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Re: HP-3456A - Question Regarding Resistance Measurement

 

Did you considet temperature coefficient
Quoting n4buq <n4buq@...>:

I have two brand new 1% tolerance, metal-film resistors that I am looking to use in a project. One is 90M and the other is 50M and I'm using my HP-3456A to measure them.

The 50M tests within 1% (around 49.8M).

The 90M tests at just over 92M which is about 2% over nominal.

2-Wire and 4-Wire show about the same differences.

My meter is not recently calibrated so I know I cannot really trust either measurement; however, does it make sense that if both resistors are indeed within 1% (as they should be given that they're new), would one test correctly and one test incorrectly?

I realize that new parts may not be in spec and at least one of these may be an example of that but these were bought from reputable suppliers (e.g. not eBay purchases) so I suspect they are within tolerance and my meter may be giving me false readings.

If both tested with the same relative difference (e.g. both showed +2%), then that might make better sense but I'm curious as to whether it's possible/probable that if both are in tolerance that the meter would show that kind of variance.

Yeah, I know. Weird question and maybe too many variables but thought I'd see what the experts say.

Thanks,
Barry - N4BUQ
HP-3456A - Question Regarding Resistance Measurement

 

I have two brand new 1% tolerance, metal-film resistors that I am looking to use in a project. One is 90M and the other is 50M and I'm using my HP-3456A to measure them.

The 50M tests within 1% (around 49.8M).

The 90M tests at just over 92M which is about 2% over nominal.

2-Wire and 4-Wire show about the same differences.

My meter is not recently calibrated so I know I cannot really trust either measurement; however, does it make sense that if both resistors are indeed within 1% (as they should be given that they're new), would one test correctly and one test incorrectly?

I realize that new parts may not be in spec and at least one of these may be an example of that but these were bought from reputable suppliers (e.g. not eBay purchases) so I suspect they are within tolerance and my meter may be giving me false readings.

If both tested with the same relative difference (e.g. both showed +2%), then that might make better sense but I'm curious as to whether it's possible/probable that if both are in tolerance that the meter would show that kind of variance.

Yeah, I know. Weird question and maybe too many variables but thought I'd see what the experts say.

Thanks,
Barry - N4BUQ
Re: HP435 measuring head? kW's?

 

On Wed, Oct 7, 2020 at 11:22 AM, Robin Szemeti wrote:
They all have their place
Of course, they do!
My all and only (or almost only) claim is posters on the subject don't seem to know that.
Re: HP435 measuring head? kW's?

 

On Sat, Oct 10, 2020 at 10:46 AM, Dave Smith W6TE wrote:
Building a 11683A isn¡¯t as simple as using an old 8481A and a few precision resistors.
You know...I'm glad you said this... and I enjoy that guy's blog... but, there are only not very loud crickets, when it comes to posts/reports of whether home-brew 11683As actually function as intended. (I'd compare this project to many of the old Radio Electronics magazine projects that... allegedly... didn't live up to the specs... and often needed a rework, or an editorial insertion, in subsequent issues, of the mag. These "projects" are consumer entertainment for perusers. And, they're candidates for future projects: projects fun to imagine, but never actually constructed. )
That conjectured... I'll take a different tack... and would like to pose... allegedly... how many of the posters here (and elsewhere... i.e. YouTube)... are making claims considering the validity of used, and cheap, "heads" (i.e. H.P. 8080 coaxial power sensors)... how many are making claims because they are vendors up selling junk?
Re: Hp-410c parts?

 

Thank you!

On Mon, Oct 12, 2020 at 9:39 AM David M <dgminala@...> wrote:
Never mind.. I found the part number.? It's a B-1493, which doesn't show up anywhere but in the NSN system.? From the characteristics given, the NTE121 or NTE179 should be a good sub.
The B-1493 is a
Germanium PNP,
BVcbo = 60V
Pd = 90W
Iv = 7A
Hfe = Unknown

Cheers,
DaveM

--
Paying Attention, Not a Tutor!
Re: Agilent 54831M

 

Well you can do it either with a standard IDE drive. Your only challenge will be powering it up. If you have a laptop drive, it will be easier, but you might only have a 3.5 inch drive. 3.5 inch drive can be power up from an other power supply. I did it, it's not clean, but it works (for testing).?

For a permanent solution, I recommend you an SSD. They usually use SATA, so you'll want to get an IDE to SATA interface(). I used them in that scope and others equipements and they work fine. An other big advantage of using standard SATA SSD is that you can plug it into your computer without adapters. If you want to install a newer Windows version, you'll want to be able to swap drives easily! The power supply can be a bit tricky. You'll need a standard power cable from an old power supply and a bit of creativity. I can't remember where I plugged it. I think it was on the front floppy, but I could be wrong.
Re: Hp-410c parts?

