Posts Tagged Replica 1
What I’ve been up to…
Posted by eric in Apple, General Software, Hardware, Opinion on October 26, 2008
Not that anyone who finds my blog will actually CARE what I’m up to, but it’s my blog and I run this dog & pony show! 
My projects as of late have mostly been electronic in nature. I’ve actually had three projects on the burner:
Replacement of the capacitors on my Mortal Kombat 2 arcade machine’s CRT controller
This was far more time consuming that I thought it would be. Not because it took me an actually long time to desolder and replace the capacitors on the board, but ordering the CORRECT caps and waiting for them to be delivered took the most time. I decided to use Mouser for my components and they delivered as promised. I posted pictures of my extracting the CRT controller here. From what I was able to gather with some Google-Fu and the few English markings on the board, I determined it was a Wei-Ya C829HR CRT board. Of course there aren’t any cap kits for this board (for whatever reason), so I had to order all the caps (about 30) one by one getting their voltage and capacitance from the one’s that are currently on the board. The one cap that I wasn’t able to find (easily) a replacement for was this monster bipolar 75v 4.7uf cap.
FINALLY finishing my Replica 1 computer (which I posted about starting here… over a year ago)
I know, totally lame right? I’d like to say it got put down during the move and I forgot but I literally think it was just the time of year and I was tired of freezing my ass off in the garage with only the glow of a soldering iron to keep me warm 
So I picked back up the kit and finished soldering the rest of the 50-or so IC pins and fired it up. I got a response on the video port but when I reset I get random giberish. I checked and the oscillator is clocked in at 1mhz and voltage at the test points looks OK. I’m thinking it’s probably a bad rom. I’m currently e-mailing the project creator and he’s been very helpful!
Building a Blue Box
This year I decided to be Woz for Halloween (I figured Fat Nerd is an outfit I’d be able to pull off ) and I wanted to have a sweet accessory to go with my outfit of a vintage apple shirt, name tag and rockin facial har. I decided what cooler than actually building a function blue box! I found this schematic which seems to be the defacto one that everyone since the 80’s has been using. The down side? Exar no longer makes the XR2207 voltage controlled oscillators. I tried to get samples straight from the company, but no luck. I was able to find them through some IC resellers, but they wanted $30 per chip, so F’ that noise!
Again, I activated some hardcore Google-Fu and found this slick project by a website called ProjectMF.org. He used a PIC microcontroller to generate the frequencies which is waaaaay easier and makes sense in a more modern world I used his schematics and again ordered the parts from Mouser. I was able to solder together the power supply portion and will fire up the PIC programmer later this week! Super cool!
So anyways, I haven’t been hacking away on the code or software projects lately but I find my creativitiy comes and goes through phases. I’m just in a hardware one right now, but I’m sure sooner or later I’ll fire up Visual Studio again
Cheers!
Building the Replica 1 (Part 1)
Recently I had been cruising the internet looking for fun IC projects that would allow me to build a small computer and play around with it at a low level. I felt that it would be a great way to learn low level computer functions while expanding my knowledge of electronics.
I ran across a kit that is being sold by Briel Computers called the Replica 1. The Replica 1 is a software compatible clone of the original Apple 1 which was created by Steve Wozniak back in 1976. The Replica 1 kit starts at $159 for the unassembled version.
The Replica 1 has the same specs as the very first Apple 1:
- MOS Technology 6502 CPU
- 32K RAM
- 8KB EEPROM
- Support for APPLE 1 Expansion Cards
In addition to the original specs of the Apple 1, the Replica 1 also adds a Serial Port for programming, an RCA TV Output Port and an optional USB Interface (USB Replica 1 kit costs $184). Power can be provided by one of three methods. The first is ATX power provided by a modern ATX power supply. Second is a port for an external 5V DC Power Supply. The third option is to power the Replica 1 via power supplied from the USB port when plugged into a computer.
When I purchased my kit, I opted for the USB version that wasn’t pre-assembled. You CAN purchase the unit pre-assembled, but I think that takes away from the fun of ordering a kit computer. My order was included in the June 1st batch and was shipped exactly on June 1st. My hats off to Briel Computers for a very quick turn around.
The Replica 1 arrives in a well packed USPS box. Inside the box is a large zip lock bag which contains the Printed Circuit Board, a smaller plastic bag containing all the capacitors, resistors, diodes, connectors and whatnot. Also included in the large zip lock bag is four IC tubes which include the IC sockets and the IC’s. The CPU included in the kit was actually a 65C02, which is an updated version of the MOS 6502 that includes several bug fixes and errors that existed in the original 6502.
The Printed Circuit Board is very well laid out and the silk screen is very, very well done. Makes installing the sockets and diodes very easy by clearly identifying which direction the parts are to be installed.
All the parts included in the kit seem to be ordered from the Jameco catalog. This is a handy thing to know in case you run into any issues where you’ll need to order a replacement part.
I started earlier today beginning to put together the Replica 1. I was able to lay down the sockets as well as several of the other electronic parts. Some of the solder points on the Replica 1 are very close to other debug point and ground points, so please be careful when soldering the Replica 1 together as you can very easily ground out or fry a circuit. There are several safe guards in place in the form of glass diodes to protect the Replica 1 from issues with the power sources.
I’m still in the process of assembling the Replica 1, but so far, so good! I’ll continue my review of the Replica 1 as I progress with it’s assembly.
Picture 1 — The Replica 1 on my workbench being assembled. (Sorry about the picture quality, I had to use my Blackberry as my Canon is out on loan)
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