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Re: 8340A Fault - ADC

 

开云体育

The ADC is in a wide DIP (don't know the dimensions from heart, but it has the same width as an ordinary EPROM).



-------- Original message --------
From: "Tam Hanna tamhan@... [hp_agilent_equipment]"
Date: 10/23/17 07:52 (GMT+01:00)
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] Re: 8340A Fault - ADC

?

I also googled but a minute or two.


What is the housing of that ADC IS? Worst case, one can IMHO grab an SMD part and make a fourlayer adapter at the usual PCB making suspects


On 23.10.2017 07:13, Tobias Pluess tobias.pluess@... [hp_agilent_equipment] wrote:
?

Hi Calvin


I checked the A27 parts list. Following chips seem to be used:

NE5018F DAC - can be found on eBay

1826-0881 ADC - this is actually an ADC856C. I am unsure whether this can be replaced easily, but I only searched for approx. 5min :-)

MP7533MP - a pin compatible replacement from Maxim is available, called MX7533. Should be available at the usual distributors (Mouser, Digikey, whatever).

Best
Tobias


-------- Original message --------
From: "Calvin Guan guancalvin@... [hp_agilent_equipment]"
Date: 10/23/17 04:39 (GMT+01:00)
Subject: Re: [hp_agilent_equipment] Re: 8340A Fault - ADC

?

Hi Lex,


Yes, it’s ADC fault. The instrument has Fault annunciator lit. I asked the guy to press [shift][manual], and the ADC lights are blinking the the Entry Display. The other faults that would turn on the Fault annunciator are PEAK, TRACK, KICK, and CAL. Although the PEAK and TRK aren’t not blinking, I don’t know if they are also fault as ADC failure may automatically disable PEAK and TRACK.?

I read the 8340B A27 assembly schematic from keysight. Unfortunately, the ADC Clock control and input MUX part is mostly messed up, but the ADC chip itself seems very simple.The 8341A service manual schematic is not humanly readable.

Good thing about it is there are no other abnormal annunciator are lit. UNLEVELED is off, UNLOCK is off. My gut feels it’s something simple but I could be totally wrong.

If the store owner is nice enough, I *might* be able to visit the him to see the instrument in person. What basic tests would you suggest me to run?

Thanks,
Calvin

On Oct 22, 2017, at 5:38 PM, lexternegron@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

Hello,


It depends on who you're buying from. Personally I would go for it if I knew the basic diagnostic self tests were working, the seller isn't selling a physically damaged unit and if I had the money.?I have to ask though. Did you mean ALC? There is no fault light indicator for ADC. Possible scratch or sticker residue??It can be anything from a faulty reference to something as serious as the RF module(s) for the ALC section.

I have the manuals but it would be a written essay on here explaining or posting pics of everything in detail. Check all manual paperwork from Keysight. Its all there but everything is imho mislabeled. Search for all 8340/1/A/B models (4 models in total). This also sounds similar but may not be the same problem as another member here had.

Link to another faulty unit:?

All in all I would need further information obtained from diagnostic tests. Also its ultimately up to you but as I said, I personally would buy it and accept whatever consequences I may receive.

-Lex
?
Re: 8340A Fault - ADC

 

开云体育

I also googled but a minute or two.


What is the housing of that ADC IS? Worst case, one can IMHO grab an SMD part and make a fourlayer adapter at the usual PCB making suspects


On 23.10.2017 07:13, Tobias Pluess tobias.pluess@... [hp_agilent_equipment] wrote:

???

Hi Calvin


I checked the A27 parts list. Following chips seem to be used:

NE5018F DAC - can be found on eBay

1826-0881 ADC - this is actually an ADC856C. I am unsure whether this can be replaced easily, but I only searched for approx. 5min :-)

MP7533MP - a pin compatible replacement from Maxim is available, called MX7533. Should be available at the usual distributors (Mouser, Digikey, whatever).

Best
Tobias


-------- Original message --------
From: "Calvin Guan guancalvin@... [hp_agilent_equipment]"
Date: 10/23/17 04:39 (GMT+01:00)
Subject: Re: [hp_agilent_equipment] Re: 8340A Fault - ADC

???

