512k Hyperdrive SSD hack... suggestions? Need to run power.

[olePigeon]

So I'm attempting to build a custom Hyperdrive style upgrade for a 512k using a Supermac SCSI upgrade.  Found this in one of the machines we're going to sell, so I'm trying to pimp it out before I put it up on eBay.  The upgrade is a tiny daughtercard with a Macintosh Plus ROM and SCSI controller.  It sits where the 512k's ROMs used to be and runs a long SCSI ribbon cable to the battery compartment, providing an external SCSI BUS connector.



As you can see, the SCSI ribbon is really long, and I have a SCSI crimp-on IDC header that I can add to anywhere on the ribbon cable.

So what I'd like to do is add an internal SCSI drive.  With the SCSI2SD, it's so small I can mount it pretty much anywhere.  In fact, I already have an idea of where I want to mount it, utilizing the existing screws that already mount the floppy drive.  You can see one of the screws from the left side, it's identical on the right side (two screws hold the floppy in place.) Should be really easy.  Gonna make a custom adapter on the 3D printer, just screw it in along with the floppy like so:



So mounting it and getting the ribbon cable is a snap.  My only problem is the power to the SCSI2SD.  How am I going to do that?  Does anyone have any ideas?  Is there a simple solution?  I'd love to get this working.  A 512k with a Hyperdrive style internal SSD would be awesome!

I remember reading somewhere that there could be a BUS powered SCSI2SD?  Does that exist already?  That'd solve my power problem.

 

[olePigeon]

By the way, if I can get this working, I'm gonna make a custom badge for it.  Call it  "LudicrousDrive"  It's so fast, it's gone to plaid! :lol:

 

[Elfen]

You can pull 12V/5V off the header that connects the analog board to the logic board. I seen this done with actual hard drives in a Mac 512Ke with the SCSI upgrade to them. Best done on the Logic Board end.

 

[CC_333]

Yeah. From what I've read, such hacks done with old, contemporary hard drives proved to be too much for the already overtaxed analog board/PSU, which is probably why they're somewhat rare (I suspect this is probably because most people found it simpler to upgrade to a proper Plus, whether by buying a whole new machine, or getting the logic board-hard drive-rear bucket upgrade kit).

With the SCSI2SD, though, it shouldn't be a problem since the power draw from it would be miniscule in comparison. Especially if it can be bus powered, which would make it a very clean and completely reversible enhancement (save for the extra SCSI connector, perhaps).

I do wish I could come see it before you sell it. Do you think you'll wait a couple weeks? I'll be out on summer vacation in about 1 1/2 weeks, and so might have an opportunity to come by.

c

 

[olePigeon]

I'll do that, then.  I'll solder on a molex cable.  Should be easy.  Do you know off the top of your head which wires are 5v?  I presume black or green is ground.  Usually red is 5v, and yellow 12v.

 

[Elfen]

As I remember - Black is always ground. which is why there are several on the connector. Red is 5V and yellow is 12V, or both should be. The colors do not always line up but that is what it should the be on the color scheme. You can check it with a multimeter - checking the header with the chips set on resistance without the machine being on. Most Chips have a 5V on the first couple pins and ground on the opposite end/side.

CC- the upgrade is simple with Mac 512Ke/Plus ROMs so it it is a 512Ke, then the ROMs do not need to be upgraded. The problem is how the address & data pins go to the SCSI Chip. I'm sure if there is a memory map of the Mac 128K/512K/Plus, one can figure it out. From this, you can build a daughter board with three sockets that goes on to the ROM Sockets with two for the ROMS and the third for the SCSI Chip.

 

[MinerAl]

The +5V wire pin on the Plus's Analog board connector is position 6 (there are eleven positions so you can count from either side, but technically pin 1 is next to the empty pin 2 position: 1 _ 3 4 5 6 7 8 9 10 11). Pins 7 and 9 are ground.  Page 10 of http://home.earthlink.net/~gamba2/images/plus_analog.PDF for more detail.

