RAM/ROM Expander

One cool and useful item that came with my NEC PC-6001 is this RAM/ROM expansion cartridge. It plugs into the side of the 6001 and doubles the memory to 32KB, and it also has two ZIF sockets for ROM expansion.

At this point, I’m not sure what can be done with the ROM expansion but I hope to find out more someday. As for the RAM, many tape games require it, so it seems like something of a must-have expansion for this system.

First major problem

The ugly side of vintage computing is that they are problem-prone. When you figure PCs are designed to be replaced every two to ten years, it’s no surprise that these 25-40 year old machines start developing issues. Nobody would have imagined that these machines would still be in use all these years later.

The problems range from leaky capacitors that can be replaced for a few yen to burned-out custom chips that range from “too much money” to “you may never find a replacement for it.” The Commodore 64 user base is so big that modern replacements for many custom chips have been produced. Other platforms may or may not be so lucky.

This happened to my Sharp x1 Turbo Z, which is so far my favorite Japanese vintage computer and the one I use most. The fault is mine alone, I should have opened it up to check on the battery and capacitors as soon as I got it. Instead, I plugged it in and it worked, and I just blindly plodded forward. Lesson learned.

One night, I noticed the machine stopped loading high density disks. Well… okay. I rarely use them. I will get around to repairing or replacing the part later and just use the double density disks, where most of my games reside. But it escalated quickly, about one hour later it stopped reading all disks.

So now I have to open it, and when I do, I see there is a small amount of leakage from the battery. The battery resides on the same board as the floppy drive controller, so it makes sense quickly enough. I used my very modest soldering skills to remove the battery. There are some areas that might indicate light damage to the traces near the – symbol in the box where the battery used to be.

First step was getting a spare parts machine. These machines are expensive but fortunately there was one available on Yahoo Auctions in terrible condition. Huge areas full of noticeable scratches on the front and top, and rust on the ports on the back. It was a bit of a gamble, though, because there was no way of knowing if that machine’s floppy drive controller worked or not.

I got it for about 20% of the price of my own Sharp X1 Turbo Z. When it arrived, I checked it out and fortunately all that rust was confined to the outside; the inside was very clean. There was no battery leakage on the controller, either. I just put the board from the spare parts machine into my main one, and it all started working again. Temporary relief! I played a victory game of Tetris before going to bed for the night.

Step two was a bit more challenging. I understand some of the principles of basic computer repair, and I had some idea of what needed to be done, but my hands don’t hold steady enough to perform delicate soldering operations.

Fortunately, I have a friend here in Tokyo that is also into vintage computers and is far more skilled in that kind of thing than I am. I explained my situation and he came over and looked at it. He hemmed and hawed, nothing jumped out at him at first, but eventually narrowed it down to a small section that had some corrosion near the battery. He snipped about a half a centimeter of jumper wire and restored the connection on the underside of the PCB (the white strip near the center of the image).

And then it worked! The idea is simple enough but finding the problem, on a system he’d never even seen before, and fixing it so eloquently… that’s straight up magic as far as I’m concerned!

FM-77 System Disks

My FM-77AV20EX comes with BASIC built onto a system ROM, which makes it fast to load up BASIC and play around, and you don’t need anything else to get started using the system. But the BASIC it comes with has a big limitation: you can’t access disks or perform operations on them. This means you can’t format a disk, and while most games that make use of a data disk or save disk include a format utility, I’ve run across at least one that does not. The result was that I couldn’t play the game.

To perform operations on disk from BASIC, you need to get the “disk version” of BASIC. This is included as one component of the FM-77 System Disks set. This is so rare that I didn’t even know to look for it until it suddenly appeared in my recommended items list on Yahoo Auctions. Long story short, I just paid whatever was necessary to get it. That price was about 12,000 yen. Yikes. Let’s see what I got:

Yep, three disks, one of them blank. What a bargain! We have F-BASIC 3.0 and FM-Logo 2.0. I was willing to pay whatever the final price was, because I planned to copy them and sell them back on Yahoo Auctions later, presuming I could get almost all of my money back. Well, I only managed to sell them for 8000 yen (minus Yahoo’s fees, so nearly 7300 yen pocketed). That means I ended up paying about 5000 yen for two copied disks! I made backups and then backups of the backups, just in case.

But let’s see what we get here. It’s kind of neat. Do you remember Logo? I barely did.

Mouthy program. But I used Google to jostle my memory a bit.

The BASIC disk comes with, of course, the BASIC programming language, as well as some utilities. For example, the disk formatting utility which is basically the reason I bought this to begin with! But beyond that, it also came with a F-key command definition tool and a paint program that I don’t seem to be able to use at all, perhaps because I need a special mouse?

The BASIC disk also came with a demo of the system. Actually this was made for the FM-77, but mine is the FM-77AV20EX, so the demo works but doesn’t really demonstrate the full capabilities of the system I have it running on.

And there we have it! 5000 yen for copies of this. Welp, can’t win them all! Don’t get me wrong, it’s kind of a neat collection and I enjoy perusing the disk, just quite a chunk of change for what it is. Actually I want to find some way to get copies of this to people who need it, perhaps just have people ship blank floppies inside a postage-paid return envelope, so people don’t need to drop big yennage just to get these simple tools. But I’m not sure how I’d put that plan into action.

