Re: HP 334A - Mystery Parts on A5 Board
Barry - Maybe do a quick check with an ohmmeter?? If they're inductors they should be near shorts at DC. -Pat
On April 27, 2020 at 3:43 PM n4buq <n4buq@...> wrote:
Hi Pat,
I wondered if they're inductors or capacitors. I'm not sure that style of capacitor was around at that time so an inductor makes sense.
Thanks,
Barry - N4BUQ
----- Original Message -----From: "Patrick Manning" <pbmanning@...>
To: [email protected]
Sent: Monday, April 27, 2020 2:40:59 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 334A - Mystery Parts on A5 Board
Barry -
Those appear to be axial inductors - 20mH, 1% if I'm reading them correctly.
-PatOn April 27, 2020 at 3:22 PM n4buq <n4buq@...
mailto:n4buq@... > wrote:
I have a 334A whose AUTO function is not working correctly. It seeks an
initial null then drifts well off of that null.
I've been checking the voltages and waveforms on the A5 board and have
bound TP5 is completely dead. I've checked everything I can think of
so far and still haven't found it; however, in my exploration of that
board, I found some components that don't appear to be on either of
the schematics I have and not sure what they are. There are a few of
them and in two cases, they're tied from collector to base for two of
the transistors.
I'm attempting to attach pictures that show these parts but if that
fails, I'll add these to an album. If they do come through, I'm
talking about the darker brown components that look a bit like a
resistor but are marked a bit differently (e.g. red black black orange
brown. My presumption that is 200,000 with the brown being a tolerance
or tempco indicator but don't know.
Anyone recognize these?
BTW, the serial number prefix for mine is 1140A and one of the manuals
I have is valid for the serial number; however, I'm not sure if there
may be some Service Notes that may have included those parts. I have a
lot of microfiche and the index for the 334A mentions quite a few
updates that are not part of a manual (at least I don't think they
are). Unfortunately, the only microfiche I have is a 1972 version so
it's quite a bit older than mine.
Thanks,
Barry - N4BUQ
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Re: HP 334A - Mystery Parts on A5 Board
Hi Pat,
I wondered if they're inductors or capacitors. I'm not sure that style of capacitor was around at that time so an inductor makes sense.
Thanks,
Barry - N4BUQ
toggle quoted message
Show quoted text
----- Original Message ----- From: "Patrick Manning" <pbmanning@...>
To: [email protected]
Sent: Monday, April 27, 2020 2:40:59 PM
Subject: Re: [HP-Agilent-Keysight-equipment] HP 334A - Mystery Parts on A5 Board
Barry -
Those appear to be axial inductors - 20mH, 1% if I'm reading them correctly.
-Pat
On April 27, 2020 at 3:22 PM n4buq <n4buq@...
mailto:n4buq@... > wrote:
I have a 334A whose AUTO function is not working correctly. It seeks an
initial null then drifts well off of that null.
I've been checking the voltages and waveforms on the A5 board and have
bound TP5 is completely dead. I've checked everything I can think of
so far and still haven't found it; however, in my exploration of that
board, I found some components that don't appear to be on either of
the schematics I have and not sure what they are. There are a few of
them and in two cases, they're tied from collector to base for two of
the transistors.
I'm attempting to attach pictures that show these parts but if that
fails, I'll add these to an album. If they do come through, I'm
talking about the darker brown components that look a bit like a
resistor but are marked a bit differently (e.g. red black black orange
brown. My presumption that is 200,000 with the brown being a tolerance
or tempco indicator but don't know.
Anyone recognize these?
BTW, the serial number prefix for mine is 1140A and one of the manuals
I have is valid for the serial number; however, I'm not sure if there
may be some Service Notes that may have included those parts. I have a
lot of microfiche and the index for the 334A mentions quite a few
updates that are not part of a manual (at least I don't think they
are). Unfortunately, the only microfiche I have is a 1972 version so
it's quite a bit older than mine.
