HP 6632B power supply / electronic load in UK - Page 1
Forum section: electronics / general

author: AndyC_772
author_rank: Super Contributor
timestamp: February 06, 2013, 10:24:48 pm
content: Heads up for those of us in the UK:http://www.ebay.co.uk/itm/AGILENT-HP-6632B-Bench-DC-Power-Supply-0-20VOLT-5-AMP-Programmable-/350709211031?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item51a7e5df97Provided you don't mind that the output is on a set of screw terminals at the back, the 6632B is a superb lab power supply, and this seller has 8 left at the best price I've seen anywhere.They're accurate, very low noise, the start-up and shut down characteristics are exemplary, and they have an excellent meter built in which saves needing a separate multimeter to measure the output voltage and current. Also, the output stage can sink just as much current as it can source (5A @ 20V), so it can be used as an electronic load as well as a power supply.Downsides? Big, surprisingly heavy even for their size, you'll probably want to fit some binding posts for easy connection, and you have to set voltage and current by entering numbers on a keypad or by programming it remotely - but for quality and versatility I've yet to use a better PSU.

author: Rick
author_rank: Frequent Contributor
timestamp: February 07, 2013, 01:22:31 am
content: Quote from: AndyC_772 on February 06, 2013, 10:24:48 pmYou can place the binding posts on the front panel. The holes are there I think I can feel them but did not check to see inside (from the front panel you will not have the sense possibility on the DUT). I got mine from Finland and it is very nice. Had never used such a nice piece of equipment.

author: AndyC_772
author_rank: Super Contributor
timestamp: February 07, 2013, 07:31:42 am
content: I didn't fancy modifying the unit itself, so I just ran a bundle of cables from the rear connectors to a little box attached to the rack mount ears. The box provides both the main power terminals and the remote sense connection, and there's a 10 ohm resisor between power & sense so I can use just the power terminals on their own for convenience.

author: Rick
author_rank: Frequent Contributor
timestamp: February 07, 2013, 09:10:03 pm
content: Quote from: AndyC_772 on February 07, 2013, 07:31:42 amWhat is the 5th binding post ?

author: lewis
author_rank: Frequent Contributor
timestamp: February 07, 2013, 09:56:36 pm
content: looks like mains earth

author: AndyC_772
author_rank: Super Contributor
timestamp: February 07, 2013, 10:24:09 pm
content: Correct - the outputs are usually floating, but can be earthed. There's a fifth screw terminal on the back for this purpose.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 08, 2013, 12:35:15 am
content: <nips out to workshop with tape measure to check available gear-shelf space>Now only 7 available

author: cyr
author_rank: Frequent Contributor
timestamp: February 08, 2013, 11:06:51 am
content: Thanks for the heads up, I'm not in the UK but international shipping wasn't unreasonable so I nabbed one as well.I have one of these already, from probably the same guy in Finland already mentioned. Always regretted I didn't get both units he had left, very useful bit of kit.They are usually listed for 500$ or more on ebay, even non-working ones...

author: bingo600
author_rank: Super Contributor
timestamp: February 08, 2013, 09:19:21 pm
content: That's a nice offer.I have 2 from finland , and absolutely love them.But they are "noisy" , and i had to buy a fanless E3610A to do long term OCXO tests.I have my lab besides the bedroom , so it was the wifes order - To get the "silent"one/Bingo

author: noodlebear
author_rank: Contributor
timestamp: February 10, 2013, 10:33:04 pm
content: Just bought one of these. Thinking I may replace the fan when it gets here. Does anyone know what size the fans are?Thanks

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 10, 2013, 11:31:20 pm
content: User manual :http://cp.literature.agilent.com/litweb/pdf/5962-8196.pdfService manual :http://cp.literature.agilent.com/litweb/pdf/5962-8119.pdf

author: senso
author_rank: Frequent Contributor
timestamp: February 10, 2013, 11:44:47 pm
content: Same here, just bought one, great opportunity to buy a real power supply for my small lab at home.Thanks for sharing, and thanks Mike for the manuals.

