Upgrading Counter 53220A to Option 010 Ultra High-stability OCXO Timebase? - Page 1
Forum section: electronics / testgear

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 12:30:10 pm
content: Does anybody know, if you can buy the oscillator module as a spare part (P/N, cost?) and is it sufficient to swap the modules?Or is additional configuration change requided?

author: plesa
author_rank: Frequent Contributor
timestamp: November 17, 2016, 01:25:59 pm
content: It require new motherboard.You needs to replace 53220-66111 ($1808) with 53220-66112 ($1929).So external reference ( like use rubidium will be much cheaper ).Or open instrument and check what is missing.

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 02:12:31 pm
content: Quote from: plesa on November 17, 2016, 01:25:59 pmThanks for your reply.That's not, what I expected. On old 53131A replacing the oscillator module did the job, nothing else required.On 53220A mainboard a standard 4-pin-quartz-oscillator is implemented (DIL footprint).But there is an additional empty footprint for a bigger oscillator module (19x19mm=3/4x3/4", 5 pins).So changing the module is a possible way to go?Any pictures of an Opt. 010 Ultra High-stability OCXO Timebase available?Quote from: plesa on November 17, 2016, 01:25:59 pmDo you know a "cheap" rubidium standard with calibration certificate?The counters will be installed in production ATE - not in the calibration lab, where an existing external frequency reference could be used.

author: plesa
author_rank: Frequent Contributor
timestamp: November 17, 2016, 02:27:39 pm
content: Try to contact Agilent, in manual they are no so strict and maybe they will populate the OCXO instead of board swap.Manual says : order 53200U-010.If you needs certificate I cannot help you.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 17, 2016, 02:49:35 pm
content: I have a 53220A without OCXO and the drift was horrible but an upgrade was expensive.Actually, I got a 53230A with installed OCXO for less money than then upgrade of the 53220A.

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 02:55:42 pm
content: Quote from: HighVoltage on November 17, 2016, 02:49:35 pmCan you post a picture of the OCXO and its footprint on PCB, please?

author: dr.diesel
author_rank: Super Contributor
timestamp: November 17, 2016, 02:59:17 pm
content: You can get Trimble GPSDOs on eBay for < $150 with antenna, at least in the US.

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 03:22:59 pm
content: We cannot install separate GPS antennas for each production ATE using a 53220A.So rubidium maybe an alternative...But:I looked at the 53200A mainboard a little bit closer.There are 3 jumpers (0-Ohm chip resistors) with instruction nearby:"Remove R827 and R828 when installing Y800".Looked at the other side of PCB, and the bigger oscillator footprint is named "Y800" - tada!So I try to find a parts list to identify P/N of Y800...

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 03:33:49 pm
content: Quote from: plesa on November 17, 2016, 02:27:39 pmOK, found it in the component level manual:"Retrofitting to Option 010 (Ultra-High Stability Timebase) mustbe performed by technicians at a Keysight Technologies ServiceCenter. Refer to the list of Keysight Sales and Service offices inthe Appendix for the office closest to you.NOTE To order the Ultra-High Stability Option 010, you will need toplace an order with Keysight for 53200U-010 and identifywhich counter you have (53210A, 53220A, or 53230A)."Those cowards don't want to sell the OCXO as a spare part?

author: plesa
author_rank: Frequent Contributor
timestamp: November 17, 2016, 03:48:31 pm
content: Quote from: carl_lab on November 17, 2016, 03:33:49 pmBTW Rubidium has poor short term stability and better longterm stability and OCXO has better short term and worse long term. So check what you needs.Question is if you really needs certificate I do not think KS as default providing any certificate and calibration will be additional fee.Do you know Timelab software?

author: HighVoltage
author_rank: Super Contributor
timestamp: November 17, 2016, 03:58:29 pm
content: Quote from: carl_lab on November 17, 2016, 02:55:42 pmBoth of my counters are still under warranty and have Keysight calibration stickers.I am hesitant to remove them.May be I will try Dave's way of removing them in a safe way, when I am back in my lab tomorrow.

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 04:09:08 pm
content: Quote from: plesa on November 17, 2016, 03:48:31 pmI'm not quite sure about.Maybe changing the OCXO to a 3rd-party part and calibrating the counter with tolerances of the original Opt. 010 is sufficiant. 2000 bucks for upgrading is "just a little bit" too expensive for my understanding...Main purpose of the 53220A counters is adjustment of clocks.Quote from: plesa on November 17, 2016, 03:48:31 pmNo. It's not a laboratory application, so how could this software help anyway?