Hi Lex,


Yes, it???s ADC fault. The instrument has Fault annunciator lit. I asked the guy to press [shift][manual], and the ADC lights are blinking the the Entry Display. The other faults that would turn on the Fault annunciator are PEAK, TRACK, KICK, and CAL. Although the PEAK and TRK aren???t not blinking, I don???t know if they are also fault as ADC failure may automatically disable PEAK and TRACK.???

I read the 8340B A27 assembly schematic from keysight. Unfortunately, the ADC Clock control and input MUX part is mostly messed up, but the ADC chip itself seems very simple.The 8341A service manual schematic is not humanly readable.

Good thing about it is there are no other abnormal annunciator are lit. UNLEVELED is off, UNLOCK is off. My gut feels it???s something simple but I could be totally wrong.

If the store owner is nice enough, I *might* be able to visit the him to see the instrument in person. What basic tests would you suggest me to run?

Thanks,
Calvin

On Oct 22, 2017, at 5:38 PM, lexternegron@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

Hello,


It depends on who you're buying from. Personally I would go for it if I knew the basic diagnostic self tests were working, the seller isn't selling a physically damaged unit and if I had the money.???I have to ask though. Did you mean ALC? There is no fault light indicator for ADC. Possible scratch or sticker residue????It can be anything from a faulty reference to something as serious as the RF module(s) for the ALC section.

I have the manuals but it would be a written essay on here explaining or posting pics of everything in detail. Check all manual paperwork from Keysight. Its all there but everything is imho mislabeled. Search for all 8340/1/A/B models (4 models in total). This also sounds similar but may not be the same problem as another member here had.

Link to another faulty unit:???

All in all I would need further information obtained from diagnostic tests. Also its ultimately up to you but as I said, I personally would buy it and accept whatever consequences I may receive.

-Lex
???
Re: 8340A Fault - ADC

 

开云体育

Hi Calvin

I checked the A27 parts list. Following chips seem to be used:

NE5018F DAC - can be found on eBay

1826-0881 ADC - this is actually an ADC856C. I am unsure whether this can be replaced easily, but I only searched for approx. 5min :-)

MP7533MP - a pin compatible replacement from Maxim is available, called MX7533. Should be available at the usual distributors (Mouser, Digikey, whatever).

Best
Tobias


-------- Original message --------
From: "Calvin Guan guancalvin@... [hp_agilent_equipment]"
Date: 10/23/17 04:39 (GMT+01:00)
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] Re: 8340A Fault - ADC

?

Hi Lex,


Yes, it’s ADC fault. The instrument has Fault annunciator lit. I asked the guy to press [shift][manual], and the ADC lights are blinking the the Entry Display. The other faults that would turn on the Fault annunciator are PEAK, TRACK, KICK, and CAL. Although the PEAK and TRK aren’t not blinking, I don’t know if they are also fault as ADC failure may automatically disable PEAK and TRACK.?

I read the 8340B A27 assembly schematic from keysight. Unfortunately, the ADC Clock control and input MUX part is mostly messed up, but the ADC chip itself seems very simple.The 8341A service manual schematic is not humanly readable.

Good thing about it is there are no other abnormal annunciator are lit. UNLEVELED is off, UNLOCK is off. My gut feels it’s something simple but I could be totally wrong.

If the store owner is nice enough, I *might* be able to visit the him to see the instrument in person. What basic tests would you suggest me to run?

Thanks,
Calvin

On Oct 22, 2017, at 5:38 PM, lexternegron@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

Hello,


It depends on who you're buying from. Personally I would go for it if I knew the basic diagnostic self tests were working, the seller isn't selling a physically damaged unit and if I had the money.?I have to ask though. Did you mean ALC? There is no fault light indicator for ADC. Possible scratch or sticker residue??It can be anything from a faulty reference to something as serious as the RF module(s) for the ALC section.

I have the manuals but it would be a written essay on here explaining or posting pics of everything in detail. Check all manual paperwork from Keysight. Its all there but everything is imho mislabeled. Search for all 8340/1/A/B models (4 models in total). This also sounds similar but may not be the same problem as another member here had.

