PSU(Low quality?!) on Agilent DSO-X 2022A

[shodan@micron]

void

[nctnico]

A friend told me IRF840 marked by IR logo, but quality of engrave too poor. Right 840 fet is almost unreadable.

If it to be any other oscilloscope brand, i say definitely that is fake fets.

That is hard to judge. For example the fake FTDI FT232 chips look better than the originals.

[umkumiut]

Blowup diode after 4-5 years work on usage 3-5%  - that is hard

This scope doesn't have a hard mains switch, its PSU is always on when it is plugged in.

[Hydrawerk]

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??

[Jan Audio]

Was there an overvoltage in your power grid in Russia??

For expensive equipment and computers you need a special power socket that smooths and protects against overvoltage.
Belkin is a good brand.

[Ice-Tea]

The IRF840 is the original one. IR was acquired by Vishay, so new IR parts bear Vishay Siliconix logo.

Infineon, no?

[wraper]

Was there an overvoltage in your power grid in Russia??

For expensive equipment and computers you need a special power socket that smooths and protects against overvoltage.
Belkin is a good brand.

Those 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.

[wraper]

The IRF840 is the original one. IR was acquired by Vishay, so new IR parts bear Vishay Siliconix logo.

Infineon, no?

Part 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

[wraper]

But when i inspect PSU i found some strange(possible low quality) parts:
- IRF840 from unknown brand.
- 1N5407 - maybe ON semiconductor brand, but i doubt in origin.

However, I ordered diodes 1N5407 and MOSFET's IRF840  from Vishay, i replace all that parts.

Open the datasheet from Vishay and scroll down to the bottom for photos. https://www.vishay.com/docs/91070/sihf840.pdf And why would you doubt the origin? Also on your photos excellent build quality and all Japanese capacitors can be seen.

A friend told me IRF840 marked by IR logo,

Your friend doesn't know how IR logo looks like  .

but quality of engrave too poor. Right 840 fet is almost unreadable.

Clean with alcohol and move the light source to different angle.

[Ice-Tea]

The IRF840 is the original one. IR was acquired by Vishay, so new IR parts bear Vishay Siliconix logo.

Infineon, no?

Part 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

Heh. Didn't know. Pretty sure FETs went to Infineon, tho..

[wraper]

Heh. Didn't know. Pretty sure FETs went to Infineon, tho..

Deal 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.

Vishay Intertechnology, Inc. (NYSE: VSH) today announced that it completed the acquisition of the Power Control Systems business (selected discrete semiconductor and module product lines) from International Rectifier (NYSE: IRF) for $290 million in cash. During the December quarter 2006 the revenues for the acquired product lines were $81 million for an annual run rate of about $320 million.

[mikeselectricstuff]

Was there an overvoltage in your power grid in Russia??

For expensive equipment and computers you need a special power socket that smooths and protects against overvoltage.
Belkin is a good brand.

For expensive equipment, it is reasonable to expect them to have a PSU that isn't so fragile it dies under normal mains transients etc.

[wraper]

For expensive equipment, it is reasonable to expect them to have a PSU that isn't so fragile it dies under normal mains transients etc.

I'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?

[tautech]

This PSU is still better than those found in Siglent .............

How 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/

[Keysight DanielBogdanoff]

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.

[mikeselectricstuff]

Something I like about the R&S scopes is you can buy the exact replacement PSU from Digikey!

[Dwaine]

I have my test equipment hooked to these plugs.  Hospital grade...

[wraper]

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."

Our network is 230V+-10% 50+-0.2Hz - NOT A 285V!
See GOST 29322-2014 (IEC 60038:2009) standarts.

GOST 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.

[wraper]

Dear wraper - you can try troll me more, but i use power line controller UZM-51. I configure it  to comply with GOST standart.

Good 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?

[LapTop006]

Something I like about the R&S scopes is you can buy the exact replacement PSU from Digikey!

That'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.

[HighVoltage]

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.

[rf-loop]

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??

Over 6 years I have not seen any blown 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.

[nctnico]

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'.