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Messages - derekf
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Breakout boards / Re: FT2232 free PCB - not working, help requested
There's a couple of the little fiddly traces at the top of the pic here that have come free, and a couple on the right.
I know I've read that you can fix lifted traces, but I don't know about these tiny ones that the chip solders to. Is there any point in ordering a new chip, or is the board shot?
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Breakout boards / Re: FT2232 free PCB - not working, help requested
I have removed the scorched 4.7uF caps, and off the board they read as ~4.7uF. The power LED does not light even after being removed from the board, so I apparently overcooked it.
I started to work on troubleshooting the rest, but then I realized that the vreg was scorch-your-fingers level hot, and the FT2232 in the pin 1 corner wasn't too much cooler than that.
I'm guessing that this indicates a pretty severe short, and I'm guessing it's in that corner of the FT2232 (maybe pins 4 and 5?). It looks like if I remove L1 and L2, then pins 4 and 9 will stop getting power and if that's the problem, the heat issue will go away.
Does it sound like I'm barking up the right tree?
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Breakout boards / Re: FT2232 free PCB - not working, help requested
Looks like (from the datasheet for the VR you posted), they're not all the same -- on the ones I got from Digikey, pin 1 is input, 2 is ground, and 3 is output; on the datasheet for yours, 1 is ground, 2 is output, and 3 is input.. so I think (hope) I've found my problem. Will order some different VRs shortly and we'll see if that takes care of it. No mark on the side. Will flux/wick the chip as well.
Thanks again, for all you do.
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Breakout boards / FT2232 free PCB - not working, help requested
I have very little electronics troubleshooting experience, so I'm humbly asking for assistance. I verified that I'm getting +5v through the USB port by stabbing the backside of the connector with the voltmeter probes until I found two that read +5. I'm seeing 1.37v across the power LED, by playing with a power supply and another LED I found that it didn't light until it got 1.5 or so.
The LDO power supply confuses me. If I look at the datasheet (can't post url as a new user) it looks like pin 2 (center) is the ground and pin 1 should be the input voltage, but if I probe across those I get -1.17v; to see 5v I have to go pin 3 for + and pin 1 for -. What I put on there was Digikey PN IFX25001ME; did I get the wrong regulator?
Otherwise - can you point me in the right direction for troubleshooting? Other possibilities that come to mind is that I overheated something (the hot air seems to have discolored the two 4.7uF caps) or something's shorting, but I'd expect to see no voltage in that case.