Crack propogation to inside an IC

Yamaha EMX640 that should be

Can you encapsulate the whole area with silicone rubber to shield the area from future shocks (mechanical that is)??

Can you encapsulate the whole area with silicone rubber to shield the area from future shocks (mechanical that is)??

If the trouble returns I'll desolder it , solder in a turned pin socket , plenty of height available, and try HY62256 or TMS62256, same pinning as the original

There is nothing common about damage from g-forces.

Replace it now. The case is cracked, and at least one bonding wire is damaged. It's not a matter of if it will quit, but when. The damaged case will let moisture into the die, and it will oxidize.

cracked

crack

Cable

perhaps

pin

g-forces, without localised schock waves, leads to solder breaks of inertial items, large caps, chokes, transformers etc. This problem is just the one pin of 28 on the IC the crack ended at. I don't see how it could have started there. I suppose in some future case where unobtainable IC and nothing to loose then ties and wedges first, then Dremmel and small centride mill down to the bond area and silver loaded paint may be worth a go

cracked

crack

Cable

perhaps

pin

Its a balance of probabilities type thing. If/when the problem returned the amp was useless then yes but the problem is just in the echo section, easily switched out using the front panel sw. Owners were using sans echo and only one pa chanel functional for some tome until a problem emerged on the other pa ch. If I knew for certain that a TMS62256 or other common SRAM would replace the W24257-70LL then I would go ahead replacing now. The process of desoldering the original is more likely than not, I would suggest, to make the original non-functional by any amount of surface pressure applied to the IC casing

I suppose you've already checked to see if there were any broken circuit traces under the IC.

That would've been my first suspicion where a circuit board crack was present. With a small high intensity light (like a 1W LED), it's often possible to see things on a pcb that normally wouldn't be seen.

High stress mechanical shock can be similar to lightning damage sometimes, ya never know if ya found all of the damage.

-- Cheers, WB .............

The probability is very high that it will come back. I would never return something to a customer with a defect like that. Of course, that is why my callback rate was always under 1%. It's also why I never needed to advertise my shop.