Amiga 4000 power supply fan question

[HammerD]

The fan in my A4000's power supply sucks air INTO the case... is this correct? I seem to recall some fans being fitted backwards....

I am just mentioning this because the air flow in the case absolutely sucks and it gets very hot inside, especially with a 060 card and a CV PPC gfx card.  I have put a heatsink/fan on the 060 and also a heatsink on the CV PPC's gfx chip, but with no air flow in the case it just pushes hot air around...

I was thinking of changing the direction of the fan so it blows air OUT through the power supply and out the back of the case...and somehow fitting an 80mm fan in the case to improve air flow.

I was also thinking of towering the computer --looking at Elbox's A4000 Tower solution, but that is EXTREMELY expensive... so I was thinking of doing it myself....

[GadgetMaster]

It would be best for air to come in from the lower front of the case and to be expelled through the power supply  towards the back of the computer.

You could reverse the fan in the PSU but remember tinkering inside a power supply is not recommended as it stores lethal voltages even when turned off.

In workshops the voltage stored in the capacitors is  quickly drained using a special tool before commencing work on the unit.

Other than that the best solution for airflow would be to put everything in a tower and use the fans in that.

[Framiga]

Disconnect the PSU from the power and after 30 minutes, you can open it.

You must reverse the fan (not the wires).

I suggest you, to towerize the A4000 (i've done it some months ago). Add a fan in a desktop case, is a nightmare.

Ciao

[Erwin-K]

A4000D's run notoriously hot. There have been many solutions.

One machine I used to see at the St. Louis show had two muffin fans mounted to each side of the case!

Some years ago the fan in my machine at work froze and took the processor board out with it. I replaced the fan, but the new WarpEngine still got hot.

I discovered that there is just barely enough length in the wires to the motherboard power connector to place the power supply outside the case. I built a frame in place of the PS and mounted a 110volt (mains powered) fan in the opening in the back of the case. I ran that fan to the monitor plug in the PS so that it starts as soon as I power up.

I call this my stove pipe A4000 because the PS sitcks up like a chimney. Ugly as @#$%*!, but it has worked fine for many years.

If I could squeeze the $$$$ for a tower conversion out of my employer, I'd do it in a heartbeat.

Good Luck!

[Framiga]

@HammerD

go to:

http://amiga.org/forums/classifieds.php

to towerize your A4000D in a cheaper way.

Ciao

[Linchpin]

OR

run it in the freezer.

[amigamad]

The a4000 desktop i have put together gets hot the psu fan is the same sucking air ito the computer.its a very poor case desighn and there is no wherer for fans to go . :-o

[JimS]

HammerD wrote:
The fan in my A4000's power supply sucks air INTO the case... is this correct? I seem to recall some fans being fitted backwards....

Commodore shipped some A4000 power supplies with the fan installed backwards.  They issued a service note back in 93 to correct this... you should pull the supply and flip the fan around so it blows out of the case.

-Jim

[Iggy_Drougge]

As far as I can recall (will check when I get back home), the A4000 PSU is supposed to suck air in through the holes in the vicinity of the Zorro cards, then the air travels across the cards, along the raiser board, and the rounds it at the front, travelling across the drives and into the PSU, where the air comes out.
One solution to the cooling problem which I remember is to drill up more holes at the card cage.