Posted By
MMS
on 2019-06-17
13:45:36
 |  Re: how lowering temperature for TED CPU chips
Actually in C16 there is an additional heat source: the PSU gives an unregulated 9V, and it set to the proper voltage within the machine. (regulator)
This emits a lot of heat, and there was a similar experiment on ZX Spectrum 48K and 128K, how much heat they produce becasue of this. C16 works exactly in the same way, in fact can use ZX Spectrum PSUs.
In Spectrum +3 they changed the PSU to something similar to Plus/4 and C64 have, so that additional heat source (still exists in C16) disappeared.
Plus/4 is much smaller inside than the C16, so aregulator togeher with the extra ROMs and ICs this heat would boil the machine, but with the C64 type PSU it was still manageable.
C116: I have no clue how they manage temperature, but it should be high 
Actually one thing was not tried out yet (or at least not with measurements): the active cooling. AFAIK someone in the US has such acooling, but dunno how efficient it is.
I made a joke about it few years ago, but in fact I found it to be an interesting idea.
If you compare your "Hot points" map VS the potential airflow of a User port fan, it more or less fits to each other
Certainly the TED metal heatsing of the blocks the airflow, pls do not count with that, it was just a quick draw.
I mean more air goes towards the PLA and old ROM chips
But the 7501/8501 would get the cooling it deserves (certanly some heatsink does not hurt).
Unfortunately there are some issues:
-User port's 5V cannot provide enough current for a PC Fan. Some external fans for PC uses 5V DC from USB, but unfortunately still requires higher current.
It means you need an external USB power source
-The dimensions of the existing ones does not fit to the User port.
I planned to rebuild a Commodore modem, but it would be a brutal action to cannibalize a working C= modem, when it could also work with a Plus/4. It is also rather hard to find one here, whil in US they are more frequently available, but prices going up + shipping cost.
-the airflow is typically from inside out, while I think in our case I thing the direct cooling with "from outside to inside" (as above) airflow could be better.
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