Re: Accurately measuring 1000pF and 100pF capacitors, to calibrate 4276A?
A General Radio 1422D dual range variable would meet the specification. Needs the calbration chart though. The earlier 722D would be OK if calibrated and used at same temperature.
Not many units neet this specification. A pair of IET SCAs would do but they are not cheap. chaeapest would be to make up something as close as can with PC caps and get it measured. That's the difficult part. Most labs can't measure 100pF to 0.01%.
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Robert.
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Re: 8753C VNA option upgrade
Hello Group, I un-soldered the EEPROM from my HP8753C and went in and modified the necessary bits and I was able to enable options, 002, 006, and 010. I soldered in a IC socket and copied the original EEPROM contents to a new IC, (obtained off of Ebay), and used my programmer to copy its contents and it works fine. I also have a HP85047A and it works well with the VNA, now with options enabled. There are articles on the Internet describing what bits to modify to enable these options.
On Sunday, February 23, 2025 at 06:14:12 PM MST, Jinxie via groups.io <paul666@...> wrote:
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Here’s the deal: HP (and later Agilent) locked these options behind firmware codes tied to the instrument’s serial number. Back in the day, you’d buy the upgrade, call up HP with your serial, and they’d send you a unique key to punch in via the front panel or HP-IB interface. The process involves accessing the service menu, tweaking some settings, and entering a code that rewrites the EEPROM to flip the option on. Without that official code, it’s a bit of a gray area—legally and technically.
Now, I can’t hand you specific codes myself—those are proprietary and unique to each unit’s serial number. What I can tell you is how it’s supposed to work based on what’s out there. On the 8753E, you’d typically:
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Power it on, hit Preset, then dive into the Service Menu (usually something like System > Service Menu, though exact key combos depend on firmware—check the manual for your revision).
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Find the option enable function—might be labeled “Enter Option Key” or similar.
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Input a code, which is often a string of numbers or letters HP would generate.
The catch? Getting those codes today. HP/Agilent/Keysight don’t exactly advertise them anymore, and support for the 8753E has long tapered off. Some folks in the test equipment community—like on forums such as EEVblog or the old HP/Agilent groups—claim you can email a guy named “Caesar” (caesarv@...) with your serial number and desired options. He’s rumored to reply with codes that work, no hardware mods needed for software options like 002 or 010. For 006, though, you’re likely stuck unless your unit already has the 6 GHz source hardware—unlocking it without the right guts won’t magically extend the range.
Problem is, that email’s been floating around since at least the early 2000s, and there’s no guarantee it’s still active in 2025—or that it’s legit. Plus, messing with the EEPROM carries a tiny risk of bricking the thing if you fat-finger it. You’d need to move a jumper on the CPU board to enable writes (documented in the service manual), enter the code, and pray.
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That's about as much as I know on the subject but I'm sure there are others on this group who will further assist.
Good luck!
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Re: 8753C VNA option upgrade
?
Here’s the deal: HP (and later Agilent) locked these options behind firmware codes tied to the instrument’s serial number. Back in the day, you’d buy the upgrade, call up HP with your serial, and they’d send you a unique key to punch in via the front panel or HP-IB interface. The process involves accessing the service menu, tweaking some settings, and entering a code that rewrites the EEPROM to flip the option on. Without that official code, it’s a bit of a gray area—legally and technically.
Now, I can’t hand you specific codes myself—those are proprietary and unique to each unit’s serial number. What I can tell you is how it’s supposed to work based on what’s out there. On the 8753E, you’d typically:
-
Power it on, hit Preset, then dive into the Service Menu (usually something like System > Service Menu, though exact key combos depend on firmware—check the manual for your revision).
-
Find the option enable function—might be labeled “Enter Option Key” or similar.
-
Input a code, which is often a string of numbers or letters HP would generate.
The catch? Getting those codes today. HP/Agilent/Keysight don’t exactly advertise them anymore, and support for the 8753E has long tapered off. Some folks in the test equipment community—like on forums such as EEVblog or the old HP/Agilent groups—claim you can email a guy named “Caesar” (caesarv@...) with your serial number and desired options. He’s rumored to reply with codes that work, no hardware mods needed for software options like 002 or 010. For 006, though, you’re likely stuck unless your unit already has the 6 GHz source hardware—unlocking it without the right guts won’t magically extend the range.
