Re: 8558B centre frequency wildly unstable above 1250MHz
Be carefull with what you spray in. Some of those things conduct very good, resulting in a potentiometer that is not reacting anymore. I have just repaired a transcreiver where the former owner had sprayed contactspray in the volume pot. Now it was allway on max volume. I opened the (tripple layer) pot and cleaned it with TRI because the alcohol and ultrasonic did not get it removed. After the TRI a second ultrasonic bath and placing the wiper outside the old tracks cured the potentiometer , probably for many years to come.
Fred PA4TIM
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Op 30 aug. 2011 om 11:10 heeft "ferrymanr" <g4bbh@...> het volgende geschreven: I forgot to mention that it is important to glue the plastic tube to the nozzle otherwise the pressure will send the whole assembly including needle across the room. I used a plumbers PVC adhesive.
Dick
--- In hp_agilent_equipment@..., "tcxo" <tcxoe@...> wrote:
Interesting and informational!
Thanks,
Greg
----- Original Message -----
From: ferrymanr
To: hp_agilent_equipment@...
Sent: Monday, August 29, 2011 12:42 PM
Subject: [hp_agilent_equipment] Re: 8558B centre frequency wildly unstable above 1250MHz
I have a customised nozzle for my aerosol can of contact fluid. I still have the supplied 10cm length of tube but have fitted a hypodermic needle to the end. This allows me to get a little fluid into awkward places without spraying everything else. A careful inspection of the 10 turn potentiometer with a watchmakers lens showed that there is a tiny gap to the side of ech end connnection. I squirted it in there. The Bourns potentiometer fitted and many others have the rear cover held on with metal clips but I did not want to release these in case the whole thing came apart. That little dribble that got in did the trick.
Dick
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Re: 8558B centre frequency wildly unstable above 1250MHz
I forgot to mention that it is important to glue the plastic tube to the nozzle otherwise the pressure will send the whole assembly including needle across the room. I used a plumbers PVC adhesive.
Dick
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--- In hp_agilent_equipment@..., "tcxo" <tcxoe@...> wrote:
Interesting and informational!
Thanks,
Greg
----- Original Message -----
From: ferrymanr
To: hp_agilent_equipment@...
Sent: Monday, August 29, 2011 12:42 PM
Subject: [hp_agilent_equipment] Re: 8558B centre frequency wildly unstable above 1250MHz
I have a customised nozzle for my aerosol can of contact fluid. I still have the supplied 10cm length of tube but have fitted a hypodermic needle to the end. This allows me to get a little fluid into awkward places without spraying everything else. A careful inspection of the 10 turn potentiometer with a watchmakers lens showed that there is a tiny gap to the side of ech end connnection. I squirted it in there. The Bourns potentiometer fitted and many others have the rear cover held on with metal clips but I did not want to release these in case the whole thing came apart. That little dribble that got in did the trick.
Dick
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Re: HP 85662A Power supply issue help needed
Hi Guerrino, Congratulations for your finding! I had a similar problem in my HP-8672A. I bought it as 'unworking' at eBay... and, yes, it didn't work ;-). It is a very complex unit and I was afraid of an obscure fault... But I found that a large capacitor, which also worked on the 5V line (perhaps they are always powered when unit is plugged?) was dry. I had a similar one from an old IBM mainframe so replaced it... and until today it is working OK :-)! About replacing the other ones, of course it won't hurt but I think you can do without replacing them. But, on the other hand, if you have them handy, now it is a good moment to do it. Regards, JOSE At 09:01 30/08/2011, you wrote: Hi Jose, the issue is found, the problem came
from the RF section , there is a signal named
HPON , normally this signal is 5V and is coming
from the 5.2V power supply RF section , the
signal was strangely corrupted with 100Hz like a rectifier output.
and actually this was the case ,the output
capacitor C4 (30000 ?F 20V) in the A8 schematic
and A 23 mother board was completely dry. so no
smoothing capacitor. it is a large capacitor
from cornell dubillier, externally in good shape but the value is only 10 nF.
thanks for your interess
PS: the serial number begin with 24 so a unit
from 1984 nearly 27 years I guess if it would be
safe to change all the other capacitor in the power supply? any advice ?