author: nctnico
author_rank: Super Contributor
timestamp: February 11, 2013, 01:05:23 am
content: Still 8 available... It looks like a nice PSU but 20V is a bit low-ish and it is very large.

author: AndyC_772
author_rank: Super Contributor
timestamp: February 11, 2013, 07:48:08 am
content: Quote from: noodlebear on February 10, 2013, 10:33:04 pmI have three of these, and although they're all quite old, the fans seem to be OK. I've not felt any need to change them.The only problem I've had is that the case itself vibrated and made a lot of noise on one unit. The mains transformer leaks quite a strong magnetic field, and the case has to be tightly supported in order to keep it quiet. There's a pad stuck to the top of the transformer which is supposed to support the lid, but it can compress over time and allows the lid to move slightly. The fix is a small self-adhesive rubber foot stuck to the top of the transformer, 5 mins work at most.

author: Narmaraktuk
author_rank: Contributor
timestamp: February 11, 2013, 08:05:41 am
content: There is a service note for fixing an output glitch:http://cp.literature.agilent.com/litweb/pdf/6632B-09.pdf.

author: noodlebear
author_rank: Contributor
timestamp: February 11, 2013, 04:31:08 pm
content: Quote from: AndyC_772 on February 11, 2013, 07:48:08 amI've just heard that the fans can be quite noisy. Given the availability of near silent pc fans, I was thinking of quieting it down a bit.

author: bingo600
author_rank: Super Contributor
timestamp: February 11, 2013, 05:48:28 pm
content: Quote from: Narmaraktuk on February 11, 2013, 08:05:41 amImplemented here with a 1n4148/Bingo

author: Unknown
author_rank: Unknown
timestamp: February 11, 2013, 05:57:15 pm
content: Near silent PC fans will usually move much less air and are able to overcome less static pressure than the old noisy types.

author: bingo600
author_rank: Super Contributor
timestamp: February 11, 2013, 05:59:54 pm
content: Quote from: noodlebear on February 11, 2013, 04:31:08 pmPlease let us know if you find a suitable replacement fan.It needs to deliver a lot of air to the heat tunnel , original is afaik a Pabst 612I have found a replacement , the 632 NU (33dB) , it has same specs as the old 612 (40dB) , but i can't seem to get my hands on it.http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=160978HP 66332A, 6632B, 33B, 34B, Service.pdf - Pg.77 fandriver circuit/Bingo

author: nctnico
author_rank: Super Contributor
timestamp: February 11, 2013, 06:12:31 pm
content: Quote from: noodlebear on February 11, 2013, 04:31:08 pmThose silent fans are usually crap. What you need is a good fan from Papst which provides at least the same airflow as the original (or your PSU will overheat) and a temperature control circuit. I've build a temperature controlled fan in my HP6002A PSU. When the PSU is not heavily loaded the fan is off. It only comes on when the heatsinks get over approx. 35 C but the speed depends on the temperature of the heatsinks. The fan is only at full power when the heatsinks are approx 50 degrees. The circuit consists of a temperature sensor, an opamp, an emitter follower to provide power to the fan and some passive components.

author: AndyC_772
author_rank: Super Contributor
timestamp: February 11, 2013, 06:42:10 pm
content: The fan speed on the 6632B varies with output (or input) current. It's a gentle enough whirr at idle, but does become quite loud at full load.

author: bingo600
author_rank: Super Contributor
timestamp: February 12, 2013, 06:59:09 pm
content: Quote from: AndyC_772 on February 11, 2013, 06:42:10 pmMy units whirr are a "BIT" more than gentle , even at idle.But i guess it depends if they're in a silent environment.But i still love them , and did some accuracy/profiling with a GPIB and a HP 34401AI got an Agilent & a HP unit from FinlandIt's fun to notice that the newer Agilent uses another regulator loop than the older HP/Bingo

author: bingo600
author_rank: Super Contributor
timestamp: February 12, 2013, 07:05:58 pm
content: Ohh i did do a voltage calibration on the Agilent.Here are before & after (unloaded psu)I think i got it quite nice in the Cal. , just following the quite easy procedure & used my 34401A DMM/Bingo

