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Metrology / Re: ESI RV622A Resistor Repair
« Last post by gmilliorn on Today at 01:23:49 am »Hmm, I was basing the adjustment comment on this info in the RV722 manual:
Perhaps they changed over the years...
Perhaps they changed over the years...
3
Test Equipment / Re: Choosing between entry-level 12-bit DSOs
« Last post by KungFuJosh on Today at 01:23:21 am »What's your opinion between the two again? 😉
We're only 31 pages into the discussion--it's too early for conclusions.
Only 16 pages into the discussion with my settings. 😉
We've got to be at least half way there, then Martin can share what he already knows. 🤣
4
Projects, Designs, and Technical Stuff / Re: Brinking Light pattern for maximum attention distance at night
« Last post by CaptDon on Today at 01:22:18 am »Brinking lights only certified for use in Japan, elsewhere specify the blinking light equivalent.
5
Projects, Designs, and Technical Stuff / Re: What is Popular smaller than 0.1 inch pin header and jumper cable
« Last post by CaptDon on Today at 01:15:32 am »Xilinx used the 2mm headers before they were common. 2mm stuff on the platform programmer and then an adapter with standard .1" header pins. To say I hate Xilinx and their whacko ideas including their huge platform cable unsupported drivers screwup when functioning Win7 systems were upgraded to Win10 and suddenly the older ISE stuff could no longer find the platform cable, coupled with the newer Shitvado that works with Win10 but no longer supports the older Xilinx devices (We have 1000's of in warranty boards in the field with the older parts) are just a few of the reasons we stopped 'designing in' Xilinx products! A lot of stuff today does use 2mm headers and are commonly available in many configurations.
6
EEVblog Specific / What's the keywords for finding a yellow spudger like Dave has?
« Last post by ballsystemlord on Today at 01:10:00 am »Hello,
I tried searching on ebay and aliexpress, but I can't seem to figure out what the correct keywords are. I'd like a set of 10 identical ones if possible.
What I have found are blue and orange ones. Yuck, it must be yellow!
Thanks!
I tried searching on ebay and aliexpress, but I can't seem to figure out what the correct keywords are. I'd like a set of 10 identical ones if possible.
What I have found are blue and orange ones. Yuck, it must be yellow!
Thanks!
7
Beginners / 5V buck converter debugging
« Last post by davegravy on Today at 01:06:05 am »I assembled a 12-to-5V buck converter from an LM64460-Q1 (datasheet) and I'm not getting any output. Schematics and board layout are attached. Here was my process and observations for testing the board:
* I slowly ramped the input voltage up with no load connected and noticed no current draw until 4V at which ~50mA started to flow. At around 6 or 7V the current spiked to 1A for a few seconds and then dropped to 6mA when I reached 12V. At this point I checked the output voltage which was only ~1.2V but was very slowly rising.
* I removed supply to Vin, briefly shorted the output terminals just to discharge the output caps, and reconnected 12V input. Now I have 0V output and that's all she wrote.
I checked all the other pins and other than the Vin1 and Vin2 pins and EN, all are 0V (including VCC which is nominally a 3.3V LDO output). I desoldered the chip and found the SW1, SW2, and SW3 pins shorted to GND, so the chip seems cooked. I guess I should have pulled the plug before I got to 1A draw.
Before I solder a new chip, is there something wrong with my design that one would expect to fail like this?
Before powering I did check for shorts but I'm not sure how to test for unconnected pins... doesn't seem likely that an unconnected pin would cause failure like this however.
* I slowly ramped the input voltage up with no load connected and noticed no current draw until 4V at which ~50mA started to flow. At around 6 or 7V the current spiked to 1A for a few seconds and then dropped to 6mA when I reached 12V. At this point I checked the output voltage which was only ~1.2V but was very slowly rising.
* I removed supply to Vin, briefly shorted the output terminals just to discharge the output caps, and reconnected 12V input. Now I have 0V output and that's all she wrote.
I checked all the other pins and other than the Vin1 and Vin2 pins and EN, all are 0V (including VCC which is nominally a 3.3V LDO output). I desoldered the chip and found the SW1, SW2, and SW3 pins shorted to GND, so the chip seems cooked. I guess I should have pulled the plug before I got to 1A draw.
Before I solder a new chip, is there something wrong with my design that one would expect to fail like this?
Before powering I did check for shorts but I'm not sure how to test for unconnected pins... doesn't seem likely that an unconnected pin would cause failure like this however.
8
Repair / Re: IWATSU oscilloscope Cal signal square wave showing as ramped / curved signal
« Last post by Michelle on Today at 01:04:28 am »It's a Lecroy 350mhz 10:1 10Mohm 14pf probe (yes I tried adjusting the screw, changing it from what is pictured makes the sweep worse) hooked up to the oscilloscope's CAL tab, with the scope set to the settings the user manual suggests for calibration. It is supposed to be a square wave. I have calibrated an oscilloscope before and understand how it is supposed to work and look.
The oscilloscope is an Iwatsu 5705, I believe, and didn't come with any probes; this is just a probe I had. I was told the oscilloscope used to work but it has been sitting for a few years and been moved a couple times. I don't know the spec on the original probe besides I believe it's 10Mohm , I just assumed this one would work.
https://probemaster.com/4900-oscilloscope-probe-basic-kit-150-300-mhz/
This (4901-2) is supposed to be a compatible probe to the original iwatsu ss-0060; it's not clear to me how different this is than the lecroy PP002 I tried is.
And yes the probe works fine on another oscilloscope give me a break here guys...
The oscilloscope is an Iwatsu 5705, I believe, and didn't come with any probes; this is just a probe I had. I was told the oscilloscope used to work but it has been sitting for a few years and been moved a couple times. I don't know the spec on the original probe besides I believe it's 10Mohm , I just assumed this one would work.
https://probemaster.com/4900-oscilloscope-probe-basic-kit-150-300-mhz/
This (4901-2) is supposed to be a compatible probe to the original iwatsu ss-0060; it's not clear to me how different this is than the lecroy PP002 I tried is.
And yes the probe works fine on another oscilloscope give me a break here guys...
9
Repair / Re: Tablet does not power on, how to check battery & charge circuit?
« Last post by sleemanj on Today at 01:02:25 am »Disconnect battery, get a TP4056 charger, connect battery to charger, connect USB to charger, charge battery fully, then try again.
10
Other Equipment & Products / Re: PCBite is a brilliant oscilloscope probe holder
« Last post by quince on Today at 01:00:11 am »I've seen these in a new lab. Not really sure what the appeal is. Someone kicking the table is likely to dislodge any one of the probes. A soldered wire would never come off under minor vibration.