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Re: Distribution divider/amplifier for 10MHz GPSDO
开云体育Hi Regarding ddistribution divider/amplifier for 10 MHz in the past I have talked to others on this subject and the consensus was that the frequency response of the amplifier must be grater than 10 times ?that of the reference frequency to prevent distortion and lag we ended up using transistors that where good for 450 MHz for a 10 MHz reference ? regards Paul B From:
hp_agilent_equipment@...
[mailto:hp_agilent_equipment@...]
? ? Hello group. I`m intending to distribute, via 50 Ohm coax, frequency reference signals to my test equipment in my test bay [no relation to eBay, except that most of the equipment came from there]. I`ll be using RG58/U coax, and 50 ohm terminations, with the highest reasonable signal level reticulated. Given that the name of the game seems to be to avoid any severe reduction in SNR of the 10MHz signal comming out of the GPSDO, by the logic dividers, and impedance lowering buffer amplifiers, what considerations should be made regarding the choice of logic families, and transistors to be used? The frequencies required by the test equipment vary from 500kHz to 10MHz, and amplitudes from 100mV P-P sinewave, to 5V peak squarewave. How good must the PSU be to stop the rot getting worse, and is 1/f noise in the active devices important? Your thoughts will be appreciated. P.S.: How accurate is the Trimble Thunderbolt for this application?..............................................Thankyou,............Don Collie. No virus found in this message. |
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Re: 8566B PL1 Unlock, PL2 Unlock and Ref Unlock
This goes to show the importance of not relying on DC measurements alone - always check supplies with a scope if something is suspicious. Meter measurements alone won't show ripple and other flakiness - they just average out whatever waveform is there. ? Ed |
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Re: OT Omni Spectra Semi-Rigid Tools
On Mon, 23 Oct 2017, djn@... [hp_agilent_equipment] wrote:
Jim:Please count me in on that :) --- * * KSI@home KOI8 Net < > The impossible we do immediately. * * Las Vegas NV, USA < > Miracles require 24-hour notice. * * |
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Re: OT Omni Spectra Semi-Rigid Tools
开云体育Dan,I’d appreciate a copy. Once I’m back from a trip I’ll take what I have and bits that have been given me over the weekend and, with your permission, your information, and package it up to go on the KO4BB manual repository online.? Steve On Oct 23, 2017, at 2:21 AM, djn@... [hp_agilent_equipment] <hp_agilent_equipment@...> wrote:
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Distribution divider/amplifier for 10MHz GPSDO
Hello group. I`m intending to distribute, via 50 Ohm coax, frequency reference signals to my test equipment in my test bay [no relation to eBay, except that most of the equipment came from there]. I`ll be using RG58/U coax, and 50 ohm terminations, with the highest reasonable signal level reticulated. Given that the name of the game seems to be to avoid any severe reduction in SNR of the 10MHz signal comming out of the GPSDO, by the logic dividers, and impedance lowering buffer amplifiers, what considerations should be made regarding the choice of logic families, and transistors to be used? The frequencies required by the test equipment vary from 500kHz to 10MHz, and amplitudes from 100mV P-P sinewave, to 5V peak squarewave. How good must the PSU be to stop the rot getting worse, and is 1/f noise in the active devices important? Your thoughts will be appreciated. P.S.: How accurate is the Trimble Thunderbolt for this application?..............................................Thankyou,............Don Collie. |
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Re: 8340A Fault - ADC
Hello Tobias,
Oops. (facepalms) and I was looking at your post too! (facepalms harder). Confused your post with Tam Hanna. XD That'll do as a replacement. As for the ADC, I concur about availability. I'll have to check later on. The data book posted should be useful in knowing electrical characteristics. As for physical ones, you may have to get creative while looking for a size flexible replacement. Maybe on some of the electrical characteristics as well. -Lex |
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Re: 2225a gpib inkjet
开云体育Hi Bob, ? AFAIK the recurring problem with these little printers is the flexi ribbon cable ages and breaks meaning printing has rows of dots missing. ? Don’t recall problems with the interfaces (GPIB/Serial/Parallel). ? It is repairable but needs some skill to avoid damaging the flexi completely – typically the brake is always on the bend at the head… What do others think? ? --? Nigel ? From: hp_agilent_equipment@... [mailto:hp_agilent_equipment@...]