Thanks,
Barry - N4BUQ
|
Re: HP 334A - Mystery Parts on A5 Board
toggle quoted message
Show quoted text
On April 27, 2020 at 3:22 PM n4buq <n4buq@...> wrote:
I have a 334A whose AUTO function is not working correctly. It seeks an initial null then drifts well off of that null.
I've been checking the voltages and waveforms on the A5 board and have bound TP5 is completely dead. I've checked everything I can think of so far and still haven't found it; however, in my exploration of that board, I found some components that don't appear to be on either of the schematics I have and not sure what they are. There are a few of them and in two cases, they're tied from collector to base for two of the transistors.
I'm attempting to attach pictures that show these parts but if that fails, I'll add these to an album. If they do come through, I'm talking about the darker brown components that look a bit like a resistor but are marked a bit differently (e.g. red black black orange brown. My presumption that is 200,000 with the brown being a tolerance or tempco indicator but don't know.
Anyone recognize these?
BTW, the serial number prefix for mine is 1140A and one of the manuals I have is valid for the serial number; however, I'm not sure if there may be some Service Notes that may have included those parts. I have a lot of microfiche and the index for the 334A mentions quite a few updates that are not part of a manual (at least I don't think they are). Unfortunately, the only microfiche I have is a 1972 version so it's quite a bit older than mine.
Thanks,
Barry - N4BUQ
|
Re: HP 334A - Mystery Parts on A5 Board
Barry - Those appear to be axial inductors - 20mH, 1% if I'm reading them correctly. -Pat
On April 27, 2020 at 3:22 PM n4buq <n4buq@...> wrote:
I have a 334A whose AUTO function is not working correctly. It seeks an initial null then drifts well off of that null.
I've been checking the voltages and waveforms on the A5 board and have bound TP5 is completely dead. I've checked everything I can think of so far and still haven't found it; however, in my exploration of that board, I found some components that don't appear to be on either of the schematics I have and not sure what they are. There are a few of them and in two cases, they're tied from collector to base for two of the transistors.
I'm attempting to attach pictures that show these parts but if that fails, I'll add these to an album. If they do come through, I'm talking about the darker brown components that look a bit like a resistor but are marked a bit differently (e.g. red black black orange brown. My presumption that is 200,000 with the brown being a tolerance or tempco indicator but don't know.
Anyone recognize these?
BTW, the serial number prefix for mine is 1140A and one of the manuals I have is valid for the serial number; however, I'm not sure if there may be some Service Notes that may have included those parts. I have a lot of microfiche and the index for the 334A mentions quite a few updates that are not part of a manual (at least I don't think they are). Unfortunately, the only microfiche I have is a 1972 version so it's quite a bit older than mine.
Thanks,
Barry - N4BUQ
|
Re: Semiconductor test set advice
I've been watching the uTracer 6 development but was not aware of the other two.
I eventually need to sell off a bunch of NOS tubes of Dad's including a bunch of VT-211s. Not keen on building a 1500 V supply though to test those. I bought a military Hickock tester (TU-7/B ???), but have not started on the chore of even making a full inventory. Just sorting them took several days.
I forget the tube designation but I've got over 100 of what is basically a 6L6 with 3 V filaments which were used in aircraft intercom systems. I might need to design a guitar amp around a pair of those so I can sell them at good prices.
Sadly I've not found the 5U4Gs. I know he had a bunch because i helped look for them when we needed one to fix the TV. People pay crazy prices for them when a silicon diode would be better.
|
Re: HP 4195A NiCad Battery replacement
HI guys,
Quite a few years back I got an HP4194A dead (not booting). It 's exactly the same chassis/cpu as the 4195A that I have a pair too.
When I got it, it appeared that the CPU board battery was dead, and HP carefully designed a circuit that could not start on a dead battery.
Damn HP, but wait...
The seller was a few km from me, so I paid him a visit to see how the unit managed to not start... Blank screen sounded good to me.
I tried to make him end the auction early but he insisted on having the auction go to it's end.
The auction was starting at Eur300, and I got it for Eur350 IIRC.
What I never told the seller is that I was ready to pay Eur1700 for him to end it early... (those units are expensive and I really wanted it)?