Problem is, that email’s been floating around since at least the early 2000s, and there’s no guarantee it’s still active in 2025—or that it’s legit. Plus, messing with the EEPROM carries a tiny risk of bricking the thing if you fat-finger it. You’d need to move a jumper on the CPU board to enable writes (documented in the service manual), enter the code, and pray.
?
That's about as much as I know on the subject but I'm sure there are others on this group who will further assist.
Good luck!
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Re: 8753C VNA option upgrade
Jinxie, do you happen have keyword for unlocking HP 8753E?
Bill? W7AAZ
On 2/23/2025 4:39 PM, Jinxie via
groups.io wrote:
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Show quoted text
Is this what you need?
?
Model Number: HP 8753C
Serial Number: 3317UO1709
To add :
002, Harmonic Analysis
010, Time Domain Analysis (Std on 8702D),
?enter the keyword: 3 H T 6 U K Z Z Y 2 M M
Note: Spaces are for reading clarity only.
?
?
Do NOT install option 006 if you do not have the proper test set
(85047A), as the doubler is in the test set.
?
Model Number: HP 8753C
Serial Number: 3317UO1709
To add :
006, 6 GHz Performance,
?enter the keyword: 3 0 X S J Q Y U F V P
Note: Zeros appear as "0" with this font, the letter O appears
as "O."
?
Enjoy,
Jinxie
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Re: 8753C VNA option upgrade
Is this what you need?
?
Model Number: HP 8753C
Serial Number: 3317UO1709
To add :
002, Harmonic Analysis
010, Time Domain Analysis (Std on 8702D),
?enter the keyword: 3 H T 6 U K Z Z Y 2 M M
Note: Spaces are for reading clarity only.
?
?
Do NOT install option 006 if you do not have the proper test set (85047A), as the doubler is in the test set.
?
Model Number: HP 8753C
Serial Number: 3317UO1709
To add :
006, 6 GHz Performance,
?enter the keyword: 3 0 X S J Q Y U F V P
Note: Zeros appear as "0" with this font, the letter O appears as "O."
?
Enjoy,
Jinxie
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HP54502A Oscilloscope fail A/D test and cal
Hi. Glad to join this group.
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I have a HP54502A in fairly good condition I want to fix for my workbench. It fails on A/D test (pass D/A and rest) on CHANNEL 2 only. I have no schematics, just the SM, and if anyone knows of link to any it would be appreciated.?
Anyway, have anyone else successfully fixed this error before and what was it? I did see a blog online with at short in PS but ALL voltages seems OK and 5.2 adjusted according to SM. I have swapped the 2 ICs with heatsink around just to eliminate that. In lack of a schematics does anyone knows which IC is the DAC (A/D converter) so I at least can have a look around it and compare channels (CH 1 works perfect).
Any hints are welcomed.........
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PS. the Dallas chips has been replaced before I got the scope with a DS1230Y so guess that is not the reason??
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I got the schematics for a 54601a is that too far off or similar in chip sets used?
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Cheers
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Good day all,
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I hope this message finds you well. Apologies if this is not the correct method of sharing. This topic must have been discussed multiple times as well. If possible, I would like to ask if anyone might be able to assist with codes for the 8753C VNA.
?
Firmware version 04.02 1988
Analyzer has no options installed but, I do have an 85047A test set that can be used for 006. If anyone is willing to assist, I would be extremely grateful.
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Re: Accurately measuring 1000pF and 100pF capacitors, to calibrate 4276A?
Yep, I'm in Japan, so shipping is a consideration.. I don't have access to any standards here, besides what might pop up on Yahoo Auctions or the like.
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Re: Accurately measuring 1000pF and 100pF capacitors, to calibrate 4276A?
On 2/23/25 07:30, n4buq wrote: Capacitance standards from General Radio are readily available at places like eBay. Yes, besides the variable 722D, there are fixed caps also. Those can weigh just 8 oz and 4 inches long so more shippable to Nippon.
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Re: Accurately measuring 1000pF and 100pF capacitors, to calibrate 4276A?
On 2/23/25 07:19, Jared Cabot via groups.io wrote: Maybe polystyrene or mica are a reasonable choice? Yes GR used polystyrene for cap standards. Can you borrow some GR gear to use as a reference to put a good value number on some stable caps to use in your lab? If not I have an extra GR 722D that includes 100 pF and 1000 pF in its range you can buy. But, you're in Nippon, right?
