Feet and Boots!

The parts donor Apple II+ I am trying to repair is really a mess. Even the rubber feet were harvested for another computer. Fortunately, I found some decent rubber feet on eBay. I bought two packs of 12 20mmx20mmx8mm and it is a great replacement part for Disk II and Apple II feet.

Regarding my other project, I was pretty scared to connect the repaired IIGS Upgrade board to a power supply, half expecting everything to start smoking. It boots! First time in about 15 years:

Composite video works

and RGB works!

Apple IIGS Repairs

Here are the fruits of my labor for the past two weeks. I had already attempted to repair this Apple IIGS Upgrade board, after a battery explosion did a lot of damage to the board and chassis. However, I wasn't really satisfied with how it was working out. I purchased some copper tape, and I am impressed at the way it worked to replace the traces. Much flatter and smoother, like it should be. A couple of resistors replaced and I tinned it all. Then, a lot of continuity testing. I bought some UV cure solder mask and after some time in the sunshine and under a UV light, it looks pretty good. Not perfect, but considering the terrible damage inflicted on this board, I am impressed!

Trace repairs and new SMT resistors in R193 and R14 locations.

Trace repairs and new battery holder.

Copper Tape, UV cure Solder Mask, and a weird spatula thing.

The Hakko soldering iron definitely made this possible. I am afraid to hook up the power supply though...

Some Progress, Some Distraction

I spent some time last week working on a Google Sketchup rendition of my hypothetical Apple IIb. The idea is to solve some of the problems with the Apple II+ as a incremental update. It is clear from the Apple II+ design that some of these fixes were deliberately removed from the design late in the process, possibly to keep cost down and possibly because the Apple III was on the horizon. For instance, the odd keyboard decoder arrangement and missing switch clearly contemplated lowercase and a keypad, but the final design did not include either. Here are my specs:

• 80 columns. This is difficult without a full terminal card, which was how most Apple II+s were upgraded.
• Upper/lower case keyboard. Shouldn't be too hard, other than a new character ROM.
• Separate keyboard with numeric keypad. This didn't catch on until after the Apple III, but it should be a relatively easy addition.
• Integrated disk drives.
• Integrated monitor. I'm indifferent here. Although I really think the Tandy TRS-80 Model III and Apple Lisa are some of the best looking retro computers.
• Two serial ports, and a parallel port. This just requires a few expansion cards.

So, mostly a standardized, well equipped, Apple II+ with a few conveniences we have come to expect. Here is my first rendering with elements borrowed from Lisa I and Apple IIe Google Sketchups:

So, that's the progress. The distraction is work on my Apple IIGS Upgrade. Rather than take on another project (Apple II+ logic board), I decided to dive head first into fixing the IIGS. After replacing some of my previous repairs with copper tape, and a lot of soldering, it looks pretty good. The solder mask is curing under UV light, so I will have pictures tomorrow.

Apple II Development

I am pretty amazed at the current rate of development of new Apple ][ conveniences and devices. It is worthwhile to look up from a project to see what others are doing every once in a while.

VGA adapters for the Apple IIc and IIGS seem to be hot right now.

The Nishida Radio Disk II adapters are gaining more and more features, including a nice looking web interface!

Big Mess O' Wires had added Apple II support to the Floppy Emu Disk Emulator.

It's impressive to have a microcontroller with more power than the Apple II strapped on the back of it. Although it does feel like cheating sometimes...

I merely managed to find a switch that perfectly fits the Apple II keyboard encoder for enabling lowercase once the character ROM is updated. It is labeled "ONLEDA MTS-202" and is a knock-off of some old high-quality switch, I'm sure. Good ebay search terms : Right DPDT toggle switch. Just take note of how the pins are oriented to make sure you get the right ones. I'm putting mine away for a rainy day.

A new style of Apple II prototyping card popped up on ebay too. Had to buy one.

