A tour of the motherboard
Mark Kaelin is a CBS Interactive Senior Editor for TechRepublic. He is the host for the Microsoft Windows and Office blog, the Google in the Enterprise blog, the Five Apps blog and the Big Data Analytics blog.
You missed one of the most amazing points here. The inside of the case, removed, in "embossed" with the signatures of every member of the Mac team, including Jobs, Woz, Andy and all.
Thos little chips at http://content.techrepublic.com.com/2346-10877_11-206772-36.html They look like Op Amps to me. Things that amplify/regulate signals. From the way they are placed I suspect they are the opamps for the read/write heads.
Missed (Ithink) the most interesting aspect of all. The inside of the case was signed by the people on the program. Watch the video "In Search of Excellence".
I have a tool at home that looks like a 2-foot long 'T'. One end is a Torx bit that will unscrew the Mac case. The other end has a pair of opposed 2" squares, one of which is attached to a lever. You insert the square into the seam that runs around the Mac and depress the lever. It then opens up the case.
Nice trip down memory lane. I had a 512K "Fat Mac" in 1986 that I upgraded to a whopping 1MB RAM. Like many others, I damaged the CRT, which has a very sensitive glass nipple. I replaced it with an amber screen which was 9" diagonal. Amazing we could do any work with these machines, but the system overhead was negligible. In 1990 I was doing plenty of RAM and SCSI HDD upgrades to SE/30s, and as late as 1995 was producing a weekly newspaper on an SE with a Full Page Display. I miss the old all-in-one Macs and Powerbooks. MIDI and DTP were awesome back then. It was special to be a computer user. Now everybody's doing it all the time, and it's gotten tedious. I got a few old Macs in the basement and I go there evenings to get disconnected and creative. It's very relaxing. Thanks for the gallery Ammo
I've seen 8kb chips on a "memory board" (size of an EISA) in military phone equipment made in 1970's
The Mac Classic (or the Skinny Mac) did not have a hard drive. It had a single 3 1/2" floppy drive. You could purchase an external floppy for between 300 and 500 dollars but no hard disks. Way too costly. Russellphoto
Perhaps the Classic didn't have them, but if you have a Mac Plus or SE, you will find Steve's and Woz's and the rest of the development teams signatures on the inside of the case. My Mac SE, circa 1989 is still beating me at chess.
This was the first REAL computer I got to work & learn on. My first computer was a Timex Sinclair 1000 (how about cracking that open), then the Commodore 64 then I broke down & spent the chubby bucks on a Macintosh Centris 610. I can't remember what I paid for that, all I know is purchased a used SCSI HD from a friend, 730Mb, I think I paid him $140.00 FOR LESS THAN A GIG.
I think the RAM count might be wrong. I had the Original Mac in 1988 and it had 128KB of RAM. I seem to recall the Mac Classic featuring only 1MB of RAM. So, think the RAM count might be off by a factor of 4. 4MB in an early Mac seems like too much.
Nice to see that. I still have an SE/30 sitting on a cupboard in my house. 68030 processor - 32Bit enabled. In 1989! The SE/30 (Classic derivative) even has 32bit colour, although that is not visible on its b/w screen. I guess that it was equipped with the same internals as the other Mac II range, which did have color monitors - LCII etc.
The SCSI (Small Computer Serial Interface) was designed as an "intelligent" computer peripheral. The idea was to offload the main processor from telling the disk drive where to find data, etc. Instead the main processor "told" the drive the data it needed (or was writing) and the drive figured out where to read / write and how to read / write the data. Thats' why the SCSI disk drive was (is) more expensive than a current disk drive, it had brains!
Those are not one 250vdc capacitor and one 220vdc capacitor, they are both 250vdc capacitors with 220 pico farads of capacitance.
Back in my earlier IT days (1990-1995) we had Mac's and PC's to support. If you notice, the Mac's of this era didn't really require the parity chip so if you look closer at the SIMM it only shows 8 and not 9. Most of the PC's did require the parity chip although on some of the older motherboards you could disable the parity so you could use the same SIMM as that in the Mac. From the pictures, one thing that also brought back memories was the SCSI hard drives - namely the resistor packs. Some of other machiens we had also used SCSI hard drives and we'd have to pull the resistor packs because they weren't at the end of the chain and they'd end up missing, lost or used on another SCSI drive. And there was a time where not all resistor packs were the same (namely different pin count) and so we use to just tape them to the drive or somewhere in side the case whenever they had to be removed. Later (I forget the maker), there were SCSI drives where the resistor packs were soldered to the PCB and you'd either jumper it or flip a dip switch to enable or disable the packs.
