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linears4 · 08-07-2009, 15:42

i repaired several hp dv series, but no way to fix it permanently with a normal reflow, they fall after a couple of months,

i think that in these hp model they don't use normal unleaded balls, but some kind of high temperature alloy, cause removing is very very hard.

jovy 7500 has no sufficient preheating area for these boards and a proper reflow will never happen, you can test during the work if the reflow is well done by trying to move the chip during reflow with a small tweezer, if touching it very gentle you can see the chip moving then the reflow is doing properly, if you feel the chip steady on the board during the reflow process, no real reflow has happen, and no long term repair will succed.

the reason why the board work after this kind of work is that the balls make good contact cause thermal dilatation, but after a medium time it will stop working again.

for a permanent fix , reballing with leaded ball 63/37 is necessary, and then you can do the modification with a copper shim to prevent failure in the future.

08-07-2009, 15:42	#14 (permalink)
linears4 Junior Member Join Date: Mar 2005 Age: 53 Posts: 32 Member: 132074 Status: Offline Thanks Meter: 13	i repaired several hp dv series, but no way to fix it permanently with a normal reflow, they fall after a couple of months, i think that in these hp model they don't use normal unleaded balls, but some kind of high temperature alloy, cause removing is very very hard. jovy 7500 has no sufficient preheating area for these boards and a proper reflow will never happen, you can test during the work if the reflow is well done by trying to move the chip during reflow with a small tweezer, if touching it very gentle you can see the chip moving then the reflow is doing properly, if you feel the chip steady on the board during the reflow process, no real reflow has happen, and no long term repair will succed. the reason why the board work after this kind of work is that the balls make good contact cause thermal dilatation, but after a medium time it will stop working again. for a permanent fix , reballing with leaded ball 63/37 is necessary, and then you can do the modification with a copper shim to prevent failure in the future.