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Re: X-Y to VGA/USB converter

EB4APL
 

Pete,

You are right, but some guys had modified theirs easily for making DC coupled low frequency software scopes and the results had been encouraging.
Since the internal A/D can handle DC, they removed the input blocking capacitors and added a (dual) op-amp as level shiftter, accounting for the A/D converters are biased to Vdd/2. A DC balance pot completes the figure.

If someone is interested I think that I can find the web page with detailed instructions.

Regards,
Ignacio


El 01/09/2011 16:43, PeterReilley escribi???:

Perhaps another approach might be easier. Use a PC and an A/D
input device. You could create an application that read 2 analog
inputs and displayed them in an X/Y manner in a window. You would
not have to worry about screen resolution. The trick is finding
an A/D input device with at least 2 input channels. I was thinking
an audio input device but I don't think that they handle DC.

Pete.



----- Original Message -----
From: "Kuba Ober"<ober.14@...>
To:<hp_agilent_equipment@...>
Sent: Thursday, September 01, 2011 10:17 AM
Subject: Re: [hp_agilent_equipment] X-Y to VGA/USB converter


Further thoughts: Now I think that the resolution will have to be
adjustable to fit to popular
widescreen LCD monitors. A 1024x768 output does not look too good when
horizontally stretched.
I think the output will have to be matchable to common LCD aspect ratios,
so even if vertically
it's 768, horizontally it may need to be more than that. I think that the
device should read the
DDC information from the monitor and use it for initial setting.

I think that having a DVI output would also be nice, since supposedly
analog inputs on monitors
are going the way of the dodo. DVI shouldn't be an issue since memory
bandwidths to a DAC and to
the DVI are obviously same.

Cheers, Kuba

On Sep 1, 2011, at 10:08 AM, Kuba Ober wrote:

I'm thinking of biting the bullet and making an affordable X-Y-(Z) to
VGA/USB converter for use with various instruments where existing X-Y
displays are dying.

I'm looking for input about the required specs and functionality:

1. Bandwidth
2. Input voltage ranges
3. Required accuracy on voltage-to-coordinate transformation
4. Requirements for sequence triggers to change colors: for example, if a
display
draws some nomenclature, and then goes on to draw traces, it'd be good to
have a way
of setting it up to switch colors automatically on certain events (X,Y in
a certain
area, retrace on X, etc).
5. Other inputs needed for interfacing with particular instruments
6. Resolution: I'm thinking it'd be a 1024x768 24bit framebuffer
7. Persistence adjustments: how many rectangular areas should there be
(upper limit),
each with its own persistence value.

I'm also wondering if there are any spectrum analyzers where display
accuracy would benefit
from taking some IF frequency/ies as the X coordinate instead of a
voltage. Counting frequency
is easy. For my 7L14 I was thinking of using both IFs as the inputs; that
would improve
the accuracy of the display and would make it fixed-frequency.

I don't have any HP SAs or other instruments like that, all I have is a
7L14 spec an.

I'd try to make it as low cost as possible of course, but specs come
first.

Cheers, Kuba Ober


------------------------------------

Yahoo! Groups Links




------------------------------------

Yahoo! Groups Links
Re: Favorite bad capacitor debugging techniques?

 

Hi David:

A shorted cap across a power supply rail causes the fuse blowing that you are seeing. This is different than a cap with high ESR that causes problems similar to removing the cap. Many (most?) of the ESR problems are related to Capacitor plague.


Tantalum caps tend to fail as shorts and I think that's the problem on the board you have. Measuring very low resistance requires the use of an AC test method to avoid thermoelectric effects, see: where below 50 milli Ohms DC just did not work, even with a Kelvin connection. I think the ESR-Cap meter can detect shorted Tantalum caps, but I haven't run across any using it. I suspect that the capacitance reading will be way off while the ESR reading may be reasonable. The Heathkit GC-1000 Clock did not have any shorted Tantalum capacitors.


Shameless plug. The Russian made ESR-Cap meter I sell also measures both ESR & capacitance (it has a 2 line display).
Cap: 0.2 to 60,000 uF
Res: 0.00 to 99


Is there a way to force a Tantalum cap to fail as a short without causing it to explode?
If anyone has shorted Tantalum caps to send me, I'd like to make some measurements on them.

Have Fun,

Brooke Clarke




hp_agilent_equipment@... wrote:

Re: Favorite bad capacitor debugging techniques?
Re: X-Y to VGA/USB converter

 

Perhaps another approach might be easier. Use a PC and an A/D
input device. You could create an application that read 2 analog
inputs and displayed them in an X/Y manner in a window. You would
not have to worry about screen resolution. The trick is finding
an A/D input device with at least 2 input channels. I was thinking
an audio input device but I don't think that they handle DC.

