ProtoDAC TDA1387 X8 project

[hifinet]

Very nice looking system.

For the kits, I test all of the TDA1387 X8 modules, and reject about 7%. That's a high failure rate due to the fact that the chips are used and recycled. I would recommend buying extras if you are building on your own.

Also, prepare for failure. Solder only the active pins on the module (1,2,3,5,6,25,28). Test the setup. If everything sounds good, then you can solder the rest if you like.

I think the easiest way to remove a bad module is to clip the soldered pins with a flush cutter. Then unsolder the individual pins from the PCB and clean up the pads.

Using a desoldering tool (some, like the Hakko, are very expensive) or heat gun can also work.

Try to work with the existing PCB as much as possible, because removing components like the GPIO, RCA jacks and module is difficult. Fortunately, the most expensive parts are the Z-foil resistors, which are easy to remove, but also very easy to damage.

Another thing to mention (and it probably should be in the Builder Guide) is to test the connections after soldering the GPIO header. Using a DMM, be sure you don't have shorts between 5V power (pins 2 and 4) and ground (pin 6) and also 3.3V (pin 1). Consider not soldering pin 1 (or just remove pin 1 from the header), since it is unused. A short between 3.3V pin 1 and 5V pin 2 can kill the RPi. 

It is hard to get shorts from solder bridges of the GPIO pins due to the solder mask of the PCB, but possible if you use too much solder.