, the manual (paragraph 5-27) states
>> that "physical alignment and selection of the neon bulbs are critical"
>> and that replacement of the entire assy is the only thing to do.
>>
>> Can you speak to this at all? If I _do_ replace the neons, are
>> standard NE-2 bulbs the right thing to use?
>>
>> Thanks for your help!
|
Re: Circular polarization antenna question
I take it you`ve tried "The ARRL Antenna Book"?
Cheers!,........................................................Don C.
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----- Original Message -----
From: microwaveengineer1968
To: hp_agilent_equipment@...
Sent: Sunday, November 04, 2007 10:25 AM
Subject: [hp_agilent_equipment] Circular polarization antenna question
Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
|
Re: Circular polarization antenna question
I know how it's done at 150 MHz. Maybe you can adapt it to 36 GHz.
It's done with a hybrid ring made out of coax. Three sides are 1/4 wave and the fourth side is 3/4 wave. Feed the two antennas to opposite ports of the ring and take off the two polarizations at the other two opposite ports.
As a possible lead to a source of more information they are often used in radio astronomy.
Regards.
Max. K 4 O D S.
Email: max@...
Transistor site
Vacuum tube site:
Music site:
To subscribe to the fun with tubes group send an email to,
funwithtubes-subscribe@...
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----- Original Message ----- From: "microwaveengineer1968" <microwaveengineer1968@...> To: <hp_agilent_equipment@...> Sent: Saturday, November 03, 2007 4:25 PM Subject: [hp_agilent_equipment] Circular polarization antenna question Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
Yahoo! Groups Links
--
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.503 / Virus Database: 269.15.20/1107 - Release Date: 11/3/2007 11:22 AM
|
Re: Circular polarization antenna question
Another lead from a local ham:
For the guy looking for the circular pol horn info
Try the W1GHZ on line microwave antenna book
His best bet is the Septum feed
I really don't want to register to join the Yahoo group so I'll be
happy reading only.
Best,
-John
lothar baier wrote:
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Show quoted text
i dont have any of those books on hand, i never had much interest in antennas so i got a bunch of other books and periodicals but nothing on antenna stuff
J Forster <jfor@...> wrote: Have you looked at some of the old standard books like Kraus or the Rad
Lab series? I'd at least start there. Then perhaps the IEEE Antenna &
Propagation (or whatever it is actually called) The web is fine for some
things, but is not great on fundamental engineering.
Also, Google has an academic research function. That might give you a
lead.
Best,
-John
microwaveengineer1968 wrote:
Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
Yahoo! Groups Links
|
Re: 419A Chopper Replacement
On Sat, 03 Nov 2007 15:22:26 -0500, you wrote: I don't know about the alignment. My experience was with the opto-chopper in
the 410C. Mine was replaced as a unit by the company cal lab.
There are only a very few wire pigtail Ne's made. I think there was a means of
ID'ing which is in there by looking very carefully at the glass pinch area.
There is something stamped into the glass as I remember. You might ask someone
like BulbDirect that specializes in lamps. I remember NE2-D and NE2-J as well as the NE2; different wattages, IIRC. Harvey
Best,
-John
Christian A Weagle wrote:
--- In hp_agilent_equipment@..., J Forster <jfor@...> wrote:
Many Ne bulbs have minute amounts of radioactive material in them to
stabilize the firing point. As the radioactive emission rate decays, the
bulbs become erratic. Put in new bulbs, if you can.
That was my first impulse; however, the manual (paragraph 5-27) states
that "physical alignment and selection of the neon bulbs are critical"
and that replacement of the entire assy is the only thing to do.
Can you speak to this at all? If I _do_ replace the neons, are
standard NE-2 bulbs the right thing to use?
Thanks for your help!
|
Need cross for HP 1901-1096 PIN diode
Can someone help me with a cross for this please;
HP 1901-1096 PIN diode.
It is not listed in th ereferences I found on line.
Thanks!
David.
__________________________________________________
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Tired of spam? Yahoo! Mail has the best spam protection around
|
Re: Circular polarization antenna question
i dont have any of those books on hand, i never had much interest in antennas so i got a bunch of other books and periodicals but nothing on antenna stuff J Forster <jfor@...> wrote: Have you looked at some of the old standard books like Kraus or the Rad Lab series? I'd at least start there. Then perhaps the IEEE Antenna & Propagation (or whatever it is actually called) The web is fine for some things, but is not great on fundamental engineering. Also, Google has an academic research function. That might give you a lead. Best, -John microwaveengineer1968 wrote: Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around
|
Re: Circular polarization antenna question
Have you looked at some of the old standard books like Kraus or the Rad
Lab series? I'd at least start there. Then perhaps the IEEE Antenna &
Propagation (or whatever it is actually called) The web is fine for some
things, but is not great on fundamental engineering.
