Recent Posts

91

Test Equipment / Re: SDS800X HD Bug Reports + Firmware

« Last post by electronics hobbyist on Today at 12:52:14 am »

The setting of the trigger type edge influences the qualified trigger. In the first part of the video the trigger is not exactly stable, only if the slope of edge trigger is changed, the qualified triggers works without issues.

These two issues look the same and have been added to Bug No.14.

https://www.eevblog.com/forum/testgear/sds800x-hd-featureimprovment-disscusions/msg5459225/#msg5459225

92

Beginners / Re: Replacing SRAM IC with Flash

« Last post by Nominal Animal on Today at 12:48:28 am »

How about using 512k×8 low-power SRAM like CY62148ESL-55ZAXI, and controlling the four highest address bits (A15, A16, A17, A18) with a 16-position absolute encoder and four pull-up resistors?  With a pull-up on /CE, the stand-by current draw is just 2.5µA typical, max. 7µA, and voltage can be 2.2V–3.6V or 4.5V–5.5V.  That is, you can use 2.2V – 3.6V battery backup voltage.   Since LH52256C/CH uses 5V logic, the battery vs. normal operation voltage selection should be easy (higher voltage wins).

You'd get sixteen banks in a single pak, selectable using an absolute rotary encoder.

93

Beginners / Re: CR6842S ACDC HELP

« Last post by floobydust on Today at 12:44:49 am »

If current-sense resistor R7 goes open, this is usually because it's a fusible/flameproof part that got overloaded from a mosfet shorting out. It damages the IC and new mosfet if you are not careful to check those parts too.
A dim light-bulb tester to power this is also a good idea to save on fuses and smoke. Even a 25W lamp is all you need to power it up with no load.

94

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.

95

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!?

Note:  Looks like they have their own store:
https://nblebright.com/collections/x2-cbb61-capacitor-plastic-box

96

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.

97

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.

98

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 !

99

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."

100

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.