Help! Problems connecting 3.5" HD to Viper520

[mr_a500]

I've been attempting to connect a 3.5" harddrive to my Viper520. I already have a 2.5" HD connected. I'm using a junked crap PC power supply to power the 3.5" drive and have the 3.5" drive cable correctly connected to the Viper. I also have master/slave jumpers set.

The problem:
As soon as I turn on my Amiga, the PC power supply switches off - meaning no power to the 3.5" drive. When I turn off the Amiga, the PC power supply works again. The same thing happens when attempting to connect a CD-ROM. WTF? Any ideas?

[mr_a500]

Yes, I thought it must be something like that - signal from PC motherboard. Is there any way to disable that? (I don't want to have to search around for old power supplies - or pay for them. This was just for a quick emergency backup.)

Quote:
"btw, I wish the Viper/Mtec520 was still available"

He, he :-D I found mine in Australia a couple years ago brand new. I got the last one. I think the reason they still had it was that they didn't mention "Viper520" anywhere in the advertisement. (they're out of business now)