Also, Google has an academic research function. That might give you a
lead.
Best,
-John
microwaveengineer1968 wrote:
toggle quoted message
Show quoted text
Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
|
Re: Circular polarization antenna question
Have you tried Paul Wade's W1GHZ on-line antenna handbook? I am afraid I
dont have a clickable link. Amateur EMEers use circular polarization I
believe.
Alan G3NYK
toggle quoted message
Show quoted text
----- Original Message ----- From: "microwaveengineer1968" <microwaveengineer1968@...> To: <hp_agilent_equipment@...> Sent: Saturday, November 03, 2007 9:25 PM Subject: [hp_agilent_equipment] Circular polarization antenna question Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
Yahoo! Groups Links
|
Circular polarization antenna question
Ok guys this is not directly related to agilent t+m but im banging my
head on the wall with this !
Im looking for material on how to design and build a turnstile
polarization converter, i googled up and down but cant find anything
usefull , not even in the books i have.
The problem i have requires me to design and build a 36GHz circular
polarized horn antenna, the antenna needs to have two ports one for
right and the other one for left turn polarization .
any help would be appreciated
|
11792 and 11722A repair !
If you have a 11722 or 11792 thats bad, you can use the cartridge out
of a 8482A to fix a 11722A or a 8485A cartridge will work for the
11792A !
|
DIY Build yourself a 8487A !
8487A are still quite expensive on ebay, usually the go for $1200-1700
money i didnt wanted to spend so i was looking for a alternative.
Taking some sensors apart while working in the lab of a T+M Repair
facility i noticed a striking similarity of the cartridges used in
the R8486A/Q8486A and 8487A ! after running into a blown 8487A i used
a cartridge out of a R8486A to fix it, i send the sensor off for
calibration and it passed ! later conversation with a coleague at
agilent revealed that the cartridge used in the 8486 and 8487 are in
fact idendical !
So the idea was conceived to study what it would take to build up a
8487A !
First of we need a HP8486A R or Q will do just fine, the cartridge,
bellow case, nut and PCB can be reused, be carefull not to lose the
bellow when removing the cartridge !
Next obtain the Service manual of the 8487A (Download from agilent)
page 76 gives you a nice exploded view of the sensor bulkhead, order
MP1/2/3/4/5/6/7/8/10/11/12 total parts cost about $400
Assemble all parts, be carefull not to squish the bellow its very
small (MP9) put your sensor back together, remove the old label and
affix a new one and there you have a 8487A , same goes for the
D !
If you get a waveguide sensor for $300 and add $400 for the parts,
add another $100 for calibration (cypris) can do those, agilent wont
because the sensor wont have a S/N !
you got a 8487A for well below the average ebay cost !
Just remember, this is for your own use only, if you sell the sensor
you will have to let the new owner known that it is a clone,
otherwise it would be considered piracy !
|
DIY: Repair of HP Step Attenuators
Since Agilent continiously ups the spare part prices and discontinues
parts it has become more and more important to go past normal repair
practices.
Step Attenuators for example can be repaired without any special
tools or cleanroom enviroment !
Lets take a look at the failure modes first, there are a few:
1.) Blown pads
Usually common with spectrum analyzers if a level past the damage
level of the attenuator was applied
2.) Cracked pads, pad has developed a hairline crack due to
mechanical stress !
3.) Improper contact, the contact in between the attenuator and
contact fingers is disturbed.
4.) Stuck solenoid
Quite common if attenuator hasnt been used in awhile
After we remove the attenuator from the instrument the first step is
to obtain the pinout and build us a little test bench consisting of a
powermeter and a signal generator, the good old 8481D or 8484A will
do nicely, if you dont have a sig gen use the 50MHz calibrator output
of the 435 or 436 or similar model, connect the cal output to the
30dB pad connect the sensor and zero and calibrate meter, the meter
will read -30dBm.
