Re: HP 8970B System Check
It sounds to me like your YIG filter is not peaked, you might need to run the adjustments for the yig driver !?
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On Jun 5, 2022, at 14:44, Matt Huszagh via groups.io <huszaghmatt@...> wrote:
? I've performed some of the microwave troubleshooting described in the HP
8971C service manual. The microwave circuitry in the 8971C test set
consists of a number of paths selected with relays. These paths consist
of a simple pass-through for low frequencies directly handled by the
8970B and filters and a downconversion mixer for higher frequencies (to
translate RF frequencies to an input frequency the 8970B can
handle). I've attached an image from the service manual showing these
paths.
The first part of the troubleshooting section involves injecting an RF
signal, selecting a path, measuring the signal gain, and comparing it
with the gain computed from the individual component gains. I've also
attached an image showing these individual component gains.
The gains I measure differ a fair amount from the predicted gains.
In SSB (single sideband) 1 I'm measuring a gain of approximately 23 dB
instead of the expected 15 dB. Moreover, this gain is pretty flat across
the bandwidth as tested by moving the RF signal in 100 MHz steps.
In SSB 2, I also measure a gain in excess of the predicted value. In
this case, 24 dB instead of 19 dB expected.
In SSB 3, I measure a gain of about 16 dB instead of the 20.5 dB
expected. If I move the RF signal by 10-20 MHz (without adjusting the LO
frequency) the gain moves up more toward the expected value.
Any thoughts on what might be going wrong here? SSBs 1 and 2 suggest to
me that maybe the attenuator (AT3) is passing the signal through
un-attenuated. However, the test for SSB 3 indicates that if this is
true, then the YIG filter + attenuator combo is attenuating the signal
by a margin even more than that predicted by the third test on it's own,
which is concerning. Unfortunately, I've only been able to test SSB 3
operation at the low end of its range (2.5 GHz). I'm using my 8340 as
the LO and the only other RF signal generator I have is an 8663A, which
tops out at 2560 MHz. I've got an 8341 too, but it needs repairs.
An obvious solution to these problems would be to open up the instrument
and test components individually. Unfortunately, I can't do that yet as
I bought this unit in a supposedly functional state and may lose my
right to return it if I open it up.
All thoughts appreciated.
Thanks
Matt
 
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Re: HP 8970B System Check
I've performed some of the microwave troubleshooting described in the HP
8971C service manual. The microwave circuitry in the 8971C test set
consists of a number of paths selected with relays. These paths consist
of a simple pass-through for low frequencies directly handled by the
8970B and filters and a downconversion mixer for higher frequencies (to
translate RF frequencies to an input frequency the 8970B can
handle). I've attached an image from the service manual showing these
paths.
The first part of the troubleshooting section involves injecting an RF
signal, selecting a path, measuring the signal gain, and comparing it
with the gain computed from the individual component gains. I've also
attached an image showing these individual component gains.
The gains I measure differ a fair amount from the predicted gains.
In SSB (single sideband) 1 I'm measuring a gain of approximately 23 dB
instead of the expected 15 dB. Moreover, this gain is pretty flat across
the bandwidth as tested by moving the RF signal in 100 MHz steps.
In SSB 2, I also measure a gain in excess of the predicted value. In
this case, 24 dB instead of 19 dB expected.
In SSB 3, I measure a gain of about 16 dB instead of the 20.5 dB
expected. If I move the RF signal by 10-20 MHz (without adjusting the LO
frequency) the gain moves up more toward the expected value.
Any thoughts on what might be going wrong here? SSBs 1 and 2 suggest to
me that maybe the attenuator (AT3) is passing the signal through
un-attenuated. However, the test for SSB 3 indicates that if this is
true, then the YIG filter + attenuator combo is attenuating the signal
by a margin even more than that predicted by the third test on it's own,
which is concerning. Unfortunately, I've only been able to test SSB 3
operation at the low end of its range (2.5 GHz). I'm using my 8340 as
the LO and the only other RF signal generator I have is an 8663A, which
tops out at 2560 MHz. I've got an 8341 too, but it needs repairs.
An obvious solution to these problems would be to open up the instrument
and test components individually. Unfortunately, I can't do that yet as
I bought this unit in a supposedly functional state and may lose my
right to return it if I open it up.
All thoughts appreciated.
Thanks
Matt
|
Re: New file: Sprague capacitor types in files
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It¡¯s in a File Folder called ¡°Sprague Capacitors¡±.?
