PSU(Low quality?!) on Agilent DSO-X 2022A - Page 1
Forum section: electronics / testgear

author: shodan@micron
author_rank: Contributor
timestamp: November 06, 2018, 07:34:02 pm
content: void

author: nctnico
author_rank: Super Contributor
timestamp: November 06, 2018, 11:38:38 pm
content: Quote from: shodan@micron on November 06, 2018, 10:46:41 pmThat is hard to judge. For example the fake FTDI FT232 chips look better than the originals.

author: umkumiut
author_rank: Contributor
timestamp: November 07, 2018, 07:31:30 am
content: Quote from: shodan@micron on November 06, 2018, 11:43:21 pmThis scope doesn't have a hard mains switch, its PSU is always on when it is plugged in.

author: Hydrawerk
author_rank: Super Contributor
timestamp: November 07, 2018, 10:49:41 am
content: This PSU is still better than those found in Siglent or Rigol. Look at those big heatsinks and high quality electrolytic capacitors.If this PSU was of low quality then there would be much more parts dead, not only 1 diode and 1 fuse. When a low-quality switched PSU goes off, then often transistors and even the main IC are burned, sometimes even the scope mainboard can be damaged.For me, Keysight is still OK.Was there an overvoltage in your power grid in Russia??

author: Jan Audio
author_rank: Frequent Contributor
timestamp: November 07, 2018, 04:41:43 pm
content: Quote from: Hydrawerk on November 07, 2018, 10:49:41 amFor expensive equipment and computers you need a special power socket that smooths and protects against overvoltage.Belkin is a good brand.

author: Ice-Tea
author_rank: Super Contributor
timestamp: November 07, 2018, 04:49:44 pm
content: Quote from: blueskull on November 06, 2018, 11:46:08 pmInfineon, no?

author: wraper
author_rank: Unknown
timestamp: November 07, 2018, 04:56:40 pm
content: Quote from: Jan Audio on November 07, 2018, 04:41:43 pmThose special sockets have questionable effect. They may protect against short transients but they are useless against increased voltage. Say they won't have any effect if mains voltage suddenly becomes 300V AC.

author: wraper
author_rank: Unknown
timestamp: November 07, 2018, 04:58:49 pm
content: Quote from: Ice-Tea on November 07, 2018, 04:49:44 pmPart of IR was bought by Vishay as well, especially discrete components.https://ir.vishay.com/press-release/financial/vishay-completes-acquisition-power-control-systems-business-international-re

author: wraper
author_rank: Unknown
timestamp: November 07, 2018, 05:07:56 pm
content: Quote from: shodan@micron on November 06, 2018, 07:34:02 pmOpen the datasheet from Vishay and scroll down to the bottom for photos.https://www.vishay.com/docs/91070/sihf840.pdfAnd why would you doubt the origin? Also on your photos excellent build quality and all Japanese capacitors can be seen.QuoteYour friend doesn't know how IR logo looks like.QuoteClean with alcohol and move the light source to different angle.

author: Ice-Tea
author_rank: Super Contributor
timestamp: November 07, 2018, 05:45:00 pm
content: Quote from: wraper on November 07, 2018, 04:58:49 pmHeh. Didn't know. Pretty sure FETs went to Infineon, tho..

author: wraper
author_rank: Unknown
timestamp: November 07, 2018, 06:07:19 pm
content: Quote from: Ice-Tea on November 07, 2018, 05:45:00 pmDeal with Vishay happened much earlier. Dunno how many product lines they sold. As of IRF840, very likely they were made by Vishay even before that deal. On/Fairchild made them as well.Quote

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 07, 2018, 06:09:08 pm
content: Quote from: Jan Audio on November 07, 2018, 04:41:43 pmFor expensive equipment, it is reasonable to expect them to have a PSU that isn't so fragile it dies under normal mains transients etc.

