DSO068 LED wont Blink Replaced Y1 and C21,C22

Anything about this unique oscilloscope DIY kit
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jjay
Posts: 12
Joined: Sat Feb 03, 2018 7:02 am

DSO068 LED wont Blink Replaced Y1 and C21,C22

Post by jjay »

I have been trying to setup the scope to use USB as its power source.
I have passed the first few steps in the power up test. I get 5V and pass all test until
I got to press SW12 and see waited to see the LED blink.
Well nothing happens. I checked the LED polarity and its in the correct way. I closed JP9
to see if I would hear beeps or anything but I got nothing.
I'm not sure if the crystal or the ceramic capacitors or both are faulty. I tried replacing the capacitors
with 15's and still no LED blink. I then replaced the crystal with a new one with slightly
different MHz, it's all that I had laying around. still nothing happened, cannot get the LED to blink at all.
Please any help to tips would be well much appreciated!
I've successfully build the DSO 138 and the DSO 138 Mini. I've also build a DSO Shell and
all work nicely.
jjay
Posts: 12
Joined: Sat Feb 03, 2018 7:02 am

Re: DSO068 LED wont Blink Replaced Y1 and C21,C22

Post by jjay »

The crystal oscillator was faulty right out the box, I managed to pick up
a pack of 32.768KHz. I could not find an exact match on the websites I checked
(at least with reasonable shipping time) for a replacement for the 20MHz crystal that
came with the scope.
Anycase I got the scope to work. all voltage checks passed and the device
eventually booted. it takes a long time to actually boot and eventually
show the scope and waveform.
Pity the scope does not behave normally, e.g. it takes a long
time to detect that the waveforms signal has changed. Making it
hard if not impossible to use the scope. perhaps someone can point to a
website that stocks the 20MHz cylindrical crystals that ships in days rather
than months. I would like to see if it would make a difference having the
correct frequency oscillator.
TIP Do your BOB stuff first, it's hard to put the boards on once you have mounted some
of the bigger components like the capacitors or alarm in the same area. Do your Board on Board stuff first.
then mount normally from shortest to tallest.
rahe55
Posts: 15
Joined: Mon Apr 30, 2018 2:12 pm

Re: DSO068 LED wont Blink Replaced Y1 and C21,C22

Post by rahe55 »

Same thing happened to me - crystal defective . Detected by old HAMEG 304 Oscilloscope 30 MHz at TP14 .
I suspected damaged by high temperature (small housing soldered to PCB - am using lead-free solder / 320°C setting of iron).
Replaced by usual (as per Arduino Uno) 16 MHz crystal with larger housing and found DSO 68 to be working .
Ordered crystal 20 MHz from Reichelt here in de with same housing as above and working.
Small size not available and the bigger housing not looking too nice on the PCB - but what - it is functioning.

Experienced problems with new crystals before - not oscillating with stamped frequency of 16 MHz but 12 or 10 MHz .
Possibly wrongly marked batch . Then of course timing e.g. for serial comm is disturbed or scale of picture on oscilloscope not correct.

I built the DSO112A,DSO068 and the DSO150,upgraded by Gianluca Arena new shell for battery pack.
The DSO150 with new shell is working as expected now, for the other two I have to do some writeup in the respective forums.
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