AMB Laboratories DIY Audio Forums

[superpong]

Hi

I finish assembling Mini3 & X1. Everything seems fine. I'm really impressed with its musicality.
However when I charge my amp, I noticed that a green led does not illuminate in green according to description in "Initial check" page. Instead, the led blinks (approx 1 second on and 1 second off)
I measure B- and B+, and the voltage gradually rises.

Is this normal? or what's wrong with the led?

[MisterX]

Check the current draw between the power supply and the amp, the current draw should measure around 650mA when the LED is on.
And should read zero when the LED is off.

[amb]

Does the LED blink green or red?

[superpong]

Does the LED blink green or red?

Green

[superpong]

Check the current draw between the power supply and the amp, the current draw should measure around 650mA when the LED is on.
And should read zero when the LED is off.

umm not sure how to measure but I will try.

[superpong]

One more thing - I observe that the Led keeps blinking (in green) overnight until morning.
What makes me confused is that the charging is successful.

Does it mean that U1 (charge management controller) work but malfunction?

[amb]

Look at your U1 chip. Is it a MCP73864? The behavior you describe seems to suggest that you have a MCP73862 instead. With MCP73862, the LED will blink green when the charge cycle is complete.

[MisterX]

Check the current draw between the power supply and the amp, the current draw should measure around 650mA when the LED is on.
And should read zero when the LED is off.

umm not sure how to measure but I will try.

You have to put the meter between the amp and AC adapter to measure the current draw.
Cutting the cord on the AC adapter (or making a plug in "broken adapter") and then holding the probes can be a headache when using a handheld DMM......
Maybe A Kill-A-Watt meter would be an better solution here.

http://www.amazon.com/dp/B00009MDBU

[amb]

The problem with using the Kill-A-Watt is that it measures current on the AC side of the power adapter, and what we want to know is how much current is being drawn on the DC output. The mapping between the two is not entirely predictable.

Anyway, check the chip. If it's a MCP73862, then the blinking green LED is the correct behavior when the battery is done charging.

[MisterX]

The problem with using the Kill-A-Watt is that it measures current on the AC side of the power adapter, and what we want to know is how much current is being drawn on the DC output. The mapping between the two is not entirely predictable.

Yep, the results with kill-a-watt are not very accurate but that's fine for a quick functional test.