/g/HP-Agilent-Keysight-equipment/files/Sprague%20Capacitors
?
?
All-
Just uploaded a SS of Sprague capacitor series that I made as a quick reference for myself - feel free to add and modify as needed.? I also have scans (as found on the web) of old catalogs that I can upload if wanted but did not do so as they are approximately
100MB total and i don't want to use up storage space here for no reason.? I will gladly UL if requested.
Thanks,
Hal?
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Re: HP 8116A woes with E42 error
On Sun, Jun 5, 2022 at 12:34 AM, Swiss wrote:
Hi David,
Congratulations on the fix and thanks for letting us know.
Re. calibrating, you have to realize that apart from controls and display, there's nothing digital about the instrument. This means that its accuracies are at levels comparable to other *analog* function/pulse generators, i.e. several % deviations. If your tests indicate the instrument currently is "dead on", I wouldn't bother, unless you're looking forward to the experience. Be prepared for limited "settability". Once you start adjusting something (including supply voltages), you'd better do a full adjustment, while being prepared for the many interdependencies you're going to encounter.
The key-controlled instruments in this series are nice instruments with a convenient user interface and average-level analog performance.
Full disclosure: I like them!
I'm afraid I'll have to pass on your offer for having a drink together: I'm in Europe (Netherlands). OTOH, If you at some time plan a trip, it would be nice to have a drink (or two) together.
Have fun with your 8116A!
Raymond
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Have the replacment Capcitors foxt the problem?
Regards Paul?
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hp 5480A/5485A/5486A Signal Analyzer
Hello All,
I am searching for anything of and for an hp 5480A/5485A/5486A Signal Analyzer system circa November 1968. Has anyone worked with this machine?
For anyone having experience in signal averaging, probability, and correlation, could you offer advice for this kind of research?
Thanks in advance.
Christopher
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Re: HP 8970B battery backup troubleshooting
You may just have it done, then.
Harvey
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On 6/4/2022 2:18 PM, Matt Huszagh wrote: "Harvey White" <madyn@...> writes:
Just looking at the schematic, I wonder about a few things:
did you measure the current through (or voltage drop across) R23?
This would be both in power on and power off.
I'm assuming (as a fault mode) that the switch circuit may fail, or be
partially on when power is off.? This would be either (or both) CR3
failing or Q1 failing, which makes the battery try to drive the +5 volt
line all by itself.? In that case, I can see the backup battery going to
zero in very little time at all. This is a good point.
The current through R23 when off is in the low nA range, same as when
the instrument is powered on. This seems to be consistent with the
measurements performed with the external supply.
I also measured the DC resistance through the parallel path of CR3
(reverse bias) and Q1 and it seems to be an open circuit; at the very
least > tens of MOhm. As an additional check, I measured the forward
drop of CR3 which came out to just under 0.6V so that seems fine.
Anyway, I think I *may* have identified the culprit. There's some
corrosion on the battery holder that I think could have effectively
removed the battery from the circuit. I wasn't measuring the voltage
across the actual battery terminals, but at accessible connection points
on the PCB. So, I think the full reserve supply was being powered by the
capacitor, which is why it couldn't meet the current demands.
I applied some deoxit to the battery holder terminals and I now see a
steady 3.18V measured on the PCB at the connections to the battery.
Matt
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I have an HP 8970B noise figure meter, HP 8971C test set and HP 8340B
that I'm using as the local oscillator. I'd like to verify the operation
of the 8971C, which I purchased used. To do that, I'm performing the
"Noise Figure Measurement System Check" in the operator's manual. I
already successfully completed the "Basic Functional Checks" and "HP-IB
Functional Checks", which verify the operation of the 8970B and its
ability to control the LO.
I'm able to get through the entire system check successfully up to the
last step (step 16), which, after performing a calibration for
frequencies 1, 2, 3, 4, and 5 GHz, has the user adjust the sweep stop
frequency to 3 GHz, places the instrument in double sideband mode and
has the user confirm the noise figure reading is between 8 and 12
dB. Mine reads about 6 dB.
I performed the remaining steps in this check (recommended if that
fails) and they all perform fine.
Does anyone have experience with this system and is familiar with this
test?
The 8971C passes all power-on self-tests. I expect the next step will be
to test the microwave circuitry as part of the 8971C service
manual.