ON1EV
Guerrino -- 73 EB5AGV - JOSE V. GAVILA - IM99sm La Canyada - Valencia(SPAIN) Radio and Test Equipment....... RadioRepair BLOG...............
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Re: HP 85662A Power supply issue help needed
Hi Jose, the issue is found, the problem came from the RF section , there is a signal named HPON , normally this signal is 5V and is coming from the 5.2V power supply RF section , the signal was strangely corrupted with 100Hz like a rectifier output.
and actually this was the case ,the output capacitor C4 (30000 ?F 20V) in the A8 schematic and A 23 mother board was completely dry. so no smoothing capacitor. it is a large capacitor from cornell dubillier, externally in good shape but the value is only 10 nF.
thanks for your interess
PS: the serial number begin with 24 so a unit from 1984 nearly 27 years I guess if it would be safe to change all the other capacitor in the power supply? any advice ?
ON1EV
Guerrino
|
Sold. Thanks to all who inquired.
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--- In hp_agilent_equipment@..., "mojoehand" <mojoehand@...> wrote:
I guess no one is interested in these, as I've gotten no offers. If I don't sell them here for a small price, later in the week I'm going to list them on ebay. They seem to fetch a rather ridiculous price there.
As for whether they work, as I said, I have no way to test these. However, they came from a shop that was in the habit of tagging defective equipment and putting it in a back room. These probes were not tagged and were in the shop area with the working equipment. Based on this and the fact that all the other equipment in the shop worked, I'd say that these probes are most likely OK.
--- In hp_agilent_equipment@..., "mojoehand" <mojoehand@> wrote:
I have two HP 54701A 2.5 GHz Active Probes in plastic cases. They look complete and almost new, but I have no way to test these. I'll sell these cheap, so make me an offer. Shipping within the US will be $10 extra for Priority Mail.
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Re: HP 204B Modifications.
On Mon, Aug 29, 2011 at 3:17 PM, willcoele@... <willcoele@...> wrote: I have three 204B oscillators I'm restoring. ?One had a problem where C2 (the 3 section, 1% capacitor) had a shorted section. I replaced the shorted section with single 1%, .3uF. ?Close enough for the Government! I have encountered this also.
My problem is, I'm converting the battery units to AC. ?It has a transformer a bridge rectifier and some filtering but secondary of the transformer isn't center tapped and it's not referenced to ground. ? I used a 7812 and a 7915 regulator to provide the ?+/- 12volts but when I wired it to the transformer the plus side dropped to 5.6 volts and the minus side was 37.6 volts. The plus side was drawing more current than the minus side. ?To balance it out I used a 15v Zener diode on the minus side and the plus side increased to 25.75 volts.
It appeared to be working but when the frequency was set to 250to 1KHz, there was a small amount ripple on the + 12v. ?To reduce the ripple, I used a 1000uF electrolytic on the +12v side.
Has anyone done a similar modification? ?Is there a better way?
You could use an active rail splitter circuit: But, the most direct fix is to replace the transformer. There's probably enough room to leave the old one there for future restoration.
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I have three 204B oscillators I'm restoring. One had a problem where C2 (the 3 section, 1% capacitor) had a shorted section. I replaced the shorted section with single 1%, .3uF. Close enough for the Government!
My problem is, I'm converting the battery units to AC. It has a transformer a bridge rectifier and some filtering but secondary of the transformer isn't center tapped and it's not referenced to ground. I used a 7812 and a 7915 regulator to provide the +/- 12volts but when I wired it to the transformer the plus side dropped to 5.6 volts and the minus side was 37.6 volts. The plus side was drawing more current than the minus side. To balance it out I used a 15v Zener diode on the minus side and the plus side increased to 25.75 volts.
It appeared to be working but when the frequency was set to 250to 1KHz, there was a small amount ripple on the + 12v. To reduce the ripple, I used a 1000uF electrolytic on the +12v side.