Pete.

----- Original Message -----
From: "Kuba Ober" <ober.14@...>
To: <hp_agilent_equipment@...>
Sent: Thursday, September 01, 2011 10:17 AM
Subject: Re: [hp_agilent_equipment] X-Y to VGA/USB converter


Further thoughts: Now I think that the resolution will have to be adjustable to fit to popular
widescreen LCD monitors. A 1024x768 output does not look too good when horizontally stretched.
I think the output will have to be matchable to common LCD aspect ratios, so even if vertically
it's 768, horizontally it may need to be more than that. I think that the device should read the
DDC information from the monitor and use it for initial setting.

I think that having a DVI output would also be nice, since supposedly analog inputs on monitors
are going the way of the dodo. DVI shouldn't be an issue since memory bandwidths to a DAC and to
the DVI are obviously same.

Cheers, Kuba

On Sep 1, 2011, at 10:08 AM, Kuba Ober wrote:

I'm thinking of biting the bullet and making an affordable X-Y-(Z) to VGA/USB converter for use with various instruments where existing X-Y displays are dying.

I'm looking for input about the required specs and functionality:

1. Bandwidth
2. Input voltage ranges
3. Required accuracy on voltage-to-coordinate transformation
4. Requirements for sequence triggers to change colors: for example, if a display
draws some nomenclature, and then goes on to draw traces, it'd be good to have a way
of setting it up to switch colors automatically on certain events (X,Y in a certain
area, retrace on X, etc).
5. Other inputs needed for interfacing with particular instruments
6. Resolution: I'm thinking it'd be a 1024x768 24bit framebuffer
7. Persistence adjustments: how many rectangular areas should there be (upper limit),
each with its own persistence value.

I'm also wondering if there are any spectrum analyzers where display accuracy would benefit
from taking some IF frequency/ies as the X coordinate instead of a voltage. Counting frequency
is easy. For my 7L14 I was thinking of using both IFs as the inputs; that would improve
the accuracy of the display and would make it fixed-frequency.

I don't have any HP SAs or other instruments like that, all I have is a 7L14 spec an.

I'd try to make it as low cost as possible of course, but specs come first.

Cheers, Kuba Ober



------------------------------------

Yahoo! Groups Links
Re: X-Y to VGA/USB converter

 

These are available, I think this was discussed before.

Xtof


On 01/09/11 16:08, Kuba Ober wrote:

I'm thinking of biting the bullet and making an affordable X-Y-(Z) to
VGA/USB converter for use with various instruments where existing X-Y
displays are dying.

I'm looking for input about the required specs and functionality:

1. Bandwidth
2. Input voltage ranges
3. Required accuracy on voltage-to-coordinate transformation
4. Requirements for sequence triggers to change colors: for example,
if a display
draws some nomenclature, and then goes on to draw traces, it'd be good
to have a way
of setting it up to switch colors automatically on certain events (X,Y
in a certain
area, retrace on X, etc).
5. Other inputs needed for interfacing with particular instruments
6. Resolution: I'm thinking it'd be a 1024x768 24bit framebuffer
7. Persistence adjustments: how many rectangular areas should there be
(upper limit),
each with its own persistence value.

I'm also wondering if there are any spectrum analyzers where display
accuracy would benefit
from taking some IF frequency/ies as the X coordinate instead of a
voltage. Counting frequency
is easy. For my 7L14 I was thinking of using both IFs as the inputs;
that would improve
the accuracy of the display and would make it fixed-frequency.

I don't have any HP SAs or other instruments like that, all I have is
a 7L14 spec an.

I'd try to make it as low cost as possible of course, but specs come
first.

Cheers, Kuba Ober


Disclaimer:

Re: X-Y to VGA/USB converter

 

Further thoughts: Now I think that the resolution will have to be adjustable to fit to popular
widescreen LCD monitors. A 1024x768 output does not look too good when horizontally stretched.
I think the output will have to be matchable to common LCD aspect ratios, so even if vertically
it's 768, horizontally it may need to be more than that. I think that the device should read the
DDC information from the monitor and use it for initial setting.

I think that having a DVI output would also be nice, since supposedly analog inputs on monitors
are going the way of the dodo. DVI shouldn't be an issue since memory bandwidths to a DAC and to
the DVI are obviously same.

Cheers, Kuba

On Sep 1, 2011, at 10:08 AM, Kuba Ober wrote:

I'm thinking of biting the bullet and making an affordable X-Y-(Z) to VGA/USB converter for use with various instruments where existing X-Y displays are dying.

