Recent Posts

1

Beginners / Re: Comparator problem

« Last post by elki on Today at 12:51:45 pm »

Further investigations revealed that indeed the voltage goes above 3V on the input pin of the comparator, however, the initial pulse is below 1.5V. Looks like comparator drives it to the rail. Adding a 1k resistor to the supply rail fixes the problem at the cost of reducing the comparator output to about 1V. Not ideal.

2

Repair / Re: Rohde Schwarz CMU200

« Last post by ON4GN on Today at 12:43:44 pm »

I checked the voltages again and they are all normal.
But I tested without the CMU-B68 and I can use the CMU200 as a spectrum analyser and the RF generator is OK.
That is actualy all I need.

3

Beginners / Re: Arduino Nano V3 and LCD 128x64 how to connect them

« Last post by themadhippy on Today at 12:43:43 pm »

Soldering isn't hard.

indeed its not,however adding headers to a nano aint really an ideal starting point,might want to  get a bit of 0.1" stripboard and some extra headers and get your technique dialed in first.

4

Repair / Re: HP54600B with spike problem with and without signal

« Last post by T3sl4co1l on Today at 12:39:35 pm »

I'm guessing it's 2V/div, 5V supply, and the ramps are open bus (with weak pull-ups, but nothing reading during so it doesn't matter).  But this would be a good place to have multiple channels showing the strobe signals.

Another tweak that may be diagnostic: loading the signal (particularly the suspicious pin) with a resistor of say 1k, down to even a couple hundred ohms, pulling to VDD or GND, or with a capacitor of some 10s of pF, and see how much is necessary to cause data corruption.  Most likely, all the other signals will be well-behaved (tolerant down to, say, 200 ohm or so, or up to 30pF or more), and the suspect signal fails with much less (or in the pull-up case, potentially improves).  You will see the effect of these loads on the scope trace.

Tim

5

Beginners / Re: Comparator problem

« Last post by elki on Today at 12:37:24 pm »

The maximum voltage on the input pin does not exceed 1.5V. The issue might be elsewhere. Any other suggestions on how to protect the input signal are welcome.

> however, the same effect of the input signal getting distorted as in the 'biased' version.

Check the voltage on comparator input pin. It should not exceed 3.0V

6

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

« Last post by RethoricalCheese on Today at 12:35:30 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.

7

Repair / Re: TEK 475A VOLTS/DIV compensation problem

« Last post by fabio.deangelis on Today at 12:33:19 pm »

Thanks for your suggestion, that was my first corrective action I disassembled the rotary attenuators and thoroughly cleaned each contact with isopropyl alcohol and paper strips as advice here on this forum. Thus, the prime suspected are still the attenuator switches ? Any other areas ?

8

General Technical Chat / Re: Need 13Amp variac device to 'modulate' a water boiler.

« Last post by themadhippy on Today at 12:32:14 pm »

One more thing to consider: rapid cooling after the boil - it prevents volatile compound loss and will reduce the time period when the beer can be infected -

or pour it from the boiler straight into a container that can be sealed  air tight and let it cool naturally-aka no chill

9

Power/Renewable Energy/EV's / Re: Hobby BLDC ESC snsor connections

« Last post by langwadt on Today at 12:31:29 pm »

I'd expect the red-white-black to be for the RC-servo like pwm signal to control the ESC

You're right, it does look just like a RC servo pwm cable. But that makes no sense on a BLDC controller (unless it's used to control speed, not position).

plenty of bldc controllers with rc servo pwm interface for controlling speed

10

Microcontrollers / Re: difference between LwIP's Raw API and Socket API?

« Last post by peter-h on Today at 12:29:46 pm »

Do a search here on LWIP. Some great posts in the past, especially from a guy called dare. I also asked a load of questions

LWIP is poorly documented and the few people who really understand it rarely post in forums.