HOME  |  NEWS  |  BLOGS  |  MESSAGES  |  FEATURES  |  VIDEOS  |  WEBINARS  |  INDUSTRIES  |  FOCUS ON FUNDAMENTALS
REGISTER   |   LOGIN   |   HELP
Product News
Design Hardware & Software

Teardown Time Warp: A Look Inside the Mac 128K

NO RATINGS
View Comments: Newest First|Oldest First|Threaded View
Page 1/5  >  >>
networksguy
User Rank
Iron
Re: Brings back fond memories
networksguy   4/15/2014 3:52:13 PM
NO RATINGS
Back when Steve Jobs was fired from Apple and was off doing Next, in the mid-90's, there was an Apple program to license MacOS to third parties.  I used to own a Motorola Mac clone, which I used for several years, that was mostly built with PC parts.  During that period, I was involved in a project called CHRP (Common Hardware Reference Platform) to run MacOS, AIX (IBM UNIX), NetWare, and Windows NT on a common hardware platform based on PowerPC.  For a time, the fastest Mac on the planet was a CHRP prototype in the lab at Apple.  Then Steve Jobs returned to Apple, and immediately cancelled the licensing program.  CHRP faded after that (though I understant IBM still uses parts of it internally).

Even though it represented 3 years of my life, I didn't blame him.  The cloners were diluting the experience in the interest of saving pennies (e.g., there was a power-on switch on the PC case of my MotMac instead of the keyboard, and it used an ATA disk (that died in 2 years) instead of SCSi), and undercutting Apple on pricing.  It would have cut Apple's sales if they didn't lower prices, and cut their margins enough to prevent them from doing the good R&D they've always done if they cut prices to match.

I have usually worked on UNIX/Linux for a living, and have always had Windows machines as well, but my primary compute platform since the Mac Plus has been Apple. I usually get about 5 years usage from a Mac.  I always built a new Windows PC every year and ran Linux on it when i retired it from Windows use.  I use Linux via ssh from the Mac, and fire up Windows under Parallels on the Mac when I need to run something that's only available for PC -- it boots and runs faster than my Windows machine.

I still have a (many-times-upgraded) working Mac 128K machine, bought through the Apple Developer Program in 1984, that runs an X-10 PowerHouse controller from a year or two later (it's the only computer I own that will plug into and talk to the X-10 controller :-).  I've gotten my money's worth from it.

Ann R. Thryft
User Rank
Blogger
Re: Teardown Time Warp: A Look Inside the Mac 128K
Ann R. Thryft   4/15/2014 12:09:23 PM
NO RATINGS
bpenfold, that's very, very funny and brings back ancient memories. How about clipping that jumper on some capacitor or whatever it was? I don't even remember what or why, but I remember having to do it, and being reminded of the standard action movie motif of which color electrical wire to clip to defuse the bomb.



Ann R. Thryft
User Rank
Blogger
Re: Brings back fond memories
Ann R. Thryft   4/15/2014 12:06:36 PM
NO RATINGS
mrdon, let's hope it's still worth a lot when that day comes in the far, far distant future.



bpenfold
User Rank
Iron
Teardown Time Warp: A Look Inside the Mac 128K
bpenfold   4/15/2014 10:41:41 AM
NO RATINGS
Image 19 "To the tune of Mission Impossible, we quickly and safely remove the power supply. "

Beautiful writing!

-Barry

mrdon
User Rank
Gold
Re: Brings back fond memories
mrdon   4/14/2014 9:54:58 PM
NO RATINGS
Ann

Thanks for the advice. I'll remember the advice when my wife says it finally time to let go of the Mac. LOL

Ann R. Thryft
User Rank
Blogger
Re: Brings back fond memories
Ann R. Thryft   3/25/2014 11:16:09 AM
NO RATINGS
I haven't seen that film yet, mrdon, but am looking forward to it. Thanks for the reference to programming on the Mac: I remember when many found the idea inconceivable.
If you ever do decide to part with your SE, you might want to find out how much it's worth first before sending it to Goodwill.

Ann R. Thryft
User Rank
Blogger
Re: The Mac Pattern
Ann R. Thryft   3/24/2014 12:01:05 PM
NO RATINGS
bwilson4web, your fire sale approach to buying Macs sounds just like mine. I keep mine a really long time, like I do with my cars. My desktop computer is a G3 PowerMac that's now basically a word processor, but one that I don't have to think about. That makes it  a lot easier to do all the writing. Like me, though, with my 512K, perhaps you should have kept that 128K Mac. Today it's worth a lot more than $200.

mrdon
User Rank
Gold
Re: Brings back fond memories
mrdon   3/22/2014 11:50:26 PM
NO RATINGS
Ann

I just recently watched the movie "Jobs" and what an interesting film. As I was watching Steve Jobs and the rest of the Mac team look on while the machine was being assembled I remembered the good times I had using it in college for a Pascal programming class. I have a Mac SE in my office/lab which my wife keeps making gentle remarks about letting go of the machine and giving it to Goodwell. There's somethings I will give to the Goodwill and then there's the Mac. 

bwilson4web
User Rank
Gold
The Mac Pattern
bwilson4web   2/6/2014 3:10:15 AM
NO RATINGS
My first personal computer was a 128k Mac bought shortly after the 512K Mac came out. The price dropped to $1,650 so it became a practical, home appliance. But PCs were advertised for $1,450.

