MS-275 fan connector

[Mr. Wild]

Any idea why there is a fan connector on the inside of the amp? A bit pointless really.

Anyway, it's a bit difficult but I'm gonna use it. I left one of the bottom cover screws out and put a thin wire through the hole. My only concern is that the wire insulation might break.

I used thin coaxial wire so if the insulation breaks then the power supply ground in the fan wire and the heat sink ground will "short" first. Not really a short but these grounds are not supposed to meet. That can cause system noise I believe.

I just wish I knew how the +12V is routed to the fan connector. I would hate it if shorting that harmed the amp in any way.
Just opening up this amp felt like intruding a shrine or something

[Eric D]

The fan connector is for the MS275 fan unit. I don't think PG made a lot of them. I have one, and it is quite a bit different looking than the MS2250 fan unit. Also, the MS275 fan uses a single crossflow style fan, instead of triple computer style fans.

PG also made endplates for MS amps with a hole in them to run the fan wires. My guess would be this would help with the installation of the MS275 fan unit.

If you look under the input nulling torroid (small coil connected to power input), there is a larger transistor than the rest. This drives the fan output, and also provides power for the SG2525, and LM339.

[wooferdog]

If that were to short out does it have any protection for the transistor or will it fail and make the amp quit working ?

[LowandLoud]

MS-275 fan unit? I have never seen one before. Anyone have a picture?

LL

[Eric D]

Here are some photos of the MS fan unit...

http://www.soundbuggy.com/Eric/Car%20Au ... index.html

If the fan wires shorted out, I am pretty sure the transistor driving it would fail, and then the amplifier would quit working as well.

[ttocs]

huh never seen one of em either.... neat-OOOOOOOO

[zeropoint0.5]

Here are some photos of the MS fan unit...

http://www.soundbuggy.com/Eric/Car%20Au ... index.html

If the fan wires shorted out, I am pretty sure the transistor driving it would fail, and then the amplifier would quit working as well.

is this used with a fan board like the original ms2250, or are the fans directly connected to both pins on the board where you get a 12V signal ??

And only slowing down the fans with for example a resistor ??

love to hear some info on this...

[ttocs]

what are you hoping to accomplish by slowing the fans down?

[wooferdog]

Here are some photos of the MS fan unit...

http://www.soundbuggy.com/Eric/Car%20Au ... index.html

If the fan wires shorted out, I am pretty sure the transistor driving it would fail, and then the amplifier would quit working as well.

That's what I thought,if it don't control fan speed I would just run the fan off a relay and the remote wire to save the amp from damage if it did short the fan wires.

[LowandLoud]

Now that is cool. If i ever come across one, i will pick it up for sure.

LL

[zeropoint0.5]

what are you hoping to accomplish by slowing the fans down?

fan noise.....

on 12V they run at full speed and make a hell of a noise.....

the idle voltage of the fan pcb is around 5.2V... i measured that one time......

Indeed i would run it also off a 12V relais to avoid damaging the amp......

I will read the info and experience people will post here......

I don't need this in the direct future..... but love to here people experiences......