Author Topic: HP 6032A 60V/50A power supply problem (Read 5374 times)

ArthurDent · « **on:** September 17, 2018, 04:17:42 pm »

I bought a known defective HP 6032A power supply that is capable of outputs of up to 60V and up to 50A for probably less than the scrap metal price. It is very large power supply that is built like a tank. Once I got the covers and shields off I figured out what the problem might be. Here is a photo of one of the capacitors that was across the output. When it literally blew, it apparently spewed nasty stuff (that's a technical term) and maybe flames out of a split in the side and through the bottom. I managed to grind away all the charred layers on the thick circuit board so there is only clean fiberglass exposed and no chance of any leakage that might lead to further problems and I replaced that cap and its twin with new ones of the same make. It is amazing at what damage a lot of power can do.

Fortunately there was nothing else important that was damaged and after a good and thorough cleaning I was able to get the PS up and running again, almost like new as long as you don't look inside.

Tomorokoshi · « **Reply #1 on:** September 17, 2018, 05:00:52 pm »

What was the manufacturer of the original capacitor?

SeanB · « **Reply #2 on:** September 17, 2018, 05:36:03 pm »

Blue sleeve, made in the US of A, most likely Sprague, or Cornell Dublier.

ArthurDent · « **Reply #3 on:** September 17, 2018, 06:03:12 pm »

It was indeed a Cornell Dubilier high grade electrolytic. The original caps in the power supply were 2600/75 @ -20% to +75% and I found new replacements that were physically shorter of 2700/100 @ -20% to +20%. The process of making caps has obviously improved since the power supply was built.

coromonadalix · « **Reply #4 on:** September 17, 2018, 08:41:57 pm »

Be careful this kind of series wont give 60vdc at 50 amps, in any voltages setting multiplied by the current : it will not exceed 1000 watts

EX:
50v at 20 amps
60v at 16.6 amps
20v at 50 amps

But you're lucky to find schematics ...

60v at 50 amps would be an 3000 watts psu, totally different casing size.

I nearly got a few of theses until i've read the specs ...

ArthurDent · « **Reply #5 on:** September 17, 2018, 10:47:07 pm »

coromonadalix - "Be careful this kind of series wont give 60vdc at 50 amps..."

That isn't what I said. I was very specific saying: "capable of outputs of up to 60V and up to 50A". I didn't say that these maximums were at the same time and what I said is correct and what you will find on the spec sheet, if you check.

When you say: "it will not exceed 1000 watts", at 40 VDC it can output 30 A or 1200 watts.

https://www.atecorp.com/ATECorp/media/PDFs/data-sheets/Agilent-6030A_Datasheet.pdf

Are you implying that I should not have bought this power supply that cost me what I might spend on a meal at McDonalds??

PTR_1275 · « **Reply #6 on:** September 18, 2018, 12:20:01 am »

I have a 6012A and it is a beast of a power supply. Been looking for a 6032a for a while now, but once you take the shipping to Australia into account, the pickings are slim.

That’s awesome you got it for such a cheap price and the problem wasn’t as bad as it could be. Strange the cap died in that way though.

coromonadalix · « **Reply #7 on:** September 18, 2018, 10:30:45 am »

I did not say that ... but to some peoples the specs where misinterpreted, for those kind of psu, you have an voltage and current curve for an total of watts output, that's all

If the supply is repaired for a few $$$ and does its job, its a very good purchase.

But not for me, see the ''autoranging output'' curve, it explain everything. Some people think they output an full 50v at 60 amps, witch is not true.

Hp as many psu's using the same ''autoranging effect" in the 6xxx series ... we are lucky to have user and services manuals.

ArthurDent · « **Reply #8 on:** September 18, 2018, 05:10:57 pm »

“…to some peoples the specs where misinterpreted, for those kind of psu, you have an voltage and current curve for an total of watts output…”
“ Some people think they output an full 50v at 60 amps, witch is not true.”

A lot of power supplies have been specified for voltage, current, AND dissipation limits for decades so anyone familiar with power supplies knows this common information, but it might come as a surprise to someone new.

When you say: “I nearly got a few of theses until i've read the specs ...”, anyone who claims they were going to buy several thousand dollars worth of high end system power supplies and didn’t because at the last minute they just happened to notice the specs, isn’t a buyer I’d want in any business I might own.

Lastly, this thread is in the ‘repair’ section of the forums and that was what it, and the other replies, was about until it was thrown off topic so you could educate us about a subject that isn’t part of this thread.

Your concerns might be a good topic for the ‘beginners’ section if you think it’s important.

bitseeker · « **Reply #9 on:** September 18, 2018, 05:35:07 pm »

Arthur, how's it looking inside now? Did you have to do any trace repairs or just get rid of charring? Any ideas on what caused the massive blowout? The 6012 and 6032 are good supplies, though a bit unwieldy. I wonder if the many dead ones out there were due to the same issue and my 6032 might benefit from pre-emptive cap intervention.

nctnico · « **Reply #10 on:** September 18, 2018, 05:39:30 pm »

I have a couple of the earlier 6012A models myself and in the middle of the voltage range they can deliver 1200W. It seems there isn't an over-power protection though. I have pulled 1350 Watt (powered from 230VAC) from one of them and it just went along. Maybe the 6032A has better over-power protection though.

