FS (UK) HP 5065a Rb frequency standard + other calibrators  -  eBay UK - Page 1
Forum section: electronics / general

author: Oldtestgear
author_rank: Regular Contributor
timestamp: March 01, 2019, 07:26:21 am
content: eBay item number: 323714520022https://www.ebay.co.uk/itm/HP-Rubidium-Vapor-Frequency-Standard-5065A-untested/323714520022Listed on eBay UK. I have no affiliation with the seller but thought this would be of interest to members here. Please buy it & the other calibration kit they have listed or I might be forced to stump up the cash. Particularly tempting as the seller is not too far from home. Kit is "probably" ex Plymouth dockyard from the stickers shown on some of the other pictures.Phil

author: toastedcrumpets
author_rank: Regular Contributor
timestamp: March 01, 2019, 10:35:40 am
content: That's very expensive for a Rb standard sold as "for parts not working". I bought a Racal 2202R 1.3GHz microwave counter, with internal Rb standard (and two buffered outputs for the standard) for £365 off fleabay which was arguably far more than just a standard. It was even sold as fully working, so I had some guarantee on it. You can also buy Rb standards for £100 or less harvested from a cell-phone tower in China if you don't mind sticking a power supply, case, and BNC cables to it yourself.For example, here was a 2202R that went for £295 just recentlyhttps://www.ebay.co.uk/itm/Racal-2202R-frequency-counter-timer-Rubidium-oscillator-WORKING/123640771680?hash=item1cc9907460:g:A3AAAOSwmetcYYma

author: edpalmer42
author_rank: Super Contributor
timestamp: March 01, 2019, 03:20:23 pm
content: Comparing a 5065A to a telecom Rb is like comparing a Lamborgini to a horse and carriage!The 5065A is the 'Gold Standard' in the Rb world. They haven't been manufactured since the late 1980s, but there still isn't anything that can compare to it in terms of performance. Aging rates in the e-12/month range and Allen Deviation values in the e-13 range are not unusual.Every 5065A that appears for sale is snapped up so fast that if you blink, you missed it! Price and condition don't matter. The buyer just crosses his fingers and hopes that it can be repaired. It usually can!Ed

author: toastedcrumpets
author_rank: Regular Contributor
timestamp: March 01, 2019, 04:27:38 pm
content: Interesting! I've not really considered that aging differs between "physics-based" standards. I just looked up the 2202R's specifications which are 1e-11 in 10-100s and 5e-11 for 1 month. Please bear in mind this is the spec, so actual performance may be better.You're right about people's passion for the 5065A though:http://leapsecond.com/corby/Corby-Super-5065A-Project.pdfI still stand by the assertion that, for most uses, this is a lot to pay for a Rb standard :-P I'm fully prepared to be crucified for this heresy by the time wizzards...

author: edpalmer42
author_rank: Super Contributor
timestamp: March 01, 2019, 04:43:02 pm
content: Yes, the 'Super 5065A' project is like bolting a flux capacitor onto a Lambo.And you're right to imply that most people don't need a 5065A since other Rb standards are available for much less money. After all, most people don't need a Lambo either. But lots of us lust after them!Ed

author: KE5FX
author_rank: Super Contributor
timestamp: March 01, 2019, 04:51:02 pm
content: Quote from: toastedcrumpets on March 01, 2019, 04:27:38 pmThe big win with the 5065A is its short-term stability. Telecom-grade rubidiums can provide similar performance over hours to days, but they are about 10x noisier at taus below that. Compare the red and green traces in the first plotherefor example.This one is priced reasonably if it's complete. Being a newer unit, it will probably have a nice 10811-60109 OCXO. That said, a 5065A will require at best a thorough recapping. There are a lot of axial tantalums, and some of them are low-quality parts installed in places where their failure can prove destructive. At that point you're looking at an unpleasant, time-consuming overhaul of the lamp driver board and oven windings.

