MP 7,1 That Pegasus J2i Cage - Internal HDD Mounting

[AidenShaw]

Just ordered a J2i. Will slot in a 2TB HD from my old Mac (including a shedload of assets) and have 12TB at my disposal (plus Time Machine backup).

Have you considered buying a new high capacity drive for the J2i ?

Seems a waste to put a small drive like that in the system. Also, have you run a drive diagnostic on the old drive? It might have errors, or be old and potentially on its way to failure. I don't trust old spinners.

 

[bwinter88]

You are correct with the Molex connector pins going to more than one pin on the SATA power connector. SATA power pins are rated for 1.5 amps per pin. Molex pins are rated for multiple times that, typically 6-8 amps depending on part number.

Should be one 12v, one 5v, two grounds, and one 3.3v.

It’s possible that one of the pins on the motherboard is Power Disable that goes to SATA power pin 3. If you find a pin that gives near zero volts but isn’t ground then gives 2.5-3.6 volts when the system is sleeping, that’s Power Disable. If there is no Power Disable pin on the motherboard, then do not connect SATA power pin 3 to anything. The old standard was to feed 3.3v into pin 3. If you do that with newer drives, they’ll stay in Power Disable (off) mode all the time.

Really good info. I would assume Apple would include a Power Disable pin as it was on the 5,1 no? From this pic it looks like the Promise cable is not using two of the ten pins on the connector. I assume they decided a single ground line per power connection was adequate.

 

[joevt]

Really good info. I would assume Apple would include a Power Disable pin as it was on the 5,1 no? From this pic it looks like the Promise cable is not using two of the ten pins on the connector. I assume they decided a single ground line per power connection was adequate.

Looking at these pictures:

https://forums.macrumors.com/attachments/img_8218-jpg.882830/

The Pesky PWDIS Feature In Newer SATA Specs

The SATA 3.3 specification's Power Disable feature is one you should take into account if you plan to acquire a HDD that supports it but still use an older power supply.

www.tomshardware.com

It looks like the J2i cable is missing 3.3V and only has ground, 5V, ground, 12V.
If the power cable only has 4 conductors, I don't see where you would have a Power Disable pin. Maybe one of the grounds but probably not.

 

[Slash-2CPU]

It’s probably 5V, 12V, and 2 grounds then.

The unused pin is maybe 3.3V or maybe Power Disable; leave the lid on that can of worms. You don’t need power disable, and no normal drive has ever used 3.3V.

I’ve only ever encountered one 1.8” SSD from a kiosk type machine that needed 3.3V.

 

[HDFan]

Nope, I have loads of super fast external networked storage.

Out of curiosity how fast? 10G ethernet ports are still relatively rare, and aren't that fast ...

and they go up to 16 TB).

and 20 TB drives are coming:

Western Digital 20 TB HDD: Crazy Capacity for Cold Storage

www.anandtech.com

 

[bwinter88]

Drumroll please...the pinout is as follows, looking at the board, (or reverse of the cable connector) with the tab on top:

==============
IIIIIIIIIII​

GND​	12V+​	GND​	5V+​	GND​
GND​	12V+​	GND​	5V+​	GND​

I have a drive mounted using this cable and the internal SATA connection.


The connector is here

Molex Micro-Fit 3.0 Dual Row (10 Circuits) Male & Female Receptacle Plug, w/Terminal sockets, (Pack of 1 Complete Set)

Molex Micro-Fit 3.0 Dual Row (10 Circuits) Male & Female Receptacle Plug, w/Terminal sockets, (Pack of 1 Complete Set)

www.amazon.com

But do not attempt to make this cable without a crimp tool

iCrimp SN-01BM Ratchet Crimper AWG28-20 for XH2.54/3.96,PH2.0,PX,JST,Molex Terminal

iCrimp SN-01BM Ratchet Crimper AWG28-20 for XH2.54/3.96,PH2.0,PX,JST,Molex Terminal

www.amazon.com

And buy a nice pre-made SATA power cable to splice into instead of making it from scratch

StarTech.com 15.7 in (400 mm) SATA Power Splitter Adapter Cable - M/F - 4x Serial ATA Power Cable Splitter (PYO4SATA)

StarTech.com 15.7 in (400 mm) SATA Power Splitter Adapter Cable - M/F - 4x Serial ATA Power Cable Splitter (PYO4SATA)

www.amazon.com

 

[bxs]

Thanks much. 👍

 

[skippermonkey]

Have you considered buying a new high capacity drive for the J2i ?

Seems a waste to put a small drive like that in the system. Also, have you run a drive diagnostic on the old drive? It might have errors, or be old and potentially on its way to failure. I don't trust old spinners.

I'd hardly call 2TB small. Anyway, it's not that old and I'll upgrade it at some point. All my HDs (discs and SSDs) have worked flawlessly for years.