Thanks
Matt
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Re: HP 8116A woes with E42 error
Ozan and Raymond,
Q502 was it. Emitter-base junction was wide open.? Replaced it with the most similar PNP I could find in a 2n5771. E42 error is gone, and I have a full sine wave at both full positive and negative offset. The 5771 is not really a small signal transistor, but will see what happens in due time.
Will need to calibrate, but these 8116A are almost a whole day affair to cal. Looks dead on at first glance though. Probably will stay up late this evening and fix her up after I let her run for a couple of hours.
If both of ya are close, I'd take ya out for a beer. If ya don't drink, i'd get ya a coffee.
Hope this post helps others with the same fault I had in the future by reading this thread, and what a good resource this group is.
Thanks for the help,
David
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Re: HP 8662A - alternative attenuator configurations, 8663A Last Rev Mnl
"Michael Bierlein via groups.io" <bierl008@...> writes: I would be open to scanning the manuals for free if we could put them on archive.org (not necessarily on my archive.org account).
I am NOT a pro but I've scanned a bunch of large manuals for old Ampex VTRs and such. My scans can be viewed here
My process is:
1. Ingest with Epson DS-60000
2. Touch up with
3. OCR and assemble pdf from separate tif files via command line tools (tesseract, img2pdf, etc)
Process notes:
1. Always ingest as color, raw tif, keeping Epson's scanning software options to a minimum. I usually do 300 dpi but could do 600dpi (takes a lot longer). The DS-60000 is a great scanner and I was able to pick up a "broken" one cheaply. Has an ADF which makes quick work of a single page as wide as 50 inches or so. Think the largest page I've scanned was 11 inch height by 45 inches wide. Also has a flatbed scanner that can do 11.7 inches by 17.
2. Scantailor Advanced works well for de-skewing and removing punch holes, etc. Also binarizes the images well.
3. Use tesseract to OCR the Scantailor output, downscale the images for low resolution versions, compress the tif images, convert the tif to pdf, assemble the pdf in a single file with OCR overlaid.
If the manuals are loose leaf it would be a breeze. If they are bound then it becomes more of a problem as damage to the binding/manual can occur. For valuable manuals it would be better left to a pro in that case.
Let me know if you are interested! The manuals could be shipping cheaply via Media Mail. Thank you for offering to help Michael. I think this is a terrific solution and would produce very high quality results. I use a similar workflow though I don't have a nice scanner like the ds-60000. scantailor-advanced and tesseract are great. I also like the idea that these would be freely available on internet archive (and any other sites where we'd want to mirror them). I'd put my vote in for 600dpi if that's ok. If we want to hold onto the original TIFs I'd be happy to store these on my machine. If the manual is like all other HP manuals, the pages should be loose leaf in a binder, so it should be easy on that front. My vote goes to this option, though of course it's up to Richard. Matt
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Re: HP 8662A - alternative attenuator configurations, 8663A Last Rev Mnl
I would be open to scanning the manuals for free if we could put them on archive.org (not necessarily on my archive.org account).
I am NOT a pro but I've scanned a bunch of large manuals for old Ampex VTRs and such. My scans can be viewed here?
My process is:
1. Ingest with Epson DS-60000
2. Touch up with?
3. OCR and assemble pdf from separate tif files via command line tools (tesseract, img2pdf, etc)
Process notes:
1. Always ingest as color, raw tif, keeping Epson's scanning software options to a minimum. I usually do 300 dpi but could do 600dpi (takes a lot longer). The DS-60000 is a great scanner and I was able to pick up a "broken" one cheaply. Has an ADF which makes quick work of a single page as wide as 50 inches or so. Think the largest page I've scanned was 11 inch height by 45 inches wide. Also has a flatbed scanner that can do 11.7 inches by 17.
2. Scantailor Advanced works well for de-skewing and removing punch holes, etc. Also binarizes the images well.
3. Use tesseract to OCR the Scantailor output, downscale the images for low resolution versions, compress the tif images, convert the tif to pdf, assemble the pdf in a single file with OCR overlaid.
If the manuals are loose leaf it would be a breeze. If they are bound then it becomes more of a problem as damage to the binding/manual can occur. For valuable manuals it would be better left to a pro in that case.
Let me know if you are interested! The manuals could be shipping cheaply via Media Mail.
-Michael Bierlein
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Re: HP 8662A - alternative attenuator configurations, 8663A Last Rev Mnl
Don't disagree, just trying to make the problem a bit more quickly solvable.