Link to another faulty unit:?

All in all I would need further information obtained from diagnostic tests. Also its ultimately up to you but as I said, I personally would buy it and accept whatever consequences I may receive.

-Lex
?
Re: 8340A Fault - ADC

 

开云体育

Hi Calvin

I have the complete 8340A service manuals in paper on my desk. I try to find someone who can scan these plus size pages. My scanner at home or in the office can't do that.
Unfortunately, there are no human readable schematics available on the net. I wonder what those guys think when they upload such crappy documents - its absolutely pointless if the schematics are unreadable :-)
Anyway, I can not yet scan the whole thing, but I can make some (readable!) photographs of the A27 schematics if you like.

If you can run another self test on the unit, please do [shift][ext] which shows whether all PLLs are locked. As long as the oven is cold, REF will be flashing, which is okay, it will go away as soon as the oven has reached temperature after about 5min. The oven annunciator should be off. All other PLLs should be locked. If the YO is unlocked.... well, from my repair project you probably know that one can be lucky and the YO can be repaired, but if the YO is blown it can be messy.

If the unit is not too expensive I would go for it. ADC seems to me like a problem which should be repairable (and even if the YO is blown it would be an interesting project to fit another YO, the original 0586-7323 seems unobtanium... :-)).

I once had a 4195A where a? DAC chip had a crack and thus an internal bond junction went bad, leading to the error that the DAC was working in principle, but one single bit was not working. I hat to replace the DAC, which is still manufactured today, so it was easy to obtain a replacement. I would not be surprised if the same was true with the ADC you have problems with.

Tobias HB9FSX



-------- Original message --------
From: "Calvin Guan guancalvin@... [hp_agilent_equipment]"
Date: 10/23/17 04:39 (GMT+01:00)
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] Re: 8340A Fault - ADC

?

Hi Lex,


Yes, it’s ADC fault. The instrument has Fault annunciator lit. I asked the guy to press [shift][manual], and the ADC lights are blinking the the Entry Display. The other faults that would turn on the Fault annunciator are PEAK, TRACK, KICK, and CAL. Although the PEAK and TRK aren’t not blinking, I don’t know if they are also fault as ADC failure may automatically disable PEAK and TRACK.?

I read the 8340B A27 assembly schematic from keysight. Unfortunately, the ADC Clock control and input MUX part is mostly messed up, but the ADC chip itself seems very simple.The 8341A service manual schematic is not humanly readable.

Good thing about it is there are no other abnormal annunciator are lit. UNLEVELED is off, UNLOCK is off. My gut feels it’s something simple but I could be totally wrong.

If the store owner is nice enough, I *might* be able to visit the him to see the instrument in person. What basic tests would you suggest me to run?

Thanks,
Calvin

On Oct 22, 2017, at 5:38 PM, lexternegron@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

Hello,


It depends on who you're buying from. Personally I would go for it if I knew the basic diagnostic self tests were working, the seller isn't selling a physically damaged unit and if I had the money.?I have to ask though. Did you mean ALC? There is no fault light indicator for ADC. Possible scratch or sticker residue??It can be anything from a faulty reference to something as serious as the RF module(s) for the ALC section.

I have the manuals but it would be a written essay on here explaining or posting pics of everything in detail. Check all manual paperwork from Keysight. Its all there but everything is imho mislabeled. Search for all 8340/1/A/B models (4 models in total). This also sounds similar but may not be the same problem as another member here had.

Link to another faulty unit:?

All in all I would need further information obtained from diagnostic tests. Also its ultimately up to you but as I said, I personally would buy it and accept whatever consequences I may receive.

-Lex
?
Re: 8340A Fault - ADC

 

开云体育

Hi Lex,

Yes, it’s ADC fault. The instrument has Fault annunciator lit. I asked the guy to press [shift][manual], and the ADC lights are blinking the the Entry Display. The other faults that would turn on the Fault annunciator are PEAK, TRACK, KICK, and CAL. Although the PEAK and TRK aren’t not blinking, I don’t know if they are also fault as ADC failure may automatically disable PEAK and TRACK.?

