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Re: Frequency range of HP 5352B frequency counter

 

¿ªÔÆÌåÓý

Am 25.05.2022 um 08:56 schrieb Lothar baier:
The biggest problem you run into now in regards to upgrading a 5352B to 46GHz is finding the connector and the front/dress panel for the option 05 units.
Option 05 did not only change the connector but since the connector used had a different size you also had to change the sub and dress panel on the counter!
Now if you only interested in the functionality you can probably find a 2.4mm bulkhead connector that is long enough and adapt it to fit in the mounting hole of the 3.5mm barrel connector but if you want the unit to look like a option 05 unit things get tough?

I changed the connector with PLANAR CROWN connectors.

_._,_._

Input 1 K 1.jpg
Input 1 Planar 1.jpg

Info Need on a RF FET for a Agilent E4438C signal generator

 

¿ªÔÆÌåÓý

I am rapiring a E4438C generator. There is a FET shorted in the output of chain of the 4Ghz path. The FET is called M11X1005. I can see traces of it existing but no data. The SHF-0189Z can be used but not directly. The M11X1005 is using 6.5V on the drain but the SHF-0189 uses 8V and has higher gain and higher output.
Does anyone have either a M11X1005 Fet, data or a suitable repleacement.
I would assume something having 20dB of gain and +27dBm output.
best regards Peter
Re: 53181A 3 GHz prescaler from China

 

Now what I want is a clone of the external clocking interface for the HP33120A. It's rather complex due to creating an internal 40MHz reference.
Re: 53181A 3 GHz prescaler from China

 

Mine also came from the guy in Poland : he is on eevblog. It works well and avoids the problem with self-oscillation in some prescalers (due to being a clone of the HP design ).
Re: HP P532A Frequency Meter Manual

 

Hi John
unfortunately the 12.6 to 18 Ghz wave guide parts are not that easy to find at low cost as not used by radio amateurs
The Frequency Meter is put in series with a RF signal generator and a power detector or meter on the other port when the meter is tuned to the RF signal there is a small power reduction of about 2 db or so
Paul

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf Of Dave McGuire
Sent: 24 May 2022 23:09
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] HP P532A Frequency Meter Manual

On 5/24/22 17:04, johnasolecki@... wrote:
I recently acquired an HP P532A frequency meter. I know it's a
resonant cavity device that goes from 12.6 GHz to 18 GHz but I don't
how or what to hookup to the two flanges to get it to work.

I've seen the Signal Path video but the unit he demos is a different
frequency range and has connectors rather than flanges. There are some
manuals and app notes on eBay but each is twice what I paid for the device.
I have signal sources and detectors in the correct frequency range, I
just need to know how to connect to the flanges. Does anyone have any info?
These are "waveguide flanges". Waveguide is a common, very efficient way to move microwave energy around. See the Wikipedia article about it for an introduction.

The size of a waveguide, and thus the size of its flanges, depends on the frequency of their intended use. These are (generally) standardized, and have a standardized nomenclature. Your P532A has "WR62" waveguide flanges. If you look for a WR62 waveguide to coax adapter, you should be able to find something that makes sense.

For these frequencies you'll likely be working with type N, SMA, APC-7, or 3.5mm connectors.

There are waveguide to coaxial cable adapters available, for different sizes of waveguide flanges.

This is quite a few orders of magnitude higher in frequency than the
audio gear I normally work on...
Oh this stuff is great fun. You'd better free up some space and budget, you're gonna need it! ;)

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
Re: HP 8662A Power up - overvoltage shutdown

 

Hi.

If it is (as I think you said) a switching power supply, then usually only one output rail is regulated closely by the main switching regulation loop.

The other rails rely on either close coupling between secondary windings, plus the ratio between them and the main rail, so rely on the main rail being loaded enough for the SMPS regulator to be working close to it's designed switching ratio to also be correct, loaded or not.

Or, they use the otherwise unwanted stored energy in the transformer as a "flyback" like PSU.?? Chances are that's what the -40V rail might be, especially if it is a low current rail.? Without a representative load, they can rise almost uncontrollably to much higher levels than normal running voltages, especially at higher raw input voltages.

