Re: strange issue on Agilent 54641D MSO
If I had to guess I would say bad contact at some point. I haven¡¯t pulled the schematic to see what the front end looks like but I¡¯m thinking something loose. It only does it on channel 1 correct, channel 2 functions properly??
Andrew
|
Re: Does an HP Transformer Specification Document exist ?
hi Clay,
I am looking for specifications on the HV transformer? hp 9100-1415 ,? used in the hp 9100a Calculator ( ca. 1968 ),
that powers its electrostatic CRT display ( hp 5083-1551 ).
It would be nice to find the 9100-1415 specifications,?
Or? a NOS 9100-1415 transformer, ? Or a used one?? Or another dead one to help aid in a rewind attempt.
The 9100-1415 transformer I have is shorted.
This particular transformer has 7 leads; 3 wingdings. The HV (3.4kV) winding has a a tap at ~ 34V.?
? No information of the other 2-lead wingdings.
The transformer is an open frame ~ 2" L x 1.5" W x 1.75" H
A photo of the transformer is on this forum, in a recent post.
The HP 9100a/b Service Manual .pdf? ( large, ~ 75MB ) has a diagram of the hp 9100-1415 transformer.
thank you,
rick
?
|
The best description of the 8662/8663 power supply deficiencies that I¡¯ve seen is this YouTube video:?. ?The original power supply design is really, really poor and a ticking time bomb to expensive repairs, especially as the instrument both ages and accumulates run time. ?There are two particularly notorious axial electrolytics that in order for the instrument to operate, must pass on a 50% duty cycle over 1 ampere at a potential over 200 volts. ?The original caps are under spec¡¯d and there was a revision by HP to increase their value. ?The best practice retrofit is to increase the capacitance value further, raise the voltage rating considerably and select a cap that has a much lower ESR value and lifetime rating. ?Watch the video - the poster understands the issue and does a good job explaining it. ?I recently bought a 8663 and beefed up the supply so that this issue won¡¯t occur (again). ?Every one I¡¯ve seen had evidence of repair in the primary side of that disaster that passes for a switching supply.
toggle quoted message
Show quoted text
On Feb 19, 2023, at 5:26 PM, colingoode2000 via groups.io <colingoode2000@...> wrote:
?Is there a definitive document that details about the mods to the A2 boards and which ones should be present Also is the 8662a serial number in software available on the device?
|
The serial # would be on the label at lower right, the one that's been obliterated.? Somebody reeeeally didn't want that serial # to be known.? AFAIK it isn't recorded anywhere else.? It doesn't seem to be in the attenuator EPROM, which is the only place I'd guess you might find it. ? You have 2001-era date codes on the chips and an Agilent sticker on the EPROM, so that unit has either been upgraded or is one of the last ones made.? They were gone from the catalog by 2003. ? -- john, KE5FX ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of colingoode2000 via groups.io
Sent: Sunday, February 19, 2023 1:19 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 8662A A2 Slots? I haven¡¯t tried powering yet as there is a fault label on the front for the psu I Plan to remove all psu boards and test / replace caps etc before powering ? I can¡¯t find the serial number or may be it¡¯s been removed where should it be.
|
Is there a definitive document that details about the mods to the A2 boards and which ones should be present Also is the 8662a serial number in software available on the device?
|
|
|
Re: HP 8565A Spectrum Analyzer Noisy
Video filter has some effect but not big. Furthermore, both the noisy and the clean traces have the video filters set at the OFF position.
|
Re: Advice on how to use an SA for test point troubleshooting
Chuck -
Gotta agree with the mind reading comment. Thanks!
What I suspect is the "test point" is probably a connection between circuit elements (amp, splitter, modulator,etc.) and they specified the signal level as a diagnostic (Take a look at the system level 8340 diagram for example) and that accuracy is not terribly important. In these cases, if you can break the circuit, use a power meter as the 50 Ohm termination. If it is a PC trace, a Hi-Z probe is a better option because there is already a 50 ohm termination.
WHAT WE SHOULD ASK FOR is a picture of the circuit diagram (no more mind reading) and then we could make better recommendations.
Cheers!
Bruce
Quoting Chuck Harris <cfharris@...>:
toggle quoted message
Show quoted text
Hi Bruce,
I agree, but the person specifying that you look at that point needs
to define how. And, I am pretty sure they did... if one looks.
Reading minds is a perilous task when you are up to your hips inside
of an instrument.
-Chuck Harris
On Sun, 19 Feb 2023 12:24:06 -0700 "Bruce" <bruce@...> wrote:
Both SAs and Scopes measure voltage. If a signal level is CORRECTLY
specified in dBm, the impedance must be 50 ohms unless otherwise
stated.