I'm looking for input about the required specs and functionality:

1. Bandwidth
2. Input voltage ranges
3. Required accuracy on voltage-to-coordinate transformation
4. Requirements for sequence triggers to change colors: for example, if a display
draws some nomenclature, and then goes on to draw traces, it'd be good to have a way
of setting it up to switch colors automatically on certain events (X,Y in a certain
area, retrace on X, etc).
5. Other inputs needed for interfacing with particular instruments
6. Resolution: I'm thinking it'd be a 1024x768 24bit framebuffer
7. Persistence adjustments: how many rectangular areas should there be (upper limit),
each with its own persistence value.

I'm also wondering if there are any spectrum analyzers where display accuracy would benefit
from taking some IF frequency/ies as the X coordinate instead of a voltage. Counting frequency
is easy. For my 7L14 I was thinking of using both IFs as the inputs; that would improve
the accuracy of the display and would make it fixed-frequency.

I don't have any HP SAs or other instruments like that, all I have is a 7L14 spec an.

I'd try to make it as low cost as possible of course, but specs come first.

Cheers, Kuba Ober
X-Y to VGA/USB converter

 

I'm thinking of biting the bullet and making an affordable X-Y-(Z) to VGA/USB converter for use with various instruments where existing X-Y displays are dying.

I'm looking for input about the required specs and functionality:

1. Bandwidth
2. Input voltage ranges
3. Required accuracy on voltage-to-coordinate transformation
4. Requirements for sequence triggers to change colors: for example, if a display
draws some nomenclature, and then goes on to draw traces, it'd be good to have a way
of setting it up to switch colors automatically on certain events (X,Y in a certain
area, retrace on X, etc).
5. Other inputs needed for interfacing with particular instruments
6. Resolution: I'm thinking it'd be a 1024x768 24bit framebuffer
7. Persistence adjustments: how many rectangular areas should there be (upper limit),
each with its own persistence value.

I'm also wondering if there are any spectrum analyzers where display accuracy would benefit
from taking some IF frequency/ies as the X coordinate instead of a voltage. Counting frequency
is easy. For my 7L14 I was thinking of using both IFs as the inputs; that would improve
the accuracy of the display and would make it fixed-frequency.

I don't have any HP SAs or other instruments like that, all I have is a 7L14 spec an.

I'd try to make it as low cost as possible of course, but specs come first.

Cheers, Kuba Ober
Re: Which HP spectrum analzyer is structurally most similar to that of HP 8565A?

 

I think that following basic rules is enough: fully shielded enclosure, cable/connector
shields terminated over 360 degrees to the case (NOT the PCB!!, google Pin 1 Problem),
common mode chokes on all connections, ground plane on the component side of the PCB.
Using a linear regulator for the CPU's voltage(s) would help too, otherwise you have to
deal with CPU harmonics, USB harmonics, and regulator's that will likely mix with everything
else.

That should cover a lot of issues already methinks.

Cheers, Kuba

On Aug 27, 2011, at 12:52 AM, Jim Cotton wrote:



The real fun is keeping all the digital stuff that you add OUT of the existing analog
system...

Jim Cotton
n8qoh

________________________________
From: Amos Ku <amosku@...>
To: "hp_agilent_equipment@..." <hp_agilent_equipment@...>
Sent: Friday, August 26, 2011 2:41 PM
Subject: Re: [hp_agilent_equipment] Which HP spectrum analzyer is structurally most similar to that of HP 8565A?


Tim,

This email is to respond to your earlier email about having some VGA kit to replace the CRT.

I have an idea. Since all the display section does is to take the signal to be display (y-axis) and sweep the screen with sweep signal (x-axis), I can make up a digitized circuit that does the same thing as what CRT will do and connect the output to a LCD module that fits right into the window of HP 8565A, I can have a cheap solution for replacement of CRT tube circuit.

My idea came from here:

.

About the normalizer part. I am thinking about build up something based on the same design of normalizer in SMD and place the circuits inside the large cavity where CRT is in. I can then have all the functions I need in the same box. I am thinking about changing the weird AUX connectors to some easy to get connectors from Digikey (same pin numbers, same dimensions.)

Amos

[Non-text portions of this message have been removed]
Re: Problems with HP8753C networkanalyzer

 

Hi there Jose thanks for your mail. I tried to read your nice presentation and did some tests. I can do Cal 44 cal 45 and they pass that. but when I do Cal 48 it fails. And actually the failure got worse. I tried to work open loop to se the offset and I se a HUGE offset. setting to 300khz we should se something from 1.3-6Mhz I get 165Mhz there and going to 30Mhz give me 190Mhz and 40Mhz over 200Mhz. So what would you suggest me to do. 73 Peter
To: hp_agilent_equipment@...
From: eb5agv@...
Date: Wed, 31 Aug 2011 10:00:35 +0200
Subject: Re: [hp_agilent_equipment] Problems with HP8753C networkanalyzer




























Hi Peter,



I went through a similar problem (not exactly the same, but the error

was the same) and was able to fix it by an internal source auto-calibration.