I use this with most of my PDF manuals. I print the schemats full sized when needed and keep the collection. I can always o to the PDFs when needed.
Cheers!
Bruce
Quoting Matt Huszagh <huszaghmatt@...>:
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"Bruce" <bruce@...> writes:
There is a rather simple solution: Scan only the oversized pages.
Typically, the theory sections only change slightly over the life of
an instrument. You could scan some of the sections referring to
debugging techniques that changed over the life of the instrument and
possibly the updates section. No need to scan the entire manual. In theory, yes, but I think it's preferable to scan the entire manuals
for 2 reasons:
1. The rest of the pages are easy to scan and it would be nice for all
the page numbers to line up. It's really nice to have consistent,
complete, high-quality manuals and I think this is worth a bit of extra
effort up front.
2. The 8663A manual is a bit weird and is incomplete in some
respects. For instance, parts the digital troubleshooting section say to
refer to signature analysis codes, but these aren't actually provided
anywhere in the manual. There's a chance these were added in this
manual. We could look for these specifically, but it would be a shame to
find out at some later point that there was another omission in the
earlier manual revisions that we'd missed the opportunity to scan.
Matt
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Re: HP 8662A - alternative attenuator configurations, 8663A Last Rev Mnl
"Bruce" <bruce@...> writes: There is a rather simple solution: Scan only the oversized pages.
Typically, the theory sections only change slightly over the life of
an instrument. You could scan some of the sections referring to
debugging techniques that changed over the life of the instrument and
possibly the updates section. No need to scan the entire manual. In theory, yes, but I think it's preferable to scan the entire manuals for 2 reasons: 1. The rest of the pages are easy to scan and it would be nice for all the page numbers to line up. It's really nice to have consistent, complete, high-quality manuals and I think this is worth a bit of extra effort up front. 2. The 8663A manual is a bit weird and is incomplete in some respects. For instance, parts the digital troubleshooting section say to refer to signature analysis codes, but these aren't actually provided anywhere in the manual. There's a chance these were added in this manual. We could look for these specifically, but it would be a shame to find out at some later point that there was another omission in the earlier manual revisions that we'd missed the opportunity to scan. Matt
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Re: HP 8662A - alternative attenuator configurations, 8663A Last Rev Mnl
There is a rather simple solution: Scan only the oversized pages. Typically, the theory sections only change slightly over the life of an instrument. You could scan some of the sections referring to debugging techniques that changed over the life of the instrument and possibly the updates section. No need to scan the entire manual.
Cheers!
Brucd
Quoting Matt Huszagh <huszaghmatt@...>:
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"Richard Parrish" <Richard@...> writes:
I'm sure that these are rare. I was in a place 10 years ago that I was able to purchase a number of the end-of-life manuals with all the updates, expensive but I thought it worth it. I couldn't do it again even if they were available. The irritating thing about the manuals is that Agilent expanded single page schematics and put them in the large page format which then made a single page schematic, onto 3 11.5x18" pages; hence the large size of the manuals. I wouldn't have an issue with having someone who has the right equipment scan the manuals but it's going to be a lot of work for someone since the theory and parts lists are on 11x8.5" pages followed by the schematics or block diagrams on 11x18" (?) pages.
I purchased the full set from Keysight which is 4 volumes but I can't locate Vol1 at the moment. Thanks Richard, it's generous of you to be open to this. I've looped in
Dave at Artek who scans these manuals as a business and does a nice
job. I expect he has a scanner that can do the large pages in one piece
and can stitch the parts together, but he can confirm. If not, I've been
looking at a used scanner that can do that size (which I've been
considering anyway) and do them myself. I know of software that can
stitch images like this together and would be willing to put in the
effort, though I've never used this before so will have to give it a
test run first.
Where are you located? Obviously something local would be preferred, but
would you be open to shipping them (which others can subsidize) if not?
Matt
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Re: HP 8662A - alternative attenuator configurations, 8663A Last Rev Mnl
"Richard Parrish" <Richard@...> writes: I'm sure that these are rare. I was in a place 10 years ago that I was able to purchase a number of the end-of-life manuals with all the updates, expensive but I thought it worth it. I couldn't do it again even if they were available. The irritating thing about the manuals is that Agilent expanded single page schematics and put them in the large page format which then made a single page schematic, onto 3 11.5x18" pages; hence the large size of the manuals. I wouldn't have an issue with having someone who has the right equipment scan the manuals but it's going to be a lot of work for someone since the theory and parts lists are on 11x8.5" pages followed by the schematics or block diagrams on 11x18" (?) pages.