The mystery goop you discovered inside the case is most likely a waxy, heat induced bleed of the substance used to pack the windings of one of the transformers used in either the main AC supply, or more probably from the flyback transformer in the CRT power section. It could be capacitor dielectric bleed, but your pictures showed only sealed, canister caps, not any of the paper/wax capacitors.
Are you sure it had 4 MB of memory? For a 40 MB SCSI hard drive, which was a lot for it's time, I don't think it would be 4MB of memory. Especially when I see from the picture 256x4. I would believe 1 MB of memory, of which 256 KB was on the motherboard and 758 KB on the expansion slot. Most likely, it was sold as a 512 KB Ram with slots to bring it to 1 MB. I'm not sure, and don't remember SIMMs chips being larger than 256 KB.
I've had a number of Macs (and PCs) over the years. By far my favorite has been the SE/30. I had a carrying case around that I used to lug that sucker around between home, school & work. I *still* have it, and last I fired it up, ~1 year ago, it ran like a champ. My MacBook Air is pretty nice, too, though. And a lot easier to transport.
What size Torx do you need to crack open this baby? I began using Torx about two years ago after buying an old(er) PowerBook G3 ("Wallstreet", or maybe it was a "PDQ"). Torx 8 or Torx 6, IIRC. Just last week I "graduated" to a PowerBook G3 "Firewire" (AKA "Pismo"), which requires a Torx 8, IIRC...
Surprised that the Power/Video board was unshielded? The case of the Mac was coated with a coating that shielded the radiation. It kept cooler from not adding what was not generally needed. As for having the proper tool to open the Mac, I still have my long torx, and still have my Mac Plus, which is still working, the last time I checked.
I'd gotten a MacPlus in 1987 when I started college at U of M, Ann Arbor. Loved it. It got the extra floppy drive, so I didn't have to swap the OS out all the time. Cracked it open to add memory, maxed it out at 4 MB, in 1990. Bought an external 20 MB hard drive too. Later it was over heating, so I modded the case to add on a cooling fan. It continued to work for a few more years, but finally the capacitors in the CRT went, and the video scan collapsed. :-( I bought the replacement caps, but never went through with the install. By then, I had gotten a PC.
Using the current Technology of the time it is a lovely unit really. Great to see early VLSI stuff all over again and the very early Surface Mount stuff on the Connor Drive I had forgotten just how many chips they had stuffed onto those Boards. Only real worry with older equipment is leaking Capacitors which held some nasty stuff in them in their day. But even if you didn't have the right tools the Torx in question was a very common tool then and the equipment that was not wanted to be broken into had Tamper Proof Torx Screws in then so you needed a Torx Driver not a Bit with a Hole down the center of the Torx Head. I've still got a complete range of Tamper Proof Torx & Tri Wing Drivers that where used in those days though they don't get much use now as the Screwdrivers have all been superseded with a replaceable Bit driver for the small Electronic Work. Col
The orange SIPs along the bottom edge of the hard drive controller board photo are internal SCSI terminators. If the drive was used in an external drive enclosure and daisy chained with other scsi devices these SIPs needed to be removed to unterminate the drive.
Criminy! I was on my third Mac by then, having purchased one of the first one thousand 128K Macs while attending a Consortium school back in 1983 (or was it 84?). It's hidden away in a sealed container, inside its original carrying case, somewhere in my basement. Crack it open, and it's full of upgrades that eventually blew the power supply.
Would you mind posting a phot of that tool in photobucket or somewhere? THanks. Put close-ups,please :) Cheers
These are heat sensitive and I have seen many used in locations where they routinely are above their max working temp before you even apply any power to the unit. When you routinely overload any component it's got to fail. I find that replacing these Polyester Capacitors with Green Caps cures the problem forever or at least as long as the unit works. Col
Yeah, AMD was founded in 1969 and made some small scale processor chips around that time. It wasn't until 1975-76 that they wanted to go on par with Intel and they copied the 8080 chipset and then branched off into the RISC market as it was believed that was the future of processors. It was a shift that never really took off so they went back to PC market to follow Intel in the x86 market. Obviously as seen in this MAC, the AMD chip was simply an embedded CCU (maybe a microsequencer/Bit slice?) and not the primary processor (Motorola 68000 was).
Most Motorola-based Apple machines I've ever looked in, both 680x0 and PPC, had something from AMD in them.
The first three Macs ??The Macintosh (128k), the Big Mac (512k) and the Mac Plus (1Mb) had floppy drives only, although there was a SCSI socket for an external disc. The Mac II and the SE30 and all subsequent MAcs had internal HDs
When I was a boy... But seriously, the first hard drive I ever saw was a removable platter 14" disk with 5 Mega Bytes (yes, you read that right). I think that was DEC's RKO5 cartridge, but it was a 3rd party drive. The place I went to work in 1983 had two washingmachine size discs for the VAX, with volumne names "BLACK HOLE" and "GALAXY". 300 Meg each. It WOULD be a treat to see a Sinclair here...