Then troubleshooting was 2-3 hours (had to reverse that bit of CPU board part) and a one hour trip to the next all-kind-of-batteries-seller.
Not so damn HP :-)
Now back to the battery question, I can't remember if it was a lithium or NiCd one, but it was a very common one and I could easily find a replacement one and you should too.
Just don't replace the NiCd with NiMH, but I guess you know that.
Thanks,
Fred
|
HP 334A - Mystery Parts on A5 Board
I have a 334A whose AUTO function is not working correctly. It seeks an initial null then drifts well off of that null.
I've been checking the voltages and waveforms on the A5 board and have bound TP5 is completely dead. I've checked everything I can think of so far and still haven't found it; however, in my exploration of that board, I found some components that don't appear to be on either of the schematics I have and not sure what they are. There are a few of them and in two cases, they're tied from collector to base for two of the transistors.
I'm attempting to attach pictures that show these parts but if that fails, I'll add these to an album. If they do come through, I'm talking about the darker brown components that look a bit like a resistor but are marked a bit differently (e.g. red black black orange brown. My presumption that is 200,000 with the brown being a tolerance or tempco indicator but don't know.
Anyone recognize these?
BTW, the serial number prefix for mine is 1140A and one of the manuals I have is valid for the serial number; however, I'm not sure if there may be some Service Notes that may have included those parts. I have a lot of microfiche and the index for the 334A mentions quite a few updates that are not part of a manual (at least I don't think they are). Unfortunately, the only microfiche I have is a 1972 version so it's quite a bit older than mine.
Thanks,
Barry - N4BUQ
|
Re: Are there any HP CRT refrenece documents?
Others:
HP130B: 5AQP, 2090-0007. P1 is standard; also available with P2, P5, or P7.
HP122A: 5083-0053 (P31), 5083-0032 (P2), 5083-0033 (P7), 5083-0042 (P11).
HP182T: 5083-3970, P39.
Pete
|
Re: Are there any HP CRT refrenece documents?
Here is a list I have compiled. It is nowhere near complete; I hope it is correct.
Jeremy
HP CRTs
G-205E-2 ?175A Oscilloscope (P31) The following all carry the first four digits "5083-"
0353 130C Oscilloscope
0722 132A Oscilloscope (dual gun)
0652 140A Oscilloscope
9093 140T Oscilloscope
1452 141A Storage Oscilloscope
2587 141T Storage Oscilloscope
2511 141T Storage Oscilloscope
1752 143A Oscilloscope (P31)
1722 143A Oscilloscope (P2)
1751 143A Oscilloscope (P?)
1732 143A Oscilloscope (P7)
1442 143A Oscilloscope (P11)
0842 H30-175A Oscilloscope, high writing-rate CRT
3552 1740A Oscilloscope
5070 1741A Storage Oscilloscope
9023 180E Oscilloscope
1952 181T Storage Oscilloscope
5791 8510 Network Analyzer
3975 Unknown, seen for sale on eBay
1875 Unknown, eBay rectangular
6589 Unknown, eBay rectangular
5732 Unknown, eBay rectangular
6577 Unknown, eBay rectangular
5751 Unknown, eBay rectangular
5723 Unknown, eBay rectangular
On Mon, Apr 27, 2020 at 11:08 AM walter shawlee < walter2@...> wrote: With Tektronix, there is both a detailed CRT data dump, and a "used in" index for CRTs, but I have never found anything similar for HP.? does anyone know of any hp CRT reference data out there?? any info appreciated, as I have failed to find any for 30+ years. It seems like it must exist but I just don't know how to fin dit.
best regards,
walter (walter2 -at- )
sphere research corp.
|
Re: Wanted: HP 8445b Preselector
I have one - need your e-mail
Quoting garp6 <hrgerson@...>:
toggle quoted message
Show quoted text
hi,
Wanted: HP 8445b Preselector .