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Re: 8340A Fault - ADC
开云体育Lex,
the MP7533 is the easiest. Didn't you see my previous message?
It is the same as MX7533 by Maxim, still available :-)
Tobias
-------- Original message --------
From: "lexternegron@... [hp_agilent_equipment]"
Date: 10/23/17 12:52 (GMT+01:00)
To: hp_agilent_equipment@...
Subject: [hp_agilent_equipment] Re: 8340A Fault - ADC
?
From googling, hp crosref (link??), and bitsavers. Might have to Ctrl + F part of the name like I did for "DC856" since pdf file have a hard time reading. Signetics Corp. NE5018F - page 550
Datel Systems Inc. or Datel-Intersil ADC856C - page 145
Micro Power Systems (owned by the Exar Corporation) MP7533MP - page ???
??? need to find this. I thought the Datel one with the custom HP number would be hard.
and one more, the MUX
Precision Monolithic Inc. - page 764
These are a fountain of knowledge. Now only specs but app notes and introductions as to why to use them in design. Enjoy.
-Lex
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Re: 8340A Fault - ADC
From googling, hp crosref (link??), and bitsavers. Might have to Ctrl + F part of the name like I did for "DC856" since pdf file have a hard time reading.
Signetics Corp. NE5018F - page 550 Datel Systems Inc. or Datel-Intersil ADC856C - page 145 Micro Power Systems (owned by the Exar Corporation) MP7533MP - page ??? ??? need to find this. I thought the Datel one with the custom HP number would be hard. and one more, the MUX Precision Monolithic Inc. - page 764 These are a fountain of knowledge. Now only specs but app notes and introductions as to why to use them in design. Enjoy. -Lex |
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Re: HP 8341A sucessfully FIXED!
You did a great job Tobias. Don't sweat on it breaking. As long as you've documented everything, I'm confident it can be fixed with no problem. It was a really lucky fault though. Had something on the hybrid circuit blown.... that wouldn't have been so good.
As for the calibration software, Tony's one drive is great. If you want, there is the raw file in this group as well. I wonder what the path to failure was? You had a blown relay, a bad YTO driver, and of course that shorted feed thru capacitor. The cap was shorted in the first place before you put 1.5 Amps thru it. Heres my theory: ??? on the power supply section surged? > breaks relay but goes to YTO driver > components break on the YTO driver > something on the YTO driver causes that feed thru on the YTO to become shorted. How other components were not affected will be a mystery. Maybe they were? It can be called case closed if you can find the original fault and its pathway. Till then this is good enough. -Lex PS: I can explain what happened when that feed thru cap became 20Kohms before it became a 1 ohm short again. Normally in the AC condition, any incidental AC signal (probably from either the YTO driver or the YTO itself is suppose to pass thru to grounded case from the coil via the feed thru cap which acts as a short for AC. In the DC condition the cap is an open circuit and instead heads to the YTO driver via the wire connection. However since you put high power thru the cap the first time, it turned into a 20Kohm resistor. What this ended up doing was fixing the short to ground for DC but now you have both the DC and some AC signals mixed together going thru the wire of the -40V supply, the coil (has less impedance than 20Kohms), and the YTO driver. That is why you saw the unstable results with the YTO loop. Anyways, that feed thru cap had to be replaced one way or the other since there needs to be a short to ground case for AC but not for DC. DC goes thru the wire. |
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Re: OT Omni Spectra Semi-Rigid Tools
Jim:
I came across a 1990 M/A-Com catalog that has quite a bit of tooling in it. I tracks what you found as well.? I'm putting together a spread sheet of all the kits and numbers....Can send along to whoever wants.... Dan in Chandler, AZ Thanks so much for looking around on this! |
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Re: 8340A Fault - ADC
Hello Calvin,