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 04:11:03 pm
content: Quote from: HighVoltage on November 17, 2016, 03:58:29 pmOh, please don't do it!I don't want to be responsible, if you lose your warranty.

author: nfmax
author_rank: Super Contributor
timestamp: November 17, 2016, 04:15:11 pm
content: It looks like these counters have a reference frequency input. Can you not use an external reference source, with suitable calibration certificate? This could be almost anything with a sufficiently stable oscillator and a reference output. You might need to use a distribution amplifier, depending on the cable lengths, but for just two inputs a power splitter should be OK.

author: lukier
author_rank: Unknown
timestamp: November 17, 2016, 04:22:48 pm
content: Quote from: carl_lab on November 17, 2016, 03:22:59 pmSounds extravagant, I think typically you would have one GPSDO for the facility and then a distribution amplifier to spread the 10 MHz around to the counters.

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 17, 2016, 04:40:19 pm
content: Quote from: lukier on November 17, 2016, 04:22:48 pmYou're right, that's the better way of course, but I think installation of an antenna on roof of the production hall will not be allowed whilst other alternatives are possible (rubidium?).

author: nfmax
author_rank: Super Contributor
timestamp: November 17, 2016, 04:50:59 pm
content: We use a lot of GPS aerials here, mountedinsidea typical industrial estate metal-clad building with plastic roof light panels. Presumably enough signal makes it through the polycarbonate (?) panels to make it work. We use GPS to control the time-of-day clocks on the data acquisition systems we make, so we need the 'real thing' for testing, not just a GPSDO.

author: Dr. Frank
author_rank: Super Contributor
timestamp: November 17, 2016, 04:58:42 pm
content: Quote from: carl_lab on November 17, 2016, 04:09:08 pmHi, for which company are you working?Frank

author: Dr. Frank
author_rank: Super Contributor
timestamp: November 17, 2016, 07:09:35 pm
content: Quote from: carl_lab on November 17, 2016, 04:40:19 pmI think, for that purpose, an internal or external OCXO is fully sufficient, Rb or GPSDO is overkill.Requirement for the uncertainty of this clock adjustment is on the order of 0.1ppm. Maybe a frequently calibrated TCXO will also do the job.This can easily be done by means of a GPSDO, but in the cal lab, where it belongs to.Does your company have a lack of budget, as such an instrument w/o proper OCXO had been ordered?Frank

author: plesa
author_rank: Frequent Contributor
timestamp: November 17, 2016, 11:09:46 pm
content: I just tried to disassemble unit (stickers are not problem, they are not brittle) but the OCXO is below RF moduleSo sorry I will not remove it.Like other mentioned only R854 0R resistor is placed on bottom. Module footprint is really small.

author: dr.diesel
author_rank: Super Contributor
timestamp: November 17, 2016, 11:49:40 pm
content: In this case I'd suggest no personal modifications, in some obscure innocent you could be liable if something went wrong. If this is something you need for production, order the correct instrument or use a proper external timebase.

author: Vgkid
author_rank: Super Contributor
timestamp: November 18, 2016, 03:16:10 am
content: I will agree wit Dr. Diesel, though you could always make a small enclosure and mount a small ocxo inside of that. Though with the dip 14 sized ocxo's you could easily breadboard one inside of the unit...

author: HighVoltage
author_rank: Super Contributor
timestamp: November 18, 2016, 09:33:03 am
content: OK, Plesa was right, these stickers come off very easily, so, what is life without a risk.Here are some pictures of my 53230A with all options installedIt seems theUOCXO is hiding well.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: November 18, 2016, 05:35:16 pm
content: Nice photos.Use my TCXO equipped 53230A with EXT Ref Rubidium, or GPSDO...

