Powering a Power CD?

[G.A.Pster]

I have a Mac power CD it doesn’t have its powerbase so it’s a paperweight.

I have 10v transformers, and scsy cords, do any of you know which pins on the scsy port need to be powered to get this thing to run?

If so I could make it into a stand-alone CD player (an improvement over a paperweight).

:lol:

 

[Trash80toHP_Mini]

I have a Mac power CD it doesn’t have its powerbase so it’s a paperweight.I have 10v transformers, and scsy cords, do any of you know which pins on the scsy port need to be powered to get this thing to run?

If so I could make it into a stand-alone CD player (an improvement over a paperweight).

:lol:

That is NOT a SCSI Port! That's a generic DB-25 Connector! Apple was the only Dip$h . . . erm . . . idiotic . . . organization . . . that foisted this sub-standard connector on their users. It was used just to save room on the back of the 512ke, instead of using the Industry Standard Centronics 50 Connector that has been in use since the Mini-Computer era! Other companies followed suit, but it was a stupid notion to begin with and it's STILL a . . .

mode>

That said, unless they torqued everything out of spec (not at all uncommon within the infinite loop) they must have uncoupled some of what are "supposed to be" alternating ground/signal lines. I thought they tied all twenty-five ground lines together at the DB-25 end of their bobbed "SCSI Cable" instead of having discrete connections at both ends of the ground lines per the SCSI Spec. They may or may not have done so, but the DB-25 <-> DB-25 connector linking the two halves of the PowerCD may be something entirely different!

Check the standard pinout of Apple's DB-25 "SCSI" connector against the pinout for the Standard Centronics 50 SCSI Connector at the "peripheral" end. Hook up the DB-25 end to the PowerCD and buzz the connections on the Centronics 50 end with a continuity tester. You're looking for a few "ground lines" that aren't connected to the Ground shells of either the DB-25 or the Centronics 50. If they all connect to ground, you'll have to "roll your own cable."

But if you find one, or several, "ground lines" at the Centronics 50 end that aren't connected to ground, but to each other, dollars to donuts, you've found your "power lines." They're actually almost as good as real ground lines for shielding the address/signal lines against crosstalk.

One way or the other, you're going to have to make some kind of conversion that'll let you feed power to the PowerCD while passing through the SCSI Data and Signal lines.

BTW, 10 volts doesn't sound right, are you SURE about that?

Happy hacking, comrade! :rambo:

 

[porter]

That is NOT a SCSI Port! That's a generic DB-25 Connector! Apple was the only Dip$h . . . erm . . . idiotic . . . organization . . . that foisted this sub-standard connector on their users. It was used just to save room on the back of the 512ke

that would be a Macintosh Plus I think, not 512ke.

 

[H3NRY]

I take it you don't have the base for the Power CD? There is a base which has a power jack which takes a 7.5V-9V DC 15Watt adapter like the one for a Mac Portable or a PB 190, a standard 50-pin SCSI, and a compartment for a bunch of AA batteries. I have no idea what the pinout of the DB25 connector which connects the player to the base is, but it's not a Mac Plus SCSI connector.

 

[Hrududu]

I take it you don't have the base for the Power CD? There is a base which has a power jack which takes a 7.5V-9V DC 15Watt adapter like the one for a Mac Portable or a PB 190, a standard 50-pin SCSI, and a compartment for a bunch of AA batteries. I have no idea what the pinout of the DB25 connector which connects the player to the base is, but it's not a Mac Plus SCSI connector.

The connector for a floppy drive or CD drive would be a DB-19 connector, not DB-15 right? DB-15 is the monitor connector correct?

 

[Anonymous Freak]

I have a Mac power CD it doesn’t have its powerbase so it’s a paperweight.I have 10v transformers, and scsy cords, do any of you know which pins on the scsy port need to be powered to get this thing to run?

If so I could make it into a stand-alone CD player (an improvement over a paperweight).

:lol:

That is NOT a SCSI Port! That's a generic DB-25 Connector! Apple was the only Dip$h . . . erm . . . idiotic . . . organization . . . that foisted this sub-standard connector on their users.