The original Mac (1984) had 128 K RAM. The Fat Mac (1984) had 512 K RAM The Mac Plus (1986) had 1 MB RAM, expandable to 4 MB The Mac Classic (1990) had 1 MB RAM, expandable to 4 MB - - 1 MB on the motherboard, an expansion card added 1 MB with 2 SIMM slots for an additional 1 MB each = a total of 4 MB as seen here.
mostly right on the name. SCSI - Small Computer System Interface, it replaced SASI - Shugart Associates System Interface.
Klaatu51 has it right- inexpensive TV technology includes wax-dipped flyback transformers, and when things get warm as they age, wax often drips out. The original Macs, 128k and 512k and Mac Plus's, had passive cooling, the Classic had a fan. Kensington sold a lot of ad-on fans for the early models. Probably with good reason. My classic still works just fine. A sweet little computer. Bill
the 256Kx4 (256K,4-bit wide) Chips, count them total 8, 2-256x4 chips = 1-byte width of 256K, 8 = 1MB. two more SIMMS in the expansion slots @ 1Meg ea = 3MB, the RAM on the system/mother board itself is more likely 1MB (didn't examine the size) for Video Memory. Not sure HOW it was handled in the Mac, as far if the video was directly memory mapped to the 680x0, or was only accessible through the video controller.
If one of the founders of apple computer assembled the machine and signed the inside I beleive that its a collecter item maybe worth a couple of grand even!
Craftsman calls it a T15 - but the size of the head wasn't the problem, it was the long neck of the tool that I was missing. All the ones I had before were to short or fat - or both. :)
The Torx head screw is still very common. I keep a full set of torx drivers on hand. I replaced the keyboard on my "Classic" Blackberry 7730 recently and needed a torx driver to disassemble it. The first time I had to use a torx was around 1988 because my Compaq lugable was held together with torx screws.
...the Classic was an update of the Plus, with more RAM and the "SuperDrive" 1.4 MB floppy drive. Otherwise, it was the same technology as 1986, a lesser machine than the SE, and just repackaged to make it look modern.
Apple offered a 20 MB hard drive that plugged into the Floppy port on the back of the machine then the floppy drive pluged into it. you could use the 3.5" floppy drives from an apple II on the them but some you had to remove the daisy chain card from the inside of the drive for it to work right. I had a unidisk drive for an apple IIe that is modded to use on a mac. Thoes were the days.
The original Mac, Fat Mac, and Mac Plus had the signatures of the design team molded into the inside of the shell. As far as I remember, that ended with the Mac Plus, and the Classic and Color Classic did not have the signatures on the shell.
Are the One driver with different bits. Gone are the days when we needed specialized Screwdrivers to do the work. The one that I still love is the Head with a 15 way indent around the outer rim that sort of looks like a Reverse Torx head or a Reverse 12 Point Head. Still used a lot and very few drivers on the market to fit this fixing device. Tri Wings where another common fixing device a while ago on electronics. Or how about the Yellow Goop leaking out of the Unit here. What's the bet it's from a Yellow PVC Capacitor across either the Mains or the High Tension on the Neck Board? I used to love those things Temp Sensitive Capacitors that failed and then put a straight Short Circuit across what they where supposed to be protecting & in the process made a God Awful mess. When I used to replace them with Green Caps I got into trouble because they where not what the Design called for and it didn't matter that they worked better and didn't fail again they "The Powers That Be" wanted them replaced with the same thing so we could continue selling Repaired Circuit Boards. I had more than enough work to do without continually needing to repair the same Circuit Board every year. OH BTW I was using Tamper Proof Torx Drivers in 1976 and probably prior to that I used to have a complete set from the T 5 size up to a T 45 but while it's still useful the big one doesn't get much use these days. Also having 5 different screwdrivers in the tool box takes up a lot of room so 1 Driver with 20 or 30 replaceable bits is just so much easier to stuff in there. The tool boxes have remained as big but seem to have got heaver over the years or maybe I'm just getting older. Col
I was working for an Apple Dealer (we sold IBM PC's in the then super secret world of the Gray Market) and the upstart "Compaq" in 1984 when the Mac came out. (I can't tell you how many sales I lost because Compaq couldn't spell their name right...) I remember the signatures on the inside of the Mac case. I also remember trying to sell this $4000 beauty, and an Apple Writer printer to curious customers when it only had two software programs. MacPaint (B&W) and MacWrite. Man, I'm an old geek. But, have I got stories...whew...