So, I was bored and mounted some fans

MCS Guy

The MCS hoarder
Well, someone suggested that I should run a cooling fan for the trans and the outputs. So, I did it with sucess and here is how it went.

Parts:
- 2= Radio shack 1 9/16" fans (300mA total draw)
- 1= Bridge rectifier, 1500mA (1.5 amps)
- 1= Filter cap, 1000uf, 35V
- .5 amp fuse
- heat shrink tubing, 1/8" diameter
- soldering iron and solder

The PS trans had a 8V AC terminal. I used that terminal to feed one side of the rectifier and gounded the other end of the AC input. Hooked the positive of the fans to the + terminal of the rectifier and hooked the negative of the fans end to the - terminal (and grounded them also). The filter cap goes to the + as well and the - grounds. The fuse goes inbetween the rectifier and the AC volt tap.

This is what I came up with. I made 2 metal brackets to hold the bottom fan under the PS trans. Its is my hope that it will blow air down beside the windings and the iron core, around and down the other side. The output tube fan is mounted on the shield.

These fans are small, so they dont blow alot of air. But they do move air around so there is no hot spots under the covers.
 
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Nice job squeezing them in there...

What was the final rectified voltage? I know we calculated 'about' 11.3V or so, but was curious as to what you ended up with.
 
My comments to the fan that cools the output tubes:

1) The fan looks like it is mounted on a solid sheetmetal. I wonder how much air it can deliver to the tubes.

2) If there is some air then measure the temperature of the last tube downstream before and after mounting the fan. This tube may be hotter than before due to shadowing effects caused by the heat from the other tubes upstream.
 
1), you cant see in the picture, but there is is a hole that was dremeled behind it.

2) I was thinking this all day. I think im gonna move the fan to a central location and make small aluminum baffles to control the airflow.

But Right now, Capacitors are on the top of my list.
 
On my SCA35, I put a muffin fan blowing down on the top. I used ty-wraps to hold the fan down, passing the ties thru vent holes (lots of small holes on the top). I used a 230VAC fan running on 120VAC to keep the noise down. I plugged it into the switched outlet on the back of the amp. It keeps things nice and cool in there. Also ty-wraped a fan grill in the top of the fan to protect the fan from my fingers....
 
I like to use older CPU fans to pull air through the computer (ones that aren't on the verge of dying of course). With the large 80mm case fan at the bottom and 1-3 fans tied to theventing on the back and usually tied in to the PS with the 12V connections by splicing them into the HDD supplies. It works nicely!
 
With a little air moving is much better than without air. The tube life may therefore last a lot longer than normal. You can try using vanes to guide air to these tubes.
 
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