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JBC CD-1BQE

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Gandalf_Sr:

--- Quote from: Shock on June 12, 2019, 05:02:09 pm ---Might want to make sure on the T12 clone the SMPS has proper primary/secondary isolation, it's been mentioned the ones with the air gap may have a heatsink that has inadequate clearance.

--- End quote ---
The KSGER PSU PCB has an air gap and it is isolated by a transformer. It needs for the ground input pin to be connected to the case  though.

Shock:

--- Quote from: Gandalf_Sr on June 12, 2019, 10:58:48 pm ---The KSGER PSU PCB has an air gap and it is isolated by a transformer. It needs for the ground input pin to be connected to the case  though.

--- End quote ---

You would have to look, but apparently on some versions a heatsink is placed across the airgap, which has creepage issues.

There is probably a few other design issues like the way the mains connector is soldered to the PCB and the clearance underneath the PCB without an insulating material, but I don't design power supplies, so I'm speculating.

Edit: On the controller check if the VBAT pin of the micro has a resistor to ground (R10 on the PCB), it may cause current drain on the backup battery decreasing its life to 30 days.

snoopy:
KSGER issues !

Gandalf_Sr:
Thanks Snoopy.

Those aspects of the heatsink bridging between the high and low voltage sides looks kind of scary, I need to do something about that!

I figured the CR2032 battery was flat as the time I set was lost during power disconnects but it would have lasted all of 30 days if I hadn't have watched that video.  Anyway, I removed R10 and put a new battery holder + battery in and confirmed in now keeps time over power outages, I didn't test the current draw by the video says 1 uA which I calculate is theoretically good for almost 23 years.

I'm thinking I'll reverse-engineer the KSGER circuit onto my own PCB, has anyone already done that? I figure it's awful similar to PTdreamer's here.

snoopy:
I opened up the two units I have and both are slightly different to each other but neither seem to have the backup battery drainage problem.



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