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 19, 2016, 06:56:36 am
content: Thanks for the photos.As I supposed bigger footprint is used for (U)OCXO, inner one for standard quartz oscillator.Could you be so kind trying to look at the (U)OCXO for identifying maker and type?(I don't know if removing removing RF module is required)

author: plesa
author_rank: Frequent Contributor
timestamp: November 19, 2016, 09:13:29 am
content: For type of U OCXO you must remove RF module and after that plastic cap. You are fight that standard OCXO use the inner holes and it is much smaller.Maybe try to look into to other service manual for Keysight gear for type.I suppose they are using same UOCXO across platforms, like hey did it with 10811.BTW why you are trying to modify some production equipment which is probably covered by warranty?Did you asked repair center for quote?Why is not external UOCXO an option?

author: HighVoltage
author_rank: Super Contributor
timestamp: November 19, 2016, 10:41:43 am
content: OK, since I was curious as well, I took it apart again and removed the GPIB and 6 GHz module.The UOCXO is nicely covered with a plastic hood.Here are the picturesThe UOCXO is of following type- VECTRON- C4550A2-0281- 10.000000 MHz- 22158-0097- Made in 1240

author: HighVoltage
author_rank: Super Contributor
timestamp: November 19, 2016, 10:43:01 am
content: More pictures

author: HighVoltage
author_rank: Super Contributor
timestamp: November 19, 2016, 10:49:07 am
content: A few pictures of the GPIB interface board.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 19, 2016, 10:55:02 am
content: Interestingly, there is a CR2032 on the Front PanelOk, now back together ...

author: Dr. Frank
author_rank: Super Contributor
timestamp: November 19, 2016, 01:23:15 pm
content: HighVoltage, that's very interesting.. could you please also provide the dimensions of this OCXO, the pinning, and the output waveform (square wave or sine)?I think, VECTRON offers OCXOs with standard pinning, which might fit, but with customized specifications for KS.Maybe something like their OX-208:https://www.vectron.com/products/ocxo/OX-208.pdfFrank

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 19, 2016, 02:18:59 pm
content: Thank you very much!Now I can try to get those (U)OCXOs as spare parts.1900+ euro (as offered by Keysight distributor) for changing one of these seem to be a bit over the top...I don't know which jerk ordered counters without OCXO for clock adjustment...What I know, those counters replaced out-dated 53131 opt. 010.The specs of 53220A (without option) is inbetween 53131 without option and 54131 opt. 010.I'm not sure about warranty. The counters maybe out in the meantime...I also don't know, if warranty stickers are attached. Most gear I see here in the lab is without stickers...

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 19, 2016, 02:39:08 pm
content: Quote from: Dr. Frank on November 19, 2016, 01:23:15 pmPinning is 19x19mm, case dimensions 1"x1" (Vectron C4550A2).->www.vectron.com/products/ocxo/C4550.pdfThe grey plasic cap seems to be the same, that is used with standard oscillator.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 19, 2016, 03:00:11 pm
content: Quote from: carl_lab on November 19, 2016, 02:18:59 pmYou mean 53131?The 53131 without opt 010 was as bad as the 53220A without option 010After a few month of being off, I turned my HP GPS Time Domain on again today.Here are my three counters after a few hours of warmup and GPS-Lock on the HP Z3805A.The 53132A was upgraded by me here:https://www.eevblog.com/forum/repair/agilent-53132a-repair-(and-possible-upgrade)/msg843138/#msg843138This one is right on target in the shortest possible time.Every single time I turn it on, it is fluctuating only the last 2 digitsThe 53230A with all options was the one I opened in this threadThis one takes much longer to warmup than the 53132A to be stable after a cold startBut after one hour it has a stability about the same as the 53132AThe 53220A is without Option 010 and is horrible in comparisonAfter every cold start it finds a different spot where it settlesInterestingly, this one was just repaired and calibrated at Keysight Germany in (warranty) butis far off. Why having 15 digits, when the last 6 have no meaning?

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 19, 2016, 03:26:50 pm
content: Quote from: HighVoltage on November 19, 2016, 03:00:11 pm7 digits, not 6.Quote from: HighVoltage on November 19, 2016, 03:00:11 pmYes, exactly: 53131A.Bad combination:Laptop keyboard and my "wurstfingers"...

author: carl_lab
author_rank: Frequent Contributor
timestamp: November 21, 2016, 03:44:10 pm
content: Quote from: Dr. Frank on November 19, 2016, 01:23:15 pmWaveform is square 5Vpp, supply voltage 5V.

