Aessent Blog

Nothing like the smell of baking in the morning

Although if it could have gone up in flames it probably would have... More seriously though setting the wrong program on the oven resulted in the solder paste only partly melting and not flowing properly. That created a lot of shorts between the pins of the 0.5mm pitch TSSOP voltage translator device (an LVCH16245 from TI) on the aes2204, not pretty. The “funny” thing is that the plan was to do just one board first and then decided to through it through the window (the plan that is) and put the four prototype boards together as a batch. What could possibly go wrong?

Partly soldered aes2204 voltage translator


A lot of flux later it was possible to recover three of the four PCB.

Recovered aes2204


The fourth one has a damaged pad on pin 20 which was shorted with pin 19. The pins are now separated but pin 20 is just hanging by a thread.

Damaged LVCH16245 chip


Oh well they are prototypes so that will do. Finish looks very dodgy but at least they are functional, although board number four will have 15 signals instead of 16. Note that we are talking about the soldering finish here, the mess created by the flux as shone on the pictures does wash off and board and components are just as shiny as would be expected from any other PCB assembly.

Anyhow, it is now a few of the prototypes assembled. Needless to say the oven setup was double checked for the following boards and one went first on its own to prove everything was just right. The aes2209 is a bit denser than the aes2204 and reworking this one would have been a lot more difficult.

Completed aes2209 Raspberry Pi Camera interface board

And here they are displayed with the aes220 motherboard.