author: edpalmer42
author_rank: Super Contributor
timestamp: March 01, 2019, 05:16:33 pm
content: Quote from: KE5FX on March 01, 2019, 04:51:02 pmYeah, I can't measure 1e-12@1sec. Maybe someday......QuoteWere they really a low quality part? I thought it was just because they're all over 40 years old. Mine had some green blobs that used to be capacitors and it was one of the more recent units. Luckily, the oven wasn't affected.Ed

author: KE5FX
author_rank: Super Contributor
timestamp: March 01, 2019, 05:55:14 pm
content: Quote from: edpalmer42 on March 01, 2019, 05:16:33 pmThere are several kinds. The 'good' ones are the wet-slug tantalum types with glass end seals. These are the ones you see on things likeApollo Guidance Computerboards, and which are still available from distributors at prices on the order of a hundred bucks apiece. There are a few of those in typical HP gear of the era, including the 5065A. I've rarely if ever seen them fail.Then there are other axial electros whose construction I'm less sure about. Examples of these can be seen in Luciano Paramithiotti's 5065A repair documenthere(.PDF). These have rubber end seals. Some of these are garden-variety aluminum electros, while others I believe are tantalums of much lower quality than the high-$$$ NASA-grade parts. Both fail with high ESR, often with some visible leakage as well, and they are unfortunately much more common in the 5065A than the "good" ones.I don't bother replacing them with anything fancy, any random electrolytic from the junk box is fine as long as it tests OK. But I do try to use 105C parts whenever possible.

author: anotherlin
author_rank: Frequent Contributor
timestamp: March 01, 2019, 09:52:11 pm
content: Can somebody contact the seller and ask if he can ship to France?ebay won't let me contact him.

author: Oldtestgear
author_rank: Regular Contributor
timestamp: March 01, 2019, 10:08:34 pm
content: Close run thing but someone has saved me from buying it. Has anyone here bought it?Now if the Datron 4200 sells quickly, all temptation will be removed & I can stop dreaming about it in my home lab.PHIL

author: maat
author_rank: Regular Contributor
timestamp: March 01, 2019, 10:12:00 pm
content: @anotherlin: Sorry to disappoint. I have to confess it was me, that bought it. Contacted the seller through the cathco.co.uk website. Really nice chap. Prompt reply at this time of the day and on a weekend!Lets see if I can get it fixed

author: anotherlin
author_rank: Frequent Contributor
timestamp: March 01, 2019, 10:20:13 pm
content: Quote from: maat on March 01, 2019, 10:12:00 pmNo problemEnjoy!

author: edpalmer42
author_rank: Super Contributor
timestamp: March 01, 2019, 11:34:22 pm
content: Quote from: maat on March 01, 2019, 10:12:00 pmCongratulations and I hope you're able to restore the unit. Here's a few documents that I found online. They show some hints & tips for tuning & repairing the 5065A. The file is too big to post here.http://www.mediafire.com/file/cxq1xk9bkip0w68/5065A.zip/fileAlso, here are a few points of my own.1. If you have to use a bottom cover from a different HP instrument, you need to have insulation inside the cover to prevent shorts to the case. A good insulator can be purchased from a 'Dollar' store in the form of a flexible cutting board. It's a thin layer of polyethylene(?) that's obviously tough and hard to cut through, but it's easy to cut to size with scissors. Attach it to the bottom panel with double-sided tape. You can reduce the chances of contact in the first place by installing standoffs between the chassis and the bottom panel. My junkbox provided three non-magnetic hex standoffs that screw onto the end of the screws that hold the cardcage in place. Perfect fit!2. It's probably too late for most of these units, but it's worth stating that HP doesn't use Philips screws. They're Posidrive and if you use a Philips screwdriver, you'll damage both the screw and the screwdriver. I've seen some manuals that use bold type inside a bold box to warn techs about this but I didn't see anything in the manual for the 5065A.3. On the A18 Jumper Board or the A2 Battery Charger board, CR1 and CR2 or CR12 and CR13, respectively can overheat and damage the board. Why not do the same to them as was done for the main bridge, i.e. move them off the board? Replace them with a dual diode in a TO-220 case that uses isolated mounting to the chassis. Then there's no need for the A18 board at all. The A2 board is still compatible as long as you run a wire from the center of the dual diode to pin 8 of XA2. If you really want to retain A18 or A2 as a convenient main power disconnect point, replace the diode(s) with Schottky diodes. The lower voltage drop should deal with any power dissipation issues.Ed