RetroChallenge 2013SC

Welcome to my new blog. The RetroChallenge inspired me to start a new retrocomputing specific blog here. I will be moving my previous retrochallenge stuff from my other blog MacLCD over to here in the coming weeks. First, a list of goals for RetroChallenge 2013 Summer Challenge:

• Repair the Timex Sinclair 1000 that I recently bought on a whim (and for less than $25 shipped!) from ebay. Then I will try to write a game for it in BASIC. Assuming I get it all working I will offer the computer up as a prize in the RetroChallenge.
• Finish fixing my Apple IIGS Upgrade computer.

Since I have a busy month at work I'm going to keep my goals within reach for this challenge.

RetroChallenge 2013WW Review

This has been a fun month. I am really excited that I completed one project and hopefully provided a useful tool to the Apple II community.

Disk ][ Emulator: I just uploaded the USB AII-SPI-DSK executable and schematic. The binary is compiled for x86_64.

AII-SPI-DSK project source code is now available too. The code requires user to have libusb, libftdi and libmpsse already compiled and installed. Once you get past the Xcode project format, the code should be pretty portable to other platforms. Most of the coding was done fast and dirty, so please excuse the unavoidable errors.

The USB AII_SPI_DSK Disk ][ Emulator is by far my most complex electronics project I have ever taken on. Fortunately, the Apple Disk ][ controller card is pretty flexible with the input it can take, or I would have never completed this.

I didn't quite reach my lofty goals on this project, but I did end up with a good proof of concept and a handy device in its own right. And, because this project uses a standard SPI stream, I should be able to easily create a micro-controller based solution that actually uses an SD card! The Retro icing on the cake for this project is using 2 ICs recycled from an old Apple II+ for my build.

Apple IIe Platinum: Living a new dust-free life.

Apple IIGS: Still rusty and in pieces. A little closer to living though.

Apple //c: Still neglected with 255 ROMS. I didn't even get to think about this project.

Take a minute to check out the RetroChallenge website and see what the other participants worked on.

Good Enough

Finding ways to reduce the latency between sector transfers is getting tougher and tougher. The UM232H writes and reads packets with low latency, but when it goes back and forth between the two, significant delays occur.

I used some source code from MAME to load the different disk image formats. I had to make extensive edits to get it working outside of MAME though. ProDos and DOS 3.3 disks work fine. Most game disk images I have tried are working:

• Moonpatrol
• Choplifter
• Ms. PacMan
• Bouncing Kumungas!
• Jungle Hunt
• Donkey Kong
• Mario Bros.

Still no Karateka though.
I think it is 'good enough' for now. A computer faster than my PowerBook G4 might help. Here is video of my progress:



The LCD viewfinder is broken on the camera, so I missed my shot a few times.

I added a logging level option to the command arguments after I shot this video. I can set the verbosity at run time instead of needing to re-compile. I am working on my schematic today to make sure it is up to date.

I received my surface mount resistors for the IIgs from China earlier this week. I only needed one of each, but I could only buy 100 of each. Anybody need 198 surface mount resistors?

Speed Testing

I have been experimenting with disk images with mixed success.  ProDos based system utilities disks work fine. No luck with Karateka though :(

I fixed a few bugs that were causing the program to not move to the correct track at times. Also, I found out that libmpsse stalling was my fault - I commented out some code to limit transfer sizes thinking it didn't look right. That was causing the UM232H to get too much data and stall out. Finally, I have been experimenting to see if I can reduce latency beween data transfers. Loading a large program is still about 10% slower than running the same disk on Virtual ][. Clearly there is some room for improvement here.

FTDI has Mac OS X drivers for the UM232H. I may test out their driver to see if there is any speed to be found there. Also FTDI recently released a simpler / cheaper version of the UM232H named the UM232H-B.  $15 is a steal! You could make a Disk ][ emulator like mine for well under $20. Mine is still under $25.

Still awaiting resistors being shipped from China for my IIgs.

