Recent Posts

1

Repair / Re: Ksger T12 Sudden Death

« Last post by floobydust on Today at 12:39:26 am »

It badly needs heatsinking. The new part will roast and fail too, guaranteed.
Most controllers use SOT-223 Vregs, SOT-89 is pretty hard to cool with no copper pour on the tab like on this lemon control board. As long as 25Vin is not too much.

Russians some put in big copper wire loop soldered to the tab to make a heatsink, others lowered the input voltage adding a pre-regulator like 7805T+output capacitor by cutting the trace and adding wire jumper from the control board to the added Vreg tacked on the PSU somewhere.

To use just one IC, tack soldering a 7833T sticking up in the air would work.

2

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

« Last post by Smokey on Today at 12:35:03 am »

I think this guy is the winner:
https://www.alibaba.com/product-detail/Negative-ion-Generator-Modules-Plastic-Housing_1601044289977.html



The pricing is a little screwy though.  At $0.15 each, and 1000MOQ, that's $150 worth of product.  But they also list $3404.15 for shipping!?

3

Programming / Re: Linux Dependency Black Hole

« Last post by ataradov on Today at 12:34:26 am »

The user who built from tar.gz would not have dependency version problems.

This is not correct in general. There is no common way to define dependencies in tar.gz outside of autotools stuff, which rarely covers everything. It is mostly just basic checks.

You will have all sorts of issue if you build stuff from the source and let it be installed in your system outside of the package manager.

So we may be better, if having a big dependency mismatch,  to build from tar.gz rather than trying to use the .rpm .deb etc packages.

This is the worst idea ever. If I absolutely need to install something from the source, I at the very least specify --prefix=/opt, so it does not mess up the main file system. And then you still rely on package author not being an idiot, which is not a given.

4

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

« Last post by thm_w on Today at 12:28:59 am »

"CBB61" is chinese regulatory code for a type of film capacitors used in motor start and run. Should be a plastic cylinder?
PS Caution going to the only site explaining CBBxx codes, it has malware.

Yeah maybe that is some other classification, or maybe that is what is potted inside, this is the type: https://www.aliexpress.us/item/3256805487741980.html
Most are "single ear" or less though.

5

Programming / Re: Linux Dependency Black Hole

« Last post by mag_therm on Today at 12:28:58 am »

I ran a grep on an application tar.gz to see how the system dependencies are defined.
here is an snippet from the valgrind file  in the tar.gz :

QQ-valgrind.linux.supp:148:   obj:/usr/lib/*/libpulse*
QQ-valgrind.linux.supp:169:   obj:/usr/lib/*/libQt5Gui*
QQ-valgrind.linux.supp:182:   obj:/usr/lib/*/libfontconfig*.so.1.8.0
QQ-valgrind.linux.supp:265:   obj:/usr/lib/*/libfreetype*
QQ-valgrind.linux.supp:272:   obj:*/lib/*/libdbus*
QQ-valgrind.linux.supp:279:   obj:/usr/lib/*/libcairo*

So it seems in the tar.gz, dependency versions are not explicit, and it seems they would be from the whatever system that the tar.gz was made on.
The user who built from tar.gz would not have dependency version problems.

Then opened the .rpm (for Fedora )
Here the files are mostly .bin  and there is a /bin/valgrind on linux.
I don't know if valgrind is run again on user machine  during installation.
I suspect not because we have the dependency version problem.

So we may be better, if having a big dependency mismatch,  to build from tar.gz rather than trying to use the .rpm .deb etc packages.
Can anybody familiar with this comment?
Thanks !

6

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

« Last post by thm_w on Today at 12:24:08 am »

Then there's "audio grade"...

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

lol, 100% marketing in that case. I'm sure someone has figured out what series they are identical to, but they hide info from the datasheet.

Here is the UFG series tagline: "Rich sound in the bass register and clearer high end, most suited for AV equipment."

7

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

« Last post by floobydust on Today at 12:23:40 am »

"CBB61" is chinese regulatory code for a type of film capacitors used in motor start and run. Should be a plastic cylinder?
PS Caution going to the only site explaining CBBxx codes, it has malware.

8

Repair / Re: Motherboard has no power - Clevo W650SC

« Last post by vcolella on Today at 12:21:20 am »

Alright ! Just ordered a rosin short "detector", will try that as well as IPA. Any suggestions on where to inject the voltage ?

9

Metrology / Re: ADR1001 - Ovenized Voltage Reference System

« Last post by floobydust on Today at 12:21:08 am »

Pretty sure the fab is done in Taiwan, hermetic packaging in Philippines. Earthquake and dozens of aftershocks possibly adding a delay.
I will never forgive ADI for shutting down LT Hillview fab in Milpitas CA, which used to make our favorite ref IC's. Longtime proven quality. But it's sadly outsourced now and I would expect issues until the fab pulls it off.

10

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.