author: maat
author_rank: Regular Contributor
timestamp: March 02, 2019, 12:40:31 am
content: @Ed: Thanks for files to get me started. I will have some nice reading while I wait for my package

author: edpalmer42
author_rank: Super Contributor
timestamp: March 02, 2019, 06:33:17 pm
content: You've got a lot more reading material than those few documents. There are multiple copies of the operating/service manual online. The best quality one I've found is the 3-part version available here:http://www.kennethkuhn.com/hpmuseum/scans/. It's a long page so search for 5065A and you'll find them quickly.Unfortunately, that copy wasn't processed through an OCR system so you can't search it.Ed

author: KE5FX
author_rank: Super Contributor
timestamp: March 02, 2019, 07:37:53 pm
content: Quote from: edpalmer42 on March 02, 2019, 06:33:17 pmHere's a consolidated and OCR'ed copy ofthat version(30 MB .PDF).

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: March 04, 2019, 03:05:03 am
content: maat,Can you let me know the serial number of the 5065A?I maintain a list of "known" HP 5065A units, and it's currently at over 120 units!If interested I can give you a few things to look out for when you get ready to power it up.A "superior" performing 5065A will drop below 1X10-13th between 64 and 100 Seconds (Allan deviation)Not a lot of other standards out there that can do that!Congratulations and good luck!Cheers,Corby Dawson

author: maat
author_rank: Regular Contributor
timestamp: March 04, 2019, 06:23:52 am
content: @KE5FX: Thank you very for that scan + OCR. I will sure put it to good use.@Corby: I can certainly post the serial as soon as I get the device, but I fear it will not be before the week after next, because next week there is carneval in Germany and usually everything grinds to a halt with a lot of people taking time off...I will see in what shape the unit is, when it gets here. Maybe take some photos, but I guess there are already plenty of them out there. Then see if anything blows up if I power it on.

author: testpoint1
author_rank: Frequent Contributor
timestamp: March 04, 2019, 05:27:01 pm
content: if that is 1E-12 per month, then 30 years, 360 months, already 3.6E-10, if no calibration, that means no value for that, and the component past 30 years, some of them working in high temperature always, tolerance can not do the prediction, even calibrate it, then how long the accurancy can keep ?

author: maat
author_rank: Regular Contributor
timestamp: March 04, 2019, 09:42:48 pm
content: @testpoint1: This is not a primary standard. Nor was it meant to be. It bridges the gap between Cesium and for example a low noise OCXO.Concerning the age. I certainly hope it is well aged. I love my test gear that way. There is nothing like getting your vintage test gear back from calibration just to be told everything is within the 90 day specs after 2 years without cal. Sure thing, you got to replace a cap here and there every once in a while, but with good care stuff from the 80's will outlive us all.

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: March 05, 2019, 01:11:03 am
content: Maat,Make sure the line voltage switch is set to match your local value!There are 10 100uf electrolytics that should be checked for chemical leakage/ corrosion.They are not the hermetic type and can leak.3 on A15 and A8, 1 on A4,A6,A7, 1 one A3 that can be inspected with a mirror and flashlight through the matching network holes in A3s case. You don't want to remove A3s case unless you absolutely have to, it's a pain. What you are looking for is corrosion around the + leads and if any PC traces nearby have been affected. I DO NOT replace them if no sign of corrosion. There are also 2 20uf electrolytics on the A11 board which should be replaced, they are universally bad. I see your unit has the clock option. If the LEDs don't light up you will need to replace the 3 47uf electros on the clock board and sometimes the 2N2905A transistor. Once you power up note the lamp and cell oven readings, they should be pegged or very high. If after 50 minutes they have not come down remove power and troubleshoot the oven controller. One other check you should make cold and also once the ovens settle. Pull off the lamp power SMB from its jack just in front of the RVFR. measure the cables connector from its shield to the center pin using both polarities of your ohmmeter. You should read 3.33K Ohm. This is the total of a 2K and a 1.33K in series. If it reads appreciably high you will need to remove the lamp assy. and replace the 1.33K as it is prone to mechanical cracking which causes a jump up in value. A 1.3K 2% 1 or 2W metal oxide resistor is what I use as a replacement. If you have the 10811 oscillator retrofit you should remove the mechanical adjustment kludge entirely. You can use a longer tweaker through the adjustment hole to make the adjustments. If when you remove the kludge the end is all frayed and falling apart you may have to remove the 10811 to clean out the adjustment threads. I can detail that if needed.A7 TP2 is the definitive place to see what's happening. You can use it to align the A3. If your Quartz in on frequency (in open loop) you should be able to see the 2nd harmonic signal. Once all is aligned you should have 500mv P-P minimum. No matter what it reads you should let the unit run 7 to 10 days while monitoring. If there is any cell flooding the 2nd harmonic should slowly increase and then stabilize.Good Luck!Corby Dawson