Spring Cleaning

Get it? It’s a joke. There are springs under the keys… and I cleaned the keyboard. It’s supposed to be funny.

Anyway, after I transferred this image to my PC and looked at it, I thought, “Why did I bother cleaning it? It looks pretty good as it is!” Certainly, at a glance, it doesn’t look bad at all. But if you look closely, especially between keys, you will notice a considerable amount of grime.

I find cleaning vintage computers gives them a breath of new life. To me, it is one of the most satisfying things about this hobby. To get started, I unscrewed the case and popped off the keys, and let them soak a bit in a warm water plus orange solvent solution.

After about five minutes, I rubbed each one clean with a rag. Then I took a pretentiously artsy photograph of the keys drying, because I am so clever. Well, at least the keys are nice and clean.

While the keys were drying, I did the thankless job of cleaning the keyboard’s board itself. It’s much less noticeable and much greater a pain to clean than the keys, but I hadd it open and ready to clean, so I went ahead and cleaned it. Snap the dried keys back on and then put the case back together.

And finally, set the keyboard back up on the desk, now ready for use! Very satisfying.

Commodore 64

Wait, what? What is this doing here? The Commodore 64 is as American as apple pie, right? This is a Japanese Vintage Computer Collection blog, no? Commodore has a lesser-known side to it – Commodore Japan.

Actually, this is by far the rarest piece in my collection. I struggle to find exact numbers, but I have only seen this item appear on Yahoo Auctions four times since I started paying attention about three years ago. By contrast, I’ve seen probably 100 MAX Machines in that time, which themselves are considered quite rare.

From a distance, it looks like a standard Commodore 64. In fact, the product name is just that: Commodore 64. But this is the Japanese edition. What’s the difference? Well, in some ways they are very similar, but in other ways, they are night-and-day different.

If you crack open (not literally!) the machine, you’d think you’re looking at a regular Commodore 64. Don’t think there’s any component in here that you couldn’t find on a standard Commodore 64. CPU is the same, SID (6581) is the same, PLA is the same, VIC-II is the same, and I gather the smaller ICs are also the same. The contents of the character ROM and kernal ROM are different. We’ll look at how that pans out later.

Put the cover back on, and with a more careful look, some differences are apparent. Probably the most eye-catching thing initially is that the shift-lock key has been replaced with what we’ll call “C=-lock” (and verbalize as “commodore-lock”). Off in the opposite corner, the £ key has been replaced with the ¥ key. But take a look at those characters on the fronts of the key caps. On almost every key is a Japanese katakana character.

Before we start, we have to turn on the computer. And that’s when we see another set of differences: at the BASIC screen, the default color scheme is different, the font is different, and the amount of free memory is different (more on this later).

So let’s get to typing that katakana! When you type, though, the alphabet appears. How do you access the katakana? First, you must enter the second character mode, by pressing C= + shift (lowercase mode on a standard Commodore 64). After that, katakana is accessed the same way you access the petscii characters in the corresponding locations on a standard Commodore 64: by pressing C= and typing the characters. That’s why that C=-lock key is so useful!

The ¥ key produces the yen symbol without the need for the C= key. And although they are not visible on any key cap, there are also three kanji that the system can produce. They are directly accessible by pressing shift and typing the +, -, and ¥ keys. The characters are 年 (year), 月 (month), and 日 (day) All of the katakana and kanji characters are handled by a one-to-one replacement in the character ROM.

Katakana is usually used for writing or typing loan words from western countries, but it contains every sound of the Japanese language, meaning you could type an entire document or book with it. It would be a nightmare to try to read a large body of text that way, but it would be possible.

Compatibility with western software is varied. First, it’s NTSC only, so PAL games that don’t work on a North American Commodore 64 won’t work on this machine, either (although I feel PAL and NTSC incompatibility, while certainly extant, is overblown). Additionally, due to the character ROM difference, games that rely heavily on text may load but could be unplayable unless a custom character set is employed by the software. And most cracked software won’t work as-is because of the memory offset, although this can usually be easily worked around.

For the most part, though, I find original games load just fine. Here it is playing Alternate Reality: The Dungeon, my favorite game of the time.

The first picture is a title screen and shows the kinds of problems that may occur due to the character ROM difference. Fortunately, that’s all sorted out before the actual game starts. The second picture is from the game’s introduction. This image made a big impression on me since the first time I loaded it, and it will stick with me forever – it shows just how beautiful and vibrant this 16-color computer is really capable of being. The third is an in-game shot.

There is another option for loading games. Fastload or replay cartridges such as Epyx Fastload or Action Replay can be plugged into the system. This forces the memory to be reconfigured to the expected amount available to BASIC. In the case of Epyx Fastload, this works as long as Epyx Fastload is capable of loading your desired software. In the case of Action Replay, you can disable the fastloader, the memory will still reconfigure, and then you should have the same compatibility as a North American Commodore 64 (possibly exempting character display problems).

The box is also apparently unique. I’ve heard a couple of people who collect C64 boxes say they’d never seen this one before. It’s in a bit rough shape, but I think you can get the idea.