Adapting Thermalright XP90 HSF to LGA1155 board

Posted by crimsonpisang on   0 comments   0 trackback

So I had a Thermalright XP90 lying around which I thought it would be wasteful being kept in the storage. The HSF fits natively onto a stock PGA478 retention bracket. I've decided to try to to adapt it into a LGA1155 board.
A quick search on Google shows that the mounting holes on the are close to one another. I would just need to split the PGA478 retention bracket apart on its width.

LGA1156 dimensions

socket mounting dimensions

Instead of jumping straight away cutting the bracket and fitting them onto the board, I thought I should make a proof of concept first by building a test jig. The test jig is capable of generating heat to simulate a CPU and the copper shim acts as the CPU integrated heat spreader and can be swapped. I created a layout template for the mounting holes on Eagle cad. Going for a universal CPU socket approach, I've included the most common socket types for both AMD and Intel.


The schematic shows how the dynamic heat load was generated. By driving the mosfet in its linear region, it acts as a resistor instead of a switch, load current is set on the potentiometer and the op-amp set the gate voltage proportionately to the set current.
Looks good so far with the initial test fitting with a PGA478 and AM2 retention brackets.



I've also build a little widget to monitor the power draw of the electronic load out of parts from my junk bin. The current sensing is done by a ACS712 hall effect current sensor.


Initial load test. On stock HSF im getting. 50^c on a 65w load.


The HSF spring clips allows for a much lenient tolerance. Everything looks good at this point so far.


Due to the capacitors around the socket, I had no choice but to reduce it to each individual corner. Initially, I had thought of making it 2 by 2 to give additional support.
Take note of the clip positions, that is how I would get the 76x60mm to fit onto a 75x75mm mounting hole dimension.
The HSF fits as it should. Now for the moment of truth.





Temperature looks good. Using my Intel I5-2500K, at full load peaks at about 67'c. On the old stock alu HSF gives about 85'c at full load.


Practice the 5-R; Reuse, Reduce, Recycle, Repair, Repurpose.
Don't throw out your old stuff.
It could be possible to give them another chance.
Might make something useful along the way.
Learn something from mistakes or errors.

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