DM 800 HD Fan problem.

[Detlef]

Had a seized fan on my DM800 and it has damaged the circuit as a new one won't run either.

My question is, when does the fan run ?

1) all the time the power supply is on and connected
2) only when the box is operational (ie green light lit)
3) it is CPU temperature controlled (ie only when the CPU gets hot)
4) any other option I have omitted.

I've identified the transistor that feeds the fan but don't want to change it if it's say option "3".

Just a note: these boxes hum when the HDD is active so don't assume a hum is the fan.

Any replies, most welcome.

[cosworth4x4]

i had a dm 800 dont recall it having a fan .
was a long tome ago so i could be wrong .

[Detlef]

I didn't realise either until it started to get very hot.

It seems like an afterthought and is tacked onto the CPU heatsink but hides under the tuner.

[cosworth4x4]

mine always run hot , added a usb cooler , but dont ever recall a internal fan .

maybe one was added later or a clone ?

[Dig Deep]

On my clone I have one fan and it is Always running. Same on the 800

[Detlef]

On my clone I have one fan and it is Always running. Same on the 800

Many thanks. I think I'll just use a permanent 12Vdc point to feed the replacement fan. The standard circuit feeds it from a transistor which seems a bit of a luxury if it is always on.

Just a warning, the fans on both the genuine and clones only seem to last about 4 to 5 years. If they stop the CPU gets very, very hot and behaves erratically. So I'd advise changing them every 4 years as they are only about €6.

[digicon]

The Answer to your question is No.2 only when the box is operational if its in standby the fan switches off

[Detlef]

Thanks. That would explain why it is controlled by a transistor.