The Commodore A590 and the GVP HD+ (and therefore, probably the HD8+), can easily be modified to run from power supplied by the amiga.

The A530 may be modifiable but it's 030 will probably require even more power than the above.

I think all the devices mentioned in this topic did come with external power supplies.
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Couldn't some be modified to draw power from th parallel port?
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But that would be no different from drawing the power from the PSU!
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I know. However because most of the expansions were not designed to draw power directly from the expansion bus, I remember there were some modifications to instead take it from the parallel port. Obviously there is the danger of overloading the PSU, but at most the system would probably not boot, or would be very unstable and keep resetting.
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Okay, this expansion gave me a SCSI hard drive and 2 megs of RAM. It had NO power cord, my A500 has not been modified in any way. I made the mistake of selling it a couple of years ago. I will search through my paperwork & emails, perhaps I'll find out what it was. If I do, I'll post it for everyone for future reference.
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I don't think it can be made by Commodore themselves, or GVP, as both makes were normally always self powered from an extra PSU.

There is the Protar A500HD which works the other way around and its PSU can power the A500.

I'm about to start adding A500 hardware to the new classicamiga Hardware directory that I'm going to be launching this week, so if I find any that are powered via the A500 I will let you know.
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