 

[AidenShaw]

I'd hardly call 2TB small.

Wait until it's full....

 

[joevt]

Drumroll please...the pinout is as follows, looking at the board, (or reverse of the cable connector) with the tab on top:

==============
IIIIIIIIIII​

GND​	12V+​	GND​	5V+​	GND​
GND​	12V+​	GND​	5V+​	GND​

Is there no 3.3V easily accessible anywhere in the Mac Pro? I guess a simple circuit can give 3.3V from 5 or 12V.

 

[Slash-2CPU]

3.3v is worthless. Don't bother.

 

[bwinter88]

Is there no 3.3V easily accessible anywhere in the Mac Pro? I guess a simple circuit can give 3.3V from 5 or 12V.

You can use a buck converter, or a regulator IC. But why do you need 3.3V?

 

[joevt]

You can use a buck converter, or a regulator IC. But why do you need 3.3V?

What about a simple resistor/resistor voltage divider?

I used 3.3V to connect a couple GC-ALPINE RIDGE to my Mac Pro 2008. Not really necessary for the Mac Pro 2019 since you can't buy it without at least four Thunderbolt ports.

 

[bwinter88]

What about a simple resistor/resistor voltage divider?

It might work, but in general it’s bad practice to power ICs with voltage dividers since the voltage fluctuates with current draw.

 

[bwinter88]

Alright, well, the 4xSSD cage and 2x3.5" are done.

The STL files are here https://www.thingiverse.com/thing:4067905

From a printing service like MakeXYZ.com, The SSD cage is $85.90 to print and ship. Not bad when competing against $400.

I haven't printed the 3.5" cage so do so at your own risk, but the mounting holes are the same as on the SSD cage. I just don't know how well it fits yet.

I have the 24-core, Vega II Duo machine. I've realized in short order that SATA, even in a RAID 0 configuration, is the bottleneck in this system—in order to feed this beast enough data to really utilize all of it, you need to be using NVMe, or M.2 drives. I think the internal SATA is really only good for spinners acting as a Time Machine backup. So I will probably go down the adventure of making a cage for a 3.5" disk.

 

[bxs]

Thanks for doing this.... IMO your cage should also have a lip to use the two screws on the upper case plate to firmly secure the cage. Without this and placing 2x HDDs in the cage the weight could be excessive on the 3 back mounting holes used to hook onto the motherboard's lugs. No matter, an excellent solution... Well done. 👍

As an aside.... What kind of plastic is this manufactured cage made of? With the heated air from the processor heat sink blowing over the plastic cage the plastic 'aging' effect could mean the plastic become brittle over time and prone to cracking and ultimate failure. This would be more of a problem with 'weighty' 2x 3.5" HDD in place. Just a thought....

 

[Ludacrisvp]

Alright, well, the 4xSSD cage and 2x3.5" are done.

The STL files are here https://www.thingiverse.com/thing:4067905

From a printing service like MakeXYZ.com, The SSD cage is $85.90 to print and ship. Not bad when competing against $400.

I haven't printed the 3.5" cage so do so at your own risk, but the mounting holes are the same as on the SSD cage. I just don't know how well it fits yet.

I have the 24-core, Vega II Duo machine. I've realized in short order that SATA, even in a RAID 0 configuration, is the bottleneck in this system—in order to feed this beast enough data to really utilize all of it, you need to be using NVMe, or M.2 drives. I think the internal SATA is really only good for spinners acting as a Time Machine backup. So I will probably go down the adventure of making a cage for a 3.5" disk.


View attachment 886792

Ok so you’ve got 4x ssd in that cage, now consider there are only 2 sata connectors on the motherboard, how are you connecting those drives to the machine?

Yeah, 3.3v is worthless for drives as mainly because if it was used the IDE Molex to sata power cables could almost never be used. Generally if a drive needs 3.3v it has the circuitry on board to get it from the 5v or 12v power source.

 

[ZombiePhysicist]

Alright, well, the 4xSSD cage and 2x3.5" are done.

The STL files are here https://www.thingiverse.com/thing:4067905

From a printing service like MakeXYZ.com, The SSD cage is $85.90 to print and ship. Not bad when competing against $400.

I haven't printed the 3.5" cage so do so at your own risk, but the mounting holes are the same as on the SSD cage. I just don't know how well it fits yet.

I have the 24-core, Vega II Duo machine. I've realized in short order that SATA, even in a RAID 0 configuration, is the bottleneck in this system—in order to feed this beast enough data to really utilize all of it, you need to be using NVMe, or M.2 drives. I think the internal SATA is really only good for spinners acting as a Time Machine backup. So I will probably go down the adventure of making a cage for a 3.5" disk.