Disconnect the sensor from the attenuator and insert the Step
Attenuator, set step attenuator to 0dB, note the level on the
powermeter, now switch in the attenuator sections one by one measure
and note the level, 70dB attenuators are comprised of a 10 20 and
40dB Pad while 110dB Attenuators normally comprise of a 10 20 and two
40dB pads !
check every section individually, you should hear a click as you
enable each section, if you find a bad section note the value it
should have if all sections appear to be good repeat the test at a
higher frequency using a sig gen, if everything appears to be ok at
low frequency then most likely you have attenuator that just needs
cleaning.
Now lets take the attenuator apart, looking at the top you will see a
nut on each SMA connector, remove this nut this will allow for you to
remove the nameplate, under the plate you will see a wealth of allen
screws, remove those but note that the screws close to the SMA
connector are shorter than the other ones.
Now look at the small sideplate, not the one with the ribbon cable
but the other side - there are 4 small allen screws, remove those and
then remove the sideplate, careful not to lose the little wire mesh
here ! now slide out the u shaped cover and remove the top side.
You now have two parts, one beein the bottom side containing the
solenoids and the other one beein the top part containing the
attenuator pads.
First lets inspect the pads, you can measure them with a ohm meter,
they should measure in the vicinity of 50ohms , except of the 10dB
pad which can measure up to 70ohms or more.
Inspect the pads visually, are there any burned or cracked pads ? if
all pads look ok and check out at DC take a surgical swab and
isopropilic alcohol and carefully clean the contacts pads on the
attenuators.
Next look at the contacts, enable all solenoids and observe the
position of the contact tongues, they should be slightly above the
surface of the block, carefully clean the contact tongues with
alcohol, be careful not to bend them.
next put the solenoids back into the 0 position and look at the top
of the solenoids, you will see two little white plastic rods where
those meet the solenoid you should see little rubber rings , there
are 4 of those on each segment, usually over the years they go
briddle and then disappear, with those rings gone the attenuator wont
make contact anymore, you can buy the rings from watchmakers supply
stores as they are beein used for sprocket gaskets !
Now if your gaskets are there put the attenuator back together after
you cleaned everything and it should work now.
If you have a broken or burned pad dont stress over it the pads are
used in all HP attenuators so just find a attenuator on ebay and take
the pad you need out of it, you can also buy pads from agilent
however be prepared to pay $100-150 per
piece
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Re: 419A Chopper Replacement
At 04:22 PM 11/3/2007, you wrote: I don't know about the alignment. My experience was with the opto-chopper in
the 410C. Mine was replaced as a unit by the company cal lab.
There are only a very few wire pigtail Ne's made. I think there was a means of
ID'ing which is in there by looking very carefully at the glass pinch area.
There is something stamped into the glass as I remember. You might ask someone
like BulbDirect that specializes in lamps. Or ask on the NEON-NIXIE Yahoo group, a lot of expertise and experience there too. John Best,
-John
Christian A Weagle wrote:
--- In <mailto:hp_agilent_equipment%40yahoogroups.com>hp_agilent_equipment@...,
J Forster <jfor@...> wrote:
Many Ne bulbs have minute amounts of radioactive material in them to
stabilize the firing point. As the radioactive emission rate decays, the
bulbs become erratic. Put in new bulbs, if you can.
That was my first impulse; however, the manual (paragraph 5-27) states
that "physical alignment and selection of the neon bulbs are critical"
and that replacement of the entire assy is the only thing to do.
Can you speak to this at all? If I _do_ replace the neons, are
standard NE-2 bulbs the right thing to use?
Thanks for your help!
|
Re: 419A Chopper Replacement
I don't know about the alignment. My experience was with the opto-chopper in
the 410C. Mine was replaced as a unit by the company cal lab.
There are only a very few wire pigtail Ne's made. I think there was a means of
ID'ing which is in there by looking very carefully at the glass pinch area.
There is something stamped into the glass as I remember. You might ask someone
like BulbDirect that specializes in lamps.
Best,
-John
Christian A Weagle wrote:
toggle quoted message
Show quoted text
--- In hp_agilent_equipment@..., J Forster <jfor@...> wrote:
Many Ne bulbs have minute amounts of radioactive material in them to
stabilize the firing point. As the radioactive emission rate decays, the
bulbs become erratic. Put in new bulbs, if you can.
That was my first impulse; however, the manual (paragraph 5-27) states
that "physical alignment and selection of the neon bulbs are critical"
and that replacement of the entire assy is the only thing to do.
Can you speak to this at all? If I _do_ replace the neons, are
standard NE-2 bulbs the right thing to use?
Thanks for your help!
|