I purchased the full set from Keysight which is 4 volumes but I can't locate Vol1 at the moment. Thanks Richard, it's generous of you to be open to this. I've looped in Dave at Artek who scans these manuals as a business and does a nice job. I expect he has a scanner that can do the large pages in one piece and can stitch the parts together, but he can confirm. If not, I've been looking at a used scanner that can do that size (which I've been considering anyway) and do them myself. I know of software that can stitch images like this together and would be willing to put in the effort, though I've never used this before so will have to give it a test run first. Where are you located? Obviously something local would be preferred, but would you be open to shipping them (which others can subsidize) if not? Matt
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Re: HP 8662A - alternative attenuator configurations, 8663A Last Rev Mnl
I'm sure that these are rare.? I was in a place 10 years ago that I was able to purchase a number?of the end-of-life manuals with all the updates, expensive but I thought it worth it.? I couldn't do it again even if they were available.? The irritating thing
about the manuals is that Agilent expanded single page schematics and put them in the large page format which then made a single page schematic, onto 3 11.5x18" pages; hence the large size of the manuals.? I wouldn't have an issue with having someone who has
the right equipment scan the manuals but it's going to?be a lot of work for someone since the theory and parts lists are on 11x8.5" pages followed by the schematics or block diagrams on 11x18" (?) pages.
I purchased the full set from Keysight which is 4 volumes but I can't locate Vol1 at the moment.
Richard
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I¡¯d be happy to support that if it is possible to get it scanned.
Tony
"Richard Parrish" <Richard@...> writes:
> I just looked through my manuals and found the latest/last service manual for the 8663A which covers sn 3423 and greater.? ?For the most part, this manual also covers a good percentage of the information for the later model 8662As.? Looking thru it, it does
cover the later 2 attenuator units and the last version of the power supply section.? It is a BIG manual, measuring about 9" stacked one on top of the other.? I 'think' that the manual pn is 08663-90134 but I can't be sure because I'm missing V1 of the? 4-volume
service manual set.? This manual was labeled Agilent, not HP.? I know that 'some' of the information was in the yellow sheets in the later HP manuals.
Hi Richard,
It's great news this manual still exists. I spent a while looking for
this, including asking Keysight and a couple second hand vendors and
couldn't track it down anywhere. As far as I can tell this is pretty
rare. Do you think you might be able to scan and share it so that this
can be preserved? Or, maybe a few of us could chip in to get it scanned
by someone such as Dave at Artek?
Matt
--
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Re: HP 8970B battery backup troubleshooting
"Harvey White" <madyn@...> writes: Just looking at the schematic, I wonder about a few things:
did you measure the current through (or voltage drop across) R23?
This would be both in power on and power off.
I'm assuming (as a fault mode) that the switch circuit may fail, or be
partially on when power is off.? This would be either (or both) CR3
failing or Q1 failing, which makes the battery try to drive the +5 volt
line all by itself.? In that case, I can see the backup battery going to
zero in very little time at all. This is a good point. The current through R23 when off is in the low nA range, same as when the instrument is powered on. This seems to be consistent with the measurements performed with the external supply. I also measured the DC resistance through the parallel path of CR3 (reverse bias) and Q1 and it seems to be an open circuit; at the very least > tens of MOhm. As an additional check, I measured the forward drop of CR3 which came out to just under 0.6V so that seems fine. Anyway, I think I *may* have identified the culprit. There's some corrosion on the battery holder that I think could have effectively removed the battery from the circuit. I wasn't measuring the voltage across the actual battery terminals, but at accessible connection points on the PCB. So, I think the full reserve supply was being powered by the capacitor, which is why it couldn't meet the current demands. I applied some deoxit to the battery holder terminals and I now see a steady 3.18V measured on the PCB at the connections to the battery. Matt
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Re: HP 8970B battery backup troubleshooting
Just looking at the schematic, I wonder about a few things:
did you measure the current through (or voltage drop across) R23?
This would be both in power on and power off.
I'm assuming (as a fault mode) that the switch circuit may fail, or be partially on when power is off.? This would be either (or both) CR3 failing or Q1 failing, which makes the battery try to drive the +5 volt line all by itself.? In that case, I can see the backup battery going to zero in very little time at all.