Apple was not the only company. Iomega used it on the SCSI ZIP drives, and there were quite a few other peripheral makers that used it.

I think I even had a Compaq with one back in the late '80s or early '90s; but I may be remembering wrong.

To be accurate, GAP should have phrased it as "DB-25 port", yes. (P.S. I don't see you correcting people who improperly use "DB-xx" to refer to ports other than the width of the DB-25 port. -- For those who don't know, only the DB-25-width port is properly "DB". The port width that is used for older 9-pin serial, or 15-pin VGA, usually called "DB-9" or "DB-15" is actually "DE-9", or "DE-15", (ports with two rows of pins are 'normal', ports with three rows are sometimes appended "HD", so VGA may be called "DE-15HD"; except the "DD" size, for which three rows are normal, and four are "HD",) and the port that is used for Apple's older 15-pin Apple video plug, doing double duty as the PC "joystick" port, is properly "DA-15". The second letter refers to the width of the plug, where certain letters are defined for certain widths. See http://en.wikipedia.org/wiki/D-subminiature.)

So, back to the question at hand.

The original poster is looking for the pinout of the DB-25 port that does duty as both SCSI passthrough and power. And, yes, he is saying that he has the PowerCD unit, plus a DB-25 cable (or at least an end) to sacrifice to turn into a power connector. He just needs to know the pinout to make his custom power cable.

I offered to help him over at The Vintage Computer Forums, but my PowerCD and base appear to be firmly in storage, out of easy reach; so I referred him here.

 

[H3NRY]

Apple used 15-pin connectors for monitors from the Mac II up through the early G3s. The floppy drives used 19-pin connectors (20-pins on the mobo). CDROM drives were SCSI before they went USB, and they connected with a 50-pin Centronics plug, or on the Mac end a DB25F.

 

[Anonymous Freak]

I take it you don't have the base for the Power CD? There is a base which has a power jack which takes a 7.5V-9V DC 15Watt adapter like the one for a Mac Portable or a PB 190, a standard 50-pin SCSI, and a compartment for a bunch of AA batteries. I have no idea what the pinout of the DB25 connector which connects the player to the base is, but it's not a Mac Plus SCSI connector.

The connector for a floppy drive or CD drive would be a DB-19 connector, not DB-15 right? DB-15 is the monitor connector correct?

See my Wikipedia link for the proper use of "DB-xx".

The connector Apple used for serial on the 128k through Plus is a DE-9, as often used on PCs.

The connector Apple used on its systems for SCSI is a DB-25. For peripherals Apple used a proper 50-pin micro-ribbon (sometimes called "Centronics") port, including on the PowerCD. (The base has a proper SCSI-1 port.) (Oh, and to wander off on more naming badness, "Centronics" is a company that made parallel-interface printers. Their printers may not have become famous, but their port did. The only proper "Centronics" port is the 36-pin micro-ribbon port used on parallel printers. Yes, the proper name for that style connector is "micro-ribbon". Kind of like how "PS/2" lived on as the name of the keyboard and mouse ports from the such-named computer.)

The connector Apple used for pre-VGA video is a DA-15. (VGA is DE-15, which means it uses an 'E' size shell like a serial port, but crams 15 pins instead of the normal 9. This extra row of pins is sometimes denoted by appending "HD" on the end; which is often also combined with improper use of "DB", making a VGA port improperly called "DB-15HD" to differentiate it from the Apple pre-VGA port being also improperly called "DB-15".)

The connector Apple used for floppy was a custom width, between DA and DB, with 19 pins. So it doesn't even have a proper "Dx-19" name, since there is no letter 'x' to map to its width on the official lists of D-subminiature connectors.

 

[G.A.Pster]

[G.A.Pster] is looking for the pinout of the DB-25 port that does duty as both SCSI passthrough and power. And, yes, he is saying that he has the PowerCD unit, plus a DB-25 cable (or at least an end) to sacrifice to turn into a power connector. He just needs to know the pinout to make his custom power cable.