Has anyone done a similar modification? Is there a better way?
|
Re: Are plotters still useful?
I've done the PIC version some years ago for an HP analog spectrum
analyzer with X, Y and Pen Lift outputs. Worked reasonably well.
The algorithm holds a do nothing loop waiting for the pen lift signal to
change state to indicate start of a valid sweep. Then, the PIC samples
the X and Y lines with its on-board A/D converter, storing the data
until the pen lift changes state to reflect end of sweep. Stored data is
then outputted via serial port to the computer where it may be further
analyzed.
Depending on the sweep speed and the number of data points you require a
faster or slower clocked PIC may be selected. At the time, I used a 16F
series, but if I were doing it today, an 18F would be better.
Also did the same thing for the chart recorder output of a Tektronix TDR.
It's possible to use a digital scope in X,Y mode as you note. I've done
that as well with a Tek TDS430 DSO, but it does not permit vector lines
between samples - just X,Y dot display which makes for a less useful
display. You can offset some of that by using variable persistence and
let the dots build up over a reasonable number of sweeps, but it's not
really optimum for the application.
Jack
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On 8/29/2011 4:35 PM, Peter Bunge wrote:
It is still useful information! Thanks to all.
I have a Velleman two channel digital scope that runs on the USB on a
computer. It will do X-Y and I may try that for the units that have
analog outputs.
However for the 4815A I need two verticals and a horizontal because it
plots Z and Phase. Using the Velleman as a dual I/P scope with a
matching sweep speed and triggering it from the 4815A may work, but
sounds tricky.
I wonder about building a PIC circuit to record Impedance, Phase, and
Sweep and then sending this to another program (Excel?), or has
someone done this? Perhaps the old plotter is easier. I have seen
various adapters to get away from the HP pens that dry out after a
year even if unused. They are also entertaining to watch.
Peter.
--- In hp_agilent_equipment@...
<mailto:hp_agilent_equipment%40yahoogroups.com>, werner haussmann
<w_haussmann@...> wrote:
So I looked up the 4815A and it does not have a screen. My reply
below was only meant for instruments with a screen. Sorry
|
Re: Are plotters still useful?
It is still useful information! Thanks to all.
I have a Velleman two channel digital scope that runs on the USB on a computer. It will do X-Y and I may try that for the units that have analog outputs.
However for the 4815A I need two verticals and a horizontal because it plots Z and Phase. Using the Velleman as a dual I/P scope with a matching sweep speed and triggering it from the 4815A may work, but sounds tricky.
I wonder about building a PIC circuit to record Impedance, Phase, and Sweep and then sending this to another program (Excel?), or has someone done this? Perhaps the old plotter is easier. I have seen various adapters to get away from the HP pens that dry out after a year even if unused. They are also entertaining to watch.
Peter.
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--- In hp_agilent_equipment@..., werner haussmann <w_haussmann@...> wrote:
So I looked up the 4815A and it does not have a screen. My reply below was only meant for instruments with a screen. Sorry
|
Re: 8558B centre frequency wildly unstable above 1250MHz
Interesting and informational!
Thanks,
Greg
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----- Original Message -----
From: ferrymanr
To: hp_agilent_equipment@...
Sent: Monday, August 29, 2011 12:42 PM
Subject: [hp_agilent_equipment] Re: 8558B centre frequency wildly unstable above 1250MHz
I have a customised nozzle for my aerosol can of contact fluid. I still have the supplied 10cm length of tube but have fitted a hypodermic needle to the end. This allows me to get a little fluid into awkward places without spraying everything else. A careful inspection of the 10 turn potentiometer with a watchmakers lens showed that there is a tiny gap to the side of ech end connnection. I squirted it in there. The Bourns potentiometer fitted and many others have the rear cover held on with metal clips but I did not want to release these in case the whole thing came apart. That little dribble that got in did the trick.
Dick
|
Re: 8558B centre frequency wildly unstable above 1250MHz
ferrymanr wrote:
Found that a new Bourns 10 turn pot is rather expensive so took the risk
of injecting a little jungle juice into it. Now the 8558B is back to
normal. I love simple faults.
