MegaWatt S-700-12 switching power supply

[Tallman]

You just might make it quite forever if the parts are not kept cool enough.
I wish you guys could have heard the equipment manufactured by a company I worked for. 400 Hz fans turning 15000 rpm. They howled!

 

[Mudfoot]

Mine has a loud pitched whine that can be silenced when applying pressure on the outside body of the fan. That is an easy fix with some sort of dampening between the fan and case.

The issue that bugs me, is the howling noise of the air being drawn out. The fan is high speed. I leave my supplies on 24/7. I have become accustomed to my Tripp-lite's transformer hum. It comforts and lullaby's me. The howling... Nope, can't tolerate it.

My fix is going to be ghetto. I'm going to disable the internal fan, cut a hole in the case and mount an 120mm AC Infinity USB powered fan on it. It has an in line variable speed switch. On high speed, it's only 17 dBA. I can't hear it from 3 feet away. I use them on my amplifiers, sons Xbox and Playstation.

Unless someone has anecdotal evidence of a specific replacement fan that is super quiet, I ain't messing with trying to find one. I bought one of these types of supplies a few years ago. It wasn't as noisy, but it emitted tons of hash.

 

[ExitThirteen]

Just change the 12V internal fan to a 24V fan. The fan will still run and flow plenty of air, but will be far more quiet. That's what I have done in the past and it works well.


~Cheers~

 

[Mudfoot]

Just change the 12V internal fan to a 24V fan. The fan will still run and flow plenty of air, but will be far more quiet. That's what I have done in the past and it works well.


~Cheers~

Do you have a part number of fan you used? Did leave the resister in line with the 24 replacement?

I decided to try the 24 volt option, instead of using one of the several 5 volt fans I have. I don't want to part with what I have, since I use them for other projects.

 

[Mudfoot]

Seen in another thread they are 80 x 80 x 25 mm. I thought 12 volts. I ordered a fan for mine. I also am wondering if the use of 2 screws is letting the fan vibrate.

The 50 amp model uses a 60mm fan.

 

[w0srb]

The 50 amp model uses a 60mm fan.

My Mistake, It was 60 mm. which is what I ordered. Thanks for catching that Mudfoot.

 

[w0srb]

Mudfoot thanks for the photo. What connector was on the end of the wire.

 

[338_MtRushmore]

They are putting resisters inline now? I went with 2 12 volt fans in series. Whisper quiet and still moves a good amount of air.

 

[CB590]

Anyone got part numbers or links for the fan??

I may be upgrading soon to the 50amp MegaWatt..

 

[Mudfoot]

I've heard them referred to as Molex, but I think there's several different nomenclatures.

 

[Mudfoot]

They are putting resisters inline now? I went with 2 12 volt fans in series. Whisper quiet and still moves a good amount of air.View attachment 28588

Similar to what I had in mind. The 5 volt 120mm fans I use on my amps are barely perceptible to my ears. I'd likely only need one, but I'm sure yours stays cool. I want my supply to remain on 24/7.

 

[Shadetree Mechanic]

They are putting resisters inline now? I went with 2 12 volt fans in series. Whisper quiet and still moves a good amount of air.View attachment 28588

I did the same to mine except I used a single 24v fan at the back. I put tape over the hole for the original fan too. The 36A supply was a lot quieter but was still the loudest thing in the shack besides my tube amp. I replaced the fan in the 36A with a 24v in the factory location and now I can't even hear it. I don't run the supplies maxed out so I don't think any reduced cooling would be an issue.

 

[Wire Weasel]

Haven't owned one of the 50's yet - but If I encountered this I would do what I do will all my other 12V Muffin Fans projects. Had to do to quiet the too-noisy internal fan on the Power Supply in a RCI 2995DX. Do the same with fans I attach to any pill box heat sink.
Add a 250 ohm 2 Watt potentiometer inline with the fan's power lead. Boom you're done. Instant Adjustable Speed Control.
Do NOT select the super cheap 1/4 watt B-Type pots. Even with small fans they will be subject to burning out (the pot).
Last time I bought a 5 Lot, there was a selection of 250ohm 2 Watt'ers on eBay for under $10.
100 ohm would work great too but for some reason they are hard to find. Go up too high in Ohm Value then your desired adjustment range gets short-touchy.
The 250 ohm, 2 Watt is perfect for this purpose and will last forever on these small fans.

 

[Mudfoot]

Keep in mind...

Whatever you do to this unit, requires breaking the warranty seal.

That's what SUCKS!

 

[w0srb]

I used this one. (
SUNSKY 60mm 3-pin Cooling Fan (6015 3-pin)
Higher CFM at 39.2 and only 20 db of noise. I can live with it now.