Please contact me off-list.
thank you,
rick
|
Re: [hp70k] msib sniffer/injector interest query
Tried since a long time ! It is derived from the Hughes/Delphi connector line but specialy manufactured for HP. Delphi, of course, refused to sell to anybody outside HP. See the mechanical design guide I sent to davidandlaura and uploaded by them. On Monday, April 27, 2020, 07:53:22 PM GMT+2, Mark Kahrs <mark.kahrs@...> wrote:
Speaking of the MMS series, has anyone tried to find that connector?? HPAK calls it "proprietary"...? The closest I've found was a Packard-Hughes series (now Delphi):
But they don't seem to offer the 50 pin version.
JF, Thank you for sending the documents.
I have uploaded them here:
The interface specification?indicates that a module-based sniffer will be able to see all traffic between modules within a chassis. Traffic within a module is *not* sent over the external MSIB connectors unless it is destined (or from) a remote chassis, which significantly?reduces?the utility of an external sniffer.
Here's some more thoughts on using a 70100A as the starting point:
This above photo shows the analog board of the 70100A. This board can be removed, and a new PCB can be attached to the standoffs along the top of the module. The digital board can be left in to handle power conversion, with power being provided to the new PCB by the existing ribbon cable from the digital board.
The MSIB connector can be disconnected from the digital board, and reconnected to the new PCB. Here's a closeup:
The RFI ferrite and the MSIB connector can easily be detached and re-routed to the new PCB on the other side of the module.
If we use a Raspberry Pi zero, a USB to Ethernet adapter can be used to provide Ethernet connectivity to the front (or rear) panel. Since the MSIB connector also includes GPIB pins, it makes sense to break those out so that a USB to GPIB adapter can also be included if desired.
The PCB would thus contain the MSIB connector, glue logic to the Raspberry Pi Zero GPIO connector, a power connector, and a connector to connect to the front panel LEDs.
Any thoughts on this general approach?
Does anyone have.a CLIP for the 70100A?
Thanks,
David Slik VE7FIM
On Fri, Apr 24, 2020 at 10:08 PM David & Laura via <davidandlaura= [email protected]> wrote: JF,
Working from the MMS specification documents will accelerate this effort significantly. Can you upload the documents to the list? (or e-mail them directly and I'll upload them for you)
Thanks
David Slik VE7FIM Sorry but it is an unnecessary work : everything you look at is in the MMS_system_specs as the MMS was an open system like Tek TM500/5000 and a lot of companies (Comstron --very impressive ultrafast 4 slots synthesyzer--, Tern Technologies...) built modules for the MMS. I have most of the documents about the system and I sent all in 2014 to a guy Stewart Cobb, asking just for a feedback and prototype. No hear from him... Part of the mails with SC JF, Another interesting idea. It would actually be fairly easy to build a USB-to-MSIB interface box. The external bus is not clocked, it's done with handshaking, so any processor could implement the protocol with bit-banging. You'd need two 37-pin connectors, a bunch of RS-422 driver chips, and a microcontroller with USB. For speed, you'd want USB 2.0. There are plenty of ARM M3 microcontrollers with USB. The hardware would not be hard. Microcontroller software might be harder. The PC display end would be all software, but a lot of it. I wonder how many people would want something like that? Enough to help program it? Enough to buy one? Cheers! --Stu On Dec 17, 2014 8:30 AM, "JF PICARD" < jfphp@...> wrote: Stu Your idea about the CPLD for the bus is very interesting : bus transfers in the MMS system is governed by custom IC in the mainframe et in the plug ins, no longer supplied, and I have allready got the idea to replace these by CPLD, just an idea for me because I have no knowledge in this domain and I found nobody interested by such a project. There is perhaps a small market to offer substitute for this very special ICs. There is another very interesting subjet you will get in touch with your work : the MMS control by a PC . HP offered the 70207A/B (with various options depending of the bundled softwares and accessories : HPBasic, HPIB board...) allowing the total control of any MMS system from a PC running Windows NT. It uses an MSIB interface and a dedicated software. I am hunting it since years without any success, neither in parts nor in software... It could be a side result of your project. 73. JF On Friday, April 24, 2020, 06:27:20 AM GMT+2, Dave McGuire < mcguire@...> wrote:
? I for one think that's a fantastic idea.? I'm a heavy user of MSIB
stuff, and would love to see it extended a bit.
