Hello,
I'm having major trouble with rework on this station. I (since most likely it's profile problem) keep killing or at least damaging chips. For now I'm using 3 TCs, 2x0.127 and one 0.25, all omegas, all are within 3 degrees from each other, I try to keep the TC end on the substrate and motherboard. GPU usually moves at ~225-230C on TC, so it's more less accurate. I mainly rework old GPUs and Xbox 360 on it. I have modded it to use variable bottom temp with P-soft, bottom max temp is 260C, realistically on thinner PCB I get 200 degrees, ramp is +60C from the profile (set like that so that top heater keeps up on 5-20% power up to ~180C). Top heater is about 4cm above flip chip. My profile is:
r1:0.38 L1:130 d:1 ---> on this step it ramps very slowly up to ~ 150C and then goes to:
r2:0.5 L2:220 d:200 ---> I never need to go higher or longer than that
Whole process takes ~ 9-10min, which is long, but profile I made from an extended SAC305 reflow profile killed every chip I tried.
(5mins till GPU comes off, but back then I tried to keep the GPU at 220-221C max;
r1:0.78 L1:100 d1:20 ---> ramps up to 150, slowly goes to 180, then:
r2:0.8 L2:220 d1:200)
On this at least I don't see solder balls coming from under the flip chip, though reflow usually leads to artifacts or black screen, so no short, but also not working. If it matters flux I'm using is either Amtech NC-218 or NC-559.
I'm having major trouble with rework on this station. I (since most likely it's profile problem) keep killing or at least damaging chips. For now I'm using 3 TCs, 2x0.127 and one 0.25, all omegas, all are within 3 degrees from each other, I try to keep the TC end on the substrate and motherboard. GPU usually moves at ~225-230C on TC, so it's more less accurate. I mainly rework old GPUs and Xbox 360 on it. I have modded it to use variable bottom temp with P-soft, bottom max temp is 260C, realistically on thinner PCB I get 200 degrees, ramp is +60C from the profile (set like that so that top heater keeps up on 5-20% power up to ~180C). Top heater is about 4cm above flip chip. My profile is:
r1:0.38 L1:130 d:1 ---> on this step it ramps very slowly up to ~ 150C and then goes to:
r2:0.5 L2:220 d:200 ---> I never need to go higher or longer than that
Whole process takes ~ 9-10min, which is long, but profile I made from an extended SAC305 reflow profile killed every chip I tried.
(5mins till GPU comes off, but back then I tried to keep the GPU at 220-221C max;
r1:0.78 L1:100 d1:20 ---> ramps up to 150, slowly goes to 180, then:
r2:0.8 L2:220 d1:200)
On this at least I don't see solder balls coming from under the flip chip, though reflow usually leads to artifacts or black screen, so no short, but also not working. If it matters flux I'm using is either Amtech NC-218 or NC-559.
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