So the higher the input voltage the higher a lightly (or un)loaded low current output may be, if it is using recovered/stored energy from a "forward converter" transformer core, much like a Flyback converter.

Try providing representative loads for all output lines, especially the main regulated rail, and see what happens then.


FYI, the accepted AC Line voltage limits in the UK these days, are essentially 230V -6% +10% (so, nominally 216V to 253V 50Hz.)
But I have seen up to 255 here and on customer sites in the past, and as low as 210V in remote places.

Take care, use a fully isolated secondary 50Hz transformer to power the device (before or after the Variac) then you can safely ground the raw DC -ve side, so as to probe the main switching side current and voltage waveforms.? But be careful, there will still be lethal voltages present!? (Sometimes well over 600V, if there is an "Active power factor correction" system included in the mix.? And they too, can behave very strangely if the overall output DC side is not loaded "as expected".)


Regards.

Dave G8KBV.

--
Created on and sent from a Unix like PC running and using free and open source software:
Re: Frequency range of HP 5352B frequency counter

Lothar baier
 

¿ªÔÆÌåÓý

The biggest problem you run into now in regards to upgrading a 5352B to 46GHz is finding the connector and the front/dress panel for the option 05 units.
Option 05 did not only change the connector but since the connector used had a different size you also had to change the sub and dress panel on the counter!
Now if you only interested in the functionality you can probably find a 2.4mm bulkhead connector that is long enough and adapt it to fit in the mounting hole of the 3.5mm barrel connector but if you want the unit to look like a option 05 unit things get tough?


On May 25, 2022, at 00:34, Lothar baier via groups.io <Lothar@...> wrote:

?

It depends ,? the 46GHz option changed the input connector , the regular 5352 just as the 5351 used a 3.5mm male connector which will work to 40GHz with degraded specs which doesn¡¯t matter for a counter ,? the 46GHz option used a 2.4mm male NMD connector which is good to 50GHz , I reckon the also changed the cable assy as the 0.141 cable used already has a bunch of loss at 40GHz so using a 0.085 cable would have been a sensible choice .

I also know that initially HP used factory selected samplers for the 52 and 52 with 46GHz option so the 52 samplers had a different part#? , later on they scrapped the concept of having different part numbers and then just sold one part !

BTW the A12 board and sampler also was used in the 83711/12 series synthesizers

?

Sent from for Windows

?

From: Askild via groups.io
Sent: Wednesday, May 25, 2022 12:02 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Frequency range of HP 5352B frequency counter

?

Hi Lothar,

?

I was refereeing to Dave's question of upgrading a 40GHz 5352B to a 46GHz 5352B option 5.

And this is according to the posts I linked only connector and cable change.

?

But as also described in those posts, upgrading a 5350/1 to 5352, a resistor needs to be changed.?

?

Regards,

Askild

?

?

?

On Wed, May 25, 2022 at 12:34 AM Lothar baier <Lothar@...> wrote:

Actually not , there were also some component changes on the A12 board between the 51 and 52 Counters , you can look at the schematics of the board to figure it out

?

From: [email protected] <[email protected]> On Behalf Of Askild via
Sent: Tuesday, May 24, 2022 1:46 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Frequency range of HP 5352B frequency counter

?

Hi Dave,

?

There is some info in these posts:

?

Seems as the only difference is the connector and cable.

?

I have not yet tried to do the change to convert my 5351B to a 52. I don't have anything this high in frequency to test with.

?

Regards,

Askild

?

?

?

On Tue, May 24, 2022 at 3:55 AM Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:

On Tue, 24 May 2022 at 02:45, Lothar baier <Lothar@...> wrote:

Yes the 5352 was 40GHz however HP used the back panel for different models not just the 52 , the 5361B pulse counter for example had options for 26 and 40GHz and the 5352 had options for 46GHz

?

Thank you. Do you know if it¡¯s possible to extend the frequency range to 46 GHz? Not that I can think of a use between 40 & 47 GHz, nut if an upgrade is possible, I might be interested.?

?

Dave?

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom

?

04398DA82A9644B880F09FAFE5BA7989.png

Re: HP 8662A Power up - overvoltage shutdown

 

OMG. Yesterday afternoon I did not know that A7A1 existed. Yesterday evening, I needed
yet another signal generator and had to turn to my 8662A. That one had an easy live in the
last years because of some issues. For example it worked for 0-160 MHz, did not work from
160 to 320, worked again for 320..... and so on.

