Hrmmmm.. I've reflowed things. Didn't find any bad soldering. Maybe this requires a 2nd look. I did notice you've had this problem as well as others. Seems the EHHA's design is prone to this because of it being DC coupled. Hence the reason for the servo.
I did find this...
Here's how I would have go about troubleshooting.
1) Look for any shorts
2) Double check all components.
3) Check the BJTs using the BJT sanity tutorial an amb forums :
If there is some confusion , compare the results with the other working board.
4) Check & compare the resistances of output mosfets
Replace the faulty devices and see if you can get it working.
I know this is basic stuff and I should know most of this by now. But I just want to be sure I'm doing it right. I'd hate to create more damage than what is done.
1. Checking for shorts. Best way to do this...
2. Double checking components... I'm assuming this means one has put the parts in the their proper place.
3. Check BJTs... I'll use the recommended site.
4. What resistance should I expect for output mosfets? And at what points should I check?
I think I'll have to uncase this puppy to get a better angle on what is happening. I suppose I can use the good board to help.
Edited by Mullet - 11/12/14 at 6:08pm