Recent Posts

1

Beginners / Amphenol GT series connector - help with rewiring

« Last post by tohtorizorro on Today at 05:06:36 pm »

Hi!

I was asked to make a cable between a mixing desk and its external PSU. The owner of the desk wants to locate the PSU +10m away due to fan noise and the current cable is only about 3m long. According to him the manufacturer would charge nearly 5k€ for a 15m replacement so I thought yeah, I might be able to do it just a smidge below that 

The cable has Amphenol GT series connectors. Probably due to their wide customizability, they are not kept in stock and have a factory lead time of 16 weeks. Changing the connector type isn’t really an option either since I doubt the owner would allow it and it would probably be a lot of work at the desk end. So, preferably I'd be able make do with the connectors on the original cable.

It took me a good while to figure out how to even screw the shell open and now I would really like some encouragement before I start to mess more with it.

Here are the instructions I found for soldered connectors: (page 51 on this PDF)

• Slide the rear accessories over the wire bundle in the proper sequence for re-assembly:
  cable clamp and/or endbell first, then ferrule and (if used) coupling nut.
• Insert individual wires through the proper holes in the grommet.
• Solder wires to appropriate contacts on the rear of the connector
• Fixture the connector for reassembly using the endbell assembly tools
• Slide the grommet down the wires
• Slide coupling nut, ferrule and endbell accessories over rear of the connector and tighten.

So, it sounds like the pins are fixed to the connector (as opposed to crimped ones which are inserted and extracted with a special tool) or are they meant to be replaced before soldering the new wires?

If they are fixed, can I just remove the old wires, clean the contacts and resolder new wires in a similar fashion as with XLR/Socapex connectors?

That would be great!

2

Other Equipment & Products / Re: Dymo 550 Thermal Printer DRM Hacking

« Last post by js_12345678_55AA on Today at 05:06:05 pm »

Tested all 12 of em. All of them are still in memory.

Btw, there are 2 typos in slix2_tag_emu 11. Missing a couple commas. Not that it matters to this case.

I have added 5 more SLIX2 UIDs and their signatures for testing.
If we're lucky, DMO will only remember the last 16.

@RethoricalCheese: Could you please test them as well?


In case DMO remembers more than 16, well, then...

*W*E*L*C*O*M*E* *T*O* *R*O*U*N*D* *2*

Challenge accepted DMO!

I just read a very nice write up the other day about breaking STM32 RDP level 2 and level 1 protection:

https://sec-consult.com/blog/detail/secglitcher-part-1-reproducible-voltage-glitching-on-stm32-microcontrollers/

As luck would have it, I have a ChipWhisperer lying around 

So stay tuned.

JS

3

General Technical Chat / Re: Is LinkedIn worth keeping?

« Last post by floobydust on Today at 05:05:09 pm »

LinkedIn china shut down recently, August 2023, cut 716 jobs. Microsoft seems to have put their LinkedIn effort into china - the social media function was banned in 2016. Several years and dollars wasted on the InCareer app.
Fixing LinkedIn in the West, can't see it happening. I found "LinkedIn Mastermind Club is an AI-integrated online community portal for professionals to learn and connect." Sounds super creepy. Who needs HR when the AI can do it lol.

Look at Google+ crash and burned, you have a couple trillion $ market cap yet are totally impotent. Why?
Mega corporations can't do it. They aren't in it to make it good or to better society - it's about their hidden agenda towards data mining private information, all in the name of "advertising". Or maybe it's social control, influencing voters - who knows. Lemmings do not jump off the ice pack!

4

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

« Last post by shapirus on Today at 05:03:20 pm »

It sounds a little bit comical indeed when a 200 MHz instrument is demanded to “see” a 500 MHz signal. But yes, if you don’t care for the true amplitude – why not?

For the screenshot below, a 1.6 Vpp signal has been used, i.e. it fills the screen height at lower frequencies such as 100 MHz.

Some conclusions from this screenshot:

- the SDS800X HD can also be modded (provided that the input low-pass filter is a hardware one) to make one of the channels special, dedicated for high-frequency signals;
- the frequency counter does not fail at this out-of-spec frequency, unlike the Rigol's, so such a mod would be more useful than with the Rigol;
- it can perhaps go way above 500 MHz and still show a proper signal (save for the true amplitude, obviously), I would speculate that it can do at least 800 MHz. @Performa01 would you be willing to verify that, if you have a signal source that can go that high?