All that is necessary to do is the mathematical conversion from power
to voltage (works in general if the particular impedance is known).
An easy way to avoid the maths ias to use the FET probe to measure
the output of a working signal generator (with appropriate
termination). I find the HP FET probes a valuable asset for debugging
- protects the SA from DC and overloads (to some degree).
Cheers!
Bruce
Quoting Chuck Harris <cfharris@...>:
If the OP's description of the set point being 2-3 dBm,
is accurate, you can do nothing else but use a 50 ohm
probe to make the connection.
dBm is totally undefined at the arbitrary high impedances
of FET probes.
dBm is totally undefined at the arbitrary impedances of something
like the Andrew Zonenberg probes.
dBm is totally undefined at the arbitrary impedance of using
a resister in series with the center lead of a coax cable...
The only way the high impedance route could work is if the OP,
or the MFR, used dBm in an imprecise way, and really meant something
else. If the MFR did that, he likely would have the sort of probe
he intended listed in the necessary calibration equipment table for
the instrument.
-Chuck Harris
On Sun, 19 Feb 2023 10:29:50 -0800 "Matt Huszagh"
<huszaghmatt@...> wrote:
"Bruce" <bruce@...> writes:
If you can find ont, I recommend attaching an HP FET probe to
your SA. If you don't have one, it is a good idea to start
looking for one. I find them a valuable resource for trouble
shooting.
Note: the passive probe is unlikely to work. While a FET probe is nice, a suitable high-frequency passive probe
(like the PML series) can absolutely work up to 500 MHz and beyond.
In fact, you can make them work up to several GHz with proper
design. See the Andrew Zonenberg probes, for instance
(). Of course, the passive
probe approach mandates some sort of voltage division, otherwise
this won't work. Sticking some coax between your test point and
the oscope will just load down the circuit with a bunch of
parallel capacitance.
A typical 10:1 or 1:1 oscope probe designed for high input
impedance scope termination won't work though. Don't confuse
passive probes designed for 1M scope input impedance with those
designed for 50ohm scope input impedance.
You probably know this, but if you do use a scope and not the SA,
make sure the reference point can be connected to earth ground. If
not you'll need something to isolate it. The typical approach
would be to use a differential probe.
Matt
|
Re: Advice on how to use an SA for test point troubleshooting
Hi Bruce,
I agree, but the person specifying that you look at that point needs
to define how. And, I am pretty sure they did... if one looks.
Reading minds is a perilous task when you are up to your hips inside
of an instrument.
-Chuck Harris
toggle quoted message
Show quoted text
On Sun, 19 Feb 2023 12:24:06 -0700 "Bruce" <bruce@...> wrote: Both SAs and Scopes measure voltage. If a signal level is CORRECTLY
specified in dBm, the impedance must be 50 ohms unless otherwise
stated.
All that is necessary to do is the mathematical conversion from power
to voltage (works in general if the particular impedance is known).
An easy way to avoid the maths ias to use the FET probe to measure
the output of a working signal generator (with appropriate
termination). I find the HP FET probes a valuable asset for debugging
- protects the SA from DC and overloads (to some degree).
Cheers!
Bruce
Quoting Chuck Harris <cfharris@...>:
If the OP's description of the set point being 2-3 dBm,
is accurate, you can do nothing else but use a 50 ohm
probe to make the connection.
dBm is totally undefined at the arbitrary high impedances
of FET probes.
dBm is totally undefined at the arbitrary impedances of something
like the Andrew Zonenberg probes.
dBm is totally undefined at the arbitrary impedance of using
a resister in series with the center lead of a coax cable...
The only way the high impedance route could work is if the OP,
or the MFR, used dBm in an imprecise way, and really meant something
else. If the MFR did that, he likely would have the sort of probe
he intended listed in the necessary calibration equipment table for
the instrument.
-Chuck Harris
On Sun, 19 Feb 2023 10:29:50 -0800 "Matt Huszagh"
<huszaghmatt@...> wrote:
"Bruce" <bruce@...> writes:
If you can find ont, I recommend attaching an HP FET probe to
your SA. If you don't have one, it is a good idea to start
looking for one. I find them a valuable resource for trouble
shooting.
Note: the passive probe is unlikely to work. While a FET probe is nice, a suitable high-frequency passive probe
(like the PML series) can absolutely work up to 500 MHz and beyond.