Yesterday evening, I switched it on and got a black cloud of stench. I switched it off, opened it
and switched it on again for a clue where the cloud might come from.
No more cloud, but some error LEDs are on. Status == 81, which cannot happen according
to the manual. Display and keys still seem to work. +20V is missing which is probably the
reason for the error LEDs. The other voltages are still OK.

Since +23 is still there and +20 is not, the fault is probably on A7A1, the analog post regulator.
Q3, the corresponding transistor has already be changed. Brass case versus Alu of Q1 / Q2,
and someone applied some thermo paste.

But I don't have the circuit of A7A1. It seems not to be in the downloads from KO4BB.
There should be a part 2 ???
Does anybody have a cross reference of HP parts to the rest of the world?? I once had one
when I worked for a post-HP-company but failed to secure it.

The DC/DC converter seems to work. But then I see that the FR4 is brown below a fat resistor
that is located between 2 electrolytic caps in the air shadow, both discolored. Then it gets
bitter when I read in the HP journal about the specialists who ensured the culmination of
reliability, several pages.

cheers, Gerhard
(after too short a night)
Re: HP 8662A Power up - overvoltage shutdown

 

¿ªÔÆÌåÓý

Good chance you have an open electrolytic filter capacitor on the PSU motherboard.? From what I've seen, the supply tries valiantly to run in the presence of the resulting ripple, and it *almost* succeeds.? But the high peak-to-average ratio at the input causes the overvoltage sensor to trip.

?

-- john, KE5FX

?

From: [email protected] [mailto:[email protected]] On Behalf Of Tony
Sent: Tuesday, May 24, 2022 5:51 AM
To: [email protected]
Subject: [HP-Agilent-Keysight-equipment] HP 8662A Power up - overvoltage shutdown

?

Hi,

I'm hoping somebody can advise me how to approach a power-on issue with my HP 8662A signal generator.
Re: HP 3465A offset when input shorted

 

Low leakage (< a few pA) given the input impedance for the low DC volt ranges.? A 2N4117A/PN4117A diode connected FET perhaps? ?40V breakdown and 50 mA max gate current.? Horowitz/Hill in the Art of ELectronics use them as clamps - better than the commonly available 'low leakage' diodes!

I'd check the other end of CR9 - it should be around -3.9 V as CR11 is a 3.92V zener.? Also check R66 is 91K.

Orin.


On Tue, May 24, 2022 at 12:49 PM Chris Smith <me@...> wrote:
Ok well that was embarrassing. I found out what was wrong with it purely by accident.

Looks like CR9 was broken. I was inspecting the area around the high impedance after the 100K carbon comp input resistor and clamp and and noticed that CR9 looked a bit suspicious. I poked the leg with my DMM probe and it fell to pieces. Not sure of the failure mode exactly but now it's out of circuit it works absolutely fine. The original role was half of a voltage clamp which makes sense with respect to the offset measured. I assume it was damaged by over-voltage or was leaking.

Picture for reference. The blob of leg is actually dangling from the broken leg by a microscopic metal fibre.?



I checked the input scale was ok by attaching a voltage source to the input terminals and measuring Q16 gate and it was exactly what was expected from the divider arrangement. It appears to zero and work fine now!

Now I can't leave it like this as it's the voltage clamp on the input so it'll probably blow up something else without it if it gets overvoltage input.

The part is 1901-0586 which appears to be a TO18 canned diode. It's not in the usual parts cross references unfortunately. Vendor is HP, spec is derived from SM as DIODE - GEN PRP 30V 25MA.? As it's got en expensive package, it smells like it might be a low leakage type, possibly a diode connected BJT or FET. Any thoughts?

Re: Frequency range of HP 5352B frequency counter

Lothar baier
 

¿ªÔÆÌåÓý

It depends ,? the 46GHz option changed the input connector , the regular 5352 just as the 5351 used a 3.5mm male connector which will work to 40GHz with degraded specs which doesn¡¯t matter for a counter ,? the 46GHz option used a 2.4mm male NMD connector which is good to 50GHz , I reckon the also changed the cable assy as the 0.141 cable used already has a bunch of loss at 40GHz so using a 0.085 cable would have been a sensible choice .

