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If you want to boot one without a good battery, you need a later PowerBook AC adapter, one that puts out at least 2 amps. I use a model M5652, which is 3.0 Amps at 7.5 Volts. It's still not as reliable as having a good battery. The surge of power needed to spin up the HD is too much for the...

Now you're talkin! I've been thinking the same thing. Just don't have time to take on a project like that.

A0 is called UDS (Upper Data Select) and LDS (Lower Data Select) at the 68000 chip. That way, it can read either byte singly or both together. You're right, A0 as such doesn't usually appear naked on CPUs beyond 8-bits. By extension, 32-bit 68020s read 4 bytes at a time, so A0 and A1 are...

Use a flexible steel or plastic ruler.

To start with, A0 selects the low or high byte ROM for 8-bit read, then A1 - A16 select the individual byte in each ROM out of 65536 possibilities or 64K, so 2 x 64K = 128K bytes of address space. The original ROMs hold 32K bytes each, and they occupy half the address space. If you dump the...

As mentioned, you want to be at 72 DPI, so display a page in MacDraw or MacWrite with the rulers showing, hold a real ruler against the screen and adjust to match.

The switch goes to the chip enable pins. I don't remember the pin number off hand, but if you're building a Bass adapter, it should be noted on the diagram. Micah's ROM should work with most early SCSI drives and a Bass-style adapter. The Micah HD used a SMS 3100 SCSI-to-MFM controller card and...

Model number? Some drives like the early Conner SCSIs didn't support low level format by the user, since they had a system of assigning spare sectors for failing ones. Problem is, when all the spares are used up... and some just plain didn't work. There are some very advanced SCSI utilities...

That's do-able, too. Put two sets of ROM sockets on your SCSI adapter with a switch. A SCSI ROM isn't impossible, it's just a lot of work for a problem that's already been solved. Micah's ROMs were written by Steve Brecher, a real Mac Guru, and he spent six months refining and debugging them. I...

Yes, dead portables are becoming common in the last 2 or 3 years. The 5120s are suffering from leaky caps, mostly, and are fairly easy to fix if the corrosion hasn't spread too far. The backlit 5126es have tantalum caps for the most part which don't leak, but the voltage regulator custom IC is...

Note: I split the Apple II stuff off into a separate section. It's here now: http://web.me.com/henryspragens/Apple-II/Welcome.html As time permits, I want to add some graphics (Movies on an Apple II?) and for the very few fans of 8-bit music, a bunch more of that.

The SCSI board is simple, and if you happen across a Micah internal SCSI hard drive kit which existed for both the Mac Plus and the Mac 128 / 512, you'll have essentially the Bass SCSI port. Micah's SCSI adapter added 2 ROM sockets so the DRVR could be present at boot, and a 64K ROM Mac could...

G4 towers have 2 ATA busses, a slow ATA buss to which the optical drive and Zip Drive attach, and a fast ATA buss for hard disks. If you need big cheap modern drives, you'll need to add a PCI SATA controller. The PATA to SATA adapters take away the possibility of more than one drive on a buss...

The combo of solder and electrolyte produces a crust that doesn't conduct heat, so it's hard to melt the solder. There's also a couple of largish dabs of high temp epoxy under each cap. You are going to have to mechanically break the caps loose, I fear. I pry one of the corners up, then an...

Won't fit. The drive bay in a portable is 3.5" deep, and a CD is 5.25" diameter. It seems dual floppy Portables were very rare beasts. Portables were so expensive the few who could afford them weren't phased by the extra $800 for a hard disk.

Apple occasionally thinks different. The design of the Apple 1 and II, and the Mac were done in the absence of a bureaucracy. (See Andy Hertzfeld's wonderful stories at http://folklore.org/index.py). As a result of designing under the pirate flag, when the Apple II and the Mac first shipped...

Gaaahhh! Part numbers! In any big company everything has a part number, and that number may be on the part someplace. There is a number for the board artwork, that is the layout of the traces. There is a number for the silk screen legends. There is a number for the bare board. There is a number...

About the same. In either case, or the case of driving a CGA monitor, the scan rate has to be changed from 26 KHz (IIRC) to 15.75 or 15.62 KHz, so there has to be a frame buffer (RAM), and circuitry to deserialize the Mac video and stuff it into RAM, and circuitry to reserialize the RAM data...

The question is moot now in the USA because NTSC broadcasts have ended. ATSC digital is not NTSC.

I'll go along with that - mostly. It looks to me like the RCA cables terminate in a 2-pin plug at the mystery board, so my guess is they are wired together and bring the (mono) sound out to a stereo amplifier. The 9-pin plug is probably video for a TTL RGB monitor / projector, so neither NTSC or...