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What are the causes of this situation (image inside)?

PostPosted: Wed Oct 09, 2019 7:27 am
by batareika
Good health to all!
When checking the voltage at the test points (see table), it turned out that the alternating voltage was 2 times higher than normal (resistors R13, R 14, R 15 are normal).
What can cause this phenomenon, is it dangerous to start the oscilloscope?
Thank.

Image

Re: What are the causes of this situation (image inside)?

PostPosted: Mon Nov 04, 2019 9:42 am
by batareika
When I try to turn on the test signal appears (and disappears) the inscription "Doing VPos aligment..."

Re: What are the causes of this situation (image inside)?

PostPosted: Mon Nov 04, 2019 11:08 am
by phoeny
check R22, V4 is ADCIN which is held to 1.65V by R21 and R22. With the analog board disconnected ADCIN on the Digitalboard should be 1.65V,
if it is your problem is with the analog board, if not its the digital board


I used this schematic
https://jyetech.com/wp-content/uploads/ ... analog.pdf

Re: What are the causes of this situation (image inside)?

PostPosted: Mon Nov 11, 2019 2:52 pm
by batareika
phoeny wrote:check R22, V4 is ADCIN which is held to 1.65V by R21 and R22. With the analog board disconnected ADCIN on the Digitalboard should be 1.65V,
if it is your problem is with the analog board, if not its the digital board


I used this schematic
https://jyetech.com/wp-content/uploads/ ... analog.pdf


In my version of the analog board, the R22 resistor (and this whole cascade) is missing.