Yeah, that’s what I need.

And I’m no expert on vintage computers so keep superfluous information to a minimum. 8-o

 

[Trash80toHP_Mini]

That is NOT a SCSI Port! That's a generic DB-25 Connector! Apple was the only Dip$h . . . erm . . . idiotic . . . organization . . . that foisted this sub-standard connector on their users.

Apple was not the only company. Iomega used it on the SCSI ZIP drives, and there were quite a few other peripheral makers that used it.

I think I even had a Compaq with one back in the late '80s or early '90s; but I may be remembering wrong.

Correct, as I went on to say in that paragraph . . . [] ]'>

Other companies followed suit, but it was a stupid notion to begin with and it's STILL a . . .

The Zip went into production many years after the 512ke, the first Mac to have SCSI, IIRC. Several PC mfrs used Apple's bastardization of the SCSI Spec, but it was Apple that opened the floodgates on that particular brand of idiocy.

To be accurate, GAP should have phrased it as "DB-25 port", yes. (P.S. I don't see you correcting people who improperly use "DB-xx" to refer to ports other than the width of the DB-25 port.

Actually, the DB moniker was in such widespread use for ALL "standard density" D-shaped connectors in the computer press back in the day (and persists to this day it would seem) that I never caught on to the existence of "proper" nomenclature! Thanks for setting the record straight about the terms for the different D-Shell widths and use of the HD suffix.

Besides, it's only the DB-25/SCSI nonsense that drives me batty!

Back on topic! :

On further thought, using a straight-thru DB-25 <-> DB-25 cable to compare to an Apple DB-25 <-> Centronics 50 (a TelCo 25 Pair Connector modified by Centronics to use bails in lieu of the offset screw down lugs on TelCo connectors, BTW! [] ]'> ) would seem to be a more comprehensive test.

Meanwhile, you've piqued my curiosity, so I'll rummage through my toy boxes again! :rambo:

 

[Trash80toHP_Mini]

Rummaging Complete: [] ]'>

Take-apart complete: [] ]'>

DATA: equivocal: :scrambled:

As you can see, there's a whole lotta stuff inside the PowerCD's Base Unit. Including a Power Supply in the top section and a CD controller/SCSI Interrface PCB in the bottom of this simple lil' unit!

8-o



I checked the pinouts for Apple's 25 pin bastardization of the SCSI spec and the pins w/ lines running from them should be the ground lines on the diagram. Anything color coded in orange is a strong link to ground. Anything color coded in pencil is a tenuous link to ground. This led me to believe there was a PCB inside the Power Unit. Lo and behold, there's one whole heck of a lot goin' on in there as stated above. Someone will need to use a M <-> F DB-25 adapter as shown above, or a hacked ribbon cable, to figure out what voltages are being fed to the CD "spinner" section over which lines. It'd probly be necessary to noodle out which lines are data and control lines for this low level CD spinner to the MLB interface. It sure ain't SCSI! I'm not convinced that the "spinner" section will even work as a CD player w/o the circuitry present in the base unit's MLB.



Sorry about the "bad" news, comrade, it might work out, but I wouldn't put any money on that proposition.

 

[porter]

The Zip went into production many years after the 512ke, the first Mac to have SCSI,

So that would be the 512ke that (a) did not have a SCSI port and ( B) came out after the Mac Plus.

So apart from those problems, that would make it the first Mac with SCSI. :scrambled:

 

[Trash80toHP_Mini]

The Zip went into production many years after the 512ke, the first Mac to have SCSI,

So that would be the 512ke that (a) did not have a SCSI port and ( B) came out after the Mac Plus.

So apart from those problems, that would make it the first Mac with SCSI. :scrambled:

I defer to your expertise on the matter, especially as it would seem to fit very well into Apple's loooong history of hobbling the entry level machines to "protect" sales of the ridiculously expensive (from a PC user's point of view) high end Macs.

'sides, my brain was recently done "over easy" . . . no home fries on the side . . . it's toast! :simasimac: