JYE Tech Forum

Dear JYE,

I have a problem with the kit. I have passed the power test 1. The LCD on ok and can adjust the encoder and see the menu.

Power at +5V is ok, but the V- is around 0.68V. AV+ is ok, around 5V. I check the polarity of C27 and it is fine. I measure the power in Bob5, at pin 8 have power. Indirect measure of pin 2 at the diod size is 0V.

Do you have any suggestion to check further ?

Best wishes,
Trinh Hoai Thanh

I am waiting for the support on the DSO 068.

According to the powering-up test 2, the Bob 5 board or C27 issue. And I found that there is output at the output of BOB5 board.

So they issue comes from the faulty of BOB5 board.

Attachment is for your reference.

Look forward to the suggestion.

I removed BOB 5 board and supply 5+ power to BOB5, the out put voltage is 0.23V. It means that BOB 5 is faulty.

I de-soldered the C35 (in JYE 120) and checked, it is ok.
The diod D8 1N5819 seems ok.
C38 is ok.

The suspect component is U7, MC34063.

As per identified, the BOB5 JYE120 is malfunctioning.

While waiting for the BOB5 board, I used a temporary -5V source and the DSO068 work fine.

The picture is after calibration. I am not sure whether it is good or not because there was not much change in the wave form.