Re: ZX81 cooling fan
Posted: Mon Nov 13, 2017 1:58 pm
But note that O rings are normally used between the fan and the bolts/screws that are used to fit the fan to the enclosure/case or heatsink...
Mark
Discussion forums for users of the Sinclair 8-bit range of computers - ZX80, ZX81, ZX Spectrum, Z88, clones...
https://sinclairzxworld.com/
But note that O rings are normally used between the fan and the bolts/screws that are used to fit the fan to the enclosure/case or heatsink...
Short answer, normally yes. Either use a suitable resistor or use a lower supply voltage.Lardo Boffin wrote: ↑Mon Nov 13, 2017 1:24 pm For the electronically minded - if we reduce the voltage to the fan will it just reduce the speed a little?
I am wondering whether there will be a good tradeoff between speed (and noise) and cooling ability?
Thanks. Do you know any good quality 12v fans that are ideally 25 by 25 by 7.5 or failing that 25 by 25 by 10? I guess we could go to 40 by 40 by 10 with a little surgery...Moggy wrote: ↑Mon Nov 13, 2017 2:58 pm Rather than faff around with resistors or making the job more complicated than it needs to be just use a 12v fan tapped off 9v.
I have done this on a Fuller cased zeddy result adequate air movement and near silent running, the fan doesn't need to running at 10,000 rpm to shift enough air.
Cheap/small fans by nature are badly balanced and this is exaggerated when run at full speed as I've said before a gentle throughput is all that's required not a hurricane.
Just nipped into attic and removed a chipset fan of the same dimensions as yours,Lardo, and quickly wired it up to the 9v on my test 81 with xpand and zonx box connected and at 9v running I was surprised to find it still a tad noisy but at 5v really quiet and still a good airflow so will continue this evening to fit to a normal zeddy and post results.Lardo Boffin wrote: ↑Mon Nov 13, 2017 3:21 pmThanks. Do you know any good quality 12v fans that are ideally 25 by 25 by 7.5 or failing that 25 by 25 by 10? I guess we could go to 40 by 40 by 10 with a little surgery...Moggy wrote: ↑Mon Nov 13, 2017 2:58 pm Rather than faff around with resistors or making the job more complicated than it needs to be just use a 12v fan tapped off 9v.
I have done this on a Fuller cased zeddy result adequate air movement and near silent running, the fan doesn't need to running at 10,000 rpm to shift enough air.
Cheap/small fans by nature are badly balanced and this is exaggerated when run at full speed as I've said before a gentle throughput is all that's required not a hurricane.