I see. Sorry about the mix up. Just want to make sure. The basic tests are [Shift + Free run], [Shift + Manual] (done), and [Shift + M4]. [Shift + Free run]?is for the lighting and is to make sure all LEDs light up like Christmas. It also indirectly tests the processing side by noting that the correct behavior of the marching pattern as described in the manual. You've pressed [Shift + Manual]?for the fault annuciator already so we know to focus on the ADC. As for [Shift + M4], I don't think it'll be of any help but you can try. Actually I forget what it will do with an ADC fault. Its a diagnostic test that tests everything and will list everything. The thing to note here is that an ADC is higher in the chain vs individual components tethered to sections of the rf path. The Processing section being the highest in the chain. You're right that 8340B schematic is literally broken and 8340A (assuming this since they don't have a 8341A) is unreadable but did you try all of the manuals? 8340A 8341A 8340B and 8341B are all the same except for FM input, SYTM for 20GHz vs 26.5GHz, and a sweep output 5 vs 10 V/GHz. I do admit it is still hard to read but I've seen harder. 8673B + 8673C/D service manuals were insane before I found a recent independent scan via google search and this group. Here is a link for 8341B component level volume. (page 201) ? Be sure to read up on theory of operation for A27 in the assembly level volume as well. A21 is involved based on the RF block diagram. What its doing and how it affects A27 that would have to be read. I see "ADC timing" as the name of the signal between those boards. If worse comes to worse there is google and bitsavers for individual component catalog/product guide searches (ie. motorola, nec, pmi, national semiconductor).??or ebay at the assembly level. So far it looks good in terms of economical repair. Anything encased in a solid block of metal that is damaged on the RF path is expensive. Can still be repairable within economical means as shown by Tobias' recent post. That was really lucky though imo. If the damage was on a hybrid circuit (ie bond wire or MMIC amp, transistor, diode)..... uneconomically repairable. It can still be repaired but you'd need to be in the business of wire bonding and Microwave IC design or negotiate the replacement assembly's the price down. Prices can be negotiated down if you know if the component is used in another instrument. HP usually repurposes the same components in different equipment. An example is a hybrid circuit I thought I was doomed to be unobtainium. Turns out this circuit is used in 3 instruments. What would have been a $600 - $1500 part was negotiated down to $175. Probably lower with the way things are trending. Checking now, there is a seller selling more than 10 but doesn't know what they have. There is another seller also selling extra components along with the component of interest for half of what the lone assembly would go for. Anyways I don't believe you will have this problem or those types of hoops and hurdles. I suspect a few components on a board assembly or 2 is the issue that failed due to old age. ICs or capacitors that age with heat, cycle use, and naturally occurring chemistry (oxides and acids forming). Compare that to someone that put in too strong of a signal and blew the inputs of the AM and PM. Worse would be the RF output (that attenuator and other RF modules are not cheap) or a physical drop of the instrument or on top of the instrument due to moving. Good luck with your potential buy. -Lex |
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Re: 8340A Fault - ADC
Rapes and Stinks, no?
toggle quoted message
Show quoted text
Now all we need is someone to undig the datasheet. The moment we have that, we can slink something together with ease. I dont want to promise anything as my life currently is a bit topsy turvy and I am already caught up in projects...but if you need help, I am willing to take a look at the Design and help out. If you cant solder SMD, I might be able to help too. --- With best regards Tam HANNA (emailing on a BlackBerry PRIV) Enjoy electronics? Join 6500 other followers by visiting the Crazy Electronics Lab at Am 23. Oktober 2017 08:34:59 MESZ schrieb "Tobias Pluess tobias.pluess@... [hp_agilent_equipment]" : ? |
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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:
? |
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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:
??? |
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Re: 8340A Fault - ADC
开云体育Hi CalvinI 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
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Re: 8340A Fault - ADC
开云体育Hi CalvinI 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
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