I read the 8340B A27 assembly schematic from keysight. Unfortunately, the ADC Clock control and input MUX part is mostly messed up, but the ADC chip itself seems very simple.The 8341A service manual schematic is not humanly readable.

Good thing about it is there are no other abnormal annunciator are lit. UNLEVELED is off, UNLOCK is off. My gut feels it’s something simple but I could be totally wrong.

If the store owner is nice enough, I *might* be able to visit the him to see the instrument in person. What basic tests would you suggest me to run?

Thanks,
Calvin

On Oct 22, 2017, at 5:38 PM, lexternegron@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

Hello,


It depends on who you're buying from. Personally I would go for it if I knew the basic diagnostic self tests were working, the seller isn't selling a physically damaged unit and if I had the money.?I have to ask though. Did you mean ALC? There is no fault light indicator for ADC. Possible scratch or sticker residue??It can be anything from a faulty reference to something as serious as the RF module(s) for the ALC section.

I have the manuals but it would be a written essay on here explaining or posting pics of everything in detail. Check all manual paperwork from Keysight. Its all there but everything is imho mislabeled. Search for all 8340/1/A/B models (4 models in total). This also sounds similar but may not be the same problem as another member here had.

Link to another faulty unit:?

All in all I would need further information obtained from diagnostic tests. Also its ultimately up to you but as I said, I personally would buy it and accept whatever consequences I may receive.

-Lex
?
Re: 8340A Fault - ADC

 

Hello,

It depends on who you're buying from. Personally I would go for it if I knew the basic diagnostic self tests were working, the seller isn't selling a physically damaged unit and if I had the money.?I have to ask though. Did you mean ALC? There is no fault light indicator for ADC. Possible scratch or sticker residue??It can be anything from a faulty reference to something as serious as the RF module(s) for the ALC section.

I have the manuals but it would be a written essay on here explaining or posting pics of everything in detail. Check all manual paperwork from Keysight. Its all there but everything is imho mislabeled. Search for all 8340/1/A/B models (4 models in total). This also sounds similar but may not be the same problem as another member here had.

Link to another faulty unit:?

All in all I would need further information obtained from diagnostic tests. Also its ultimately up to you but as I said, I personally would buy it and accept whatever consequences I may receive.

-Lex
?
Re: 8340A Fault - ADC

 

Fault could be either the ADC chip or the signals controlling it. I
believe the 8340 permits direct control of the peripheral boards.
Diagnostic procedure would be to measure value at ADC input and look at
corresponding digital; values. You could pull eht ADC chip or try to run
the board in a home made test jig. Additionally, as I remember, there are
some board specific diagnostics that you can invoke.

Look over the board schematic and decide how best to attack the problem -
probably not the digital control signals as other boards using the same
control signals working (?).

Hi there,

I am looking into buying a 8340A with known problem — Fault light on,
fault code ADC. From the service manual, it says ADC fault indicates CPU
detected ADC circuit problem on A27 level control assembly. When ADC is
faulting, SYTM won’t track and won’t peak.

However, the manual has very little information on A27 troubleshooting.
What would have caused the ADC fault? How does the power-on-self-test
determine the ADC circuit is bad? Could it be as simple as bad reference
voltage on the ADC or something very involved?

Thank you!
Calvin
8340A Fault - ADC

 

Hi there,

I am looking into buying a 8340A with known problem — Fault light on, fault code ADC. From the service manual, it says ADC fault indicates CPU detected ADC circuit problem on A27 level control assembly. When ADC is faulting, SYTM won’t track and won’t peak.

However, the manual has very little information on A27 troubleshooting. What would have caused the ADC fault? How does the power-on-self-test determine the ADC circuit is bad? Could it be as simple as bad reference voltage on the ADC or something very involved?

Thank you!
Calvin
Re: HP 5335A counter without fancy options, has HPIB -- fail 2.1 U25 RAM

 

John

I could use a parts unit.
What sort of compensation do you need?