author: andyturk
author_rank: Frequent Contributor
timestamp: December 20, 2017, 08:04:10 am
content: My project for the evening was opening up a 53220A with the standard timebase and dropping in an "aftermarket" OCXO. The specs on theAbracon AOCJY3A-10.000MHz-Eseem pretty close to the original Vectron part used by Keysight, so I figured I'd give it a try. At worst, I'll have to open it back up and reverse the surgery.After replacing the oscillator and removing the two 0-ohm resistors called out on the silkscreen, the unit booted right up and passed its self test. It also registers the 010 option on the "About" screen. Surprisingly, it didn't complain about being out of calibration, but it was clearly off by ~2 Hz.I let it warm up for a while and calibrated it with 10Mhz from a rubidium source (PRS10). It seems to work well, although I'm not a time nut and don't have anything better than PRS10 to compare it to.

author: TheSteve
author_rank: Unknown
timestamp: December 20, 2017, 08:21:20 am
content: Always good to have more options. I'd give this a try if I was looking for one -https://www.ebay.com/itm/181776010665

author: HalFET
author_rank: Frequent Contributor
timestamp: December 20, 2017, 08:32:14 am
content: Rubidium reference modules run <300 bucks from the surplus telecom stockpile these days. So it'd most like be cheaper to just strap one of those to the top of the unit and get that the rubidium reference certified. Added advantage is that marketing can then claim things were calibrated atomic clocks.

author: HighVoltage
author_rank: Super Contributor
timestamp: December 20, 2017, 03:27:09 pm
content: Great to know, that the replacement workedThanks for this info, andyturkOne of these days I will get a Rubidium standard as well.I just have no idea, which one to get, there are too many options.

author: swixo
author_rank: Contributor
timestamp: February 03, 2018, 04:49:15 pm
content: Going to try this upgrade today.Got my vacuum desolder, RU GPSDO reference for calibration and the part on its way.Will update how it goes.The stock oscillator is absolute crap. Couple that with a sloppy at best factory calibration,I am a little disappointed in Keysight here.

author: swixo
author_rank: Contributor
timestamp: February 04, 2018, 04:00:57 am
content: Well it works!Swapped out the small TCXO and installed the OCXO. Cleaned up the solder fluxmess -- it looks super clean.Self tests pass. About box says OCXO installed!System is MUCH More stable after warm-up, which takes about 45 minutes. No issue there.Calibrated with RU standard and I am good to go. Total cost about 320$ which includedSaturday delivery of the part -- AND the Vacuum desolder!

author: HighVoltage
author_rank: Super Contributor
timestamp: February 04, 2018, 09:11:31 pm
content: What model and type of OCXO did you install?Pictures?

author: swixo
author_rank: Contributor
timestamp: March 04, 2018, 03:14:37 am
content: I used this:https://www.mouser.com/productdetail/815-aocjy3a-10m-eDidnt take 'after' pix, sorry. But the pix earlier in this thread are spot-on.

author: HighVoltage
author_rank: Super Contributor
timestamp: March 04, 2018, 07:39:40 pm
content: Good to know, that this mouser supplied part works well for the upgrade.I assume you did not have to change any settings and the instrument detected the new OCXO being installed.

author: swixo
author_rank: Contributor
timestamp: March 04, 2018, 11:36:18 pm
content: The procedure is changing the TCXO for the OCXO, then removing the twozero ohm resistors near the clock zone.The firmware detects that change all by itself. Whether it is the presence of thenew part alone - or the removal of the resistors is not known.s

author: TheSteve
author_rank: Unknown
timestamp: March 04, 2018, 11:48:18 pm
content: FYI the Vectron C4550A1-0213 I linked to above works just fine, and was cheap. I got mine from a different seller for 17 bucks though.

author: swixo
author_rank: Contributor
timestamp: March 05, 2018, 01:01:15 am
content: Steve - Did you install one of those EBay OXCOs in an instrument? How's the drift?

author: TheSteve
author_rank: Unknown
timestamp: March 05, 2018, 01:23:38 am
content: Quote from: swixo on March 05, 2018, 01:01:15 amYes I have one in a 53230A. I haven't checked drift lately, I'll fire up the unit and see how it looks. When I also had a factory 010 here it was every bit as good. Could be a crap shoot with a used ebay sourced one I suppose.edit:Just fired it up and compared it to my GPSDO. I do have the standby mode selected that keeps the OCXO warm. It has been more then 6 months since the last cal from the same GPSDO.

author: swixo
author_rank: Contributor
timestamp: March 07, 2018, 03:17:36 am
content: Seems like a lot of drift, doesn't it?