I also know that initially HP used factory selected samplers for the 52 and 52 with 46GHz option so the 52 samplers had a different part#? , later on they scrapped the concept of having different part numbers and then just sold one part !

BTW the A12 board and sampler also was used in the 83711/12 series synthesizers

?

Sent from for Windows

?

From: Askild via groups.io
Sent: Wednesday, May 25, 2022 12:02 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Frequency range of HP 5352B frequency counter

?

Hi Lothar,

?

I was refereeing to Dave's question of upgrading a 40GHz 5352B to a 46GHz 5352B option 5.

And this is according to the posts I linked only connector and cable change.

?

But as also described in those posts, upgrading a 5350/1 to 5352, a resistor needs to be changed.?

?

Regards,

Askild

?

?

?

On Wed, May 25, 2022 at 12:34 AM Lothar baier <Lothar@...> wrote:

Actually not , there were also some component changes on the A12 board between the 51 and 52 Counters , you can look at the schematics of the board to figure it out

?

From: [email protected] <[email protected]> On Behalf Of Askild via
Sent: Tuesday, May 24, 2022 1:46 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Frequency range of HP 5352B frequency counter

?

Hi Dave,

?

There is some info in these posts:

?

Seems as the only difference is the connector and cable.

?

I have not yet tried to do the change to convert my 5351B to a 52. I don't have anything this high in frequency to test with.

?

Regards,

Askild

?

?

?

On Tue, May 24, 2022 at 3:55 AM Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:

On Tue, 24 May 2022 at 02:45, Lothar baier <Lothar@...> wrote:

Yes the 5352 was 40GHz however HP used the back panel for different models not just the 52 , the 5361B pulse counter for example had options for 26 and 40GHz and the 5352 had options for 46GHz

?

Thank you. Do you know if it¡¯s possible to extend the frequency range to 46 GHz? Not that I can think of a use between 40 & 47 GHz, nut if an upgrade is possible, I might be interested.?

?

Dave?

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom

?

04398DA82A9644B880F09FAFE5BA7989.png

Re: Frequency range of HP 5352B frequency counter

 

Hi Lothar,

I was refereeing to Dave's question of upgrading a 40GHz 5352B to a 46GHz 5352B option 5.
And this is according to the posts I linked only connector and cable change.

But as also described in those posts, upgrading a 5350/1 to 5352, a resistor needs to be changed.?

Regards,
Askild



On Wed, May 25, 2022 at 12:34 AM Lothar baier <Lothar@...> wrote:

Actually not , there were also some component changes on the A12 board between the 51 and 52 Counters , you can look at the schematics of the board to figure it out

?

From: [email protected] <[email protected]> On Behalf Of Askild via
Sent: Tuesday, May 24, 2022 1:46 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Frequency range of HP 5352B frequency counter

?

Hi Dave,

?

There is some info in these posts:

?

Seems as the only difference is the connector and cable.

?

I have not yet tried to do the change to convert my 5351B to a 52. I don't have anything this high in frequency to test with.

?

Regards,

Askild

?

?

?

On Tue, May 24, 2022 at 3:55 AM Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:

On Tue, 24 May 2022 at 02:45, Lothar baier <Lothar@...> wrote:

Yes the 5352 was 40GHz however HP used the back panel for different models not just the 52 , the 5361B pulse counter for example had options for 26 and 40GHz and the 5352 had options for 46GHz

?

Thank you. Do you know if it¡¯s possible to extend the frequency range to 46 GHz? Not that I can think of a use between 40 & 47 GHz, nut if an upgrade is possible, I might be interested.?

?

Dave?

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
Re: Frequency range of HP 5352B frequency counter

Lothar baier
 

¿ªÔÆÌåÓý

Actually not , there were also some component changes on the A12 board between the 51 and 52 Counters , you can look at the schematics of the board to figure it out

?

From: [email protected] <[email protected]> On Behalf Of Askild via groups.io
Sent: Tuesday, May 24, 2022 1:46 AM
To: [email protected]
Subject: Re: [HP-Agilent-Keysight-equipment] Frequency range of HP 5352B frequency counter

?

