Thread
Fanless LCIII/ LC475?
Having tested it pretty thoroughly last night and today, I can report that my fanless scheme won't work as planned for either model.
Without a fan, and even with the top removed, the 33mhz LCIII+ gets very hot in a couple of spots, especially on the 68030; the slower 25mhz LCIII is a bit better, but still too hot for me to be comfortable running it fanless. The heat from the 68030 especially surprised me, as I thought that all 68030s ran cool.
The LC475's 68LC040 gets pretty hot as well, of course. I went to the lengths of spinning down the hard drive via Sleeper, installing a 33mhz 68LC040 from an LC630 board (with the thought that running it at 25mhz would keep it cool), and popping a large heatsink on the processor. I then put on the lid and went away for an hour. After an hour, the whole centre of the logic board was warm, the heatsink was distinctly hot, the PS was getting too warm -- and I figured that this was just not a good idea.
Now, were I do run the LC475 without the top on, and arrange matters so that it got convection ventilation, I suspect that all would be fine. Will ponder that as an alternative possibility. I have been wondering about trying to make myself a sort of 68040-based Cube, so maybe now is the time.
Without a fan, and even with the top removed, the 33mhz LCIII+ gets very hot in a couple of spots, especially on the 68030; the slower 25mhz LCIII is a bit better, but still too hot for me to be comfortable running it fanless. The heat from the 68030 especially surprised me, as I thought that all 68030s ran cool.
The LC475's 68LC040 gets pretty hot as well, of course. I went to the lengths of spinning down the hard drive via Sleeper, installing a 33mhz 68LC040 from an LC630 board (with the thought that running it at 25mhz would keep it cool), and popping a large heatsink on the processor. I then put on the lid and went away for an hour. After an hour, the whole centre of the logic board was warm, the heatsink was distinctly hot, the PS was getting too warm -- and I figured that this was just not a good idea.
Now, were I do run the LC475 without the top on, and arrange matters so that it got convection ventilation, I suspect that all would be fine. Will ponder that as an alternative possibility. I have been wondering about trying to make myself a sort of 68040-based Cube, so maybe now is the time.
I think you need to get some temperature readings.
maybe use a IR thermometer?
You can sit around 130 degrees F and be just fine.
Touching 130 degrees is going to hurt like hell.. but is perfectly safe for your computer, well most of it. That is a little much for the hard drive in my opinion.
but only way to know is to leave it on after an hour and get some readings.
maybe use a IR thermometer?
You can sit around 130 degrees F and be just fine.
Touching 130 degrees is going to hurt like hell.. but is perfectly safe for your computer, well most of it. That is a little much for the hard drive in my opinion.
but only way to know is to leave it on after an hour and get some readings.
You know what is better than fanless? A fan controller! 
Thanks for the info/ ideas.
I haven't exactly been working steadily on this, so I haven't yet sourced a thermometer to check, but on further research, 130ºF seems to be well within the maximum telerances for the 68040, which according to the Motorola datasheet is a whopping 110ºC, which is enough to burn. So fanless should still be possible.
To make things as "cool" as can be, though, I am toying now with the idea of popping the 475 logic board in the "display" of a Classic front bezel I have lying around, so making it into something computerartsy. The board would be mounted about 1.75" behind the bezel to allow for good airflow, but, you know what? In my mock-ups, it actually looks pretty darned cool. Air circulation would then deal with the heat dissipation.
I don't need the bezel and I don't need a monitor for the AppleTalk router in question — so it might just work. Drive and ps would be relocated to the rear. Doesn't even need a floppy. And no machines will be killed for the hack: I have the spare parts.
I haven't exactly been working steadily on this, so I haven't yet sourced a thermometer to check, but on further research, 130ºF seems to be well within the maximum telerances for the 68040, which according to the Motorola datasheet is a whopping 110ºC, which is enough to burn. So fanless should still be possible.
To make things as "cool" as can be, though, I am toying now with the idea of popping the 475 logic board in the "display" of a Classic front bezel I have lying around, so making it into something computerartsy. The board would be mounted about 1.75" behind the bezel to allow for good airflow, but, you know what? In my mock-ups, it actually looks pretty darned cool. Air circulation would then deal with the heat dissipation.
I don't need the bezel and I don't need a monitor for the AppleTalk router in question — so it might just work. Drive and ps would be relocated to the rear. Doesn't even need a floppy. And no machines will be killed for the hack: I have the spare parts.
Something I've discovered during the process of uprading my '475 is that the simple trick of turning the fan upside down has the effect of dramatically improving cooling (this way it sucks air upwards into the case and blows it out through the case slots and floppy drive).