PWM Fan Controller Increase base speed

[tfixrepairs]

OK, so far I came up with simple solution just to set fan speed with potentiometer by integrating simple 555 timer. I just can't figure out the values for resistors and caps I should be using. If anyone could shed some help I would appreciate it.

Here's the circuit:

**broken link removed**

 

[Reloadron]

OK, the circuit you have posted is just a 555 timer configured as an astable pulse generator. That is not what you want. More on that later.

The basic 555 or LM555 timer is not reliable running off a 3.3 volt supply, it likes between 4.5 and 16 volts. The National Semiconductor data sheet can be found here. A better choice for low voltage applications would be a timer like the ICM7555 the data sheet for which can be found here.

What you want is PWM control. This is where the pulse train output runs at a fixed frequency (period) and the on time of the pulses are varied. A circuit that will do that using a 555 or 7555 can be found here. Note the pulse illustrations. That is PWM. Additionally in the link they do show a Vcc of 3 to 16 volts but if you want to run at 3.3 volts you may do better with a 7555. I have no clue if the 7555 can drive the fan speed input of a PS3 less possibly an added transistor.

Ron

 

[tfixrepairs]

Thanks a lot for explanation. I've built the 555 timer but it doesn't seem to do the job at all. So I think my best bet would be to go for 7555 IC. Would someone be able to help me build a circuit that would include a timer running of 3.3V and pulsing a signal which would be controllable by a potentiometer.

Or is it the same circuit as 555 timer except the 555IC would be changed with 7555IC?

Regards

 

[tfixrepairs]

This is a new PWM controller circuit I came up with as Reloadron suggested. Would this be OK to output a pulse of 3.3V and to modify it's amplitude by a resistor?

**broken link removed**

 

[Reloadron]

Give it a try and see what you get.

Ron

 

[4pyros]

Just a thought but would not moving the fan sensor to a hotter spot in the box give you the same effect. Andy

 

[Reloadron]

Just a thought but would not moving the fan sensor to a hotter spot in the box give you the same effect. Andy

Hi Ya Andy

Suggested that earlier but guess not. Never paid much attention to the PS3 but if you start getting into their cooling the Internet is full of overheating problems. During my Google wandering I was also surprised at the cost of replacement OEM fans for the things. THis type 3 wire fan, unlike most PC fans uses PWM input on that one lead so I assume they likely have an on board MOSFET configuration. All I could gather is the things run hot during extreme gaming and shut down a lot. That plus an expensive OEM fan. I would like to find the thermistor location and heat the little sucker up and see what it does.

Ron

 

[4pyros]

Reloadron; Yes the box is just to small.

 

[tfixrepairs]

Hi,

This is what is being sold on eBay

**broken link removed**

The guy is asking £20 for it.

Does anyone recognize the components?
How could this thing be built?

The description is:

This internal Fan Mod uses pulse width modulation to increase the base speed of your internal fan.

Your internal fan increases and decreases in speed, as the console detects a change in temperature in the machine.

This Pulse Width Modulator increases this base level, by 40%, so that it will always work above this level, and will siginficantly keep the temperature down inside your console. The Module will increase and decrease the speed above the base level, as required.

Regards.

 

[Reloadron]

The obvious 2N3704 is a common NPN switching transistor likely used as an output driver to the fan side. I can't tell what the 14 pin dip chip is in there. The identifying markings are sometimes intentionally removed.

This is where a scope would be nice. Much as I Googled and of all the new things I saw about the PS3 something I did not see was the actual PWM frequency used?

Early on I mentioned the use of a pulse stretcher. I would venture a guess based on the image that is what the designer is doing. You have the +12 volts and common going to the fan, that is the circuit power also. Then he takes the actual PWM signal and applies pulse stretching making the PWM on time for each pulse longer. There are a few resistors and maybe a cap or two under the goop.

I can tell you this. My currency conversions suck but I would venture that £20 (GBP) is about $31 USD and the cost for all parts including board and connectors is about 1/3 of the cost they sell for. Keep in mind that is pure speculation on my part. However, not bad if you sell enough of them.

I would like to know that PWM frequency.

Ron

 

[MikeMl]

This entire thread is based on the premise that the existing PWM duty cycle is much less than 100%, therefore increasing it from say 50% to 90% will run the fan faster, and move more heat out of the box. If, OTOH, the PWM duty cycle is already >90%, then increasing it to 100% will do nothing!

 

[4pyros]

Mike thats right. The fan is so loud thay try and run it slow to keep the noise down. But by the time it kicks into high gear it is to late and the box is already to hot to cool down even at max speed before it overheats and shuts down. Andy

 

[Reloadron]

This entire thread is based on the premise that the existing PWM duty cycle is much less than 100%, therefore increasing it from say 50% to 90% will run the fan faster, and move more heat out of the box. If, OTOH, the PWM duty cycle is already >90%, then increasing it to 100% will do nothing!

Mike, while I agree the PS3 forums are loaded with threads complaining about overheating. There are also a pile of aftermarket solutions out there to address overheating. It was suggested by you as well as myself the OP apply a constant 3.3 volts to the control line to see if the fan would speed up. I don't know what the OP has actually tried. That method was used in a video I came across as well and the PS3 sounded like a jet ready for launch. Anyway, based on what I have read over and over again as to the PS3 they have cooling issues. Now be it lousy engineering for airflow or slow fan speed I don't know. Since the OP lacks a scope I have no clue but if he wants something along the lines of what has been posted, then yes, I suggest stretching the pulses and that assumes they are less than full speed.

Ron

 

[tranvanthien]

Hi all !

Could you show me 3 wire grey,black and brown on PS3 FAT fan is ? And make a PWM controller like this.

http://www.fixmypcdoctor.com/product.php?productid=12&cat=4&page=1

. I think it used IC555 to make PWM. thanks.

 

[Reloadron]

Hi all !

Could you show me 3 wire grey,black and brown on PS3 FAT fan is ? And make a PWM controller like this.

http://www.fixmypcdoctor.com/product.php?productid=12&cat=4&page=1

. I think it used IC555 to make PWM. thanks.

Your link did not work?

Ron

 

[tranvanthien]

Your link did not work?
Ron

OK. Link is Ok no problem.Other way try to access this link

http://www.killerbug.net/PS3_MB_MODS.html

Anyway, i've made a PWM circuit to control PS3 Fan on my FAT PS3. It'd worked great. I'll post my circuit for you soon

 

[tranvanthien]

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