Hi Dave,

?

There is some info in these posts:

?

Seems as the only difference is the connector and cable.

?

I have not yet tried to do the change to convert my 5351B to a 52. I don't have anything this high in frequency to test with.

?

Regards,

Askild

?

?

?

On Tue, May 24, 2022 at 3:55 AM Dr. David Kirkby, Kirkby Microwave Ltd <drkirkby@...> wrote:

On Tue, 24 May 2022 at 02:45, Lothar baier <Lothar@...> wrote:

Yes the 5352 was 40GHz however HP used the back panel for different models not just the 52 , the 5361B pulse counter for example had options for 26 and 40GHz and the 5352 had options for 46GHz

?

Thank you. Do you know if it¡¯s possible to extend the frequency range to 46 GHz? Not that I can think of a use between 40 & 47 GHz, nut if an upgrade is possible, I might be interested.?

?

Dave?

--

Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
Re: 53181A 3 GHz prescaler from China

 

I¡¯ve upgraded my 53181 with an eBay prescaler and oven timebase. I believe I got them from a fellow in Poland. No problems at all. For the timebase I calibrated it to a rubidium standard as described in the manual.?
Re: HP P532A Frequency Meter Manual

 

On 5/24/22 17:04, johnasolecki@... wrote:
I recently acquired an HP P532A frequency meter. I know it's a resonant cavity device that goes from 12.6 GHz to 18 GHz but I don't how or what to hookup to the two flanges to get it to work.
I've seen the Signal Path video but the unit he demos is a different frequency range and has connectors rather than flanges. There are some manuals and app notes on eBay but each is twice what I paid for the device.
I have signal sources and detectors in the correct frequency range, I just need to know how to connect to the flanges. Does anyone have any info?
These are "waveguide flanges". Waveguide is a common, very efficient way to move microwave energy around. See the Wikipedia article about it for an introduction.

The size of a waveguide, and thus the size of its flanges, depends on the frequency of their intended use. These are (generally) standardized, and have a standardized nomenclature. Your P532A has "WR62" waveguide flanges. If you look for a WR62 waveguide to coax adapter, you should be able to find something that makes sense.

For these frequencies you'll likely be working with type N, SMA, APC-7, or 3.5mm connectors.

There are waveguide to coaxial cable adapters available, for different sizes of waveguide flanges.

This is quite a few orders of magnitude higher in frequency than the audio gear I normally work on...
Oh this stuff is great fun. You'd better free up some space and budget, you're gonna need it! ;)

-Dave

--
Dave McGuire, AK4HZ
New Kensington, PA
HP P532A Frequency Meter Manual

 

I recently acquired an HP P532A frequency meter. I know it's a resonant cavity device that goes from 12.6 GHz to 18 GHz but I don't how or what to hookup to the two flanges to get it to work.

I've seen the Signal Path video but the unit he demos is a different frequency range and has connectors rather than flanges. There are some manuals and app notes on eBay but each is twice what I paid for the device.
I have signal sources and detectors in the correct frequency range, I just need to know how to connect to the flanges. Does anyone have any info?

This is quite a few orders of magnitude higher in frequency than the audio gear I normally work on...

Thanks, ????????????????
Re: 53181A 3 GHz prescaler from China

 

¿ªÔÆÌåÓý

Same thing for me, the option 3GHz (from China) works fine with my 53132A.

I¡¯ve done sensitivity test when I bought it, and it was OK.

?

Yves

De?: [email protected] <[email protected]> De la part de Keith
·¡²Ô±¹´Ç²â¨¦?: 24 mai 2022 00:07
??: [email protected]
Objet?: Re: [HP-Agilent-Keysight-equipment] 53181A 3 GHz prescaler from China

?

I bought one a while back for my 53132A. I haven't done much testing of it, but it seems to work just fine.?

Keith

Re: HP 8662A Power up - overvoltage shutdown

 

On Tue, 24 May 2022 at 16:41, Tony <tonycox01@...> wrote:
I've done further checking.

The machine is rated for use in the UK at 230V,and the main selector voltage switch is set correctly and the two fuses are rated correctly (2.5A and 0.5A).