@ArthurDent: good you got it working again! Something electrolytics just explode or it could be someone ran it from a higher AC voltage than it was configured for. I have rebuilt a couple of 6024A power supplies in which all the electrolytics had failed. The new capacitors are way smaller and I went for high quality ones.

ArthurDent · « **Reply #11 on:** September 18, 2018, 08:05:52 pm »

A reply to the last two comments: There was some damage (well, more than a little) done to the circuit board but the board is very thick so I basically could scrape a lot of fiberglass away to get to nice clean stuff. The caps I used as replacement were 100VDC instead of the original 75VDC ones but that was mainly because of what I could find as a close replacement.

The biggest problem, and those of you who have looked at the bottom with the bottom cover off, is that the circuit board is mounted in a large u-shaped chassis and you can't get to those capacitor terminals to unsolder the old caps to replace them. There are some cut-outs in the chassis so I could look under the chassis and estimate where the pins were. I then drilled a small pilot hole through the chassis and generally got right over the cap terminal on the first try. Then, using a 1/2" drill with a sleeve on it for a stop so I couldn't drill beyond the thickness of the metal chassis, I drilled holes directly over the solder terminals of the 2 caps. The original caps had 3 terminals but the replacements had 2 with slightly different spacing. This actually worked out well because it allowed me to drill a new hole for one lead in a good solid part of the board. After soldering with a good wattage size iron to make sure I had a good solder connection I used some 'barge cement' to make sure they would be solidly mounted on the circuit board.

The next part was cleaning up what was vented onto other nearby part and that took some time. Some components looked a little nasty but cleaned up well. I had to make sure that nothing got under any component plus I had to carefully check that I hadn't left any stray aluminum chips from all the drilling that might short something out later. Trying to hold something that heavy upside down with 2 hands and give it a good shaking isn't easy. After making sure I had it clean and everything plugged in and back in place, I plugged it in and it worked!

I suspect that there wasn't any defect in the cap that blew but most of these supplies are probably used in industrial applications where they are on for long hours over years. Components fail so I'm not surprised. I didn't go out seeking a supply like this to buy but stumbled on it for sale on a public listing site with a lot of other equipment. I bought a lot of all defective stuff really cheap and got a lot of it working, most with far simplier problems than this HP 6032A power supply.

bitseeker · « **Reply #12 on:** September 18, 2018, 09:47:19 pm »

Thanks for the additional info, Arthur. Drilling holes to access the cap terminals is an interesting solution. I'll have to remember that.

ArthurDent · « **Reply #13 on:** September 18, 2018, 10:16:29 pm »

The alternative to drilling the holes to access the cap terminals was to completely dismantle the entire supply to get the large circuit board out of the chassis to get to the terminals on the bottom of the circuit board. I didn't want to attempt that so I thought about it for quite some time and came up with this plan which worked great and was far simpler. It didn't look too bad when I was finished drilling either.

bitseeker · « **Reply #14 on:** September 18, 2018, 11:01:32 pm »

Yeah, it's not unusual to have access holes for getting to screws, pots, etc. I've had a look inside mine before and I wouldn't want to have to take it all apart, either.

dacman · « **Reply #15 on:** September 18, 2018, 11:10:40 pm »

Those supplies have 1000W on the front panel, but I like to place a sticker on them with the actual specified rating.

Connecting it across a high voltage high current source can cause capacitors to explode. (I know someone that connected one across an industrial room-sized backup battery when they were supposed to connect it across a shunt. Procedure: 1) Disconnect shunt. 2) Blow up power supply.)

drussell · « **Reply #16 on:** September 18, 2018, 11:13:46 pm »

Wow, that was quite the capacitor explosion!

coromonadalix · « **Reply #17 on:** September 18, 2018, 11:40:55 pm »

I don't want going thru this .... hell of an dismantling process to change the fan.

nctnico · « **Reply #18 on:** September 19, 2018, 07:30:35 pm »

I used to have a 6002A myself. I had to take it apart because the crowbar got activated while a battery was attached to it. That caused quite a few traces to get burned. When disassembling several wires which where soldered into the board got loose as well so I resoldered all of them.

Deni · « **Reply #19 on:** January 11, 2020, 08:04:15 am »

My 6032A decided that it has an EPROM fault. Since it is pretty old, I guess EPROM contents faded out. I would appreciate if somebody can help me to reprogram it by reading out contents of a valid one.
Please note that I am talking about code EPROM (U6 in the schematics), not data storage EEPROM ! Any help would be highly appreciated.

pejjo · « **Reply #20 on:** January 04, 2021, 11:13:44 pm »

Did you get hold of any eprom file?

octillion · « **Reply #21 on:** January 10, 2021, 04:27:18 am »

I have an older style HP 6032A, where the GPIB card consists of two boards. In this revision, the EPROM is labeled U8. I attached the binary in case it helps anyone (the ".txt" suffix is just to get the forum to accept it).

The EPROM is an Intel D27128A, and was soldered directly to the board. The label reads
5080-2122
REV. A
8839

Some videos from Keysight showing the differences:
Older revision:
Newer revision:


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Author Topic: HP 6032A 60V/50A power supply problem (Read 5374 times)

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