msg wrote:

John wrote:

snip

One of the problems with blowing out electronics with high pressure air
is the ultrasonic vibrations that are set up by the air. The vibrations
can break the fine junctions on the chip itself.


Huh? A standard cleaning protocol involved immersion in an ultrasonic
freon bath, now replaced by other less-inert solvents; this involved
considerably more sonic power than that produced by an air nozzle.
Certainly one must exercise care when cleaning around delicate parts
such as fine-wire coils without encapsulation, paper parts, etc., but
by and large there is little risk in pressurized air cleaning (120 psi)
and IMHO the benefits far outweigh any small risks. I've been doing
it for far more years than I care to admit with excellent results on
industrial, military and consumer electronics. I have also had very
good results using high-pressure hot detergent and water for difficult
greasy accumulations; the cleaner is much like a dentist's tool or
a 'Water Pic' rather than the familiar domestic pressure washer.

The key in wet cleaning of electronics is a proper bake-out protocol
to insure that parts (such as transformers) with high-potential
connections are dry internally to prevent breakdown before applying
power.

Regards,

Michael



On older circuit boards when ic's were first introduced it was not
recommended to use high pressure air on the boards. One of the main
failure points on early chips was the bonding of the leads to the chip.
This has since been solved but I still remember having boards fail
after they were blown off with high pressure air.



John