[Premium-Rx] Raven Research Multicoupler R1110 - a warning to all owners

[Bob Betts]

Michael:
Glad to hear the thing is back up and running, and thanks for the analysis.
When designing some Mil-Spec equipment, some of the power areas must be protected with either a conformal coating or tropical lacquer, depending on the spec. I remember some environmental testing we did many years ago, where, after applying a thin, dry salt coating to certain areas of DC supplies, that we could easily get a galvanic corrosive process started. Once started, the action is systemic, in that it is self-sustaining. The salts from the galvanic action (copper salts) combines with atmospheric moisture and become renewable electrolytes. The process is very exponential. Many of our projects involved the maritime/marine industries, so you can imagine the steps required to avoid salt ingress.
 
As to the leads of the chip becoming consumed, that's probably just a proximity effect of them being in the area of contamination. Even beryllium copper or phosphor bronze will eventually donate their copper content to the galvanic activity. Plain brass components and copper PC Bd traces won't last long at all. One of the best protection measures for PC traces is plain and simple solder tinning (tin/lead solder bath re-flowing).
 
What you experienced is kind'a rare for home use gear, unless you live near the ocean, but if the condition was already established, then it usually is just a matter of time. I more frequently encounter leaky NiCad corrosion -- just repaired a 6790-GM that was badly eaten up by that. If you suspect any other areas of potential problems, the old sodium bicarbonate solution wash (baking soda and water) followed by alcohol rinse is great preventative medicine.
 
I don't have any experience with the Raven, but have built my own Multicoupler for in-house shack use. http://www.bobsamerica.com/icm-nulticoupler.html
I was interested in the specs you provided ... thanks for that.
 
Good signals,
 
Bob, N1KPR


http://www.bobsamerica.com
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--- On Sat, 11/17/12, Michael O'Beirne <michaelob666 at ntlworld.com> wrote:


<snip>
The failure of the washer would have lead to DC leakage from the metal
chassis to the body of the IC effectively creating a battery and causing
corrosion from one of the poles - the chassis.  Not sure how this lead to
corrosion of the IC's pins and no doubt some clever cloggs here will tell
us.

73s
Michael
G8MOB

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