Please, check my WEB at for more

information about what I did and the results. If you have any doubt,

just ask :-)



I hope it helps!



Regards,



JOSE



At 09:54 31/08/2011, you wrote:



hi group I have a HP8753C analyzer option 6 (6Ghz) that has a
HP85047 testset. I get the following error when power on. No IF
found check R input levelPhase lock lost when I se my display I
have not strait line under 90Mhz. There is like noise on the line
there. I did some tests in CW mode and se I loose my phase lock
going under 87Mhz. Looking on the Cw signal with a spectrumanalyzer
I se a very unstable signal. So when going below 87Mhz the display
say Phase-lock lost. Going above make a stable frequency signal.
Measurering the power out of the source (level set to 0dBm out say
around -11dBm but that is after a loss of 6dB in a powersplitter
(hp11667). so output od source is around -5dBm measured at 1Ghz.
Level is flat over the range. What can be the root course for that
problem. Best regards Peter Hansen OZ1LPR


--

73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN)

Radio and Test Equipment.......

RadioRepair BLOG...............

8648C Sig Gen 1E5 Option

 

Does anyone know details or availability of the 1E5 high stability timebase option for the HP 8648C 3.2 GHz signal generator?

I have an 8648C without this option and would consider adding the option if it can be found or substituted.

--
Best wishes,

Larry McDavid W6FUB
Anaheim, CA (20 miles southeast of Los Angeles, near Disneyland)
Re: Replacement for 08565-60084 attenuator in HP 8565A...

Amos Ku
 

Stuart,

Sorry, forgot to tell you. I am also an design engineer working in an R&D company. On my job, I need to develop all level of electronics. I would like to have some decent equipment that I can do some measurements. I do not want to always wait until I come to work everyday. I want to be able to do some at the leisure of my home.

On top of my job, I am also an ambitious hobbyist who wishes to build and test things at home. I think spectrum analyzer is a good tool to have.

Yes, you are right. I do not need to have it. However, I just came across a broken one on ebay and I thought getting one may help me to do more interesting research of my own and help to boost my growth in my job related knowledge.

Everyone has different needs and some are satisfied with low end equipment. Some may be a little ambitious and want to always go a little further than most other people.

Amos



________________________________
From: "stuartl73@..." <stuartl73@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 2:31 PM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...


?
Amos, in all honesty I don't know why you want a spectrum analyzer. They do two things; measure frequency (to some accuracy up to and including frequency counter resolution) and measure RF power or voltage, across a known low return loss impedance, again to some accuracy depending on the age and cost of the analyzer. In all but the newest and most expensive analyzers, time is not displayed against frequency and amplitude.

You now state that you are willing to give up the ability to accurately measure the signal level. You might as well buy an inexpensive frequency counter and RF power meter. That costs less and takes up a lot less bench space .For my needs, I would rather have my Spectrum Analyzer.

Stuart K6YAZ

Los Angeles, California

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 1:12 pm
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Stuart,

I think before I can afford that attenuator, probably I may just calculate the loss and attenuation and buy appropriate attenuators when they are needed each time...

Amos

________________________________
From: "stuartl73@..." <stuartl73@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 12:08 PM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Amos, what you are dealing with is an attenuator specifically made for that one instrument. They are in short supply and are crucial for the analyzer to work properly and to display the actual input level on both the screen and readout LED.
Anything but the proper part will degrade the instrument, and possibly create a "Frankenstein's monster", with outboard "fixes". I hope you realize that you are involved in a possibly very expensive and time consuming project; and may have to settle for "good enough" rather than a 100% reliable, accurate instrument.

Stuart

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment@... <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 11:24 am
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Will,

Yeah. I have thought about this option too. But that means I have to give up the ability to internally choose attenuation.

Right now, I am facing the issue of choosing the cable that go between the RF connector and the coax switch (K2). No experience on choosing or specifying one before.....

Amos

________________________________
From: "w0eom@..." <w0eom@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 8:50 AM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Amos - you can use an external atten. to keep the input signal below +20
dbm.

Will

In a message dated 8/31/2011 1:06:30 A.M. Pacific Daylight Time,
amosku@... writes:

Hi all,

With help from friends in this group, I have found the schematics in the
manual, and I also identified the five missing parts in the HP 8565A that I
cheaply bought from ebay.

Now, I found it difficult to find a cheap source for 08565-60084
attenuator.

Does any one know the replacement part for 08565-60084 (A34, RF
attenuator) in HP 8565A? It does not seem to be easy to obtain this attenuator
($400). I wonder if anyone knows any information about this attenuator.