5

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

« Last post by gf on Today at 05:02:05 pm »

Agreed. In addition I'd like to add that sin x / x reconstruction (which is a relatively simple filter to implement) can reconstruct a sine wave little over  fs / 2.5  (0.4 * fs).

Well, there is no such thing as THE sin(x)/x interpolation. In order to make sin(x)/x practically usable, it must be truncated and windowed. And both the truncation length and the window function are still variables which determine the reconstruction limit of the resulting filter. I agree of course that 2.5 can be considered a common value.

6

Power/Renewable Energy/EV's / TPS61021A boost regulator can't handle 50mA

« Last post by hlab on Today at 04:59:43 pm »

Hello all,

I'm in need of some pointers for a problem I have with a TPS61021A boost circuit. I've designed a small GPS tracker device that is supposed to run from a single AA battery. The boost circuit is supplies a 3.3V LDO with 3.6V, with a maximum draw of 150mA. Without the GPS unpowered, the entire circuit draws around 25mA, and the boost converter has no problem operating all the way down to 0.5V as the datasheet indicates, with around 80% efficiency at this voltage. But as soon as I connect the GPS module (which is using 25-30mA), the efficiency drops off a cliff. At 2.0V, the input current is 1A. If I decrease the input voltage further to 1.5V, input current quickly rises to 3A (which is the internal current limit) and output voltage falls out of regulation. L1 is BDHE002016101R0MQ1 1uH inductor from Pulse Electronics, with a saturation current of 3.6A. C1, C2, and C3 are CL21A476MQYNNNE, with an effective capacitance of 18.8uF at 3.6V. The output voltage of the boost converter is spot on 3.6V, so I can rule out the resistor divider being incorrect. One point that may or may not be relevant is that when I supply 3.6V on Vout with the the boost converter disabled, I get ~2V at Vin. The datasheet seems to indicate this shouldn't be happening due to the 'True output disconnect' feature.

Troubleshooting I've done so far

• My first thought was the inductor was saturating for some reason, so I put an identical inductor in parallel with L1, but the efficiency numbers were the same.
• I forgot to add the feedforward capacitor to the current design, but I haven't experienced any instability issues. Just to rule this out, I've added a 10pF cap in parallel with R2, but I didn't see any difference in efficiency.
• I tried adding/removing output capacitance, still no effect.
• At higher input voltages like 3.0V, I'm seeing the expected 2MHz switching frequency on the scope, and nothing stands out as unusual. Tonight I will collect more datapoints with the scope.
• All of these findings have been replicated on multiple units, so I don't think faulty components are to blame.

At this point, I'm starting to wonder if there's a problem with the layout, given the relatively high switching frequency of 2MHz. The chip's ground pad extends on the same layer to the input and output caps. There's also an uninterrupted ground plane under the whole circuit. I tried to minimize the switching loop size, but maybe there's something I missed.

Any suggestions from power supply gurus out there?

Best Regards,
Caleb

7

Test Equipment / Re: Magnova oscilloscope

« Last post by nctnico on Today at 04:58:42 pm »

They said it is passively cooled.
Rotating it 180 probably isn't a problem, 90° probably is.

No. From the description: Therefore a fan is unnecessary in normal operation and the Magnova can run silently. This clearly says the Magnova oscilloscope does have a fan. Just that is may not be on all the time depending on use & environment temperature.

8

Test Equipment / Re: SDS800X HD Wanted Features

« Last post by Martin72 on Today at 04:57:29 pm »

As I've written here before, this is a Christmas wish list.
You write all sorts of things on it, in the knowledge that not all of them can and will happen.
Most of the time and for most people.
I really hope that nobody actually believes that the Siglent development team will sit down, leave everything else behind and work through the lists.
For a device with a starting price of 359€....
If a few things are realized here, then this is a pure service to the customer, a goodwill in the truest sense of the word and we can then be happy about it, because these are free enrichments.
But I've also had to read here before, yes, a lot should be done in 6-12 months.
You don't know what to say about that either...
Super cheap, super quality, must be able to do everything and have everything.

9

Repair / Re: Laser Level Charger PCB ID

« Last post by Shaky on Today at 04:50:33 pm »

You could have a battery pack with "memory", meaning  they could show some voltage  but wont charge if everything is okay ...

I didn't realise Li-ion suffered from the memory effect ! Thought that was just NiCd + NiMH, you learn summat new everyday - cheers. 

10

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

« Last post by Antonio90 on Today at 04:48:48 pm »

You guys are making me jealous
Gotta grab the dremel and drill my new Ryzen. I might be able to measure 5GHz somewhere around the die with my brand new passive probes.