author: AndyC_772
author_rank: Super Contributor
timestamp: February 12, 2013, 07:21:15 pm
content: Quote from: bingo600 on February 12, 2013, 06:59:09 pmIt's all relative. Mine live in a lab with a rather noisy old Tek scope, and a stereo that's on the big side for the room

author: noodlebear
author_rank: Contributor
timestamp: February 12, 2013, 10:18:23 pm
content: Quote from: bingo600 on February 11, 2013, 05:59:54 pmAs far as I can see this one moves more CFM than the original with only 17.4 dBA. There is no graph available for the fractal with CFM and pressure though.http://www.fractal-design.com/?view=product&category=4&prod=75

author: noodlebear
author_rank: Contributor
timestamp: February 13, 2013, 09:25:01 pm
content: Received mine today. Definitely too noisy for me, also that transformer hum is quite loud, I'll have to do Andy's mod and add a foot inside.

author: Dave
author_rank: Super Contributor
timestamp: February 20, 2013, 09:30:54 am
content: Just ordered mine. The seller accepted my offer for 100GBP. Shipping to my country is very reasonable as well - only 30GBP for a device that weighs 15kg.

author: KJDS
author_rank: Super Contributor
timestamp: February 20, 2013, 04:02:45 pm
content: I'm glad you're all enjoying them.From testing these, I've found that some at low current have the case resonant with the fan speed.If anyone else wants to order, I've still got a lot more in stock, however I've almost run out of monthly selling allowance again so please email kev at kjds-ltd dot com for details.

author: noodlebear
author_rank: Contributor
timestamp: February 20, 2013, 05:04:00 pm
content: Quote from: KJDS on February 20, 2013, 04:02:45 pmJust out of interest, where did you find them all? Seems like a huge number (>50?) and all in used condition!

author: Telstar
author_rank: Contributor
timestamp: February 22, 2013, 01:54:14 pm
content: Quote from: alm on February 11, 2013, 05:57:15 pmYep, you have to look at fans designed for watercooling radiators, but if the size is under 120mm, it will be a bit hard to find a good and quiet fan.

author: noodlebear
author_rank: Contributor
timestamp: February 22, 2013, 02:08:08 pm
content: Quote from: Telstar on February 22, 2013, 01:54:14 pmRight, that's what the consensus seems to be, but I don't see why from the specs.The original fan:http://www.ebmpapst.com/en/products/compact-fans/axial-compact-fans/axial_compact_fans_detail.php?pID=53771moves about 18 CFM at the lowest pressure.This one:http://www.fractal-design.com/?view=product&category=4&prod=75moves 20 CFM.Although graphs against pressure aren't given for the fractal, there is a maximum pressure given, I'm just not sure how to translate that into a graph similar to the papst one.I've sent them an email to see if they'll send me a graph.

author: Telstar
author_rank: Contributor
timestamp: February 22, 2013, 09:09:03 pm
content: Also note that the published specs of fans are usually WAY optimistic. Try to find test reports on computer hardware websites. Only the most reputable brands are decently consistent with specs (such as Sanyo-denki, Noctua. Delta).

author: mzzj
author_rank: Super Contributor
timestamp: February 22, 2013, 10:07:51 pm
content: 6632B fans are cross-breed between concrete mixer and russian turbojet.Seriously guys, almost anything is quieter than these 20 year old ball bearing fans...

author: bingo600
author_rank: Super Contributor
timestamp: February 23, 2013, 07:46:58 pm
content: I just thought i was pointed to a replacement :-(https://www.eevblog.com/forum/testgear/review-teardown-agilent-u8001a-30v-3a-linear-power-supply/msg195142/#msg195142/Bingo

author: KJDS
author_rank: Super Contributor
timestamp: February 28, 2013, 03:42:03 pm
content: ebay have very kindly increased my selling limits, so I've now put a few more of these back on ebay. Should anyone want to buy direct then they'll be cheaper.