? ? ? ? ? ? -Dave
On 4/23/20 3:59 PM, Jan de Jongh wrote:
> Dear all,
>
> While building my 3rd hp70k-mms system, I want to assess the interest in
> a project idea I've had for the past two years or so: A
> *sniffer/injector* for the hp70k module-interconnection protocol
> (*msib*). All (hardware/software) open source; this is not a commercial
> proposal (apart from e.g. cost-price PCB delivery).
>
> The very rough basic idea is to take a single-width hp70k module
> (likely, for-parts-only), strip everything inside apart from the msib
> interface and mechanical interfaces, and put inside one or more PCBs that:
>
>? * Interface with the msib bus such that 'basic bus transactions' can
>? ? be captured;
>? * Store these 'transactions' into (e.g.) a pcap file on an ssd
>? ? connected to a (say) an embedded Raspberry Pi;
>? * Transfer these 'transactions' over 1 Gbps Ethernet (copper/Fiber
>? ? Optic) from the Raspberry Pi;
>? * Interface over Ethernet both from the front and the rear;
>? * Import the pcap 'transaction' into Wireshark (on a remote machine);
>? * Interpret the 'transactions' using an hp70k-msib dissector;
>? * Perhaps add power monitoring, etc.;
>? * ...
>
>
> This would be the basic first-order requirements of the project. In
> subsequent phases, injection of messages/transactions on the bus and
> running HP calibration (HP-BASIC) software from virtualized containers
> could be implemented.
>
> *My questions:*
>
>? * Is any project already working on something like this that I can
>? ? join (I could not find any)?
>? * Would this be interesting enough to the amateur hp70k community? Is
>? ? there sufficient added value to a tool like this over merely
>? ? swapping modules in order to get things to work?
>? * Does a tool like this have the potential to increase the public
>? ? knowledge on the hp70k mms? Could it reveal calibration data? Is it
>? ? worth it?
>? * *Would anyone be willing to help?* I figure that even a first
>? ? attempt at a working prototype would take over a year, but various
>? ? components of the project (like the pcap format definition,
>? ? wireshark dissectors, web-based interfacing, RPi firmware, KiCAD PCB
>? ? design of bus interfacing, ...) could be isolated and
>? ? designed/implemented in a team-effort... Needless to say this
>? ? project would required >=4 committed enthusiast aficionados...
>
>
> Thanks in advance for your thoughts/vision on this, BR,
> Jan - pa3gyf
>
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Are there any HP CRT refrenece documents?
With Tektronix, there is both a detailed CRT data dump, and a "used in" index for CRTs, but I have never found anything similar for HP.? does anyone know of any hp CRT reference data out there?? any info appreciated, as I have failed to find any for 30+ years. It seems like it must exist but I just don't know how to fin dit.
best regards,
walter (walter2 -at- sphere.bc.ca)
sphere research corp.
|
Re: [hp70k] msib sniffer/injector interest query
Speaking of the MMS series, has anyone tried to find that connector?? HPAK calls it "proprietary"...? The closest I've found was a Packard-Hughes series (now Delphi):
But they don't seem to offer the 50 pin version.
JF, Thank you for sending the documents.
I have uploaded them here:
The interface specification?indicates that a module-based sniffer will be able to see all traffic between modules within a chassis. Traffic within a module is *not* sent over the external MSIB connectors unless it is destined (or from) a remote chassis, which significantly?reduces?the utility of an external sniffer.
Here's some more thoughts on using a 70100A as the starting point:
This above photo shows the analog board of the 70100A. This board can be removed, and a new PCB can be attached to the standoffs along the top of the module. The digital board can be left in to handle power conversion, with power being provided to the new PCB by the existing ribbon cable from the digital board.
The MSIB connector can be disconnected from the digital board, and reconnected to the new PCB. Here's a closeup:
The RFI ferrite and the MSIB connector can easily be detached and re-routed to the new PCB on the other side of the module.