Dick G4BBH Me too! I recently "repaired" a Tek 7B53A and a Fluke 8600A with about $0.10 worth of contact cleaner generously applied to the switches. Both units were EBay "Parts - not working" specials. The Tek unit appeared really dead. After using the contact cleaner, it showed some life, but still not useful (occasional random sweeps). I left the unit powered in in my mainframe and after a few hours looked over and it was working perfectly. Hasn't missed a sweep since! Best regards, -- Bob Smither, PhD Circuit Concepts, Inc. ========================================================================= "The beauty of the second amendment is that it will not be needed until they try to take it." --Thomas Jefferson ========================================================================= Smither@... 281-331-2744(office) -4616(fax)
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Hello,
I have an HP3468A that appears to have a bad control ROM. The unit just
cycles between power up (lights up all elements on the display and a
brief display of:
OV.LD C:3111
and repeat. The processor is being reset through U504 / U550B pin 7.
All the power supplies look stable and clean.
After doing what analog checks I could and finding nothing, I did the
Signature Analysis tests in the Service Manual. The Free Running SA -
SA0 signatures are correct. The signatures in the General Signature
Analysis - SA1, are incorrect which points to the control ROM, U502.
U502 is a Mostek MK36752P. HP part number is 1818-1753. The pin out
looks like that of a Motorola MCM68764 UV erasable PROM, which I can get
on EBay.
Would anyone on the list know where I could get a file with the contents
of that PROM (or even better, an HP part 1818-1753)?
Many thanks!
--
Bob Smither, PhD Circuit Concepts, Inc.
=========================================================================
If a person has integrity, nothing else matters.
If a person doesn't have integrity, nothing else matters.
=========================================================================
Smither@... 281-331-2744(office) -4616(fax)
|
Re: 8558B centre frequency wildly unstable above 1250MHz
I have a customised nozzle for my aerosol can of contact fluid. I still have the supplied 10cm length of tube but have fitted a hypodermic needle to the end. This allows me to get a little fluid into awkward places without spraying everything else. A careful inspection of the 10 turn potentiometer with a watchmakers lens showed that there is a tiny gap to the side of ech end connnection. I squirted it in there. The Bourns potentiometer fitted and many others have the rear cover held on with metal clips but I did not want to release these in case the whole thing came apart. That little dribble that got in did the trick.
Dick
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--- In hp_agilent_equipment@..., "tcxo" <tcxoe@...> wrote:
Congratulations Dick!
It might be helpful to the rest of us to know the details of how you injected the cleaner. Did you drill a hole into the case? Or???
Cheers!
Greg
----- Original Message -----
From: ferrymanr
To: hp_agilent_equipment@...
Sent: Monday, August 29, 2011 4:23 AM
Subject: [hp_agilent_equipment] Re: 8558B centre frequency wildly unstable above 1250MHz
Found that a new Bourns 10 turn pot is rather expensive so took the risk of injecting a little jungle juice into it. Now the 8558B is back to normal. I love simple faults.
Dick G4BBH
--- In hp_agilent_equipment@..., "tcxo" <tcxoe@> wrote:
Noisy / Intermittent / Bad tuning potentiometer?
-Greg
----- Original Message -----
From: ferrymanr
To: hp_agilent_equipment@...
Sent: Sunday, August 28, 2011 4:26 PM
Subject: [hp_agilent_equipment] 8558B centre frequency wildly unstable above 1250MHz
I have an 8558B which becomes totally unstable if the centre frequency is set above about 1250MHz at any span setting. If the span is sufficiently wide it is clear that the SA it is covering perfectly up to about 1550MHz or 1600MHz with some loss of sensitivitity at the top end. When the centre frequency is set above about 1250MHz the frequency display becomes random from blank up to some random number. This indicates to me that the control voltage is unstable above that frequency setting. The display looks like it is jumping all over the spectrum (have I discovered 'spread spectrum').
Any suggestions as to a likely cause or common problem before I delve into the murky depths.
