Author Topic: OWON SDS7102V - problem with encoders  (Read 588 times)

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Offline mati998

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OWON SDS7102V - problem with encoders
« on: December 12, 2019, 09:33:21 pm »

I have a very big problem with OWON SDS7102. I bought used oscilloscope without any guaranty but in pretty good price. It turned out that there is a strange issue: all of encoders don't work. I checked them using multimeter and they seem to work but there is no response when I turned them. I replaced IC's on keyboard PCB (2x 74hc4051d and 1 x 74hc393) but it didn't help. All buttons, including buttons in encoders works good, so I don't know what is a cause of problem. Could you give me some tips what I shold check becasue I really want to repair it. 

I found the cause - there wasn't resistor R6 10k. I soldered new one and it seams to work. Now I'm going to do more tests. :)
« Last Edit: December 16, 2019, 01:58:42 pm by mati998 »

Offline atferrari

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Re: OWON SDS7102V - problem with encoders
« Reply #1 on: December 16, 2019, 05:04:01 pm »
Hi there

SDS 7102V

Two days ago I noticed that the vertical control of channel 2 is not changing the VOLTS/DIV value in the expected sequence (1 2 5 or reverse). It even skip steps or returns to any possible value following no logic. A nightmare that took me several hours to identify.

Considering the encoder seems to go in mechanical steps, one at a time as expected, I concluded that it could be wrongly working software.

Any suggestions or comments? The local service (not exactly an official one, is not even answering the phone).

Agustín Tomás
In theory, there is no difference between theory and practice. In practice, however, there is.

Offline mati998

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Re: OWON SDS7102V - problem with encoders
« Reply #2 on: December 17, 2019, 08:44:31 pm »

I have to admit that after soldering the resistor R6 everything worked but very, very unstable. I tried to understand what this key PCB works and I mesured signals going to U7, U26, U27. It turned out that on one of encoder (on input) instead of direct current there was very noisy signal (on my old analog scope it looked a bit like square wave). So i added two capacitors 100 nF between first and middle pin and middle and third and all knobs started working! Now i want to add capacitors on each encoder to be sure that it will be working correctely. It is shown there what to should do:
Maybe it will be solution of your problem.
Good luck!

Offline scopeman

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Re: OWON SDS7102V - problem with encoders
« Reply #3 on: December 25, 2019, 11:41:59 pm »
IIRC Owon has a replacement board that is fairly inexpensive for this scope. I think it was something like 20USD a couple of years ago.

Email them and ask.


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