If obtaining one is difficult, what options do I have?

Also, I wonder if this attenuator is really needed to make the system work.

Thanks in advance.

Amos



[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]






[Non-text portions of this message have been removed]
Re: Replacement for 08565-60084 attenuator in HP 8565A...

 

Amos, in all honesty I don't know why you want a spectrum analyzer. They do two things; measure frequency (to some accuracy up to and including frequency counter resolution) and measure RF power or voltage, across a known low return loss impedance, again to some accuracy depending on the age and cost of the analyzer. In all but the newest and most expensive analyzers, time is not displayed against frequency and amplitude.

You now state that you are willing to give up the ability to accurately measure the signal level. You might as well buy an inexpensive frequency counter and RF power meter. That costs less and takes up a lot less bench space .For my needs, I would rather have my Spectrum Analyzer.

Stuart K6YAZ

Los Angeles, California

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 1:12 pm
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...





Stuart,

I think before I can afford that attenuator, probably I may just calculate the loss and attenuation and buy appropriate attenuators when they are needed each time...

Amos

________________________________
From: "stuartl73@..." <stuartl73@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 12:08 PM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...


Amos, what you are dealing with is an attenuator specifically made for that one instrument. They are in short supply and are crucial for the analyzer to work properly and to display the actual input level on both the screen and readout LED.
Anything but the proper part will degrade the instrument, and possibly create a "Frankenstein's monster", with outboard "fixes". I hope you realize that you are involved in a possibly very expensive and time consuming project; and may have to settle for "good enough" rather than a 100% reliable, accurate instrument.

Stuart

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment@... <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 11:24 am
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Will,

Yeah. I have thought about this option too. But that means I have to give up the ability to internally choose attenuation.

Right now, I am facing the issue of choosing the cable that go between the RF connector and the coax switch (K2). No experience on choosing or specifying one before.....

Amos

________________________________
From: "w0eom@..." <w0eom@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 8:50 AM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Amos - you can use an external atten. to keep the input signal below +20
dbm.

Will

In a message dated 8/31/2011 1:06:30 A.M. Pacific Daylight Time,
amosku@... writes:

Hi all,

With help from friends in this group, I have found the schematics in the
manual, and I also identified the five missing parts in the HP 8565A that I
cheaply bought from ebay.

Now, I found it difficult to find a cheap source for 08565-60084
attenuator.

Does any one know the replacement part for 08565-60084 (A34, RF
attenuator) in HP 8565A? It does not seem to be easy to obtain this attenuator
($400). I wonder if anyone knows any information about this attenuator.

If obtaining one is difficult, what options do I have?

Also, I wonder if this attenuator is really needed to make the system work.

Thanks in advance.

Amos



[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]









[Non-text portions of this message have been removed]
Re: Replacement for 08565-60084 attenuator in HP 8565A...

Amos Ku
 

Stuart,

I think before I can afford that attenuator, probably I may just calculate the loss and attenuation and buy appropriate attenuators when they are needed each time...


Amos



________________________________
From: "stuartl73@..." <stuartl73@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 12:08 PM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...


?
Amos, what you are dealing with is an attenuator specifically made for that one instrument. They are in short supply and are crucial for the analyzer to work properly and to display the actual input level on both the screen and readout LED.
Anything but the proper part will degrade the instrument, and possibly create a "Frankenstein's monster", with outboard "fixes". I hope you realize that you are involved in a possibly very expensive and time consuming project; and may have to settle for "good enough" rather than a 100% reliable, accurate instrument.

Stuart

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment@... <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 11:24 am
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Will,

Yeah. I have thought about this option too. But that means I have to give up the ability to internally choose attenuation.

Right now, I am facing the issue of choosing the cable that go between the RF connector and the coax switch (K2). No experience on choosing or specifying one before.....

Amos

________________________________
From: "w0eom@..." <w0eom@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 8:50 AM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Amos - you can use an external atten. to keep the input signal below +20
dbm.

Will

In a message dated 8/31/2011 1:06:30 A.M. Pacific Daylight Time,
amosku@... writes:

Hi all,

With help from friends in this group, I have found the schematics in the
manual, and I also identified the five missing parts in the HP 8565A that I
cheaply bought from ebay.

Now, I found it difficult to find a cheap source for 08565-60084
attenuator.

Does any one know the replacement part for 08565-60084 (A34, RF
attenuator) in HP 8565A? It does not seem to be easy to obtain this attenuator
($400). I wonder if anyone knows any information about this attenuator.

If obtaining one is difficult, what options do I have?

Also, I wonder if this attenuator is really needed to make the system work.

Thanks in advance.

Amos

[Non-text portions of this message have been removed]








[Non-text portions of this message have been removed]
Re: Replacement for 08565-60084 attenuator in HP 8565A...