Thanks
Dick G4BBH
[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
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Re: Question about Service Manual Copyrights
Most units did not come with complete service manuals. They had to be purchased separately. I believe HP has made all their old manuals public domain. Actually I believe they have been requesting any old manuals be uploaded to their site as a service to the users of the older equipment. That is why some are not of good quality. Some are even military versions of the manuals.
Artek Media has some of the best copies available. Most if not all of what he has he copied himself to a higher standard than most of the rest of us can. He charges a very modest amount for his time. I am only a satisfied customer. No connection to his operation. He is also a member of this group and may chime in with more exact information on what you asked. The link to his site is below:
Steve, KJ5RV
br4av01 wrote:
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A simple question to anyone who may know: what are the legalities of copying HP service manuals? Some of them seem to be in the public domain, since they are offered on the HP information web site. But some of these electronic manuals are very low resolution, and practically unusable for repair purposes. Did each piece of test gear come with a service manual or did they have to be purchased separately? Just curious, since the market for used service manuals commands a premium for the printed materials.
Thanks,
br4
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Re: Question about Service Manual Copyrights
Agilent controls all copying and distribution of their manuals. They
will license you if you contact them through the proper channels with
certain stipulations as to what you can and can not distribute copies
of. Just because they offer it for free download on their web site does
NOT mean it is in the public domain. Free sites like KO4BB.com and BAMA
have letters of agreement from Agilent to distribute copies of free
Agilent manuals. Agilent only allows non Agilent sources (such as
ourselves...Artekmedia) to distribute PDF manuals for products that are
officially no longer supported. They had a huge crackdown in about 1995
and have sporadically taken a few "unauthorized" sources to task since then
Cheers
Dave
President
Artekmedia
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On 8/29/2011 11:54 AM, br4av01 wrote:
A simple question to anyone who may know: what are the legalities of
copying HP service manuals? Some of them seem to be in the public
domain, since they are offered on the HP information web site. But
some of these electronic manuals are very low resolution, and
practically unusable for repair purposes. Did each piece of test gear
come with a service manual or did they have to be purchased
separately? Just curious, since the market for used service manuals
commands a premium for the printed materials.
Thanks,
br4
--
Dave& Lynn Henderson
Manuals@...
www.Artekmedia.com
PO Box 175
Welch,MN 55089
|
Question about Service Manual Copyrights
A simple question to anyone who may know: what are the legalities of copying HP service manuals? Some of them seem to be in the public domain, since they are offered on the HP information web site. But some of these electronic manuals are very low resolution, and practically unusable for repair purposes. Did each piece of test gear come with a service manual or did they have to be purchased separately? Just curious, since the market for used service manuals commands a premium for the printed materials.
Thanks,
br4
|
Re: Are plotters still useful?
I use a HP plotter to draw pcb layouts. I made an adapter from an old pen to hold a CD marker. It plots straight at the PCB and after plotting it is going in the stuff that solves the copper. I made a pcb for a 16 pin 2x2 mm AD power detector with this methode. Some pictures here :
Fred PA4TIM
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--- In hp_agilent_equipment@..., Jack Smith <Jack.Smith@...> wrote:
For instruments that use an HPIB plotter, a Prologix USB-HPIB adapter
and John Miles' 7470 program.
Once the plot is in your computer you can then print it on any printer
your computer works with, or save it as a GIF file, etc.
Jack
On 8/29/2011 10:51 AM, Peter Bunge wrote:
What do you use to record outputs from HP test equipment?
I have two plotters (7045B single & 7046B dual pen) but I simply use
my camera to photograph the screen. The thought of ink and paper is a
turn off, and pens are always a problem. Also these analog plotters
would not plot a scale; they must be carefully calibrated and the
units written in on graph paper.
I also have an HPIB plotter (7475A) that might work with some of my
gear like the 8566A spec analyzer or 8505A Network Analyzer, but what
about the 4815A Vector Impedance Meter?
Is there an interface to a modern printer?
|
Re: Are plotters still useful?