 

Never mind.. I found the part number. ?It's a B-1493, which doesn't show up anywhere but in the NSN system. ?From the characteristics given, the NTE121 or NTE179 should be a good sub.
The B-1493 is a
Germanium PNP,
BVcbo = 60V
Pd = 90W
Iv = 7A
Hfe = Unknown

Cheers,
DaveM
Re: Hp-410c parts?

 

The zener diodes seem fairly easy to replace. ?A quick search on Mouser's web site comes up with the following as suitable replacements:
CR6 = MTZJ39SB R0G, a 36.3V 500mW Zener 2% ?$0.22 each
CR8 = TZX6V2C-TR, a 6.2V 500mW 2% ?$0.19 each

The power transistor isn't a 2N3106. ?From what I can find, the 2N3106 is a large stud cased SCR. ?What's the HP part number for the transistor?

Cheers,
Dave M
Re: Agilent 54831M

Bostonman
 

I'm in the process of downloading it (finally).

Looks like I should get the whole thing. Now I need to get a spare drive and burn it.

One problem: this scope only has a 44-pin adapter (3.5" to 2.5") and the drive only has 44-pins. Power comes in on a breakout connector on the adapter which a tiny connector (that doesn't mate well) provides 5V and ground.

A standard SSD has a SATA connector (?), so I need I need to get a drive that's compatible with the connectors in this scope.
Re: Hp-410c parts?

 

I have a few 410Cs. I've restuffed the caps in a couple of them. For one of them, I designed a small PC board that holds modern caps and ran wires down to an adapter plate with solder posts. That worked but it was rather kludgy. I keep looking for a better solution for these. Maybe Hayseed Hamfest could be talked into making some replacements.

Good luck with it.

Thanks,
Barry - N4BUQ

----- Original Message -----
From: driftwoodturning@...
To: [email protected]
Sent: Sunday, October 11, 2020 6:33:10 PM
Subject: [HP-Agilent-Keysight-equipment] Hp-410c parts?

I have three Hp-410c meters. I bought the Ss boards from Ashley (kiss
electronics) for one of them. I would like to replace ALL of the
electrolytic capacitors, the two diodes on the a7 board, A7CR6 (1902-0026)
and A7CR8 (1902-0049), maybe even replace the power transistor 2N3106 (I
think that¡¯s the number). Has anyone already done the work to find modern,
current part numbers for these units? I am having little to no luck finding
them. I would appreciate standing on your shoulders.

Thanks in advance,
Jeff
Hp-410c parts?

 

I have three Hp-410c meters. I bought the Ss boards from Ashley (kiss electronics) for one of them. I would like to replace ALL of the electrolytic capacitors, the two diodes on the a7 board, A7CR6 (1902-0026) and A7CR8 (1902-0049), maybe even replace the power transistor 2N3106 (I think that¡¯s the number). Has anyone already done the work to find modern, current part numbers for these units? I am having little to no luck finding them. I would appreciate standing on your shoulders.

Thanks in advance,
Jeff
Re: Clarification : Brass gears for the 8640B

 

Many thanks to you Jeff, you have certainly saved me lots of trouble when explaining to my buyers how to install the gears :-P. (No of course they are not molded -- some people love calling them names as I've seen on multiple occasions but I rather enjoy it :-O)
Jon - my gear sets are available for purchase off ePray. Just search for "Brass gears 8640B" and you'll hit my listing. Good luck with your 8640B restoration!
Cheers - Ram
Re: Agilent 54831M

 

¿ªÔÆÌåÓý

Hello,

just cackle, if I can be of use!


Tam

With best regards
Tam HANNA 

Enjoy electronics? Join 15k7 other followers by visiting the Crazy Electronics Lab at
On 2020. 10. 10. 15:20, julien.monette@... wrote:

Don't worry, I save way more time with this group that I can ever give back, so it's really my pleasure.?

I'll upload it an other way (not zipped, so everything can be download once at a time). I'll post the link when it's ready!

Re: HP8656B attenuator input and output connectors

 

Hi Mark

The two attenuator modules in a HP 8656B are not the standard HP rectangular ones, they use a deep drawn metal top hat soldered or spot welded onto a metal base, very possibly they are irreparable.

I hate to admit this but I have almost sixty years experience in the electronics/RF world, there are not many connectors that I cannot identify and have adapters to and from.