 

Amos; You may learn a lot by working on this project, but the knowledge and results may not be what you expected. I've had to abandon similar projects when I replaced one suspect part only to find out there was another problem revealed by the replacement. When you get to the point where a part or assembly isn't available at a reasonable price, or time-frame, where do you go?
The 8656A represents the state of the art, at that time, and relies on a lot of specialized components working reliably together. HP had a real advantage because they designed and built a unique RF attenuator. They were so good that many were sold to other companies to use in their products. My Gigatronics model 600 signal generator (10 to 8000 MHz) uses a special HP programmable attenuator, and is a major factor in it's success.

Stuart
K6YAZ
Los Angeles, California

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment@... <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 12:36 pm
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...





Stuart,

Good reasoning. This is my dilemma: 1. To get the system up and working by any condition, 2. Or spend more money to get the complete system. Unless I can run into someone sells cheap on ebay, I may have to get stuck with this attenuator if I am choosing option 2.

Amos

________________________________
From: "stuartl73@..." <stuartl73@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 12:08 PM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...


Amos, what you are dealing with is an attenuator specifically made for that one instrument. They are in short supply and are crucial for the analyzer to work properly and to display the actual input level on both the screen and readout LED.
Anything but the proper part will degrade the instrument, and possibly create a "Frankenstein's monster", with outboard "fixes". I hope you realize that you are involved in a possibly very expensive and time consuming project; and may have to settle for "good enough" rather than a 100% reliable, accurate instrument.

Stuart

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment@... <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 11:24 am
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Will,

Yeah. I have thought about this option too. But that means I have to give up the ability to internally choose attenuation.

Right now, I am facing the issue of choosing the cable that go between the RF connector and the coax switch (K2). No experience on choosing or specifying one before.....

Amos

________________________________
From: "w0eom@..." <w0eom@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 8:50 AM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Amos - you can use an external atten. to keep the input signal below +20
dbm.

Will

In a message dated 8/31/2011 1:06:30 A.M. Pacific Daylight Time,
amosku@... writes:

Hi all,

With help from friends in this group, I have found the schematics in the
manual, and I also identified the five missing parts in the HP 8565A that I
cheaply bought from ebay.

Now, I found it difficult to find a cheap source for 08565-60084
attenuator.

Does any one know the replacement part for 08565-60084 (A34, RF
attenuator) in HP 8565A? It does not seem to be easy to obtain this attenuator
($400). I wonder if anyone knows any information about this attenuator.

If obtaining one is difficult, what options do I have?

Also, I wonder if this attenuator is really needed to make the system work.

Thanks in advance.

Amos



[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]









[Non-text portions of this message have been removed]
Re: Replacement for 08565-60084 attenuator in HP 8565A...

 

Re: Favorite bad capacitor debugging techniques?

J. Forster
 

Most people sdon't use a real (GR or HP) to measure ESR.

-John

=================



Fred, after your message, I got to thinking about my previous measurements

(of that replacement capacitor). My ESR readings looked *way* too low, so
I re-measured a NOS Sprague 1000 uF cap today, using the GR 1689 LCR
Digibridge.

Today, a good 1000 uF cap measured:

Test
Freq.........Capacitance...........D...................ESR.............
120 Hz..............999.21 uF.........0.0857..........0.11493 ohm...
1 kHz................952.74 uF..........0.4704.........0.07851 ohm...
10 kHz..............844.97 uF..........?????...........0.07212 ohm...

Because my earlier measurements were 9 months ago, I'm not entirely sure
which LCR meter I used for that project.

Anyway, I think today's measurements are more believable. Maybe I had a
"short between the headsets" so to speak 9 months ago during the original
measurement?

John, the GR 1689 LCR Digibridge automatically switches from "Capacitance"
to "Resistance" mode if your cap is shorted. In other words, it's
immediately obvious your cap is shorted. IIRC, the same would be obvious
if you're using a HP LCR meter.

-Greg


----- Original Message -----
From: Pa4tim
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 11:26 AM
Subject: Re: [hp_agilent_equipment] Favorite bad capacitor debugging
techniques?



What model ESR meter you use ? I guess a HP bridgde. With 6.5 digits this
is not one of the ESR "indicator" kits. How low can you measure.
I use an analog meter, it goes upto 40 ohm ( but I made it non lineair for
better resolution under 1 ohm, and accurate down to 100nF. But I think I
change this and make it switchable between 1 ohm full scale and 40 ohm. (
not that this is important because if the meter corners it is good, the
last cm on the scale is 1 Ohm so about 50 mOhm resolution)

Fred PA4TIM
Re: Replacement for 08565-60084 attenuator in HP 8565A...