So I looked up the 4815A and it does not have a screen. My reply below was only meant for instruments with a screen. Sorry
From: werner haussmann <w_haussmann@...>
To: "hp_agilent_equipment@..." <hp_agilent_equipment@...>
Sent: Monday, August 29, 2011 9:21 AM
Subject: Re: [hp_agilent_equipment] Are plotters still useful?
?
If the 4815A has the ability to dump the plotter sequence (HPGL) into a file you can create an image from that, or feed it to the Agilent Screen capture program to create the image for you.
?
Look for a command like "OUTPPLOT" or the like. Most instruments that write to a plotter can also be set up to write the HPGL data to a file on a PC.
Once you have that, you can 1. write a program to create an image, 2. use the Agilent Screen Capture 2.0 program to read the file and make an image, or 3. create an Add-in for the Screen Capture program that will get the data and show it as an image.
?
I know nothing of the 4815A, but most of the HP instruments that wrote to a plotter on GPIB, can also be queried or set up to dump the HPGL into a file.
?
So the first question; Does the 4815A have GPIB to plot the screen?
?
See here:
?
Werner
From: Peter Bunge <bunge@...>
To: hp_agilent_equipment@...
Sent: Monday, August 29, 2011 8:51 AM
Subject: [hp_agilent_equipment] Are plotters still useful?
?
What do you use to record outputs from HP test equipment?
I have two plotters (7045B single & 7046B dual pen) but I simply use my camera to photograph the screen. The thought of ink and paper is a turn off, and pens are always a problem. Also these analog plotters would not plot a scale; they must be carefully calibrated and the units written in on graph paper.
I also have an HPIB plotter (7475A) that might work with some of my gear like the 8566A spec analyzer or 8505A Network Analyzer, but what about the 4815A Vector Impedance Meter?
Is there an interface to a modern printer?
[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
|
Re: Are plotters still useful?
If the 4815A has the ability to dump the plotter sequence (HPGL) into a file you can create an image from that, or feed it to the Agilent Screen capture program to create the image for you.
?
Look for a command like "OUTPPLOT" or the like. Most instruments that write to a plotter can also be set up to write the HPGL data to a file on a PC.
Once you have that, you can 1. write a program to create an image, 2. use the Agilent Screen Capture 2.0 program to read the file and make an image, or 3. create an Add-in for the Screen Capture program that will get the data and show it as an image.
?
I know nothing of the 4815A, but most of the HP instruments that wrote to a plotter on GPIB, can also be queried or set up to dump the HPGL into a file.
?
So the first question; Does the 4815A have GPIB to plot the screen?
?
See here:
?
Werner
From: Peter Bunge <bunge@...>
To: hp_agilent_equipment@...
Sent: Monday, August 29, 2011 8:51 AM
Subject: [hp_agilent_equipment] Are plotters still useful?
?
What do you use to record outputs from HP test equipment?
I have two plotters (7045B single & 7046B dual pen) but I simply use my camera to photograph the screen. The thought of ink and paper is a turn off, and pens are always a problem. Also these analog plotters would not plot a scale; they must be carefully calibrated and the units written in on graph paper.
I also have an HPIB plotter (7475A) that might work with some of my gear like the 8566A spec analyzer or 8505A Network Analyzer, but what about the 4815A Vector Impedance Meter?
Is there an interface to a modern printer?
|
Re: Are plotters still useful?
For instruments that use an HPIB plotter, a Prologix USB-HPIB adapter
and John Miles' 7470 program.
Once the plot is in your computer you can then print it on any printer
your computer works with, or save it as a GIF file, etc.
Jack
toggle quoted message
Show quoted text
On 8/29/2011 10:51 AM, Peter Bunge wrote:
What do you use to record outputs from HP test equipment?
I have two plotters (7045B single & 7046B dual pen) but I simply use
my camera to photograph the screen. The thought of ink and paper is a
turn off, and pens are always a problem. Also these analog plotters
would not plot a scale; they must be carefully calibrated and the
units written in on graph paper.
I also have an HPIB plotter (7475A) that might work with some of my
gear like the 8566A spec analyzer or 8505A Network Analyzer, but what
about the 4815A Vector Impedance Meter?
Is there an interface to a modern printer?
|
