Has anyone experienced ramsey going goo-gaa?

[Castellen]

Never seen that exact problem myself, but have seen various ICs go faulty where they misbehave when heated up.

You did well to find the problem, not so easy to track down!

Fitting a heatsink/fan to the faulty device may not be the ideal soloution as I've found these kind of faults can get worse over time.
Best bet is a replacement.  It's soldered to the PCB in the A4000D, so you'll need some SMD tools to steam a replacement on.
Should be easy enough to find another, I have a few spares here if needed.  From memory the A4000D Ramsey was mainly revision 07??
Better not fit an earlier revision (like from an A3k) as there may be compatibility problems.

[Castellen]

Hmm, as far as using a toaster oven for SMD soldering goes, I would not reccommend it!

Didn't look at that website, but you can appreciate that solder melts at 250-350°C and very close to Ramsey are plastic connectors which have a much lower melting temperature.  You do the maths


PLCC soldering is a piece of cake once you get used to it.  Fortunately the the pitch and spacing of the component legs in the A4000 are very large, making the job even easier.
You can do the job with a "pyropen" if you're careful, but better to use a proper hot air or infrared SMD soldering tool.

Remove the faulty device by first gently pre-heating the area, then focus on the pins of the device, moving the SMD tool in a circular pattern.
Gently apply upward pressure under one corner of the device.  Suddenly the solder will reach the melting point, and it will lift off.

Using a hand soldering iron and solder wick, clean all solder off the pads and clean away residue with isopro alchohol.

At this stage you can fit a PLCC socket, or a new device.

Sockets are tricky and you need to have a small nozzle for the SMD tool to solder it on without melting the socket.

It's easy to fit a new device straight to the PCB.  Run a ring/bead of fresh solder paste over all the PCB pads, you usually need slightly more than you think.
Place the new device on the board, getting polarity correct and lining up each pad perfectly.

Use the SMD tool to melt the solder on a couple of pins in one corner only.
Check again everything is still lined up perfectly.  Then heat all the solder paste all the way round.

Carefully inspect all pins for solder shorts and unsoldered pins.

Unsoldered pins can be fixed by applying a tiny bit of solder paste and re-heating.

Small shorts can be fixed by heating the pins and running a needle or tiny steel spike between the device's pins.
Solder shorts underneath (and larger ones) are cleared by using a hand soldering iron with solder wick.


Once finished, check again for solder shorts, clean away flux with alchohol and power up the system.


Hope that helps

Anthony.