Amos Ku
 

Stuart,

Good reasoning. This is my dilemma: 1. To get the system up and working by any condition, 2. Or spend more money to get the complete system. Unless I can run into someone sells cheap on ebay, I may have to get stuck with this attenuator if I am choosing option 2.


Amos



________________________________
From: "stuartl73@..." <stuartl73@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 12:08 PM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...


?
Amos, what you are dealing with is an attenuator specifically made for that one instrument. They are in short supply and are crucial for the analyzer to work properly and to display the actual input level on both the screen and readout LED.
Anything but the proper part will degrade the instrument, and possibly create a "Frankenstein's monster", with outboard "fixes". I hope you realize that you are involved in a possibly very expensive and time consuming project; and may have to settle for "good enough" rather than a 100% reliable, accurate instrument.

Stuart

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment@... <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 11:24 am
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Will,

Yeah. I have thought about this option too. But that means I have to give up the ability to internally choose attenuation.

Right now, I am facing the issue of choosing the cable that go between the RF connector and the coax switch (K2). No experience on choosing or specifying one before.....

Amos

________________________________
From: "w0eom@..." <w0eom@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 8:50 AM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...

Amos - you can use an external atten. to keep the input signal below +20
dbm.

Will

In a message dated 8/31/2011 1:06:30 A.M. Pacific Daylight Time,
amosku@... writes:

Hi all,

With help from friends in this group, I have found the schematics in the
manual, and I also identified the five missing parts in the HP 8565A that I
cheaply bought from ebay.

Now, I found it difficult to find a cheap source for 08565-60084
attenuator.

Does any one know the replacement part for 08565-60084 (A34, RF
attenuator) in HP 8565A? It does not seem to be easy to obtain this attenuator
($400). I wonder if anyone knows any information about this attenuator.

If obtaining one is difficult, what options do I have?

Also, I wonder if this attenuator is really needed to make the system work.

Thanks in advance.

Amos

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]

[Non-text portions of this message have been removed]
Re: Replacement for 08565-60084 attenuator in HP 8565A...

 

Amos, what you are dealing with is an attenuator specifically made for that one instrument. They are in short supply and are crucial for the analyzer to work properly and to display the actual input level on both the screen and readout LED.
Anything but the proper part will degrade the instrument, and possibly create a "Frankenstein's monster", with outboard "fixes". I hope you realize that you are involved in a possibly very expensive and time consuming project; and may have to settle for "good enough" rather than a 100% reliable, accurate instrument.

Stuart

-----Original Message-----
From: Amos Ku <amosku@...>
To: hp_agilent_equipment@... <hp_agilent_equipment@...>
Sent: Wed, Aug 31, 2011 11:24 am
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...





Will,

Yeah. I have thought about this option too. But that means I have to give up the ability to internally choose attenuation.

Right now, I am facing the issue of choosing the cable that go between the RF connector and the coax switch (K2). No experience on choosing or specifying one before.....

Amos

________________________________
From: "w0eom@..." <w0eom@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 8:50 AM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...


Amos - you can use an external atten. to keep the input signal below +20
dbm.

Will

In a message dated 8/31/2011 1:06:30 A.M. Pacific Daylight Time,
amosku@... writes:

Hi all,

With help from friends in this group, I have found the schematics in the
manual, and I also identified the five missing parts in the HP 8565A that I
cheaply bought from ebay.

Now, I found it difficult to find a cheap source for 08565-60084
attenuator.

Does any one know the replacement part for 08565-60084 (A34, RF
attenuator) in HP 8565A? It does not seem to be easy to obtain this attenuator
($400). I wonder if anyone knows any information about this attenuator.

If obtaining one is difficult, what options do I have?

Also, I wonder if this attenuator is really needed to make the system work.

Thanks in advance.

Amos



[Non-text portions of this message have been removed]
Re: Replacement for 08565-60084 attenuator in HP 8565A...

Amos Ku
 

Will,

Yeah. I have thought about this option too. But that means I have to give up the ability to internally choose attenuation.

Right now, I am facing the issue of choosing the cable that go between the RF connector and the coax switch (K2). No experience on choosing or specifying one before.....



Amos



________________________________
From: "w0eom@..." <w0eom@...>
To: hp_agilent_equipment@...
Sent: Wednesday, August 31, 2011 8:50 AM
Subject: Re: [hp_agilent_equipment] Replacement for 08565-60084 attenuator in HP 8565A...


?
Amos - you can use an external atten. to keep the input signal below +20
dbm.

Will


In a message dated 8/31/2011 1:06:30 A.M. Pacific Daylight Time,
amosku@... writes:

Hi all,

With help from friends in this group, I have found the schematics in the
manual, and I also identified the five missing parts in the HP 8565A that I
cheaply bought from ebay.

