From 2005 XC90 CEM

A Volvo mechanic showed me this bit of insanity. The CEM1 circuit board
sits on top of CEM3 circuit board and they are soldered to each other via
header pins. CEM3 is conformably coated but CEM1 is not. The difference due
to exposure to elements is obvious. What possessed Volvo to protect one
board and not the other?

http://www.viatrack.ca/Misc/CEM1.JPG
http://www.viatrack.ca/Misc/CEM3.JPG

--

Boris Mohar

On 10/6/2009 2:32 PM, Boris Mohar wrote:
was not correctly sealed @ the factory. When I replace the CEM I use a
good glue to make sure that there is no water egresses in the passenger
compartment near the CEM
Glenn K
Certified Volvo Technician 2008
ASE Certified Technician 2008

Boris Mohar wrote:

That is strange.

The corroded one looks repairable though, I've fixed pinball machine CPU
boards that were in much worse shape from the memory backup battery
leaking all over them. Vinegar wash followed by a careful scrub with a
brass bristled brush can work wonders.

Boris Mohar <borism_void_ (AT) sympatico (DOT) ca> wrote:

I would head over to the local electronics store and pick up some
products meant for such application- a board cleaner and there should
also be a spray available to seal the surface from moisture. be sure
to tell them that it is an assembled component and not just a circuit
board. I would not spray on the components (put a bit of painter's
tape on them). They may need air circulation for cooling. If nothing
like that is available, use WD-40 and a toothbrush. That should also
help keep the moisture problem at bay.
__ __
Randy & \ \/ /alerie's
\__/olvos
'90 245 Estate - '93 965 Estate
"Shelby" & "Kate"

I have seen a GM car with zinc blocks attached to the body to act as
sacrificial anodes I am interested in what Mr Sweet or Mr Klien think of
this seriously /
"James Sweet" <jamesrsweet (AT) gmail (DOT) com> wrote

Jon Robertson wrote:

Well it ought to reduce body corrosion, but I seriously doubt it would
have any effect on the inside of electronics. There exist potential
differences due to power supplied to the circuit and whatever is more
positive will be the anode either way.

Zinc is often used on boats, and works well to prevent corrosion of
metal hardware.