Hi guys,
This is my first post on here, but I have been a "guest" for about 2 months. I have been thinking about this problem with the iPhone 3Gs on firmware 3.1.2 charging on the F series. I have an F900 and have done some testing that has yielded some interesting results.
First thing - it appears the 3rd party and official Apple cables both charge the iPhone 3Gs when the USB end of the suspected cable is plugged into a wall mount USB charger with 5V output. I have tested this with 3 wall mount USB chargers. The official Apple charger, a Kodak charger and a no name charger. All of them charge the 3Gs with the official Apple cable, and the 3rd party no name cable.
The same cables, when plugged into the USB input on the F900 does not charge. My only reason for this is that the voltage output from the F900 does not match the required input for the iPhone 3Gs to charge. So this would resolve the issue of pinout mappings and disabling chips, right?
My question to anyone who is savvy: can we get information to build some kind of small inline USB voltage transformer that will fit between the F series unit USB input and the USB end of the multimedia cable?
If this is possible I would be willing to build a test unit - and possibly help build working units for anyone interested.
I do not know the output voltages coming from the USB input on the F900, and what pin they match up to, but I'm fairly confident this is this issue causing the iPhone 3Gs to not charge.
Let me know your thoughts...
-Ben