If we use a Raspberry Pi zero, a USB to Ethernet adapter can be used to provide Ethernet connectivity to the front (or rear) panel. Since the MSIB connector also includes GPIB pins, it makes sense to break those out so that a USB to GPIB adapter can also be included if desired.
The PCB would thus contain the MSIB connector, glue logic to the Raspberry Pi Zero GPIO connector, a power connector, and a connector to connect to the front panel LEDs.
Any thoughts on this general approach?
Does anyone have.a CLIP for the 70100A?
Thanks,
David Slik VE7FIM
On Fri, Apr 24, 2020 at 10:08 PM David & Laura via <davidandlaura= [email protected]> wrote: JF,
Working from the MMS specification documents will accelerate this effort significantly. Can you upload the documents to the list? (or e-mail them directly and I'll upload them for you)
Thanks
David Slik VE7FIM Sorry but it is an unnecessary work : everything you look at is in the MMS_system_specs as the MMS was an open system like Tek TM500/5000 and a lot of companies (Comstron --very impressive ultrafast 4 slots synthesyzer--, Tern Technologies...) built modules for the MMS. I have most of the documents about the system and I sent all in 2014 to a guy Stewart Cobb, asking just for a feedback and prototype. No hear from him... Part of the mails with SC JF, Another interesting idea. It would actually be fairly easy to build a USB-to-MSIB interface box. The external bus is not clocked, it's done with handshaking, so any processor could implement the protocol with bit-banging. You'd need two 37-pin connectors, a bunch of RS-422 driver chips, and a microcontroller with USB. For speed, you'd want USB 2.0. There are plenty of ARM M3 microcontrollers with USB. The hardware would not be hard. Microcontroller software might be harder. The PC display end would be all software, but a lot of it. I wonder how many people would want something like that? Enough to help program it? Enough to buy one? Cheers! --Stu On Dec 17, 2014 8:30 AM, "JF PICARD" < jfphp@...> wrote: Stu Your idea about the CPLD for the bus is very interesting : bus transfers in the MMS system is governed by custom IC in the mainframe et in the plug ins, no longer supplied, and I have allready got the idea to replace these by CPLD, just an idea for me because I have no knowledge in this domain and I found nobody interested by such a project. There is perhaps a small market to offer substitute for this very special ICs. There is another very interesting subjet you will get in touch with your work : the MMS control by a PC . HP offered the 70207A/B (with various options depending of the bundled softwares and accessories : HPBasic, HPIB board...) allowing the total control of any MMS system from a PC running Windows NT. It uses an MSIB interface and a dedicated software. I am hunting it since years without any success, neither in parts nor in software... It could be a side result of your project. 73. JF On Friday, April 24, 2020, 06:27:20 AM GMT+2, Dave McGuire < mcguire@...> wrote:
? I for one think that's a fantastic idea.? I'm a heavy user of MSIB
stuff, and would love to see it extended a bit.
? ? ? ? ? ? -Dave
On 4/23/20 3:59 PM, Jan de Jongh wrote:
> Dear all,
>
> While building my 3rd hp70k-mms system, I want to assess the interest in
> a project idea I've had for the past two years or so: A
> *sniffer/injector* for the hp70k module-interconnection protocol
> (*msib*). All (hardware/software) open source; this is not a commercial
> proposal (apart from e.g. cost-price PCB delivery).
>
> The very rough basic idea is to take a single-width hp70k module
> (likely, for-parts-only), strip everything inside apart from the msib
> interface and mechanical interfaces, and put inside one or more PCBs that:
>
>? * Interface with the msib bus such that 'basic bus transactions' can
>? ? be captured;
>? * Store these 'transactions' into (e.g.) a pcap file on an ssd
>? ? connected to a (say) an embedded Raspberry Pi;
>? * Transfer these 'transactions' over 1 Gbps Ethernet (copper/Fiber
>? ? Optic) from the Raspberry Pi;
>? * Interface over Ethernet both from the front and the rear;
>? * Import the pcap 'transaction' into Wireshark (on a remote machine);
>? * Interpret the 'transactions' using an hp70k-msib dissector;
>? * Perhaps add power monitoring, etc.;
>? * ...
