Apple III low voltages and IDE solution

5 posts / 0 new
Last post
Offline
Last seen: 3 months 3 days ago
Joined: Feb 14 2021 - 10:11
Posts: 6
Apple III low voltages and IDE solution

Hi everyone,

 

Just finished recapping the PSU of an Apple III and tested the output voltages. Got good values on the positive +5V and +12V but the negative voltages are low, -10,8V and -3.9V since this is without load on the PSU are these values ok? I only recapped the RIFAs and the big caps on the 110V side.

Since I don't have a Profile Disk is there any modern adapter to connect a CF or SD card to simulate a hardrive on the Apple III?

Thanks for any help

Dr. Webster's picture
Offline
Last seen: 17 hours 18 min ago
Joined: Dec 19 2003 - 17:34
Posts: 1716
I'm not aware of any modern

I'm not aware of any modern equivalents to the ProFile hard drive -- that was a custom unit, not just an IDE drive in an enclosure. (IDE didn't even exist back then.) However, the Floppy Emu has been made to work with the Apple III and is probably the best solution (and also the most flexible, since it'll also work with any Apple II or Mac machines you might also have):

https://www.bigmessowires.com/2017/01/25/floppy-emu-on-the-apple-iii/

Offline
Last seen: 11 hours 9 min ago
Joined: Jul 31 2014 - 17:48
Posts: 55
Do you know what type of

Do you know what type of memory board is on your Apple III? If it is the newer 5v type (two rows of sockets) then I think there is not much else using the negative voltage rails so you will probably be ok. If you have the 12v type (three rows of sockets), then you will likely need to sort the power supply negative rails out. Those ram chips use multiple supply voltages with one being -5v.

 

For modern storage options in the A3 that are still available for purchase, you can use a Booti card in there with the appropriate driver. If you already have some other AppleII prodos compatible type card, like CFFA or CFFA3k, then these copuls be used as well. You can get generic block mode driver that will work with these here:

https://github.com/robjustice/Problock3

There are ready made disk images available in the releases section.

 

/Rob

Offline
Last seen: 3 months 3 days ago
Joined: Feb 14 2021 - 10:11
Posts: 6
Thanks for the suggestion

"I'm not aware of any modern equivalents to the ProFile hard drive -- that was a custom unit, not just an IDE drive in an enclosure. (IDE didn't even exist back then.) However, the Floppy Emu has been made to work with the Apple III and is probably the best solution (and also the most flexible, since it'll also work with any Apple II or Mac machines you might also have):

https://www.bigmessowires.com/2017/01/25/floppy-emu-on-the-apple-iii/"

 

 

Thanks for the suggestion and I have been using Floppy Emu for loading software but I want to emulate a harddrive.

 

Paulo

 

 

 

Offline
Last seen: 3 months 3 days ago
Joined: Feb 14 2021 - 10:11
Posts: 6
rjustice wrote:Do you know
rjustice wrote:

Do you know what type of memory board is on your Apple III? If it is the newer 5v type (two rows of sockets) then I think there is not much else using the negative voltage rails so you will probably be ok. If you have the 12v type (three rows of sockets), then you will likely need to sort the power supply negative rails out. Those ram chips use multiple supply voltages with one being -5v.

 

 

Hi Rob,

 

I have a 256k with 5v memory board. The Apple III is working fine so maybe the negative voltages aren't important (??) but I will try to buy another Apple III to confirm.

 

The Booti card seems to be a great idea to simulate the HD, I just need to wait until they are available from ct6502.org

 

Paulo

Log in or register to post comments