Thursday, September 24, 2009


I just realized all four of the A14F are installed backwards...

OK, so it took me about 2 hours to fix this major screwup. The A14Fs are back in business.

LM323K Voltage Regulator Installation

UPDATE: Feb.17.2010 - Please note that the A14F recitifier diodes are installed backwards in the above and below images.
I fixed this soon afterwards, before I applied power. See my later posts!

Tonite I installed the LM323K voltage regulator (5v / 3a).
A pair of magnetized wire strippers came in handy to drop the screws into place. Needle nose plyers would have worked fine too I guess. I used a tiny amount of masking tape to tape the washers to the screws so that I could drop them into place easily. The area is too tight to get your fingers into (maybe you can, but I could not).
This was a bit more frustrating than I thought it would be, but everything is now soldered into place. There are 2 insulating washers in the upper left of the image above. You do not need these insulating washers - Just bolt the LM323K as is, to ensure a good grounding connection to the PCB.

Soldering resistors and ceramic capicitors

So today I got a package in the mail from Surplus Sales.... which contained all of the carbon composite resistors (EXCEPT for the (12) 3k ohm), the ceramic caps, the 47pF capacitor, and the 100 ohm video trim potentiometer. I soldered the A14F rectifiers, the MPS transistor (video signal), the .1uF, .01uF and .001uF ceramic disc capacitors, the 47pF dipped cap, and the 14.138 Mhz crystal.
In the image at the top, you can see that I shorted the (2) "6502" bridges, as well as the No DMA bridge. I used wire that was trimmed from the resistors to short the (2) "6502" bridges.
(The No DMA short only has one hole in the PCB, not sure why?)

Anyhow, here are a couple of things that I learned tonite:

1) The MR501 rectifier diodes have wire leads that are too big for the holes in the PCB so I used A14F rectifiers instead. (A friend of mine sent me these from Ca. as I could not find them anywhere -- apparently they are only 15 cents each at the electronics shops in the Bay Area)

2) If you are working with ceramic caps with really short leads, make sure that you tape them to the PCB before you solder them. Otherwise they might fall out when you turn the board over. And if they do fall out *while you are soldering*, as did for me, you will be swearing for the next 15 minutes trying to get the solder out of the holes so that you can start over. Luckily, it only happened once. I didn't have much luck removing the solder using copper braid. So I ended up using a piece of trimmed resistor wire and a pair of plyers to hold the wire (so I wouldn't burn myself). I reheated the solder in the hole while plunging the resistor wire into the hole until it came loose. After a few tries I was able to remove enough solder to get the capacitor back into place AND TAPED to the PCB before attempting to solder. (I will purchase a solder sucker soon...)

3) If you use too much solder on resistors, caps and diodes, the solder will seep through to the other side and "ball up", creating small BB like balls of solder on the top of the PCB. (Maybe my iron is a little hot?)

4.) I am finding that a setting of about 3.4 on my soldering iron is a good heat to work with.
I let the iron heat up for at least 5 minutes before using it.
(Model = Weller WLC100)

Tuesday, September 15, 2009

Today a package arrived from, more parts for the Apple 1 clone! So tonite I soldered the 1N4001 diodes (4) and the (3) voltage regulators (-12v, +12v and 5v).
My Apple 1 board stencil was not readable, so I broke out the other board I have which does have a readable stencil around the regulators, so I've included a picture.

Saturday, September 12, 2009

So today I finally took the plunge and started soldering IC sockets, diodes and axial capacitors onto my Apple 1 clone. I guess it took about 3.5 - 4 hours total. I took my time in effort not to screw up. I taped each IC socket to the front of the board with masking tape, one at a time, as I soldered them so that they were nice and flat against the circuit board. After soldering all of the IC sockets, I soldered the IN914 diodes, then the 22uF axial capacitors. Then I did the large cap, and then the (2) 2400 uF caps.
Note the 11000uF 25v capacitor to replace the impossible to find 5300uF cap. ( Tip from a former Apple Engineer )

Monday, September 7, 2009

Interview with Monroe Postman, Original Apple 1 owner

Monroe Postman Interview


Hello everyone, I am here speaking with Monroe Postman, one of the few owners of the original Apple 1 computer.

Hi Monroe, can you tell us about your background, and what sparked your interest in computing?

I got my Bachelor of Electrical Engineering (BEE) before schools were offering Computers as a Major. My long term interest in computers turned professional when I joined the UNIVAC 1 staff at New York University in the early 1950s, which led eventually to a career in designing digital computers. I also taught microprocessor equipment design in the 1970s under a National Science Foundation grant.

What can you tell us about your experience as a HomeBrew Computer Club member?

I attended The Homebrew club after it started meeting at the Stanford Linear Accelerator (SLAC) and stayed until it left that venue. I was not an "active participant;" I just listened with rapt attention as the revolution got under way.

Is it true the Lee Felsenstein thought he was in charge, but wasn't really?
Was it a free for all?

My recollection was that Lee did keep order, but wasn't "bossy." There were at least 100 people at a typical meeting, but it was hardly a free for all. And there were plenty of disagreements, but the atmosphere was generally civil.

Did you ever get to meet Steve Wozniak? If so, what can you tell us about that encounter?

I only met Steve Wozniak briefly, years later, when I asked him to sign my Apple 1, I believe at the Computer History Museum in Mountain View. He was very cordial.

Did you ever see Woz demo the original Apple at the club?

Yes, I recall seeing a demo in the lobby of SLAC. I think that he was also at the First West Coast Computer Faire held in 1977 in San Francisco. That was very exciting!

Where and when did you purchase your Apple 1?

I bought it at an estate sale, in around 1980.

What made you decide to put your Apple 1 up for sale?

I guess as a collector, my interests have evolved over time. And there are so few of these Apple 1s out there, it’s time for someone else to enjoy it.

If you could give any bit of advice to people just getting into computers, who might be interested in either software programming or hardware design what would you tell them?

I've been a hardware engineer, using a bit of programming or machine code to modify and test my designs. If I were just entering graduate school, this time I would opt to study bio-engineering which is an exciting mix of many engineering disciplines. Every engineer should know which end of a soldering iron is hot! I know that is so 20th century . . .

It seems we’re always at the end of one exciting era in the history of computers and at the beginning of another. Leave it to Apple with the iPhone to have introduced one of today’s most interesting computing platforms, with wifi, location awareness, color touch screen, video and all of its other features it is changing the way people compute.

In my own life, I have recently been working at the Department of Veterans Affairs, using sensors, hydraulics and computer control to build solutions that provide rehabilitation and assistance to stroke victims, paraplegics and quadriplegics.

Monroe, thank you very much for your time, it has been a great pleasure.

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