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2D72 incorrect reading

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Post time 2024-3-25 17:48:07 | Show all posts |Read mode

Hi everyone,


recently I discovered that my 2d72 device provides incorrect readings (DMM mode) for alternating voltages. Instead of reading 220VAC on a household outlet, it reads a voltage of 380-400VAC (verified with another instrument). I also noticed that it gives inaccurate readings for resistances and electrolytic capacitors (which it doesn't read at all). The oscilloscope and function generator are working correctly. The current firmware version is 2021090901 FPGA: V07. Do you have any suggestions?


Marco

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 Author| Post time 2024-3-29 01:03:51 | Show all posts

I tried to reload the firmware downloaded directly from Hantek, but nothing changed (I also tried the previous firmware). Since customer support refuses to provide assistance as it wasn't purchased through official channels (bought on AliExpress in 2020), this weekend, as suggested in other threads, I'll try to disassemble it and check the components around the CS7721CN chip. Hopefully, it's not the chip the issue...

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 Author| Post time 7 day(s) ago | Show all posts
Edited by Marco67 at 2024-4-8 18:06

Although it may not seem to be of interest, I'll provide an update on the repair. I hope it can be useful for others.
As observed with others, the section near the chip has two resistors completely burned, R14 and R15, while a third, R16, is blackened but the value seems to be correct at 46.4K. I'll now proceed to order the replacement parts, including R16. I'll keep you updated. Thank you all.


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Post time 6 day(s) ago | Show all posts
Marco67 replied at 2024-4-8 18:04
Although it may not seem to be of interest, I'll provide an update on the repair. I hope it can be u ...

Thanks for your information.

R14:  10K,0.1% 0603           

R15:  1K,0.1% 0603           

R16:  46.4K ,1% 0603

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