After writing up the PC with a mouse, the salesman asked,"Do you want a monitor and keyboard?" that brought the PC price $1,750. I bought the 128K Mac the next day and our Macs have been bought in the 'fire sale' after the latest Mac models come out.

The M68000 had a unified, 24-bit address space, versus the segmented memory of the PC chips that used a linker trick, 'overlayed memory.' The M68000 had 32-bit registers and math versus the 16-bit Intel chip. Today virtual memory gives a unified address space hiding memory pages.

I could not afford the RS-232 driven, dot-matrix printer so I got the printer handbook with the codes. I wrote a printer emulator on my work VAX and simply printed Mac graphics into bit-mapped files, which printed on the VAX dot matrix printer and VT-series terminals. This upgraded my career beyond operating system programmer.

Eventually we sold our 128k Mac for $200. Over the years, I had cleaned the lint out of the mouse encoders and once replace a soldered-in, fuse. Apple had an unusual fondness for soldered in fuses.

I'm typing this note on a G4 PowerBook resting on top of a G3 PowerBook. The network connection is via a MacBook (Intel) because WiFi is no longer compatible with the G4. Macs have legs and a long life that often outlasts peripheral technologies.

Bob Wilson, Huntsville AL

etmax
User Rank
Gold
Re: Not just a power supply
etmax   2/1/2014 4:35:54 AM
NO RATINGS
Hi Alex, I used to repair TV's for a living. The early mostly valve colour TV's used to generate a no load ~40kV because the circuits were fairly high resistance. There was a triode wired in parallel with the CRT that was fed a signal that was effectively the inverse of the magnitude of the average beam current (around 5mA peak) so that the image size wouldn't change as the brightnes changed (and with it the EHT).It also prevented the EHT from getting high enough to produce X-Rays.

This stabilised the EHT to around 27.5kV deemed to be the highest save voltage that wouldn't produce significant X-Rays. If you turned the brightness right down in a darkened room you could see the anode plate glow red because it was effectively 27.5kV x 5mA = 137W disipated in around 3"sq. It was a rough and ready way to regulate such a high voltage.

When they switched to silicon rectifiers which have a much lower impedance and transistor or SCR horizontal deflection circuits, this load triode became unnecessary.

To my knowledge there is no commercial CRT out there that has higher than 27.5kV EHT. It would need significant lead shielding.

Monochrome TV's used to have only about 18kV EHT and didn't need output regulation due to lower beam currents.

As to discharge of the EHT when working on them, we used 2 screwdrivers crossed and it had to be done several times because of the impedance of the capacitor plates (formed by the graphite outer coating and whatever material was used to line the interior. We just kept crossing them until the crackling stopped.

A colleague of mine showed me that if you hold the 27.5kV cap when the TV is off and then turn on the set you can be charged up to that voltage without discomfort as long as you were wearing good insulated sold shoes and kept clear of earth.

I agreed with his theory, but always considered to much could go wrong like having a pinhole in your shoes and having sweat get into it etc. so I never recommended it to anyone as a dare and never tried it.

The focus voltage on a colour TV was also in the vicinity of 5kV and I got belted by that badly enough to have a 1mm hole burned into my finger that took a year or so to heal properly. The current was never enough to cause VF (it was DC also) but the power disipated could effect significant burns.

 

Page 1/5  >  >>
Partner Zone
Latest Analysis
These are the toys that inspired budding engineers to try out sublime designs, create miniature structures, and experiment with bizarre contraptions using sets that could be torn down and reconstructed over and over.
Connected sensor-enabled applications will improve the consumer experience -- and generate new revenue streams.
PowerStream is deploying the microgrid at its headquarters to demonstrate how people can generate and distribute their own energy and make their homes and businesses more sustainable through renewables.
Printrbot unveils its all-metal Printrbot Simple, bringing durability to low-cost 3D printers.
Today's robots should be respected, and humans should be wary of their growing skills and sophistication. Quite simply, robots are better than us in a lot of ways. Here are 10 of them.
More:Blogs|News
Design News Webinar Series
3/27/2014 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
2/27/2014 11:00 a.m. California / 2:00 p.m. New York / 7:00 p.m. London
12/18/2013 Available On Demand
11/20/2013 Available On Demand
Quick Poll
The Continuing Education Center offers engineers an entirely new way to get the education they need to formulate next-generation solutions.
Apr 21 - 25, Creating & Testing Your First RTOS Application Using MQX
SEMESTERS: 1  |  2  |  3  |  4  |  5


Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.
Next Class: April 29 - Day 1
Sponsored by maxon precision motors
Learn More   |   Login   |   Archived Classes
Twitter Feed
Design News Twitter Feed
Like Us on Facebook

Sponsored Content

Technology Marketplace

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
Copyright © 2014 UBM Canon, A UBM company, All rights reserved. Privacy Policy | Terms of Service