author: wraper
author_rank: Unknown
timestamp: November 07, 2018, 06:24:34 pm
content: Quote from: mikeselectricstuff on November 07, 2018, 06:09:08 pmI've seen "normal transients" like 285V for few hours hours several times a week in Russia. And some PSUs will die regardless of how well they are made if there is a large quantity in the wild. Of course you can reduce failures by using mil grade or ridiculously overspec components but who will buy that at price it would cost?

author: tautech
author_rank: Super Contributor
timestamp: November 07, 2018, 07:31:56 pm
content: Quote from: Hydrawerk on November 07, 2018, 10:49:41 amHow can you know ?Of some hundreds sold over 5+ years, never a PSU failure.Only seen one Siglent DSO PSU failure on this forum in my time here.OTOH, a few Aigsights, just one:https://www.eevblog.com/forum/testgear/hosed-by-my-msox-3024a/

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: November 08, 2018, 07:16:03 pm
content: Sorry to hear about this!Having looked at our failure reports for these, the PSU is not a super common failure point. These supplies also can handle a pretty broad range of mains inputs, but I'm not sure we've tested it at "285V for a few hours."I'll see if there's anything I can do about getting these PSUs orderable, but I suspect your component swap will do the job.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: November 08, 2018, 08:13:09 pm
content: Something I like about the R&S scopes is you can buy the exact replacement PSU from Digikey!

author: Dwaine
author_rank: Frequent Contributor
timestamp: November 08, 2018, 11:31:42 pm
content: I have my test equipment hooked to these plugs. Hospital grade...

author: wraper
author_rank: Unknown
timestamp: November 09, 2018, 12:40:21 am
content: Quote from: shodan@micron on November 09, 2018, 12:17:25 amGOST and reality at some places is different. I measured it with multimeter after wondering why 230V motors in certain devices overheat and eventually fail. And it was in the middle of the city, not somewhere in rural area where you would expect it the most.

author: wraper
author_rank: Unknown
timestamp: November 09, 2018, 01:05:51 am
content: Quote from: shodan@micron on November 09, 2018, 01:00:22 amGood for you. If all is so nice and dandy and you are certain about voltage supplied to you, why would you use uzm to begin with? I did not say that your PSU particularly died because of any external problems. BTW I've repaired some super expensive 2kW server PSUs, sometimes they fail too, so what?

author: LapTop006
author_rank: Unknown
timestamp: November 09, 2018, 08:26:36 am
content: Quote from: mikeselectricstuff on November 08, 2018, 08:13:09 pmThat's great when it happens.It's even better if you remember to check this *before* you do a heap of visible, non-reversable mods to nice high-end audio production equipment to mod in a new supply, only to find the exact part number still available from Digikey for $30.

author: HighVoltage
author_rank: Super Contributor
timestamp: November 09, 2018, 10:07:51 am
content: I had a PSU fail on an Agilent MSO7034B, that was also not much used, it seemed.Although I bought it used and do not know the entire history.At least they are easy to repair.https://www.eevblog.com/forum/repair/keysight-mso7034b-teardown-and-repair/So far the repair has worked out and in 2 years since then, I had no problems.

author: rf-loop
author_rank: Super Contributor
timestamp: November 09, 2018, 11:05:07 am
content: Quote from: Hydrawerk on November 07, 2018, 10:49:41 amOver 6 years I have not seenanyblown Siglent PSU in any Siglent equipment what I have handled and what I know and I know quite lot of them. Least I know quite soon if any of them fails. But up to this day, nada.But I have seen lot of HP-Agilent equipments failed PSU's (some of them are really total junk quality, made by some third party as cheap as can... perhaps in some american car-garage "factory" or in some poor undeveloped D level country "all can do" factory, pants, shoes and PSU's or what ever) But yes, I have seen also HP-Agilent high quality ones of course.

author: nctnico
author_rank: Super Contributor
timestamp: November 09, 2018, 09:56:46 pm
content: Still I'm pretty sure HP/Agilent/Keysight is selling 100 maybe 1000 times more products compared to Siglent so statistically it makes no sense to compare. Especially based on anecdotal 'evidence'.