Dennis

--------------------------------------------

On Sun, 10/22/17, John Griessen john@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

Subject: [hp_agilent_equipment] HP 5335A counter without fancy options, has HPIB -- fail 2.1 U25 RAM
To: hp_agilent_equipment@...
Date: Sunday, October 22, 2017, 2:52 PM

Anyone want it?? Parts of it?? No
oven crystal in there, no 1.2GHz input C.


------------------------------------
Posted by: John Griessen <john@...>
------------------------------------


------------------------------------

Yahoo Groups Links



? ? (Yahoo! ID required)


? ? hp_agilent_equipment-fullfeatured@...
HP 5335A counter without fancy options, has HPIB -- fail 2.1 U25 RAM

 

Anyone want it? Parts of it? No oven crystal in there, no 1.2GHz input C.
Re: OT Omni Spectra Semi-Rigid Tools

 

Not mentioned in this catalog, but there are content
lists for the individual parts.

JimMc


On Sunday, October 22, 2017, 10:35:36 AM PDT, Steve - Home Steve-Krull@... [hp_agilent_equipment] wrote:


?

Jim,


Any mention of a T-200/500? That’s what I have here.

Thanks,

Steve
WB0DBS



On Oct 22, 2017, at 11:42 AM, J Mcvein jmcvein@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

?

I have a 1991 OS catalog here, and there is a tooling
section.? T-250 is listed as SSMA-(OSSM), T-450A is TNC.
T-400 is for Type N.

I have never been fortunate enough to find a T-200 in good
shape in the surplus wild.

JimMC


On Saturday, October 21, 2017, 5:52:30 PM PDT, djn@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:


?

Thanks Steve.


I also have found the Tyco instruction sheets that show the use of the tooling. They also reference the M/A-Com and Omni-Spectra part numbers for the various tools.

However, the T-250A/450A is a mystery still......

Also, they must have made kits for N and TNC, but I find no reference to them...

So, I was wondering if Omni-Spectra ever put out tool info in their literature/catalogs...

Dan
Re: OT Omni Spectra Semi-Rigid Tools

 

开云体育

Jim,

Any mention of a T-200/500? That’s what I have here.

Thanks,

Steve
WB0DBS



On Oct 22, 2017, at 11:42 AM, J Mcvein jmcvein@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

?

I have a 1991 OS catalog here, and there is a tooling
section.? T-250 is listed as SSMA-(OSSM), T-450A is TNC.
T-400 is for Type N.

I have never been fortunate enough to find a T-200 in good
shape in the surplus wild.

JimMC


On Saturday, October 21, 2017, 5:52:30 PM PDT, djn@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:


?

Thanks Steve.


I also have found the Tyco instruction sheets that show the use of the tooling. They also reference the M/A-Com and Omni-Spectra part numbers for the various tools.

However, the T-250A/450A is a mystery still......

Also, they must have made kits for N and TNC, but I find no reference to them...

So, I was wondering if Omni-Spectra ever put out tool info in their literature/catalogs...

Dan
Re: OT Omni Spectra Semi-Rigid Tools

 

I have a 1991 OS catalog here, and there is a tooling
section.? T-250 is listed as SSMA-(OSSM), T-450A is TNC.
T-400 is for Type N.

I have never been fortunate enough to find a T-200 in good
shape in the surplus wild.

JimMC


On Saturday, October 21, 2017, 5:52:30 PM PDT, djn@... [hp_agilent_equipment] wrote:


?

Thanks Steve.


I also have found the Tyco instruction sheets that show the use of the tooling. They also reference the M/A-Com and Omni-Spectra part numbers for the various tools.

However, the T-250A/450A is a mystery still......

Also, they must have made kits for N and TNC, but I find no reference to them...

So, I was wondering if Omni-Spectra ever put out tool info in their literature/catalogs...

Dan
1740A Horizontal setup

[email protected]
 

Hi everyone,


I'm restoring a 1740A back to health again and its up and running but some form of calibration is now required.


  1. I have a Heathkit IG 4505 calibrator and the volts / div is pretty accurate with the exception of the 100v setting, scope reads 90v?
  2. The width of the trace is more than the screen, by about twice the screen width and I don't seem to be able to find in the service manual how to adjust this aspect?
  3. Sometimes there is another wave superimposed on the screen but of a far lower
  4. Also there is visible on some timebase speeds more than others, visible flyback lines and in instances it looks like another trace in the background?