In fact, you can make them work up to several GHz with proper
design. See the Andrew Zonenberg probes, for instance
(). Of course, the passive
probe approach mandates some sort of voltage division, otherwise
this won't work. Sticking some coax between your test point and
the oscope will just load down the circuit with a bunch of
parallel capacitance.
A typical 10:1 or 1:1 oscope probe designed for high input
impedance scope termination won't work though. Don't confuse
passive probes designed for 1M scope input impedance with those
designed for 50ohm scope input impedance.
You probably know this, but if you do use a scope and not the SA,
make sure the reference point can be connected to earth ground. If
not you'll need something to isolate it. The typical approach
would be to use a differential probe.
Matt
|
Re: Does an HP Transformer Specification Document exist ?
? I have wondered the same thing about HP transformers over the years.? HP In Loveland, Colorado for years had a separate facility we referred to as the Components Building.? They wound transformers for a lot of the products made at the main Loveland facility and maybe other HP facilities.? You could even spec out a transformer and have one designed and wound for a custom "Electronic Tool" or a prototype instrument.? I did that a few times over my 23 years with HP.? I always wanted a catalog of what was already available as it seemed rather inefficient to spec out a transformer and have it designed and wound when you knew there were already several production or prototype designs that would fit the need.? I never heard of a transformer catalog, but there had to be a way of sharing the info as some transformers were used in other products at other divisions.
? The drawings (like in the TEK catalog) were transferred to microfiche cards (think punched cards with a patch of film in the middle) and then kept on file so you could order a paper copy by part number, or even the card so you could use it on a 'fiche reader in your area and avoid the "blue lines" for larger prints that were basically blueprints and faded in the light over time.
? The HP Corporate Microfiche "Parts Information Report" was the primary database of all the HP parts for many years, but generally held less information for each part and seldom had drawings.? Working from the 'fiche to find a part number would have been a huge task.? I never found a way to to electronically access the parts data prior to leaving HP.? I always wondered how the microfiche transition to electronic documents was done and what that database looked like, I'm glad I didn't have that job!? I never saw what system they moved to before my exit in 2000 but knew they had been working on it for years? Too bad I wasn't friends with a "materials engineer" or whoever had their finger on the pulse of the parts databases.? It would have be awesome to have some sort of access to the data.
? If you have an HP part number I could look it up to see if it is in the PIR I have access to (1991 or prior).? I don't remember what it had for transformer data.? There are a lot of entries in the 9100-xxxx range and a reverse lookup is really only good for a manufacturer PN to HP PN lookup (for purchased parts) due to the many transformers HP used. The limited data in the PIR would be a handicap as well.? There was also a "Where Used" 'fiche that I thought was part of the PIR but I do not have that section of the PIR if it was in there.? I only know one other person that remembers the "where used" 'fiche.? It was awesome if you had a part number, you could look and see what instruments and HP Divisions used it.? I recently asked the only Engineer I know still at HP and he had never heard of such a thing, so if it still exists electronically, the rank and file may not be aware of it.
? HP did publish one parts catalog that I have, it is the 91 page 1998 picture book "Northern Colorado Divisions Hardware Catalog".? The pictures weren't great and didn't scan well when I tried many years ago, but I imagine it could be done with a a camera or modern scanner.? It hasn't proven very useful to me, but it was kind of a neat idea and is in really good shape for a 45 year old soft bound catalog.?
Clay
?
|
Re: Advice on how to use an SA for test point troubleshooting
Hi Tony ? Just looking at your post and the excellent advice given I think there are a few pointers I can give you as I strongly advise you invest in the following ? I use DC blocks on my spectrum analysers when probing around to protect the input ? Depending on the job but a useful tool is a short length of semi rigged one end the centre conductor as a probe the other end a SMA? this is connected to a DC block then coax to the SA ? DC block suggest you look out for a HP 0960-0092 this is infect a DC return use the dc return on the SA side it also acts as a handle for the above although it spec is to 18 GHz it works well above 20 GHz and is a semi permeant fixture on my 26 GHz analysers? cost about ?40 Not good for specific levels but close enough and gives a value to work with ? Active probe suggest you look out for a HP1120A they work to 500 MHz? cost about ?60 - ?100 depending on parts it comes with ? Paul ? ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Andrew
Sent: 19 February 2023 19:28
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Advice on how to use an SA for test point troubleshooting ? One type of probe that could be used for this purpose is a passive probe with a bandwidth of at least 500 MHz and a maximum input voltage that exceeds +2 dBm. A passive probe is typically less expensive and simpler to use than an active probe, but it can introduce some loading and attenuation to the circuit under test. Another option is an active probe that has a frequency range that covers 500 MHz and a maximum input voltage that exceeds +2 dBm. An active probe uses a built-in amplifier to boost the signal and minimize loading effects, but it can be more expensive and may require additional power. In addition to selecting an appropriate probe, it's important to properly calibrate the spectrum analyzer before taking measurements. This typically involves setting the reference level, center frequency, and resolution bandwidth to appropriate values based on the signal being measured.
