JBL charge 4 dead motherboard?

[HR19]

I have a JBL charge 4 Bluetooth speaker. Motherboard appears to be having some kind of issue. When I power it with my lab bench supply it peaks a little less than 1A for a second or two then won't do anything. I've tried using the battery pack, which seems to be good, but also no dice. It also does not appear to respond to being plugged in to charge. No obvious signs that I can see of any damage to the board. I tested the speaker independently and it seems to be functioning correctly. Can anyone see anything in these pictures that I don't see? Or does anyone know a likely component of failure for these for me to test? Or have any ideas about other ways to test components? Thanks in advance!

 

[Nigel Goodwin]

Rather surprisingly, the service manual is available:

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That should help you fault find.

 

[HR19]

Thanks, but I have a different board revision, and I'm not sure I understand that service manual well enough for it to help me unless you're suggesting I just physically, manually check every single component on the board? I'm going someone has experience with this board or a similar one and can help me out.

 

[Nigel Goodwin]

Thanks, but I have a different board revision, and I'm not sure I understand that service manual well enough for it to help me unless you're suggesting I just physically, manually check every single component on the board? I'm going someone has experience with this board or a similar one and can help me out.

No, that's not how you mend things - you need to fault find, start by checking voltages and finding where it's coming from, and where it's not going that it's supposed to.

 

[HR19]

No, that's not how you mend things - you need to fault find, start by checking voltages and finding where it's coming from, and where it's not going that it's supposed to.

Thanks I can start working on that. Still going to cross my fingers that someone knows how to deal with this board in particular or has some specific troubleshooting steps that they know of that might help with this board. Since power seems to begin to flow when I initially push the power on button, it'll make tracing hard because I only have a couple of seconds before the power discontinues.

 

[Nigel Goodwin]

You need to understand how the system works - there must be 'something' used to switch the power, a transistor, IC, or whatever, this is probably controlled by a signal from a processor, the processor is probably fed from a separate permanent power supply, often supply rails are labelled, with such things as SW5V (switched 5V) or 5V (could be permanent 5V).

 

[HR19]

You need to understand how the system works - there must be 'something' used to switch the power, a transistor, IC, or whatever, this is probably controlled by a signal from a processor, the processor is probably fed from a separate permanent power supply, often supply rails are labelled, with such things as SW5V (switched 5V) or 5V (could be permanent 5V).

Yeah that makes sense. The thing is the IC seems to be getting power somehow because when I push the power button there is an inrush of current for about 1 to 2 seconds which peaks around 1A.

 

[rjenkinsgb]

How many cells are in the battery and what voltage is that giving?