If I can find out to link photos etc from my Flickr account I could show you these in photo and maybe video formats to give you more of true picture of whats happening then rather hoping that I can describe?it well enough so you can understand what I mean.?


Anyone able to offer any assistance with this at all? I have the service manual but it does not make it very clear on how to do these things unless of I'm going blind.


Graham
Re: HP 8341A sucessfully FIXED!

 

开云体育

Hi Tony

wow, cool, thanks. These files should work for the 8341A as well I think. I will give it a try ;-)
Since I cannot run HP Basic stuff, I will translate the programs to Python which runs nicely with GPIB cards and USB adaptors. I already did that with the calibration program for the HP 4195A.

Thanks
Tobias

From: hp_agilent_equipment@... [hp_agilent_equipment@...]
Sent: Sunday, October 22, 2017 17:07
To: hp_agilent_equipment@...
Subject: Re: [hp_agilent_equipment] HP 8341A sucessfully FIXED!

?

I have the one for the 8340B if that helps.

Original files here:

?

Unlocked files here:


I think I may also have put this in the files section of the forum.

TonyG
?
Re: HP 8341A sucessfully FIXED!

 

I have the one for the 8340B if that helps.

Original files here:

?

Unlocked files here:


I think I may also have put this in the files section of the forum.

TonyG
?
Re: HP 8341A sucessfully FIXED!

 

开云体育

Hi,
I saw that there was an automated test program which calibrates the attenuator and the ALC using HPIB commands.
However, I didn't find that program on the net.
Does anyone have a copy of it?

Tobias
Re: 5342A: blown sampler?

 

开云体育

My counter counts reliably up to 20 GHz. I could not yet test higher frequencies.
I wonder whether somebody has a ROM dump of it?
It would be nice if I could add the DAC option, but this requires a newer ROM which my unit does not have.

Tobias


-------- Original message --------
From: "Steve A starmux64@... [hp_agilent_equipment]"
Date: 10/21/17 10:48 (GMT+01:00)
To: "Steve - Home Steve-Krull@... [hp_agilent_equipment]"
Subject: Re: [hp_agilent_equipment] Re: 5342A: blown sampler?

?

I have a 5342A with option 005 which extends operation from 18GHz to 24GHz. It has the original N-type connector though. So I expect there must be other hardware changes, or as Steve K suggests selected parts.? The option cost $500 extra.

Steve


On ?Friday?, ?October? ?20?, ?2017? ?02?:?00?:?22? ?PM? ?BST, Steve - Home Steve-Krull@... [hp_agilent_equipment] wrote:


?

I’ve done the connector change and, using a good quality SMA, I have two 5342As that count reliably to 26GHz and one that just won’t count reliably above about 21GHz. I don’t have a 5343A to compare to but I wonder if maybe they were just hand-selected 5342As?


73,

Steve
WB0DBS



On Oct 20, 2017, at 7:38 AM, Tobias Pluess tobias.pluess@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

?

Hi Harke,

oh, interesting. So the upgrade to 26 GHz, which would actually be a 5343A, changes only the connector? :-)
This is funny, because I use a HP 8563E spectrum analyzer at work, which operates fine at 26.5 GHz using a N connector!

Best
Tobias


From: hp_agilent_equipment@... [hp_agilent_equipment@...]
Sent: Friday, October 20, 2017 14:13
To: hp_agilent_equipment@...
Subject: Re: RE: [hp_agilent_equipment] Re: 5342A: blown sampler?

?

Hello Tobias,

Congrats on the repair! Happy for you the sampler was fine! I can only comment on the frequency range. I have a number of HP equipment (including the HP5342A) that are spec'd to 20-22 GHz and with an (expensive) option that range can be extended to 26 GHz. The only hw change is the input connector that goes from N to APC3.5. No other change! Try the counter at 24 GHz and you will see it will work!
Good luck!

Harke


On Friday, October 20, 2017, 2:05:31 PM GMT+2, Tobias Pluess tobias.pluess@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:


?

