Tuesday, January 20, 2009

Nondestructive cooling for Dreambox DM800 HD

I got sick and tired of the Dreambox DM800 HD locking up all the time and read several places that this was due to heating problems. This happens especially when you run HD channels.

The Dreambox DM800 HD does not contain a fan, so I decided to include one myself. I did not want to destroy anything or cut any wires so I started looking at different pins/connectors that I could connect a fan to. Two options were candidates: the header next to the Broadcom cpu (JTAG header?) and the power supply to the internal SATA harddrive that I have got. Neither were easy to find any good information as to what voltage they had or if they could source sufficient current. I decided to use the same trick that everyone else are using: Connect to the USB port.

I found an old 12V cpu fan that I salvaged from an old computer and stripped the wires. I had a spare USB male to USB female cable that I removed the shielding from, cut the red and black wires, stripped them and connected them to the wires for the fan. Now the fan was running ok. The wires for the fan now goes nicely through the hole where the eSATA connector earlier was connected.

The USB 2.0 standard gives a maximum current of 100mA. At 5V this would be 0.5W. My fan was supposed to draw 1.5W at 12V, but the DM800 has no problem running it. It even seemed to have no problem booting up the first time I connected the power plug.
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