Hi Charles!

What type of terminations do the networks have? Concave or convex? If they're
convex, there's your problem.

When I was out in California working at Smart Modular Technologies, we built
Pipeline Burst memory modules that had 22-chip resistor networks on the
backside of the SIMM modules. Same as you, we had bridging problems out the wazoo.
Tried doing things with the stencil and nothing seemed to help.

Started looking at the network itself and learned that there are two
termination styles, concave and convex. We were working with the convex type. We had a
Panasonic rep in at the time, and I spoke with him about the problem. He said
for us to switch over to concave terminations. As soon as we switched over,
bridging magically disappeared.

-Steve Gregory-


> We have a new assy. that uses 1206 capacitor networks. We are have a
> serious
> problem with bridging and unsoldered connections. We think we may have
> solved
> the non soldered problem by increasing the soak before reflow but still have
> the bridging. Anybody have similar experiences? We are using a 5 mil.
> stencil. The other parts all seem to solder well. We are considering having
> the apertures for these parts reduced. Any suggestions would be greatly
> appreciated.
>
> Charles Caswell
> The Big Kahuna
>


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