This is a great solution of ICOM A2 reworkwith a heatsink which is cooling both chips.
(GREAT THANKS to B1257)
Now here are some pictures about the heatsink I made.
Picture1 As you can see in my way the heatsink is made with two parts. The main center plate which will later touch the complete case for a better heat dissipation. And second the small CPU plate which is glued with a special Thermal Bound paste for FPGA chips on the center plate. You can see the compound type on the picture.
Picture2 Shows the Temp in C° after an idle running time of the head about 30 minutes, without any cooling.
Picture3 Original there are two pads for the cooling, but not one is touching the case, after a longer time the complete case will warm up in a way that the both chips are near out of max temp range, which is in a normal grade about 70°C. For our heatsink I will use a small pad for the MICREL chip to give me the right contact to my center plate. Second reason is that the pad gives me a little bit place for a realignment to center the main plate with both chips.
Picture4 You can see new srewls and bolts to compensate the new height. The screwls dimension of the innerside srewls is 2.5x12mm (countersunk bolt, this is important, because we cant fix the center place in the case if there is not enough place with normal screwls.)
Picture5 Be careful to center the plate exactly with vary the three plastic bolts, may you have to cut it a little bit. Check the space between the case and the center plate one or more times. Take care that both chips are touching the heatsink, because some cases can vary the height.
Picture6 Apply compound paste to the center plate, where the heatsink is later touching the case for the best heat dissipation.
Picture7 For the best way take care that the complete heatsink is touching the case. See the red arrow.
Picture1 As you can see in my way the heatsink is made with two parts. The main center plate which will later touch the complete case for a better heat dissipation. And second the small CPU plate which is glued with a special Thermal Bound paste for FPGA chips on the center plate. You can see the compound type on the picture.
Picture2 Shows the Temp in C° after an idle running time of the head about 30 minutes, without any cooling.
Picture3 Original there are two pads for the cooling, but not one is touching the case, after a longer time the complete case will warm up in a way that the both chips are near out of max temp range, which is in a normal grade about 70°C. For our heatsink I will use a small pad for the MICREL chip to give me the right contact to my center plate. Second reason is that the pad gives me a little bit place for a realignment to center the main plate with both chips.
Picture4 You can see new srewls and bolts to compensate the new height. The screwls dimension of the innerside srewls is 2.5x12mm (countersunk bolt, this is important, because we cant fix the center place in the case if there is not enough place with normal screwls.)
Picture5 Be careful to center the plate exactly with vary the three plastic bolts, may you have to cut it a little bit. Check the space between the case and the center plate one or more times. Take care that both chips are touching the heatsink, because some cases can vary the height.
Picture6 Apply compound paste to the center plate, where the heatsink is later touching the case for the best heat dissipation.
Picture7 For the best way take care that the complete heatsink is touching the case. See the red arrow.
After the heatsink mod the temps are always inside the specs. I remember 5 hours idle running about 40.5C° room temp about 26°C.
Attachment:
Heatsink Dimension PDF overview
Sketup File
I hope this helps you to mount the heatsink in a proper way.
So advice to all -
To avoid issues, please check the PCB design (with the cooling plate) before your buying. when buying from China, it seems obd2france.com is one of the safest way to make sure of things quality.
This is their ICOM A2 pcb with a cooling plate
(BIG THANKS to B1257 in http://cartechnology.co.uk/)
Original - from obd2france.com
obd2 francais service technique:How to rework ICOM A2 with heatsink for Cooling chips
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bmw icom francais
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bmw icom francais
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