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From: adamd@rhi.hi.is (Adam David)
Newsgroups: comp.sys.atari.st,comp.sys.atari.st.tech
Subject: Re: Need a cooling fan for my 1040ST with ZRAM upgrade
Message-ID: <2994@krafla.rhi.hi.is>
Date: 31 Mar 91 00:23:00 GMT
References: <1991Mar26.192606.8264@cs.wayne.edu>
Followup-To: comp.sys.atari.st
Organization: University of Iceland
Lines: 31

In <1991Mar26.192606.8264@cs.wayne.edu> pbh@jake.cc.wayne.edu (Patrick Haggood) writes:

>> J. Harris writes about how his ST with ZRAM stops running after a few
>> hours, then when left off for 2-3 hours, boots fine.

>I've been having the same problems with my ST.  I figured it was heat,

It could be heat affecting the memory board, heat from the power supply
spreading through the metal shielding and motherboard, or the Atari power
supply is pushing its limits.

By far the most heat in the computer is the power supply. I haven't
calculated the power loss in that supply but it doesn't look very efficient.
There are two choices available. A fan was already mentioned. The best place
in a 1040 for a fan is just to the right of the power supply, blowing upwards.
A good fan would draw most of its air from the side where the power supply is.
Venting slats also have to be opened up in order to get a reasonable airflow.

I chose the other (and probably simpler) solution. I removed the power supply
altogether and fitted a diskdrive power connector where the switch used to be.
Plug in any off-the-shelf power supply and go. All the heat is outside where it
belongs, also there is no danger of accidently pulling out the (DC) power cord
because it is a snap fit. I have room in the computer box now for an internal
hard disk and am not restricted to using the standard Atari PSU with all its
shortcomings. If the standard PSU must be used it can be mounted in an aluminum
box. To avoid RFI leakage it is a good idea to use a screened cable for the DC
power and close with metal the hole where the AC power cord used to plug in.

I hope this will help someone.
--
Adam David.  (adamd@rhi.hi.is)