|
Er, not EEPROMs, but EPROMs, probably 2732s or 2764s. ? -- john, KE5FX ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of John Miles
Sent: Sunday, February 19, 2023 12:16 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 8662A A2 Slots? Yeah, that's an updated CPU board with a lithium battery. ?Not super common, but a good upgrade from the original design that put NiCds next to the most expensive/delicate RF hardware. ? The older 8662As had a separate board full of low-density mask ROMs.? This newer one probably has one or two firmware EEPROMs, hence no need for the older ROM board. ?There will be another EEPROM somewhere with the attenuator correction data. ? -- john, KE5FX ? ? What¡¯s the serial number of your unit? HP got rid of the ROM/RAM board in put all the necessary ROM/RAM on an existing board after some revision. Is your unit working? If so, your unit is almost certainly complete. Even if not, my guess is it¡¯s still probably complete. ? On Sun, Feb 19, 2023 at 5:10 AM colingoode2000 via <colingoode2000=[email protected]> wrote: I have an 8662a oscillator which has a missing board may be two My question is what should be fitted in the right hand A2 slots coloured Green Blue Purple Grey and White I am missing a Rom Ram board but I have found two
|
Yeah, that's an updated CPU board with a lithium battery. ?Not super common, but a good upgrade from the original design that put NiCds next to the most expensive/delicate RF hardware. ? The older 8662As had a separate board full of low-density mask ROMs.? This newer one probably has one or two firmware EEPROMs, hence no need for the older ROM board. ?There will be another EEPROM somewhere with the attenuator correction data. ? -- john, KE5FX ?
toggle quoted message
Show quoted text
From: [email protected] [mailto:[email protected]] On Behalf Of Matt Huszagh
Sent: Sunday, February 19, 2023 8:21 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP 8662A A2 Slots? What¡¯s the serial number of your unit? HP got rid of the ROM/RAM board in put all the necessary ROM/RAM on an existing board after some revision. Is your unit working? If so, your unit is almost certainly complete. Even if not, my guess is it¡¯s still probably complete. ? On Sun, Feb 19, 2023 at 5:10 AM colingoode2000 via <colingoode2000=[email protected]> wrote: I have an 8662a oscillator which has a missing board may be two My question is what should be fitted in the right hand A2 slots coloured Green Blue Purple Grey and White I am missing a Rom Ram board but I have found two
|
Re: strange issue on Agilent 54641D MSO
It has been doing it for like 2 months or so. No abuse or measurement that triggered it (at least not something I recall, it has not been used much lately)
Wilko
|
Re: Hot air soldering tool
Another vote for the Quick 861DW - I've had one for a few years, it's always performs very well, no matter if you're trying to reflow a couple surface mount resistors with the air turned way down, or have it running full tilt to heat up a big area and desolder a huge chip.
There's also the Aten ST-862D.
Here's a comparison between the two:
I started with one of the cheap ebay/china 858D hot air tools. They work too, but the heater is much lower wattage so you can't get as much heat at higher airflow settings. The Quick is definitely a step up
"Steve - Home" <sw.krull@...> writes:
> I¡¯m considering a hot air soldering tool and am looking for recommendations. I have a bench top Hart 200A with top and bottom heat to do larger parts but I¡¯m looking for a hand held unit for small parts and repair work. There seems to be a lot of cheap import stuff and then some really expensive units. I don¡¯t need a combination unit with a soldering iron as I have enough irons already. Is there anything in the $200 or so range anyone would recommend?
This is about $100 above your target, but I have the Quick 861DW and
it's excellent.
Matt
|
Re: Advice on how to use an SA for test point troubleshooting
?
You may also use a differential probe, it is important to pay attention to the probe's input impedance and the common mode rejection ratio (CMRR) of the probe and oscilloscope. The input impedance of the probe can affect the signal being measured, and the CMRR is important for rejecting noise and interference in the measurement.
|
Re: Advice on how to use an SA for test point troubleshooting
?
One type of probe that could be used for this purpose is a passive probe with a bandwidth of at least 500 MHz and a maximum input voltage that exceeds +2 dBm. A passive probe is typically less expensive and simpler to use than an active probe, but it can introduce some loading and attenuation to the circuit under test.