Hope you are keeping well and avoiding the Covid virus, stay safe

George G6HIG Dover UK
On Sunday, 11 October 2020, 01:42:35 BST, Mark Bielman <mbielman@...> wrote:


Hi George,

Good point. I work in the RF world so...

The units I have dealt with are (typically) both female SMA's on the body of the unit (rectangular shape) with the ribbon cable connectors for the solenoids.

Mark

Re: HP8656B attenuator input and output connectors

 

Hi George,

Good point. I work in the RF world so...

The units I have dealt with are (typically) both female SMA's on the body of the unit (rectangular shape) with the ribbon cable connectors for the solenoids.

Mark
Re: HP8656B attenuator input and output connectors

 

Hi Mark

I actually wonder at just how few know the difference between an SMA, SMB and SMC connector. There is at least one HP signal generator that uses an SMC on the attenuator input and an SMA on the output, but it is arguable if it is from the same era.

George G6HIG Dover UK
On Sunday, 11 October 2020, 00:37:16 BST, Mark Bielman <mbielman@...> wrote:


All the HP attenuators from this era that I have seen use SMA connectors.

Mark

Re: HP8656B attenuator input and output connectors

 

The front connector required is definitely an SMA MALE the rear connector is definitely an SMA FEMALE. Direct adapters to BNC can be had on cheaply eBay, they are used for some Beofang Hand portables.

George G6HIG Dover UK
On Sunday, 11 October 2020, 00:16:03 BST, Syd via groups.io <nhuq1@...> wrote:


In this unit the attenuator has input and output RF cables connected to it.. I would like to make a couple of test cables using RG316 cable with a BNC MALE on one end of both cables and the other end of the two cables with male and female connectors to measure the RF at the input and the outputs of the attenuator. I thought that these fittings,
to and from the attenuator, were SMC, MALE? and FEMALE, but I was wrong!? What kind of MALE and FEMALE connectors do I need to connect to these cables and sockets to/from the attenuator?
syd/wt1v

Re: HP8656B attenuator input and output connectors

 

All the HP attenuators from this era that I have seen use SMA connectors.

Mark
HP8656B attenuator input and output connectors

 

In this unit the attenuator has input and output RF cables connected to it.. I would like to make a couple of test cables using RG316 cable with a BNC MALE on one end of both cables and the other end of the two cables with male and female connectors to measure the RF at the input and the outputs of the attenuator. I thought that these fittings,
to and from the attenuator, were SMC, MALE? and FEMALE, but I was wrong!? What kind of MALE and FEMALE connectors do I need to connect to these cables and sockets to/from the attenuator?
syd/wt1v
Re: HP435 measuring head? kW's?

 

True, if you want to use the switch, but the 11683A-H01, which is required for later meters can?use?a voltage input which bypasses the switches.



The schematic here:



Shows that when using the external reference, the range switch isn't used at all.

The home-brew 11683A works as a 11683A-H01 with the REF SELECT switch set to EXT as in the procedure here on pages 42-46:



So - even the expensive switch isn't good enough in some circumstances!

Orin.


On Sat, Oct 10, 2020 at 10:49 AM Dave Smith W6TE <w6te@...> wrote:

Building a 11683A isn¡¯t as simple as using an old 8481A and a few precision resistors. The range switch in the HP 11683A is not your run-of-the-mill SP 10 pos rotary switch. HP used a very low resistance contacts in the switch. In fact, there¡¯s a procedure in the 11683A¡¯s manual for checking the integrity of the switch. The switch has an in house part number and Keysight lists the switch at $3.000!

?

Gud luk

?

Dave

?

From: [email protected] <[email protected]> On Behalf Of Orin Eman
Sent: Saturday, October 10, 2020 10:35 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP435 measuring head? kW's?

?

On Sat, Oct 10, 2020 at 7:07 AM Tom Holmes <tholmes@...> wrote:

By the way, what is involved in calibrating a power meter, not the sensor?

?

An 11683A, 432A plus 478A-H75 sensor, a counter and a DMM.

?

11683A is rare, but you can make one from a dead 8481A (and there are plenty of those around):

?

?

Then you just need a stable voltage source in the range of a few hundred uV to 15.8 V.

?

I made one and using a Fluke 343A as a voltage source and 34461A to measure the voltage, my 346A gave readings well within specs.

?

Calibrating the power reference is difficult... it requires the H75 option for the 478A sensor (good luck finding that) and a somewhat complicated procedure involving measuring voltages from the 432A.

?

Orin.

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