Hi all,

problem solved: as I said, the counter was counting fine on the low frequency input, but on the high frequency input, it displayed only zeros. The reason was that
a) the -5.2V operating voltage was out of the spec
b) the solder joint between the semirigid coax to the front panel's N connector cracked, thus the semirigid was no longer connected to the connector. I re-soldered and now it counts fine (only tested with 2 GHz so far).

I wonder whether it is possible to replace the ROM. It would be nice to add option 004, the DAC. I have couple of DAC80 here, however, opt. 004 needs a different ROM, unfortunately.

I also read that there was an option 005, which extends the frequency range to 24 GHz. Does someone know what option 005 actually was? was it a different sampler, or something that can easily be changed?

Tobias

From: hp_agilent_equipment@... [hp_agilent_equipment@...]
Sent: Wednesday, October 18, 2017 04:37
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] Re: 5342A: blown sampler?

?

Hi,

Your measurements with the diode mode suggest the sampler is OK, digital meters don't use the same amount of current to test resistance as older analogue meters and that's the reason you didn't get their readings.


I agree with Steve, you may need to replace a number of the 1826-0371, either on the A8 main VCO, A4 offset VCO or both.


I'd also check the A5 output to see if you're getting drive to the sampler driver and then check the sampler driver A26 itself.


I'd check in that order, check the VCOs are outputting signal, check the A5 to ensure it's outputting a signal to?A26 and it should alternate between the two VCOs, then check A26.


To check the sampler driver A26?you really need a?spectrum analyser. As most spectrum analysers have a capacitor (DC block) in the front end you need to terminate the A26 module with 50 Ohm and then measure what you see ac ross that with the spec an, if you see lots of harmonics then all is good. You will not see anything?(apart from the 325MHz drive) without a dc return for the step recovery diode.


If the A26 is not working that could either be the SRD or it could be U1 on the A26 module - I have seen faulty U1 ICs in the past, most likely due to heat - they run very hot.


For the 1826-0371, you can buy fakes/replicas/copies off ebay or do what I do, I make a small smd pcb with 2 x 2sc3356 transistors, 2 x 100 ohm resistors and a 120 ohm resistor in the emitter lead?(all smd components)?with pins to fit in the DIP footprint. You'll see the schematic for the 1826-0371 on a number of the 5342A schematics. I've not had any issue with my made up boards yet.


If you find it is U1 on the A5 module I can also give you an alternative circuit for that but it is not quite optimised yet ?and?requires short leads to minimise parasi tics.


Good luck

Greg
Re: KNOBS HP1701 SCOPE

Irvin Schwartz
 

Hi? Keith;......

Thanks for the reply...
My scope the HP 1701, has three (3) knobs on the shafts
that control 'Main TIME/DEV, Delay TIME/Dev, and Sweep
Select'.? I beleive they were used on several 170x series
up the 1707 model..? I've checked invetory of the usual
old part suppliers to no avail... Hoping someone in the
group my have something they will part with ,even a
parts unit.? (reasonable $$$)

Thanks Again..? ...BOB...? ? ? KD0IJI@...
--------------------------------------------

On Sat, 10/21/17, 'Keith Cockburn' keith77777@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:

Subject: RE: [hp_agilent_equipment] KNOBS? HP1701? SCOPE
To: hp_agilent_equipment@...
Date: Saturday, October 21, 2017, 5:59 AM
Re: 8566B PL1 Unlock, PL2 Unlock and Ref Unlock

 

The failed cap has an ESR of 56.32k and slowly dropping.? The capacitance is 48.78nF and rising.? This was measured with an Agilent 1733C.? I have an HP bench unit down in the lab so I'll walk down later but generally it agrees with this little handheld I wonder why I still have it.

The Mallorys were worth trying for the price.? I did find brand new Mallorys later today for $12.? But with ebay, you never really know what you get when they have more than one.

The weird thing is the way this thing failed. I never thought about switching an LM317K regulator on and off like that by pulsing the ref pin.? ?So the -10v supply is used to set the reference for the 12V supply and because this cap was bad, the -10V was pulsing up and down at 12Hz switching the 12v off and on.??
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