author: TheSteve
author_rank: Unknown
timestamp: March 07, 2018, 04:01:18 am
content: Quote from: swixo on March 07, 2018, 03:17:36 amNot at all from what I can tell. The specs of the factory unit gives +- 50 ppb per year and another +-50 ppb from cal. That would be +- 1 Hz. Now this is only half a year but the error is only 0.05 Hz - seems pretty darn good to me.

author: swixo
author_rank: Contributor
timestamp: March 07, 2018, 09:18:52 pm
content: Fair.But when your unit can show 15 digits, it seems like a lot. I am looking at this OCXO:http://www.morion-us.com/catalog_pdf/mv291.pdfThe ULN version is 8E-13 short term. Imagine THAT in your counter. Thisunit appears to be able to fit in the spot for the OCXO, and will fit under thecover. I have another Morion OXCO, and it clocks in the E-12 all the time.s

author: TheSteve
author_rank: Unknown
timestamp: March 07, 2018, 10:33:26 pm
content: In my case it is all just for fun, my entire lab is locked to the same reference source(GPSDO or Rb.)

author: swixo
author_rank: Contributor
timestamp: March 08, 2018, 02:07:17 am
content: All of this is just for fun! I lock to an SRS FS740, super stable.Also want the built in oscillator to be good!

author: EE-digger
author_rank: Frequent Contributor
timestamp: March 08, 2018, 02:30:36 am
content: Good thread. I have a 53132A with a Ebay - Polish reference osc. and Rb lab reference for now.I'm disturbed by Agilent / KS no clean flux residue. I hope our scopes aren't full of that stuff. I don't trust it. Yes, it should be benign (low SIR, good ROSE numbers) but it also acts as a "gatherer" for dust, dirt, stray solder bits (ok, this can be good).

author: Andrew
author_rank: Contributor
timestamp: September 01, 2018, 08:37:03 am
content: I'm considering a similar upgrade to a 53220A using the Abracon AOCJY3 10ppb part.A couple of questions in relation to ocxo's:1) Abracon offer a 5ppb option in the AOCJY3 series however it's temperature range is restricted to 0 to 50C. The 10ppb part is -20 to 70C. What would be the maximum ambient temperature that the 50C part reliably operate?2) The lock range to an external reference is narrower for the oem ocxo part, 0.2ppm, versus 2ppm for the tcxo part. Does this mean there is some performance gain using the ocxo even with an external reference? Perhaps this would be noticable on the faster 53230 model?ThanksAndrew

author: jpb
author_rank: Super Contributor
timestamp: September 01, 2018, 04:22:41 pm
content: If you're using the counter indoors I'd think that the 0 to 50C part should be fine (temperature wise - I don't know about its suitability generally), it is very unlikely that the internals of a counter would get significantly hotter than the ambient - they are not high power devices and the main source of heat would probably be the ocxo but it would be in quite a lot of empty space. If you're planning on using the counter in on expeditions to the Sahara or the South Pole it might be better to use the wider temperature range or if you keep the counter in a rack with hot, high power gear on either side.The narrow lock range is because ocxos generally have a much narrower tuning range (frequency versus voltage gain). They are better quality crystals (SC cut) but for the purposes of a counter there would be no advantage when it is locked to an external source as the external source will determine the timing over longer periods such as that of the counter gate. For RF generators the phase noise is more important but for a counter it is of less importance.Here is a quote from the Stanford Research Systems SR620 counter manual:Quote

author: Andrew
author_rank: Contributor
timestamp: September 06, 2018, 06:40:11 am
content: Thanksjpbthat answers many questions.Interesting that measurement times shorter than the PLL bandwidth are not considered important compared to the internal clock jitter. I would have thought this would be an issue for counters like the SRS620 25ps and Keysight 35ps 53230A but apparently not.

author: pamphonica
author_rank: Regular Contributor
timestamp: December 18, 2019, 08:00:04 pm
content: I just put in a Vectron C4550A1-0213 from Ebay (from China) into my 53220A. It oscillates fine but the internal reference voltage output seems to be missing (looks like open-circuit), so the calibration routine failed.My fix (for now) was to re-install R828 (0R) which re-connects the internal +5v reference to the adjustment circuitry. This strap was needed for the original smaller oscillator module as it has no reference voltage output. Cal worked perfectly once this was done.Has anyone put in one of these specific new/used devices from Ebay and tried the "Cal Step" routine? If this is a feature of this secondhand module, so be it, but if yours worked fine, than please let me know so I can get a replacement from the vendor.The datasheet shows that ref voltage output can be removed as an option.-Jeremy

author: TheSteve
author_rank: Unknown
timestamp: December 19, 2019, 05:18:33 pm
content: Quote from: pamphonica on December 18, 2019, 08:00:04 pmI've used that exact OCXO - you should not need to install R827 or R828 for it to work perfectly.

