Recent Posts

91

Beginners / Re: Looking for a SMD version of a U2008B

« Last post by Nominal Animal on Today at 12:20:25 am »

So, the part numbers are U2008B-MFP, U2008B-MFPY, U2008B-MFPG3, U2008B-MFPG3Y, I belive?  It looks like Atmel manufactured these in Heilbronn till 2008, with Telefunken Semiconductors GmbH & Co. KG continuing the manufacturing 2009-2012; so there might be both "ATMEL" and "TFK" branded genuine SOIC-8 ICs out there.

Aside from eBay/AliExpress, rxelectronics.com, good-chips.com, veswin.com, depu.net all claim to have new old Atmel/Microchip ones in stock, but you'd need to request a quote.

92

Manufacturing & Assembly / Re: Source for small "potting boxes"??.....

« Last post by thm_w on Today at 12:13:32 am »

Searching for potting module case or similar.

They call it "CBB61" which looks like its used for motor capacitors as well, various products.
Can always try to work back from the end product and ask the manufacturer if they are willing to share who they buy the cases from. Depending on how friendly they are.

93

Manufacturing & Assembly / Re: Source for small "potting boxes"??.....

« Last post by Smokey on Today at 12:09:46 am »

It will probably be epoxy. No release.  The potting box becomes the outside of the thing.

94

Manufacturing & Assembly / Re: Source for small "potting boxes"??.....

« Last post by floobydust on Today at 12:06:29 am »

Hammond Plastic Potting Boxes 1596 Series
OT I don't know what mould release to use for silicone, if that's the potting compound.

95

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by awakephd on Today at 12:01:14 am »

At least part of what you're talking about are modifications that bring some of the features that can simply be unlocked on the relevant Siglent being discussed in this thread.

The other part would be customizations to the UI.

Which features in particular? I ask out of ignorance, since I have yet to get my hands on even a basic DSO.

Are there features on the Rigol that are not on the Siglent, or which would have to be hacked to get on the Siglent? I have gained the impression that the Rigol might have more ability to create side-by-side windows showing different but related data ... ? If that is true - and please forgive my ignorance if it is not! - I'm not sure how useful that is in practice. Again, I plead ignorance - but I do feel a bit less ignorant as a result of the many helpful replies on this thread.

96

Beginners / Re: First PCB - how does it look?

« Last post by ataradov on Yesterday at 11:47:45 pm »

There is no ground pour. All your components are just hanging in the air. EDIT: I see your comment about the ground. Well, the ground is basically the most important part with voltage regulators and similar power-related devices.
 
Instead of those pointlessly thick traces, move capacitors as close to the IC pins as possible.

The datasheet has recommended PCB layout. Yours is not even close.

97

General Technical Chat / Re: new propellantless drive company

« Last post by m98 on Yesterday at 11:45:33 pm »

The physics sound whacky, and I can say that nobody in the EP community is taking any of this seriously. That said, I'm looking forward to Martin Tajmar getting bored again and trying this out.

98

Test Equipment / HP 16700 PSU in 230V region woes

« Last post by FrodeM on Yesterday at 11:45:06 pm »

Have anyone here experienced problems with the power-supply of the HP 16700 logic analyzer blowing up when running in 230V regions? I am in particular thinking of the Celestica 7000 variety, which does claim to handle 230V just fine but I have had two blow on me so far.

The first time it was the switcher for the standby power source. An all-in-one TOP227Y switch mode regulator in a single TO-220 package. This blew quite violently, taking out a whole trace on the PCB, some resistors in its path, as well as D7.

For the second one , it was a small 8-pin chip, probably part of the main regulator. Fortunately, not as violently and this far I only found D7 as the only other part that has blown.

Is it just me, or does this PSU have really slim margins?

Some notes on the design. I plan to fix the second one with parts from the first one, and I'm in the process of drawing up a schematics as a consequence. I now see that the main board of the PSU uses a charge-pump type of design, instead of switching a transformer. That explains why D7 is very prone to damage: it's the main boost converter diode. All current driving the unit passes through it, and with 230V mains it is natural that the flyback suges it needs to pass will peak harder.

Does anyone else have similar experience with these supplies?

99

Projects, Designs, and Technical Stuff / Re: Nichicon UPJ for switching power supplies - what's so special about these caps?

« Last post by wraper on Yesterday at 11:43:35 pm »

Then there's "audio grade"...

Ideally suited for first class audio equipment where qualitative and quantitative
comfortableness is required.

https://www.mouser.com/datasheet/2/293/e_ukz-1513448.pdf

Stupid tax grade.

100

Projects, Designs, and Technical Stuff / Re: Nichicon UPJ for switching power supplies - what's so special about these caps?

« Last post by bdunham7 on Yesterday at 11:38:31 pm »

Or "automotive" grade is another one, it meets automotive spec (wide temperatures, reliable, etc.) but you can freely use it for other designs.

Then there's "audio grade"...

Ideally suited for first class audio equipment where qualitative and quantitative
comfortableness is required.

https://www.mouser.com/datasheet/2/293/e_ukz-1513448.pdf

So many people love Nichicon for whatever reason, but they had capacitor failures in the plague times just like the cheap brands.  And they have a high degree of market wankery.  They're not my go-to brand at all.