Got an HP 6654A 0-60V 9A PS with a weird configuration, wtf? - Page 1
Forum section: electronics / testgear

author: SharpEars
author_rank: Unknown
timestamp: November 02, 2014, 02:35:52 am
content: I just came into possession of a used HP 6654A power supply that has no voltage/current knobs on the front. This is not because it is missing them, there isn't even a cutout for them in the front panel. Is this some sort of special version of it or what, because the PDF from Keysight and all other ones I see for sale on eBay seem to indicate that there should be knobs.Serial number is: 3021A-001XXHere's how it should look with the knobs (image from testbuyer.com):Now imagine that someone took an erase and erased the knobs and the gray silk screen above them that labels them.

author: Yago
author_rank: Frequent Contributor
timestamp: November 02, 2014, 02:49:13 am
content: A link to the manual:http://www.keysight.com/main/editorial.jspx?cc=GB&lc=eng&ckey=1000002297:epsg:man&nid=-35689.384724.00&id=1000002297:epsg:man

author: cncjerry
author_rank: Unknown
timestamp: November 02, 2014, 02:51:39 am
content: Take away the knobs and you can't change the voltage or current. I believe there to be three versions of that supply: 1) with knobs; 2) no knobs and no cutout; 3) no knobs but small cutouts with calibration type pots under your usual stickers. The last of which I have only seen not used. I believe if it has the pots they are only for calibration not for every day use and if that is the case, the calibration would be off.I've been looking for a programmable supply. Let me know how it works out.That is a pricey supply from what I remember.Jerry

author: SharpEars
author_rank: Unknown
timestamp: November 02, 2014, 02:52:00 am
content: Quote from: Yago on November 02, 2014, 02:49:13 amAnd there the knobs are on Page 86 of that manual, but in my version, no knobs!

author: SharpEars
author_rank: Unknown
timestamp: November 02, 2014, 03:00:01 am
content: Quote from: cncjerry on November 02, 2014, 02:51:39 amActually, you theoretically don't need the knobs to change/voltage current, because there are up/down buttons for both on the left hand side of the entry group (click on the image below to see the button labels more clearly):It's a pricey sucker, but I got it for a good deal along with its little brother, a 6653A (of course that one has the dang knobs, just to piss me off)...One negative, right off the bat is that the minimum voltage adjustment is in 26 mV steps on the 6654A, so if you need finer adjustment than that, you're SOL. On the other hand, 60 V at 9 amps isn't something you can do with a Rigol, Siglent or even a modern Tektronix supply.

author: VK5RC
author_rank: Unknown
timestamp: November 02, 2014, 06:56:51 am
content: Can't you enter the voltage and current directly from the keypad? I have a 6632 and use the store recall values function (a small post it note reminds the preset V & I) as the knob method is v slow.

author: SharpEars
author_rank: Unknown
timestamp: November 02, 2014, 12:51:07 pm
content: Quote from: VK5RC on November 02, 2014, 06:56:51 amYou sure can and that is how I use it 99% of the time. The up/down keys (and knobs if you've got them) are just for minor adjustments to tweak the voltage/current.

author: cncjerry
author_rank: Unknown
timestamp: November 04, 2014, 07:07:54 am
content: Here's a question for you: if you have the knobs and it is in remote mode, can your tweak the power supply? I think the panel would be locked out, wondering about the knobs.I am going to go look for one of those supplies. I recently bought a bunch of supplies and meters. Hate to say how many supplies as I got carried away, but two full tektronix tm506 frames and a 503. Each supply has plus/minus 0 to 20v with an added 5v. So it is 12 x 2 plus the 12 +5v supplies. The variable supplies float so you can link them together to 400v. I have an old HP 0-24V at 40A that I can weld with as well. Having the multiple supplies allows me to set the current limiting for each stage which has proven useful.The other thing that is a great deal right now and seems to be overlooked is the HP matrix switch. I just ordered one with four modules for $49 plus like $18 shipping. I can monitor the supplies easier using the switch. For $40 more you get a module that has a 4x4 (I think) isolated BNC matrix that is good to 300 MHz. There is another that is good to 1Ghz. So now I can switch various signals under test into and out of my meters and scopes programmatically.Now I just have to remember what I was working on when I needed the supplies...

author: SharpEars
author_rank: Unknown
timestamp: November 04, 2014, 02:39:58 pm
content: Quote from: cncjerry on November 04, 2014, 07:07:54 amYes, I've become a supply hog myself lately. Don't know why, but I just can't pass up a good deal on a quality supply. Just got myself a Power Designs 2020B as well to add to my collection and two more 5 1/2 digit voltmeters to add to the two 6 1/2 I already have. I think I've caught the "Voltnut" virus from you guys - not as dangerous as Ebola, but far more expensive!As far as your remote mode question, I don't use this functionality, so sorry but I can't answer your question.I can say this, these supplies produce a rock stable voltage when viewed with a 6 1/2 digit voltmeter into even the smallest of loads. The noise characteristics are very good also, given their peak output. Theironlyshortcomings are weight (a back breaking 54 lbs or so each), the desk space needed to hold them and the inability to adjust/monitor voltage at the 1 millivolt "Voltnut" level.If you're not a weightlifter and don't have a strong wife/friend to help you with moving and positioning the thing, don't bother getting one, because lifting them and moving them around by yourself is a bit**! I know, I've lifted and moved around both supplies. Just putting them on a high table by yourself and/or stacking them requires quite a bit of effort and smart posturing so as not to injure your lower back. It's not like a 55lb/25kg dumbbell, because the weight is unevenly distributed over the large area of each unit, so you really have to be careful with it.Fortunately, they have handle belts on both sides which given the weight are quite comfortable to use. Got to hand it to HP for that and the use of one hell of a heavy transformer in these things, which is where I think the majority of their weight comes from. Well that and the steel framing, I suppose.

author: KJDS
author_rank: Super Contributor
timestamp: November 04, 2014, 03:05:09 pm
content: Quote from: SharpEars on November 04, 2014, 02:39:58 pmI turned up to an auction house last year to collect some equipment that I'd bought from just a very out of focus photo.I was slightly surprised that two of the boxes were 230lbs (110kgs) each. I hope I never have to deal in anything so heavy again.

author: SharpEars
author_rank: Unknown
timestamp: November 04, 2014, 06:35:01 pm
content: Quote from: KJDS on November 04, 2014, 03:05:09 pmOuch, lifting 230lbs is a three person job if not four. I am thinking fork lift territory...