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Re: Accurately measuring 1000pF and 100pF capacitors, to calibrate 4276A?
Capacitance standards from General Radio are readily available at places like eBay. Barry - N4BUQ
I've recently been tweaking my 4276A LCZ meter, and I am now at the point of needing 100pF and 1000pF capacitor standards.
?
All the rest of the things are easy, I can measure resistors etc to sufficient digits, but the capacitors I'm less sure about.
?
?
Does anyone have a good suggestion on how to measure capacitors accurately, assuming I have a full complement of test gear, but no reliable direct capacitance measurement gear beyond my 34461A multimeter in capacitance mode or my Der EE DE-5000 LCR meter? (I also have a 4263B LCR meter, but it is unknown regarding calibration and adjustment, and will have to remain so until I find a copy of the adjustment software, or reverse engineer it myself...)
?
The 4276A calls for 100pF and 1000pF for adjustment procedures, and 1pF, 10pF, 100pF and 1000pF for performance verification, all calibrated to 0.01% accuracy at 1kHz and within 0.1% of their nominal values.
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I have made a bunch of 4-wire kelvin BNC adapter PCB's that attach directly to the instrument's BNC connectors, which work excellently for the open, short, and resistance values, so I can easily use them for the capacitors too.
Maybe polystyrene or mica are a reasonable choice?
?
?
Any tips and help would be greatly appreciated.
Thanks!
Jared
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Accurately measuring 1000pF and 100pF capacitors, to calibrate 4276A?
I've recently been tweaking my 4276A LCZ meter, and I am now at the point of needing 100pF and 1000pF capacitor standards.
?
All the rest of the things are easy, I can measure resistors etc to sufficient digits, but the capacitors I'm less sure about.
?
?
Does anyone have a good suggestion on how to measure capacitors accurately, assuming I have a full complement of test gear, but no reliable direct capacitance measurement gear beyond my 34461A multimeter in capacitance mode or my Der EE DE-5000 LCR meter? (I also have a 4263B LCR meter, but it is unknown regarding calibration and adjustment, and will have to remain so until I find a copy of the adjustment software, or reverse engineer it myself...)
?
The 4276A calls for 100pF and 1000pF for adjustment procedures, and 1pF, 10pF, 100pF and 1000pF for performance verification, all calibrated to 0.01% accuracy at 1kHz and within 0.1% of their nominal values.
?
I have made a bunch of 4-wire kelvin BNC adapter PCB's that attach directly to the instrument's BNC connectors, which work excellently for the open, short, and resistance values, so I can easily use them for the capacitors too.
Maybe polystyrene or mica are a reasonable choice?
?
?
Any tips and help would be greatly appreciated.
Thanks!
Jared
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Re: HP 3403C True RMS Voltmeter display fault
It happens! I'm okay with that, especially since they were a high chance they were defective anyway. I'll update soon, at least for the supplies and clock.?
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Re: HP 8670B amplifier - does it ring a bell with anyone?
Am 23.02.2025 um 08:51 schrieb DF6NA Rainer:
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Show quoted text
HP 83020A 2-26,5GHz - 30dB gain - 30dBm out
Am 22.02.2025 um 23:54 schrieb David Feldman via groups.io:
Hi All,
Today (22 Feb) had access to the HP 8670B unit that started this conversation. I've attached three internal photos with close-up of any identifying information I could see.
Did some RF testing at 2, 6, 10, 14 and 18 GHz. It appears to have 30-40 dB of gain and 1-3 watts output power. As the test set-up was not particularly friendly (an ancient Wiltron sweeper and Narda 7000A operating in power meter mode that was about +/- 1 dB off HP 8484A), once the (much) higher than expected max output power was observed, we switched to a Narda 30 dB high power attenuator (intended only to 6 GHz), after a cursory check indicated that it just got lossier as it was operated well above it's specification.
Anyway, there was no indication of how the internal potentiometers would need to be adjusted, nor how the unit uses those, but at least for now at? 6 GHz it seems to be usable.
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Re: HP 8670B amplifier - does it ring a bell with anyone?
HP 83020A 2-26,5GHz - 30dB gain - 30dBm out
Am 22.02.2025 um 23:54 schrieb David Feldman via groups.io:
toggle quoted message
Show quoted text
Hi All,
Today (22 Feb) had access to the HP 8670B unit that started this conversation. I've attached three internal photos with close-up of any identifying information I could see.