I had problems with over voltage. I got UK Power Networks to reduce the voltage. But speaking to their engineers, UK Power Networks aims to supply consumers 245-250 V in rural areas.? They get far more complaints about under voltage than over voltage, and of course, higher voltages means less power wasted by them.?

I always set my equipment for 240 V. My mains voltage is pretty constant 235 +/- 4 V. But I am fairly close to an 11 kV transformer.?

Although the UK is officially 230 V, I don¡¯t think anyone is trying to move us to 230 V.?


Tony
_._,_._,_
Dave
--
Dr. David Kirkby,
Kirkby Microwave Ltd,
drkirkby@...

Telephone 01621-680100./ +44 1621 680100

Registered in England & Wales, company number 08914892.
Registered office:
Stokes Hall Lodge, Burnham Rd, Althorne, Chelmsford, Essex, CM3 6DT, United Kingdom
Re: first post - new home lab - tips on using HP/Agilent gear

 

¿ªÔÆÌåÓý

I think these "prefer" a sine wave but will accept either.

From: [email protected] <[email protected]> on behalf of Samudra <samudra.haque@...>
Sent: Tuesday, May 24, 2022 10:34 AM
To: [email protected] <[email protected]>
Subject: Re: [HP-Agilent-Keysight-equipment] first post - new home lab - tips on using HP/Agilent gear
?
On Tue, May 24, 2022 at 11:58 AM, Mark Bielman wrote:
Samudra,

I did this with a KTS-250 (the smaller version, setup as 1 input x 8 outputs) and I changed everything to 50 Ohms... works great. Not sure you need to though.
Have the schematic somewhere in my stash. Not much to it. I think the resistors are in a SIP so I used the DIY method instead of buying some.

I would NOT recommend connecting all the inputs together as that would load the GPSDO too much. If you need more than 8 references, better to:
Feed GPSDO output to KTS input. Use 1 of the 8 KTS outputs and connect to another KTS input. Etc, etc. Then each KTS group will have 7 reference outputs except the last one will have 8.

Follow that?

Have fun!

Mark
Interesting.- thank you Mark. I don't mind DIY, if I had a schematic. I would appreciate a suggestion if we can convert it 50 ohm distribution. That's a resistor network at the end of the signal path or so, per the youtube video tear down I think. But if 75/50 ohm in such a small signal chain is not really critical for distributing 10 MHz, to a short few runs of BNC cable - then all the better. Yes, I did get the tip to use two stages for distribution of the 10 MHz ref clock.?

The GPSDO device is s a Chinese clone of PLL-GPSDO BG7TBL. Just arrived and waiting for it to warm up with the antenna outside my window. The output is noted as "SINE WAVE,6dBm+-2dB", so that's fairly hefty and wondering if this is useful or do we need to attenuate it for a cleaner signal? I'll hook up an oscilloscope shortly to see the 10 MHz carrier.?

Do HP equipment mind a sine-wave and not a square wave? Haven't read the big manuals yet in detail :-)?
Re: HP 3465A offset when input shorted

Chris Smith
 

Ok well that was embarrassing. I found out what was wrong with it purely by accident.

Looks like CR9 was broken. I was inspecting the area around the high impedance after the 100K carbon comp input resistor and clamp and and noticed that CR9 looked a bit suspicious. I poked the leg with my DMM probe and it fell to pieces. Not sure of the failure mode exactly but now it's out of circuit it works absolutely fine. The original role was half of a voltage clamp which makes sense with respect to the offset measured. I assume it was damaged by over-voltage or was leaking.

Picture for reference. The blob of leg is actually dangling from the broken leg by a microscopic metal fibre.?



I checked the input scale was ok by attaching a voltage source to the input terminals and measuring Q16 gate and it was exactly what was expected from the divider arrangement. It appears to zero and work fine now!

Now I can't leave it like this as it's the voltage clamp on the input so it'll probably blow up something else without it if it gets overvoltage input.

The part is 1901-0586 which appears to be a TO18 canned diode. It's not in the usual parts cross references unfortunately. Vendor is HP, spec is derived from SM as DIODE - GEN PRP 30V 25MA. ?As it's got en expensive package, it smells like it might be a low leakage type, possibly a diode connected BJT or FET. Any thoughts?
25161 - 25180 of 151497