Amiga 4000 Desktop Fan?

[TjLaZer]

Ok whats the deal with the 4000.  The Fan should blow air in or out?  I have my 4000 open today doing some troubleshooting (iBrowse crashes, maybe due to 3128 installed) and think my fan is blowing air into the drive cage.  Hard to tell.  I have it fully loaded see my sig.  With a Sony CDRW drive too.  Is the fan on the PS at the back near the CDROM?  Or at the back of the 4000?

[Ilwrath]

Ok whats the deal with the 4000. The Fan should blow air in or out?

Yes.  Supposedly, some originally blew air out the back of the case, but most (including all stock ones I've encountered) suck air into the case through the power supply.  

The best solution I've seen is to open the power supply and physically face the fan in the opposite direction.  Then, remove the faceplate from the 5.25" bay and install an intake fan in that position.  (Thereby bringing cool air in the front, and blowing hot air out the rear of the machine)

[Brian]

@Ilwrath
With a CDRW in the machine he can hardly sacrifise and 5.25" place for airintake.

@TjLaZer
The air should be drawn out the right rear of the case... to improve airflow the backplates can be removed for better airintake and make sure the hd/floppy cables are as much away from the PSU's as possible and neatly tucked away. Drawing air through the 2nd diskdrive space won't do much good cooling the CPU card and zorro cards so don't bother... better to try to increase the airintake from the rear using small fans.

[Castellen]

Most of the units I've worked with have the power supply fan blowing air OUT the back.  The theory is cooler air is sucked in from outside the case where it cools the system first, as opposed to pre-heating the air with the power supply :-)
You can easily check this by holding a small bit of tissue paper or cotton up to the fan.  It'll either get blown out, or try to get sucked in.

I agree with Ilwrath, one of the best case cooling solutions is a 2nd fan forcing air in the front.
You can set up ducts and dividers to get airflow where you want it as well.
Try to get a fan with a dust filter attached.  The main problem with fans is the amount of dust and crap they suck in.

Do you think it's heat causing IB to crash?
If you get lots of weird system behaviour and crashes after running it for a short time, this might be the case.

Also try gently flexing the motherboard by pressing down on it while it's running.  If pressure in a certain location always results in a freeze or crash, there are possibly solder joint problems, or connector problems (memory SIMMS, CPU board connector).
In the case of a bad solder joint, it's a matter of reflowing all the components in the suspect area, often fixes it.  You'll need SMD tools and good soldering experience to fix it properly.

Clean all connectors (Zorro edge connectors, memory, CPU board) using a small brush and isopropyl alcohol, or better yet, use one of the special lubricating/cleaning sprays for gold plated contacts.

[JimS]

Commodore released a service note about this... The fan should blow out of the A4000 case. The fan is in the power supply, just behind the 5.25" drive bay. That means the fan should blow thru the power supply and out the back. CBM recomended using a piece of tissue at the back vents to determine the direction of the airflow.

[HopperJF]

JimS wrote:
Commodore released a service note about this... The fan should blow out of the A4000 case. The fan is in the power supply, just behind the 5.25" drive bay. That means the fan should blow thru the power supply and out the back. CBM recomended using a piece of tissue at the back vents to determine the direction of the airflow.

Sounds dangerous!
I'd keep well away from the back of the A4000 when this happens  :-D

[TjLaZer]

OK mine blows out.  So thats good.

Well I am trying to find out what caused my iBrowse to crash all the time.  Mostly on eBay though.  BUT on my 3000 060 sys it works fine all day long!  So it must be my 4000.  I had issues with my DKB 3128 before so I removed it and i still get crashes, but not as often.  I am stumped.

[Roj]

I have one of these in my desktop case. Evercool Bay Freezer It's a tight fit and it takes up the 5.25 bay, but it's made a noticeable improvement in the case temp. It blows air out strong enough to be felt about ten feet away, and the case top is cool to the touch now. Before it was so warm I was half tempted to leave the cover off.

[weirdami]

The best solution I've seen is to open the power supply and physically face the fan in the opposite direction.

Wouldn't it be easier to switch the fan's power wires around so the power is reversed or is there something special about the shape of the fan?

[Ilwrath]

Wouldn't it be easier to switch the fan's power wires around so the power is reversed or is there something special about the shape of the fan?

Well, that would change the direction of rotation, but I don't know if the stock A4000 fan is unidirectional.  It might make more noise or be more likely to fail if you hook it up backwards.  (When I had mine apart, instead of facing the fan in the opposite direction, I replaced it with an Enermax whisper fan that I pointed outward.)

[Karlos]

A guy around here called Patrik did some A4K case modifications to improve the air circulation. Even uploaded the shots to the gallery...

[JimS]

Sounds dangerous!
I'd keep well away from the back of the A4000 when this happens  :-D

Yeah... we never sold many 4000s, but I remember that there wasn't much airflow out those back vents after blowing over the power supply. There's not much danger of the tissue being sucked into the system. :-)  It might be worth considering putting another fan on there somewhere.

 

[yogisumo]

The PS in the A4000 desktop is meant to pull air in from the right side at the back.  The air is supposed to move over the slots before reaching the cpu and then being blown out the back of the power supply.
 
I had a revision 3.0 Commodore cpu board with the 25mhz 040 in it originally.  This cpu board revision had issues with heat.  As the interior temperature would go up ( not abnormally ) the machine would get progressively slower and then lock up.  I solved the problem by putting everything into an old 386 AT tower.  Then I put a CSPPC 50mhz060/233mhzPPC with 128 megs ram on it.  That turned out to have an issue with heat also.  So, I put extra fans blowing on the ppc.  I think the cpu fan for the 233ppc might not be adequate.  

Anyway, first thing to look for would be heat related problems considering the accelerator you have.  Also pull out expansion cards and try the machine with no cards in the slots.  Some older cards don't always behave well in newer machines.  An other issue might be a weak power supply.

 

[BoingBoss]

Hi TjLaZer,

The Amiga 3000 is a higher quality computer then the Amiga 4000.  I keep telling people to stay away from the Amiga 4000 because they were poorly designed and nothing but problems, but nobody listens to me.  The Amiga 3000 Tower is much higher quality then both the Amiga 3000 and 4000, mainly because it was designed a lot like the Amiga 2000 Series.  My advice:  sell the Amiga 4000 on eBay.  Then take that money and buy yourself and Amiga 3000 Tower or two Amiga 2500 computers.  Believe me when I tell you that you will have less problems with these Amiga models.     :-D

[Jose]

@BoingBoss

While I remember DaveHaynie saying himself that the A4000 wasn't a great desing I'm pretty sure it's much better then the A2000, wich only has crippled Zorro2 and doesn't even have a PPC solution.