Another option is an active probe that has a frequency range that covers 500 MHz and a maximum input voltage that exceeds +2 dBm. An active probe uses a built-in amplifier to boost the signal and minimize loading effects, but it can be more expensive and may require additional power.
In addition to selecting an appropriate probe, it's important to properly calibrate the spectrum analyzer before taking measurements. This typically involves setting the reference level, center frequency, and resolution bandwidth to appropriate values based on the signal being measured.
|
Re: 5086-7337 *Yig Oscillator issue*
Yup, you got point :)
I¡¯ll search a resistor to apply that method, ohm law at it¡¯s best.
Regards,
Ruben
|
Re: Advice on how to use an SA for test point troubleshooting
Both SAs and Scopes measure voltage. If a signal level is CORRECTLY specified in dBm, the impedance must be 50 ohms unless otherwise stated.
All that is necessary to do is the mathematical conversion from power to voltage (works in general if the particular impedance is known).
An easy way to avoid the maths ias to use the FET probe to measure the output of a working signal generator (with appropriate termination). I find the HP FET probes a valuable asset for debugging - protects the SA from DC and overloads (to some degree).
Cheers!
Bruce
Quoting Chuck Harris <cfharris@...>:
toggle quoted message
Show quoted text
If the OP's description of the set point being 2-3 dBm,
is accurate, you can do nothing else but use a 50 ohm
probe to make the connection.
dBm is totally undefined at the arbitrary high impedances
of FET probes.
dBm is totally undefined at the arbitrary impedances of something
like the Andrew Zonenberg probes.
dBm is totally undefined at the arbitrary impedance of using
a resister in series with the center lead of a coax cable...
The only way the high impedance route could work is if the OP,
or the MFR, used dBm in an imprecise way, and really meant something
else. If the MFR did that, he likely would have the sort of probe
he intended listed in the necessary calibration equipment table for
the instrument.
-Chuck Harris
On Sun, 19 Feb 2023 10:29:50 -0800 "Matt Huszagh"
<huszaghmatt@...> wrote:
"Bruce" <bruce@...> writes:
If you can find ont, I recommend attaching an HP FET probe to your
SA. If you don't have one, it is a good idea to start looking for
one. I find them a valuable resource for trouble shooting.
Note: the passive probe is unlikely to work. While a FET probe is nice, a suitable high-frequency passive probe
(like the PML series) can absolutely work up to 500 MHz and beyond.
In fact, you can make them work up to several GHz with proper design.
See the Andrew Zonenberg probes, for instance
(). Of course, the passive
probe approach mandates some sort of voltage division, otherwise this
won't work. Sticking some coax between your test point and the oscope
will just load down the circuit with a bunch of parallel capacitance.
A typical 10:1 or 1:1 oscope probe designed for high input impedance
scope termination won't work though. Don't confuse passive probes
designed for 1M scope input impedance with those designed for 50ohm
scope input impedance.
You probably know this, but if you do use a scope and not the SA, make
sure the reference point can be connected to earth ground. If not
you'll need something to isolate it. The typical approach would be to
use a differential probe.
Matt
|
Re: Advice on how to use an SA for test point troubleshooting
"Chuck Harris" <cfharris@...> writes: If the OP's description of the set point being 2-3 dBm,
is accurate, you can do nothing else but use a 50 ohm
probe to make the connection.
dBm is totally undefined at the arbitrary high impedances
of FET probes.
dBm is totally undefined at the arbitrary impedances of something
like the Andrew Zonenberg probes.
dBm is totally undefined at the arbitrary impedance of using
a resister in series with the center lead of a coax cable...
The only way the high impedance route could work is if the OP,
or the MFR, used dBm in an imprecise way, and really meant something
else. If the MFR did that, he likely would have the sort of probe
he intended listed in the necessary calibration equipment table for
the instrument. Ok, fair enough. I had assumed 2-3 dBm meant into a 50ohm load presented by whatever is downstream of this. If it's 2-3 dBm when you load it externally with 50 ohms, then yes of course you'll want to load it. It does seem a little odd to ask you to change the circuit behavior when probing though, which is what will happen if you load it down by an external 50 ohms. But, admittedly, I haven't seen this sort of test point much so maybe I'm just not familiar with the typical procedure here. Minor nit: passive probes like the Zonenberg probes aren't "arbitrary impedance". They're designed for specific division ratios into a 50 ohm input, so they have a very well-defined impedance, at least over the specified bandwidth. Matt
|
KB2LMN
Paul Bicknell
RubenRubio