author: pamphonica
author_rank: Regular Contributor
timestamp: December 19, 2019, 08:25:25 pm
content: Thanks Steve, I've asked the vendor for a replacement. I know that these modules can be ordered with no reference voltage output. It's re-assuring to know your identical one worked fine with the 0R resistors removed as indicated.-JeremyUpdate: the vendor says that these modules have no connection to pin 4 (voltage ref out). There are a number of vendors on Ebay but all at higher prices. Maybe I'll try another vendor and see if these ones are cheap because of faults. Weird.

author: rkeller
author_rank: Contributor
timestamp: October 21, 2020, 07:17:29 pm
content: Is there a consensus on the OCXO DIY upgrade.Hesitant to take apart and start soldering in Chinese sourced Vectron C4550A1-0213's that have been removed from other equipment.Tried to find these new but no Joy.Has anyone got a concise DIY upgrade path. I checked Keysighthttps://www.keysight.com/main/editorial.jspx?cc=US&lc=eng&ckey=2190178&nid=-33609.959902.02&id=2190178It states the 010 upgrade is "not available" for those of us with non 010 units.Seems simple enough, but for now the OCXO with the GPS timebase at 10 Mhz going in the back works but isn't the best solution especially if I need to carry the unit to another work station.Thank you,Russ

author: tkamiya
author_rank: Super Contributor
timestamp: October 21, 2020, 08:10:58 pm
content: High-end counters often don't come with OCXO standard and built-in oscillators are usually awful. This is because it is expected that customer will either use shop standard or pick an OCXO. Shop standard being more common, later customers don't have to pay for extra. This will be a significant amount of money when buying ten or more counters! Standard oscillators are there just to check that the equipment works. It was never meant to be used for measuring anything.I typically don't like internal OCXO on counters. It means separate calibrations and they will never be exactly the same. This makes it impossible to check correlations. Also, counters will keep OCXO turned on while equipment is turned off. That means heat generation and power consumption. Having few of these, it adds up.If this is for business, I would really NOT mess with it myself. I would have certified hands do certified work and come back with certificate of the job performed and the result. Can't imagine what would happen if unthinkable happens and thousands of miscalibrated products going out the door. Compared to that, what HP charges is cheap.

author: F64098
author_rank: Regular Contributor
timestamp: March 09, 2022, 02:30:20 pm
content: Quote from: pamphonica on December 18, 2019, 08:00:04 pmI bought a bundle of 5 used OCXOs and 3 of them have the 4V Reference output enabled. Looking at the markings there are no differencies in type or mfg date.Try your luck:https://de.aliexpress.com/item/4000760950500.htmlPut one in my 53220A and i'm very happyBest regardsFrank

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: March 10, 2022, 04:05:20 pm
content: No Luck...Leider, ist dieser Artikel nicht mehr verfügbar!

author: F64098
author_rank: Regular Contributor
timestamp: March 10, 2022, 04:50:31 pm
content: Oh i'm very sorry,got my items just a few days ago and c&p the link withoutan actual click on it.But there are other sellers with similar items.From my view it is now shure, that the suffix -0213 don't sayanything about the optional reference voltage on pin 4.Another user made the same experience:https://www.eevblog.com/forum/metrology/how-to-unsolderremove-ocxo-from-pcb/msg4030306/#msg4030306HTHFrank

author: hartvige
author_rank: Newbie
timestamp: January 18, 2023, 03:18:31 pm
content: Just got a couple of C4550A1-0213 devices off Ebay, and both of these do not drive the reference voltage (4.0V nominally) out on pin 4.It seems really odd that devices with the same marking and P/N (-0213) behave differently in this regard.Someone mentioned that the pin 4 output was a selectable option in the P/N.However, looking at:https://www.vectron.com/products/ocxo/C4550.pdfThis does not seem to be the case. As I read the DS, all devices should drive this pin. Which begs the question: the -0213 devices that don't do this, are they simply broken?