author: bingo600
author_rank: Super Contributor
timestamp: February 28, 2013, 07:39:21 pm
content: Wutttt ....Does ebay regulate how many units you are allowed to sellI didn't know that ....Is that based on amount of $$$ or number of units or ??/Bingo

author: KJDS
author_rank: Super Contributor
timestamp: February 28, 2013, 07:59:04 pm
content: Quote from: bingo600 on February 28, 2013, 07:39:21 pmIt's based on both. Until you've a confirmed address and bank account it only 10 items and £1000 per month. Once those are confirmed then it goes up to £3500 and 100 items per month. After that you can increase it once a month but you need a phone call to their selling allowance team where they review your performance. Fortunately I've been reasonably successful in increasing that each month. it does make quite a lot of sense, there's a significant learning curve to be climbed with getting quality stock in place, packaging, dealing with customers emails, other selling channels, keeping the accounts up to date, sorting out VAT returns, visiting suppliers, visiting customers, repairing units that don't work before sale. I spent most of December where I spent several hours of each day repairing microscopes. I've still got a few to fix but at least I enjoy fixing them.I'm used to running a business, so it's not that much of a struggle but I can see why ebay don't want sellers trying to dive into the deep end and drowning.I'm looking forwards to next month when there'll be some new test equipment on sale that hopefully will be as popular as the power supplies have been.

author: Christopher
author_rank: Frequent Contributor
timestamp: March 09, 2013, 12:43:19 pm
content: Got mine recently, need to add some binding jacks soon.Very loud transformer hum and fan. Nothing wrong with that though.Going to get one or two more over the coming month.

author: nctnico
author_rank: Super Contributor
timestamp: March 09, 2013, 10:28:43 pm
content: Quote from: KJDS on February 28, 2013, 07:59:04 pmYou mean you have more of those stereo microscopes? They do look interesting but it may take some effort convincing the misses to drive to England :-)

author: SeanB
author_rank: Super Contributor
timestamp: March 10, 2013, 05:24:39 am
content: Just take a train through the froggies and enjoy the views.

author: BillyD
author_rank: Regular Contributor
timestamp: May 03, 2013, 09:30:29 pm
content: Just to say thanks to KJDS for sending me one of these in good condition, good time and very well packaged for transit. Good dealing with you and thanks for the quick and efficient service.Billy.

author: dexters_lab
author_rank: Unknown
timestamp: May 09, 2013, 08:04:03 am
content: I picked one of these up too, arrived yesterday. Working perfectly if a little dusty on the inside. Dont think the fan is too noisy, certainly quieter than my rigol ds1102!

author: KJDS
author_rank: Super Contributor
timestamp: May 09, 2013, 08:41:53 am
content: It's good to know they're arriving safely.I've just listed a large list of new arrivals in the buy/sell/wanted forum, including some more interesting HP supplies.

author: Tooms
author_rank: Unknown
timestamp: May 09, 2013, 09:25:15 am
content: Hii see that your selling an video microscope and i think Dave is looking for one, so maybe there is an option for a deal between Dave and you if that is what he needs.http://www.ebay.co.uk/itm/JVCYK-C1380-professionsal-colour-video-microscope-with-boom-stand-and-light-/350786639816?pt=UK_BOI_Medical_Lab_Equipment_Lab_Equipment_ET&hash=item51ac8357c8/Tooms

author: dexters_lab
author_rank: Unknown
timestamp: June 10, 2013, 01:38:23 pm
content: Lol, just thought i'd see if i could get some hp replacement feet for my 6632...erm yea saw the price and instead bought some large rubber feet off ebay!

author: bingo600
author_rank: Super Contributor
timestamp: June 12, 2013, 12:57:18 pm
content: Just saw this , and it could be a promising fan replacement ... If i could only get those fans in EUhttps://www.eevblog.com/forum/testgear/hp-6632a-fan-replacement-and-front-panel-posts//Bingo

author: dexters_lab
author_rank: Unknown
timestamp: June 15, 2013, 09:00:19 pm
content: Yea saw that thread, i'm not bothered about the fan noise but i have made a box with posts that mirrors the rear connections on about 1/2 meter of 2.5mm cable, prefer that to front mounted posts and you get easy access to the sense connections as well.Will post pics up.Wouldnt have thought finding a decent fan would be a problem if you wanted to swap it, unless its an odd size?