>
>
> This would be the basic first-order requirements of the project. In
> subsequent phases, injection of messages/transactions on the bus and
> running HP calibration (HP-BASIC) software from virtualized containers
> could be implemented.
>
> *My questions:*
>
>? * Is any project already working on something like this that I can
>? ? join (I could not find any)?
>? * Would this be interesting enough to the amateur hp70k community? Is
>? ? there sufficient added value to a tool like this over merely
>? ? swapping modules in order to get things to work?
>? * Does a tool like this have the potential to increase the public
>? ? knowledge on the hp70k mms? Could it reveal calibration data? Is it
>? ? worth it?
>? * *Would anyone be willing to help?* I figure that even a first
>? ? attempt at a working prototype would take over a year, but various
>? ? components of the project (like the pcap format definition,
>? ? wireshark dissectors, web-based interfacing, RPi firmware, KiCAD PCB
>? ? design of bus interfacing, ...) could be isolated and
>? ? designed/implemented in a team-effort... Needless to say this
>? ? project would required >=4 committed enthusiast aficionados...
>
>
> Thanks in advance for your thoughts/vision on this, BR,
> Jan - pa3gyf
>
--
Dave McGuire, AK4HZ
New Kensington, PA
|
Re: How to check the accuracy of an HP 5342A frequency counter
Another thing that can happen to an Rb source is that its built-in OCXO may age/drift too far out of its normal range, for the correction action to properly lock it to the Rb signal. However, the lock indication should not come on in this case, so there is probably something else going on.
I'm not familiar with the Rb in question here, but I know for instance, that old ones like my Efratom M-100s, have provisions for adjusting the OCXO back to a proper tuning range to acquire lock. One of my units had a part failure in its PLL, and was stuck way off in frequency until that was fixed, and the OCXO readjusted. It also properly indicated the failure by never indicating a lock, until after it was fixed.
It's odd that you get a lock, with it apparently so far off. If you have a detailed manual for the unit, you should study it to see the internal frequency plan. A definite, constant offset from the desired frequency could be a result of the control loop locking to a wrong harmonic from the internal synthesizer, due to a part failure or misadjustment. That's the only way I can picture getting an actual, valid lock indication, yet wrong frequency.
Most Rbs synthesize a very particular frequency from the 10 MHz OCXO reference, then multiply it up to the ~6.8 GHz Rb resonance, then use phase detection techniques to steer the OCXO in the right direction and place to get and hold a particular difference between the Rb resonance and the synthesized harmonic. There are various frequency plans used, but this difference frequency is often set up to be in the 100 Hz to 300 Hz range.
Your 170 Hz error falls in this range, so I can picture maybe the unit has slipped a cog, so to speak, and is locked to a wrong harmonic, or on the wrong peak of the phase detector signal.
If you can find a coarse adjustment on the Rb's internal OCXO, you can try tweaking it toward the right frequency, as measured on your other gear - assuming now they are correct and the Rb is wrong. If the Rb isn't busted, you may find as you tweak, that the lock indicator will go out, then magically pop back on when the output frequency reads near 10.000000... MHz. If this happens, then you have reset it to the right cog, and it should be OK operationally, and likely more accurate than the other gear. Then you can look into fine adjustments and perfecting the setup.
Good luck.
Ed
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Re: How to check the accuracy of an HP 5342A frequency counter
Complicating the issue is the presence of a frequency adjust trimmer on each unit, which presents an unknown as to whether it has been adjusted and by whom.? It's a strong possibility that this voting process is flawed, and that the one renegade reading could be the correct one.
However with an arror of over 100 Hz at 10 MHz, comparison with WWV is easy and desirable.
We are not agonizing over one part in 10 ^-11 here, but a sloppy 10 ^-5.
Bob
On Monday, April 27, 2020, 10:14:54 AM PDT, Greg Muir via groups.io <big_sky_explorer@...> wrote:
The “three oscillator” approach is a practice that has been used by NIST (NBS) for decades for comparison of their frequency & time standards.? It also provides a level of redundancy should there be a failure of one of the standards.? But now with improved methods of frequency/time generation (the current cesium fountain clock) it becomes more of a moot point as to what is accurate in their domain.
