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-   -   Amiga 2000 fan mod help (http://eab.abime.net/showthread.php?t=99945)

Elahrairah 07 December 2019 13:02

Amiga 2000 fan mod help
Hi guys and girls

So I did a fan replacement on my old Amiga 2000, noctua fan, the one recommended, 12v Noctua NF-A8 ULN. I did the wiring and when I test it the fan spins, low noise, perfect.
But when I connect the motherboard to the power supply the Amiga boots for a few seconds and then stops. No picture, nothing. All cards (I don't haved any) and floppy are removed.
Tried the old fan and everything works again. Amiga boots and works fine.
What am I doing wrong?
Also maybe good to mention the metasl psu cover has small (ventilation?) holes. It's not like the Amiga 2000 psu I've seen online. Maybe this type of psu doesn't support it?

katarakt 13 December 2019 11:25

The problem is you're using an elec&eltec powersupply in combination with this fan. This power supply needs a fan with a minimum consumption of around 0.7+ watts and the noctua has a lower power consumption...therefore the powersupply switches into protection mode.

You have to solder a 270 ohms/2 watts resistor in paralell to the fan connector and it will work! I've done this with a blacknoise M8-S1 with 0.36 watts and it's working excellent. Your noctua will work too if you're going to solder the resistor.

Jope 13 December 2019 12:27

Resistor I guess?

hooverphonique 13 December 2019 13:08

Sounds like the fan works, but the Amiga won't boot - then I don't think it's anything to do with PSU protection mode.

Are you using the original A2000 PSU? If so, maybe the noctua fan is causing (larger) ripple on the +12V rail, and this could be due to the electrolytic capacitors in the PSU being dry and need replacement.

katarakt 13 December 2019 14:44

Sure, i meant resistor...have edited my post.

No, it's exactly the symptom with an elec&eltec what Elahrairah described with too low fan-power consumption! I'm sure it's an elec&eltec and he will confirm it is :)

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