IIGS Upgrade Change of Plans

I have been struggling to get libftdispi to output anything of use and dealing with libmpsse constantly freezing the UM232H, so I decided to try a change of challenges for the day:

I have been checking ebay for a good deal on a IIGS logic board. I finally found one for a good price and it's local so I can avoid shipping costs. However, after taking a close look at the pictures of the board, I realized that the standard IIGS logic board does not have the connectors for the Apple IIe power supply and keyboard (it does have the solder points though). Fortunately, the connectors are pretty standard. I figured though, if I am going to have to pay over $40 to solder connectors on a new logic board, I may as well try to repair my own board. So the logic board went into the dishwasher to get cleaned up. I have had good results cleaning a board this way, just make sure to dry it off completely! The board is a mess. There are vias that are corroded completely through, leaving a cumbly substance behind. There are traces that are completely gone. Some traces are corroded under the solder-mask, so you can't even tell there is a problem at first. There are surface mount resistors that have a pad corroded through. A couple of hours of mask scraping, continuity testing and soldering tiny wires got me here:

Repairs to Battery Area	Repairs to Back of Board Resistors R193 and R14 had to be removed

Now I have to find the appropriate resistors to replace the corroded ones. I can't find any surface mount components locally, so off to ebay...

Retro Research

I took some time this weekend to get a jump on the Retrochallenge. As the Disk ][ emulator will be my first hardware build from the ground up using standard digital logic integrated circuits, I have been doing a lot of research and note taking. Copying or just assembling an existing circuit can be hard enough on in its own. Learning a new (for me) technology (even if it is excruciatingly well documented) takes a lot of time and preparation.

As Sun Tzu said:

To rely on rustics and not prepare is the greatest of crimes; to be prepared beforehand for any contingency is the greatest of virtues.

Speaking of "rustics":

Rusty IIgs Horror Show!	Reading Material

Oddly enough, my automotive bodywork skills may come in handy here.

I can't encourage any electronics experimenter enough to get one of these data books. These cost me $1 a piece at my local surplus store. Sure the data-sheets for all of these ICs are online, but it is so much easier turning a page than searching, finding and opening the right PDF, saving it, closing the pop-up ads...

Retrochallenge 2013WW

I just noticed the call to arms for the Retrochallenge 2013 Winter Warmup. I tried to enter in the past, with no luck. In fact, I never got around to even starting that project. Since then, my interests have moved from early Apple Macintoshes to Apple II's. So my projects for the Retrochallenge 2013 Winter Warmup are as follows:

Apple II Disk Emulator
Unfortunately, 5 1/4 inch floppy disks are hard to come by these days if you want to play around with online disk images. ADT is a great project that I have used with some success in the past, but for the most part, you need disks or live connection to another computer. Other projects, including one created during a previous Retrochallenge, require a connection to another computer and cannot use disk images. I would like to build an SD card based virtual disk drive for an Apple II using standard commodity hardware you can find on ebay. There are some projects out there, but none do exactly what I want. I have an idea for converting the Disk II signal to SPI to read it from a microcontroller or an FTDI serial UART.

Apple IIgs Upgrade Restoration
I used to own a pristine Apple IIgs upgrade with original version 00 ROMS. I still own it but it is no longer pristine. The clock battery inside the computer exploded several years ago, causing serious damage to the logic board and rust on the case and power supply. My plan is to get a new logic board and repair the rust damage, restoring the IIgs to working condition.

Apple //c ROM Upgrade
I have an Apple //c with original version 255 ROMs. I just bought some AT29C256 EEPROMs from ebay which appear to be compatible with the Apple ROMs. My hope is to get an updated ROM image onto one of them somehow. I own a Mac and I don't own a ROM writer, so I am hoping I can get a simple ROM writer made with some standard ICs. A few counters to increment the address and a shift register to shift in the data from my FTDI UM232H should do the trick.

Fortunately, work is pretty slow in early January, so I think I can get at least one of these projects completed.