No trace
Re: No trace
Exactly, no change on the display. But the the signal change all way to cpu. 3 level, high, medium and low. As it should if you look at the R23 output. CPLSEL input 15 at U1. Display can change sometimes with power reset or factory reset. But it change random, not by SWA1 position.
Re: No trace
One more idea: check VDDA ( analog power ), better directly at pin 9 of CPU. May be bad soldering, defective PCB ( lines or holes ), defective elements, etc...
Re: No trace
It is very hot in 1117 stabilizer. And Stm32.
Earlier I wrote that they are cold. I was wrong.
Faulty chip?
Measure the resistance between SENSEL0 and GND? . Analog board is disabled.
Earlier I wrote that they are cold. I was wrong.
Faulty chip?
Measure the resistance between SENSEL0 and GND? . Analog board is disabled.
Sorry for bad english. I use Google translator.
Re: No trace
Or measure the cplsel, 3V at AC, 1.5V at DC and low at GND, from the pin 15 chip U1.
Re: No trace
It looks like STM32 was hit by ripple of voltage, and something inside it ( protective diodes at one or more pins ? ) shorted.DanilinSA wrote:It is very hot in 1117 stabilizer. And Stm32.
Earlier I wrote that they are cold. I was wrong.
Faulty chip?
And may be it getting worse with time...
I had the same situation - "7.5V" label at power supply, and I believed... As a result - STM32 and 1117 are absolutely shorted ( and I was lucky - display is not damaged ). I had to change my prosessor and 1117, reflash, and now it work. Power - from computer USB. I will add 78M09, filter capacitors ( 100uF at 3.3v line ) and Zener diodes to avoid that situation in the future...
Re: No trace
Yes a shorted U1 can explain this. Maybe the box should be redesigned so av 9V battery fits inside. Cheap power supply's is just cheap power supply's 
This is what I use.
This is what I use.
- Attachments
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Re: No trace
Ping SENSEL0 (PA1) shorted to ground. If you switch the gain - in conditions when SENSEL0 1 = strongly heated chip and a stabilizer.
Probably faulty chip. I try to lift the leg to check individual tracks and output.
Probably in the manufacture of payment has not been tested.
Probably faulty chip. I try to lift the leg to check individual tracks and output.
Probably in the manufacture of payment has not been tested.
Sorry for bad english. I use Google translator.
Re: No trace
Look for my post. Helped me a replacement and programming STM. Damaged by bad plugged the analog. Symptom identical. No reaction AC, DC, GND. Show only a horizontal line.
Re: No trace
Bad. Many marriage.
And the company says it is on this occasion?
Free replacement of a defective product is not made?
And the company says it is on this occasion?
Free replacement of a defective product is not made?
Sorry for bad english. I use Google translator.
Re: No trace
Well I bought a Dso138 and solder it and it did function from beginning. So I put the shell in garbage as I do with junk.
Maybe I will buy an other one, like the size. I use it for car repair, oxygen sensor, wheel sensors and other stuff.
I bought a Dso138 and solder it and it did function from beginning. So I put the shell in garbage as I do with junk.Maybe I will buy an other one, like the size. I use it for car repair, oxygen sensor, wheel sensors and other stuff.