author: maat
author_rank: Regular Contributor
timestamp: March 05, 2019, 11:07:54 pm
content: Thank you very much for the detailed instructions Corby. This is very much appreciated. It comforting to know that there is someone who has a lot of experience repairing these goodiesI'll keep my fingers crossed, that whoever opened the lid didn't cause a chainsaw massacre. So far the parcel hasn't moved a bit, so I guess it will be some time next week before I can get my hands on it.

author: maat
author_rank: Regular Contributor
timestamp: March 14, 2019, 10:07:19 pm
content: Finally the Rb standard arrived and I had the time to have a look at it. What a poor thingIt really makes me sad to see it in such shape.But first the good news: It is an option 3 device. That means it has the clock option and a backup battery (or rather had, because the battery has spilled it innards). It also has the 10811-60109 OCXO fitted. And as an added bonus it was with Agilent in 2011 and got calibrated.Now the bad: On the ouside, the device looks like it has been exposed to the elements (maybe disposed and saved from the dumpster).And the ugly: On the inside I was greeted with a bag of miscellany labeled "nuts and screws" (and for a bonus leaky caps, that were pulled out). Someone already tried to repair it and gave up. One board has new caps the rest is leaking. The lamp is disconnected and cables are flying all over the place.So lets start the fun, grab the isopropyl and get cracking. I will remove the corpse of the battery first and then check out the Rb lamp first to see if it is broken. Fingers crossed...I will start a seperate thread over in the repair section soon to document my efforts.@Corby: Attached you will find a picture with the serial number of the poor fella.

author: 5065AGuru
author_rank: Frequent Contributor
timestamp: March 15, 2019, 01:50:18 am
content: Maat,A picture from the top with the cover removed would be helpful!Thanks for the serial number. A 2632A prefix is a nice later version!Personally I usually remove the battery back and live without it. The corrosion caused can severely damage a unit. Once power is applied monitor the photo-I reading. It should jump up from zero after a few minutes and after an hour should have stabilized. This tests the lamp! No need to open up the optical unit to test the lamp. Do make the 3.33K resistance checks I mentioned earlier. If you need any help please let me know. It's definitely worth the effort!Cheers,Corby

author: edpalmer42
author_rank: Super Contributor
timestamp: March 15, 2019, 02:02:19 am
content: Maat,It's horrible to see a sweet piece of equipment like that treated so poorly. Looking forward to your thread, but I'd put it in the Metrology section rather than repair since the 5065A is definitely a metrology-grade device.I think that Corby knows more about the 5065A than the designers, so if he can't help you, ..... well, ...... you're screwed!Ed

author: Drewbie
author_rank: Contributor
timestamp: September 13, 2019, 12:13:03 pm
content: Any update on the repair?Corby, you might want to add to the option list:H89 = BNC output on rear of unit for 4.433MHZ (PAL TV subcarrier frequency)

author: Zucca
author_rank: Unknown
timestamp: September 13, 2019, 01:29:53 pm
content: https://www.eevblog.com/forum/metrology/hp-5065a-rubidium-standard-repair-log/

author: maat
author_rank: Regular Contributor
timestamp: September 13, 2019, 07:54:22 pm
content: Did not get much done recently, because I am working on my phd thesis (laser electronics and stuff). I will definitely pick it back up, once I need a brake from writing