Harvey
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On 6/4/2022 1:15 AM, Matt Huszagh wrote: I received a faulty HP 8970B displaying errors (E80 and E26) related to
backup battery / attenuator calibration data troubles. I measured the
voltage across the 3V coin cell in-circuit to be about 2.93 V. However,
the replacement, which showed 3.4V out of circuit, quickly dropped to
about 2.5V in circuit. Sure enough, when I checked the next morning E80
had reappeared (indicating the NVRAM lost data) and the battery voltage
was now only a few tens of mV. Now, when I use a fresh battery the
voltage drops quickly to basically 0.
This obviously sounds like something's shorting the output but when I
power it externally and place an inline meter in current mode, the
current only reads about 4nA. The power draw of the NVRAM in standby is
spec'd at 10nA typical, so this seems reasonable. Also, the NVRAM seems
to work fine when the unit is powered on (I can program new attenuator
calibration data). But if there's no short at the output, why are my
batteries dying? I've attached the battery portion of the schematic. VB
is attached to the TC5564APL-15 NVRAM supply.
FYI, I've run the 8970B through a bunch of the operator's checks and
it's passed everything, so there doesn't seem to be much wrong with it.
It's also worth mentioning that I think I saw a pretty significant
dielectric absorption effect from the tantalum across the battery. I
noticed after the first time I powered the circuit externally that when
I measured the voltage across the battery supply terminals with no
battery (or supply) in place, the voltage read >7V (into a >10GOhm
meter). This persisted after I shorted and released the supply
terminals. When I removed the tantalum this voltage went away so I think
it's a dielectric absorption or memory effect. This is doubly strange to
me, because if this can supply the voltage on its own, why can't the
battery + cap do it?
Matt
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Re: HP 8970B battery backup troubleshooting
"Askild" <megafluffy@...> writes: I don't know the 8970B, so this is just my general thoughts.
Just to verify that I fully understand. When you measured the lover voltage
of the replaced battery, this was measured at the battery terminals, with
the instrument off, and not after the CR4 diode right? That's correct. Measured at the battery terminals with a >10GOhm input impedance voltmeter. Instrument off and disconnected from line. And when you measured 4nA you added an external power supply (or battery)
with current measure inline, connected to the battery terminals, and the
instrument was off? Also correct. I used an HP 6632A DC power supply set to 3V (also tried 3.3V) and 20mA current limit with my multimeter in line in current mode. Battery obviously removed. Instrument off and disconnected from line. If I'm correct in my assumptions, you might look more at what you did
between these measurements.
Did you remove a card to replace battery and put it back?
Did you remove any cover? These results do suggest measurement/operator error. I can't yet think of anything else to explain it. But, I must have performed the measurements 5 or more times because they seemed so strange and got consistent results. I didn't actually do anything to the instrument other than remove and replace the battery. To access this battery, I remove the cover and the digital control board then folds out, but is still electrically connected to the rest of the instrument. During all these measurements the cover remained off and the control board remained folded out. None of that setup changed between measurements. I'll try both measurements again though just to be sure, and I'll make sure nothing else about the setup changes. You could also do a current measurement over a longer time, maybe for some
reason the current consumption go up after the instrument has been off for
a while. Yeah I was wondering this when I was wrapping up last night. Worth investigating either way. I'm going to look into programming a setup over GPIB so I can get a plot of the voltage and current over time with good time-granularity. Maybe that will provide a clearer picture. Could it be related to the content of the memory? Some bits set make
current consumption go up, but now I'm just guessing wild. That would seem strange, but maybe. Let us know if you find out any more Will do, and thanks for your thoughts. The only update so far (which is not all that relevant to this I think), is that the capacitor across the battery (C13) seems totally fine despite the memory effect I measured in it. I measured it on my 4192A out of circuit and capacitance is 10.5u, ESR is 0.5Ohm and insulation resistance is >GOhm, and when measured on my 4192 doesn't appear to be much of a function of bias voltage up to the rated 20V level. Matt
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Hi, I have a version for serial number 2251A and 2309A. This is the original hard copy manual. If you need a particular section of this manual, I can scan that part and return it to you as a PDF. ? -Yves ? ? I am looking for the 8350B service manual for S / N prefix lower than 26XXX, I have P / N 230400-216, on the net I find only the print of October 92 with P / N 08350-90092, I need the one printed previously
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Michael A. Terrell
Paul Bicknell
Christopher Tucker