Did some RF testing at 2, 6, 10, 14 and 18 GHz. It appears to have 30-40 dB of gain and 1-3 watts output power. As the test set-up was not particularly friendly (an ancient Wiltron sweeper and Narda 7000A operating in power meter mode that was about +/- 1 dB off HP 8484A), once the (much) higher than expected max output power was observed, we switched to a Narda 30 dB high power attenuator (intended only to 6 GHz), after a cursory check indicated that it just got lossier as it was operated well above it's specification.
Anyway, there was no indication of how the internal potentiometers would need to be adjusted, nor how the unit uses those, but at least for now at 6 GHz it seems to be usable.
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Re: Vintage parts for sale
Thank you for not replying. ?
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Show quoted text
From: [email protected] On Behalf Of NICK K. PLUMIDAKIS via groups.io
Sent: Friday, February 21, 2025 6:05 PM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Vintage parts for sale? -------- Original message -------- Date: 2/21/25 17:52 (GMT+02:00) Subject: Re: [HP-Agilent-Keysight-equipment] Vintage parts for sale Hey, here is the link to pictures of parts.,
Let me know what you need.
I prefer to sell all of them.
Best Jurek
?On 21/02/2025, 16:49, "Alexander Huemer via groups.io" <[email protected] <mailto:[email protected]> on behalf of aziD5eeth9fe@... <mailto:[email protected]>> wrote:
Hi!
On Fri, Feb 21, 2025 at 12:51:21PM +0100, jerzy przezdziecki via groups.io wrote:
> I am closing down my father’s long-standing workshop, which
> specialized in tube and radio technology using components available in
> the 1970s and 1980s. There are hundreds of germanium diodes,
> transistors, ceramic tubular capacitors, styroflex capacitors and
> power resistors—both new and desoldered. There’s a large quantity of
> these components. If anyone is interested, I can send photos and a
> detailed description.
Some pictures and a list of items would be appreciated.
I personally could imagine to want a 'grab bag' of a small quantity of
the individual items. You know, 'just in case'.
-Alex
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Re: HP 8670B amplifier - does it ring a bell with anyone?
Now look up HP83020A and see if there's any info.
?
Ed
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Re: HP 8670B amplifier - does it ring a bell with anyone?
Hi All,
Today (22 Feb) had access to the HP 8670B unit that started this conversation. I've attached three internal photos with close-up of any identifying information I could see.
Did some RF testing at 2, 6, 10, 14 and 18 GHz. It appears to have 30-40 dB of gain and 1-3 watts output power. As the test set-up was not particularly friendly (an ancient Wiltron sweeper and Narda 7000A operating in power meter mode that was about +/- 1 dB off HP 8484A), once the (much) higher than expected max output power was observed, we switched to a Narda 30 dB high power attenuator (intended only to 6 GHz), after a cursory check indicated that it just got lossier as it was operated well above it's specification.
Anyway, there was no indication of how the internal potentiometers would need to be adjusted, nor how the unit uses those, but at least for now at 6 GHz it seems to be usable.
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Re: 8596E Spectrum Analyzer Fault
Not sure about 'autocouple' but the actual range seems to be irrelevant. I've tried several. It's the instant the 'stop' frequency is entered that brings on the fault, whether that be by keypad or datum knob.
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Re: HP141T solid state replacement for the neon reference.
Guys, ? I have built 4 more of the BE19400013B neon replacement boards and I am about to relist them on Ebay. ? Mike ?
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From: [email protected] <[email protected]> On Behalf Of Michael Bafaro via groups.io
Sent: Saturday, February 22, 2025 10:05 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP141T solid state replacement for the neon reference.? Guys, ? The 4 units of the BE19400013B have been sold.? I have started building 4 more and when they are built and tested I will relist it on Ebay. ? Mike Bafaro ? ? Guys, ? I have just built and tested 4 more units of the neon tube replacement for the 141T (BE19400013B), and they are listed on Ebay.?? If you wish to buy directly from me, I can be reached at m.bafaro@....? It is listed as item # 306099745539 on Ebay. ? Best wishes, Mike Bafaro WA9ZEO
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Jinxie
Bill Carver
Mr Lurpak's Electronics Rescue
Jared Cabot