Now, I found it difficult to find a cheap source for 08565-60084
attenuator.

Does any one know the replacement part for 08565-60084 (A34, RF
attenuator) in HP 8565A? It does not seem to be easy to obtain this attenuator
($400). I wonder if anyone knows any information about this attenuator.

If obtaining one is difficult, what options do I have?

Also, I wonder if this attenuator is really needed to make the system work.

Thanks in advance.

Amos

[Non-text portions of this message have been removed]




[Non-text portions of this message have been removed]
Re: Favorite bad capacitor debugging techniques?

 

You are right.

I have seen caps that lost allmost all capacitance with perfect ESR, i have seen caps that leaked over 15 mA at 350V, blew out a lot of dielectrium but still perfect ESR.
I have seen caps with good capacitance, no leakage but bad ESR.
I have seen a cap with a internal ripped or broken conductor. That lookes like severe dielectric absorbsion. ( is that called soakage ?) capacitance not possible to measure because you could not unload the cap. It gave 100 V on the voltmeter and even if you short it, no effect.

I use a ESR meter just for fun, i like to examine components. In switchers I use it to test caps, not to find a problem. I used to do that but not any more. I measure with scope and DMM and as a result of that I most times find the problem. After I find it, and it is a cap I use the ESR meter, C meter and test DC leakage to be sure and for fun.

Fred PA4TIM

Op 31 aug. 2011 om 19:58 heeft "J. Forster" <jfor@...> het volgende geschreven:

If a capacitor is pulling a bus down, an ESR meter is really not the right
tool. A short and a good cap both have a low ESR!

-John

===============


----- Original Message -----
From: "Pa4tim" <fredschneider@...>
To: <hp_agilent_equipment@...>
Sent: Wednesday, August 31, 2011 10:26 AM
Subject: Re: [hp_agilent_equipment] Favorite bad capacitor
debugging techniques?


What model ESR meter you use ? I guess a HP bridgde. With
6.5 digits this is not one of the ESR "indicator" kits. How
low can you measure.
I use an analog meter, it goes upto 40 ohm ( but I made it
non lineair for better resolution under 1 ohm, and accurate
down to 100nF. But I think I change this and make it
switchable between 1 ohm full scale and 40 ohm. ( not that
this is important because if the meter corners it is good,
the last cm on the scale is 1 Ohm so about 50 mOhm
resolution)

Fred PA4TIM

FWIW, I usually check caps on a GR-1650-A but often
leakage is important and is not measured by the usual
impedance bridge. My usual arrangement is to use a small,
regulated DC power supply and a meter capable of indicating
quite low values of current. My Tektronix DMM goes low
enough. I've found paper caps that test good on the bridge
but have excessive leakage and won't work in some circuits.
Leakage is a primary test for electrolytics. There _are_
capacitance bridges like the GR 1617-A that will also
measure leakage and supply a variable bias internally but I
don't have one. A megohmeter will also do provided you have
one which will run at voltages suitable for the caps.



--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@...


[Non-text portions of this message have been removed]
Re: Favorite bad capacitor debugging techniques?

J. Forster
 

If a capacitor is pulling a bus down, an ESR meter is really not the right
tool. A short and a good cap both have a low ESR!

-John

===============


----- Original Message -----
From: "Pa4tim" <fredschneider@...>
To: <hp_agilent_equipment@...>
Sent: Wednesday, August 31, 2011 10:26 AM
Subject: Re: [hp_agilent_equipment] Favorite bad capacitor
debugging techniques?


What model ESR meter you use ? I guess a HP bridgde. With
6.5 digits this is not one of the ESR "indicator" kits. How
low can you measure.
I use an analog meter, it goes upto 40 ohm ( but I made it
non lineair for better resolution under 1 ohm, and accurate
down to 100nF. But I think I change this and make it
switchable between 1 ohm full scale and 40 ohm. ( not that
this is important because if the meter corners it is good,
the last cm on the scale is 1 Ohm so about 50 mOhm
resolution)

Fred PA4TIM

FWIW, I usually check caps on a GR-1650-A but often
leakage is important and is not measured by the usual
impedance bridge. My usual arrangement is to use a small,
regulated DC power supply and a meter capable of indicating
quite low values of current. My Tektronix DMM goes low
enough. I've found paper caps that test good on the bridge
but have excessive leakage and won't work in some circuits.
Leakage is a primary test for electrolytics. There _are_
capacitance bridges like the GR 1617-A that will also
measure leakage and supply a variable bias internally but I
don't have one. A megohmeter will also do provided you have
one which will run at voltages suitable for the caps.



--
Richard Knoppow
Los Angeles
WB6KBL
dickburk@...
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