?
The principle is simple:
?
Compare source A against source B.
Note frequency difference.
But which source is off-frequency?
Compare source a against source B against source C.
Most likely you will see two sources that closely agree.
More are better but there can be limits.
?
Greg
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Re: How to check the accuracy of an HP 5342A frequency counter
The “three oscillator” approach is a practice that has been used by NIST (NBS) for decades for comparison of their frequency & time standards.? It also provides a level of redundancy should there be a failure of one of the standards.? But now with improved methods of frequency/time generation (the current cesium fountain clock) it becomes more of a moot point as to what is accurate in their domain.
?
The principle is simple:
?
Compare source A against source B.
Note frequency difference.
But which source is off-frequency?
Compare source a against source B against source C.
Most likely you will see two sources that closely agree.
More are better but there can be limits.
?
Greg
|
HP5351B High frequency input connector
The high-frequency input connector on an HP 5351B I just purchased appears to be missing the input connector. I believe it was an APC-3.5. There appears to be a missing insert. I'm looking for tips on how to repair or replace this connector. For my purpose a type N connector would be acceptable as a replacement. I have the service manual. It looks like there is a cable assembly. One part number for the APC-3.5 and one for the type N.
Thanks, Jim
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Re: Semiconductor test set advice
Quite complete info on the Tek 575/175 is here:
including 1963 catalogue pages, the Op/Serv manuals and the 'Some
Transistor Measurements Using the Type 575' app note I'm about halfway
thru re-doing.
There were two versions: one with 0 to 20/200V Peak Voltage Range and the mod 122C with 0 to 20/200/400V capability.
You might also want to dig up the three recent and quite good
iterations of vacuum tube testers as they interface with a PC. They are
the uTracer:
the eTracer:
and the much more ambitious, capable, costly and, I'm told, difficult to
build RoeTest:
Best,
Bill Perkins
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Re: Semiconductor test set advice
On 4/27/20 12:38 PM, David C. Partridge wrote: The lead developer was unbelievable; his stated position was that any API (yes, API!) that hasn't changed in the past few weeks "isn't being updated" and is therefore "dead". Believe it or not, it actually went downhill from there. OMG who hired that idiot!
He sold himself to the company's (largely nontechnical) management as a "cool" modern developer who could develop "cool" and "fresh" web interfaces. He went on to go from employee to contractor, then started his own consulting firm, still doing the same job for that same company, and bilked the company for large amounts of money. Beware the word "fresh" coming from "tweenager" software developers. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
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Re: Semiconductor test set advice
...and we wonder these days why people have the attention span of a hyperactive gnat.? It aggravates me when they constantly make little changes to interfaces so that things that were there are either no longer there, or move a bit, or work differently.? It feels like gaslighting - I swear I did this last week, why does it not seem to work now?!? Design it then leave it the eff alone!!? There's something to be said for panels with knobs and switches on them - people are less inclined to rearrange them for? ?...reasons... -Pat
On April 27, 2020 at 11:58 AM Dave McGuire <mcguire@...> wrote:
On 4/27/20 10:02 AM, Reginald Beardsley via groups.io wrote:Occulus, Thanks. Yahoo changed the interface so that it doesn't show unread messages in the SPAM bin :-(
As a consequence I've been forgetting to check and empty it as I used to do every day.
I do wish that "developers" would realize that people do *not* want the UI to change constantly.
Actaully I think it's what a lot of the kids DO want. If it looks the
same as it did yesterday, it's not "FRESH!"
I worked with some developers a few years ago that were of that
mindset. They were doing the web app and back end that talked to
firmware I was writing. The lead developer was unbelievable; his stated
position was that any API (yes, API!) that hasn't changed in the past
few weeks "isn't being updated" and is therefore "dead". Believe it or
not, it actually went downhill from there.
-Dave
--
Dave McGuire, AK4HZ
New Kensington, PA
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