Recent Posts

1

Security / Re: Microsoft repackages apps with a telemetry .NET wrapper

« Last post by RoGeorge on Today at 01:32:10 pm »

This is not a surprise from them, remember the keylogger from Microsoft, part of the Windows 10?
https://www.pcworld.com/article/423165/how-to-turn-off-windows-10s-keylogger-yes-it-still-has-one.html

It was all official, a keylogger and more (speech input spyware) inside Windows, for telemetry and such, and you were agreeing with that in the EULA.  With reassurements that the collected data is anonymous and for your own good, of course.  So, not for spying, only to give you a "better experience" in the future. 

2

Repair / Re: Nichicon Electrolytic Capacitors leaking - common problem? ( Rifa X and Y also)

« Last post by Zenith on Today at 01:28:03 pm »

Im in the middle of recapping the P/S on an HP 8080A. Found all the rifas but still something wrong... test pins at the p/s are all reading correctly (A = 11.8v,  B = 5v ~ 1.8v saw, etc.) but nothing at the multicon. Hoping someone has a schematic or a link.
THx!

Almost all HP manuals are easily available on the WWW. I'd be surprised if this wasn't.

If you are very unlucky it will be a PSU HP bought in from another company, and the schematic isn't available.

3

Test Equipment / Re: SDS800X HD - Issue disscusions - is it me, or the scope?

« Last post by eTobey on Today at 01:19:26 pm »

New issue:
Wrong measurement:
X2 of the measurement should be, where the arrow points to (last rising edge). When i move gate "B" just a tiny bit to the left, then the measurement is rendered invalid. The measurement is also rendered invalid, if i put the upper level of C3 above high level of C4 (slightly under it).

To me it looks like a bug.

4

Projects, Designs, and Technical Stuff / Re: Vacuum Fluorescent Display Driver

« Last post by bostonman on Today at 01:17:15 pm »

I'll check with a scope.

I read that thread. personally I'd like the path of bench testing the VFD solo as a second step rather than risk damaging it (assuming it's not the culprit).

Since the fourth and fifth digit work sporadically, my assumption is: this isn't a short in the VFD. Before it seemed the fourth and fifth digit was failing around >15MHz, but then it began working correctly. Sometimes the display would show the frequency in ten or maybe eleven digits, other times the full twelve; but it was always the correct frequency (ignoring the in correct decimal and comma locations - at least I remember/believe they were wrong).

The only consistent error is the 12th digit segment C (?) remaining illuminated. Maybe periods/commas, but I believe those shift too.

5

Test Equipment / Re: Micsig Current Probe CP2100A/B Tests and Comparing

« Last post by ceut on Today at 01:16:26 pm »

I have made a little battery module for it, with a very lowcost powerbank module MH-CD42 and a switch+capacitor at the output: it works great 

Also, some last tests I have made with my Keysight DMM  (U1233A)

As the Keysight DMM have many hidden settings, I have activated the "Scale" mode with x10 attenuator=>so it shows the good reading with the Micsig on the input 
(The bargraph shows the real input voltage, and the "Scale" mode convert it on the main display, with the scale we choose in the settings)
No need to think at all

All with my RD600P PSU short cutted, and "0" done before the first mesurement.
I have to say that this Micsig is really super accurate 

6

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by hans on Today at 01:15:44 pm »

Okay then, so probably my best bet is to ignore the feed, InMail spam (you can turn that off), don't add recruiters as contacts, and only log on when I need something done.

I've now hibernated my account to see if I will use it in the future. I'm actually going to jobhunt within now and a year probably, so lets see if I can do it without.. That would be final nail for me, as my gut feeling is still to get rid of it but only if that's to no (real) disadvantage

7

Projects, Designs, and Technical Stuff / Re: more modern version of tl494?

« Last post by coromonadalix on Today at 01:12:07 pm »

even at 1kw   ...  lots of things are involved    input stages,  PFC  if there is,  main power section ...

not a project for beginner   

8

Beginners / Re: New multimeter, is the thermometer good or better standalone?

« Last post by BILLPOD on Today at 01:11:33 pm »

Hi, I'm going to buy a new multimeter because I want a few more things (like capacitance measurement). These multimeters have very few differences and one of them is the temperature measurement, the UT890C+ and UT89X has it while the UT890D+ and UT89XD doesn’t.
Thank you

The UT890D+ does not do temperature,......Isn't temperature measurement what you were originally seeking

9

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

« Last post by gf on Today at 01:11:10 pm »

yes 2.5 is not derived from theory, its probably from empirical testing of imperfect sampling mechanism (presence of jitter/harmonics/hi-freq more than nyquist limit)...

It is primarily a compromise with the computational complexity of the interpolation filter (and consequently, the number of extra samples which need to be acquired in order that the settling phase of the filter can be discarded). For example, the frequency response of a sinc function, truncated to a length of 20 sample intervals, and then windowed with a Kaiser window, happens to start rolling off at approx. 0.4 * sample_rate (or sample_rate / 2.5), see figure3.

10

Projects, Designs, and Technical Stuff / Re: Small and inexpensive direct thermal printer to print labels

« Last post by tooki on Today at 01:09:44 pm »

I believe the brother label printers (usually USB, thermal, a wide variety of cheap clone labels available) are supported by drivers within the CUPS printer control system in Linux.

They probably are, but for inventory labels like this, where it’s likely that bar codes are involved, you don’t want to print using regular OS print drivers, you instead want to use the printer’s own command language to ensure that bar codes are printed perfectly sharp.

Receipt printers intended for integration in POS terminals used to be primarily from Epson and had parallel or serial interfaces.

Epson and Star Micronics are the two heavyweights in that market.