View attachment 886792

So will your cage hold 4 15mm drives? The real value for such a cage is to fit say 4-6 15mm 2.5" U.2 drives that are all NVMe, and you can connect to a HighPoint 7120 card. Then you just use the sata power connector to power those drives.

Actually, I think a bay that has room for one 3.5" spinner and say 2 to 4 2.5" U.2 drives would be amazing. You could throw in one 16TB spinner for time machine via sata. and then hook up the U.2 drives to the PCIE card. If you could fit 4 15.36 TB Micron 9300 Pro U.2 drives, and one 16TB Seagate Exos spinner, that would be a hell of well packed storage bay.

Also, I would try to make a more open design. I wouldnt want a cage surrounding the drives and want to have a minimal skeleton holding the drives so maximize airflow around the drives.

Regardless, Kudos on getting your own storage bay working! A very excellent and handsome result!

 

[bwinter88]

Thanks for doing this.... IMO your cage should also have a lip to use the two screws on the upper case plate to firmly secure the cage. Without this and placing 2x HDDs in the cage the weight could be excessive on the 3 back mounting holes used to hook onto the motherboard's lugs. No matter, an excellent solution... Well done. 👍

As an aside.... What kind of plastic is this manufactured cage made of? With the heated air from the processor heat sink blowing over the plastic cage the plastic 'aging' effect could mean the plastic become brittle over time and prone to cracking and ultimate failure. This would be more of a problem with 'weighty' 2x 3.5" HDD in place. Just a thought....

I have ABS printed parts that have sat outside in the sun or over my stovetop for years, I don’t think you give the material enough credit. It’s quite robust. There are also three lugs on the top of the case that the cage hangs from, which are more than enough to hold the weight. I tried making the tab at the two screw holes, but it would be too thin to add much structural benefit. It fits very snugly—it’s not going anywhere, even if you tip the machine.
[automerge]1578252003[/automerge]

Ok so you’ve got 4x ssd in that cage, now consider there are only 2 sata connectors on the motherboard, how are you connecting those drives to the machine?

I have an internal SAS card leftover from my 5,1. Interestingly, I thought I would have to replace it after I learned that the RAID utility wouldn't run on Catalina—until I realized it would still run fine in Windows Boot Camp. Configure the onboard RAID using Windows, and when you pop back to macOS, the drives appear as normal!

If you could fit 4 15.36 TB Micron 9300 Pro U.2 drives, and one 16TB Seagate Exos spinner, that would be a hell of well packed storage bay.

Crazy! I wish I had that kind of money to spend on drives.

 

[bxs]

So will your cage hold 4 15mm drives? The real value for such a cage is to fit say 4-6 15mm 2.5" U.2 drives that are all NVMe, and you can connect to a HighPoint 7120 card. Then you just use the sata power connector to power those drives.

Actually, I think a bay that has room for one 3.5" spinner and say 2 to 4 2.5" U.2 drives would be amazing. You could throw in one 16TB spinner for time machine via sata. and then hook up the U.2 drives to the PCIE card. If you could fit 4 15.36 TB Micron 9300 Pro U.2 drives, and one 16TB Seagate Exos spinner, that would be a hell of well packed storage bay.

Also, I would try to make a more open design. I wouldnt want a cage surrounding the drives and want to have a minimal skeleton holding the drives so maximize airflow around the drives.

Regardless, Kudos on getting your own storage bay working! A very excellent and handsome result!

The Promise Pegasus J2i's cage has an internal vertical space of 72mm. Thus 4x 15mm drives can be installed with air space between them without to much bother. Just need some caddy to hold all of them in place. Not sure though how to power all 4x 15mm units.

 

[ZombiePhysicist]

I figure you can split from the SATA power

The Promise Pegasus J2i's cage has an internal vertical space of 72mm. Thus 4x 15mm drives can be installed with air space between them without to much bother. Just need some caddy to hold all of them in place. Not sure though how to power all 4x 15mm units.

I figure you can split from the SATA power connectors. I figure 2 spinners draw more than 4ssds.

 

[Zdigital2015]

I'd hardly call 2TB small. Anyway, it's not that old and I'll upgrade it at some point. All my HDs (discs and SSDs) have worked flawlessly for years.

2TB is a flea bite at this point...

All HDDs work flawlessly until they don’t...AMD the begins the wailing and gnashing of teeth. Don’t trust them any further than you can throw them.

 

[bwinter88]

These are actually kind of fun to make and I have some leftover parts, enough for 3-4 more. PM me if you want one.

 

[bxs]

Can you explain what this cable is used for ? Thanks...

 

[bwinter88]

Can you explain what this cable is used for ? Thanks...

This is how you power any internal SATA drives. The cable is only available as part of the $400 Pegasus J2i cage, this is so people can still hook up drives without having to buy the whole kit.