You should be able to use T-Tap connectors (of the appropriate gauge) and make it easily removable too!

 

[NJRoadfan]

The newest SCSI2SD solves this problem as it can be run off of termination power. The actual Hyperdrive used a power daughter board that tapped off of the AC input.

 

[olePigeon]

Come to think of it, since it's an add-on board only connecting to the ROM sockets, I have to wonder if it has powered termination on that SCSI BUS.  It may be why it's external-only.

I think I'll try out those T-Taps, looks nifty and doesn't require soldering.

 

[max1zzz]

I'v been considering doing this doing this with my 512k with a MacGusto II upgrade for a while, the only reason i haven't done it so far was that the theoretical current draw of the SCSI2SD was surprising high, possibly up to 700ma during writes and i wasn't sure how much spare capacity is in the macs PSU (especially with the extra draw from my upgrade board, which adds scsi, 2mb more ram and a 68881 (when i get around to installing one))

I have been planning to measure the actual current draw for a while, but I haven't got around to it yet...

 

[techknight]

yea, you dont need 12V at all on the SCSI to SD. it is not used. 

On HDDs, the 12V was used to run the servos. 5V for logic. 

 

[olePigeon]

First prototype of the 512K2SD bracket.  Won't know until I get home if it fits, I didn't bring the whole computer in.  But it looks nice so far.

 

[CC_333]

Indeed!

Too bad we don't have more of these SCSI-upgraded 512k's, or else I'd suggest doing this to all of them!

By the way, did you assemble a disk image for putting on the SCSI2SD? I'm too slow getting to mine, so I think if you'd send me what you have somehow, I could proceed much faster with getting the 5 SCSI2SDs I have operational.

c

 

[olePigeon]

I have two folders set up with all the software.  When I'm done erasing the SD cards, I just copy everything over.

 

[olePigeon]

And the cable reaches.  There's about 2 inches of play with the cable after the bucket is on, so it's a much tighter fit obviously than before, but there's room to thread the cable without any strain.  Though, you still have to be careful.  There's room, but not much.

Just need some minor repair on the SCSI board itself and I'll be able to test it.

I'm wondering if it'd be any easier to just flip the board around.  I'll have to experiment.

 

[CC_333]

I have two folders set up with all the software.  When I'm done erasing the SD cards, I just copy everything over.

OK. Maybe when we meet up, you could give me a copy of them on a spare SD card?

Also, what are we going to do with the Pluses? We could conceivably hack a SCSI2HD in those as well, and the best part would be that the hardware already has SCSI support, so most of the work has been done.

Combine that with a ROM-Inator, and we have a SuperPlus!

As for the Classic II's, well, they're harmless

c

 

[olePigeon]

Hehe.  I'm gonna include 2 of these parody badges with the auction.

 

[max1zzz]

Indeed!

Too bad we don't have more of these SCSI-upgraded 512k's, or else I'd suggest doing this to all of them!

By the way, did you assemble a disk image for putting on the SCSI2SD? I'm too slow getting to mine, so I think if you'd send me what you have somehow, I could proceed much faster with getting the 5 SCSI2SDs I have operational.

c

Perhaps new upgrade boards could be manufactured.... I have the schematics for the MacGusto II board in my 512k (but we would have to ask ddenowh (one of the original creators of the board, who sent me the parts for mine) if we made a carbon copy of it) However as that requires substantial modification of the 512k's logic board most purists would disagree with it

But I would think it would be possible to make a MacSnap style solderless upgrade (assuming the macsnap scsi cards don't require any soldering? I know their ram cards don't) providing the NCR5380 scsi chips can still be got hold of

 

[olePigeon]

If someone has an xray machine (or whatever you use to image motherboard layers,) I could let you borrow my Supermac.  It just sits in the ROM slots, no soldering.