Commodore Plus/4

I picked this machine up for $90 at the VCF East Consignment sale. I don’t know much about it so I’ve been watching some videos and reading forums to try and catch up. It turns out that this was a series of computers that came in between the C64 and C128. It was not directly compatible but was intended to be a new line focused on business use. This line is now known as the Commodore 264 series, or TED Series. It was not well received and was not a big seller in the US.

I put my digital voltage meter on the 1 & 2 pins on the power supply and made sure the right voltage was being supplied. It passed with 5.3V. I found my video cable that I got for the C64 (and TI 99/4A?) and plugged it in between the Plus/4 and the newly acquired Sharp flat screen on Input 1 with the RCA connector for Video and Audio. Then I held my breath and turned it on. It works! The video is a lot better than I get when I use the RF video on a TV. 

Now, to figure out how to get some software. I bought a Zoom Floppy adapter at the VCF Exhibits and I wondered if I could use that to transfer some software to floppies. But before I do that I need to find out if my 1541 disk drive works or not. I bought the 1541 drive at the Warrensburg garage sale years ago but I never tried to use it yet. I pulled it out of storage and attached it to the serial port of the Plus/4. Then I powered it on and powered on the Plus/4. The lights on the drive came to life and stayed at the green led. I tried getting a DIRECTORY with BASIC and it found the drive! It works!

I found some old 360K diskettes and tried to format a couple of diskettes using the HEADER command in BASIC. It worked! I formatted two diskettes. Next I tried to use the floppy to save a file and then read it back. For this I used the built in Word Processor program. I typed a few sentences and then used the command mode to save a file. When I entered the command correctly and a valid file name the program accessed the drive and wrote the file. Then I tried to read it back in and it worked. The 1541 drive seems to be working fine. I reset and did another DIRECTORY and it listed my newly created file. Now I will go ahead and start setting up the Zoom Floppy.

I watched a video that was helpful in pointing me to the right software to download and how to do the basic setup of the Zoom Floppy. Here:

https://www.youtube.com/watch?v=rdAzAIPkbf4

I have a Windows 10 machine on the workbench and I found a USB cable with a mini-USB end. I plugged in the USB to the Zoom Floppy but did not plug it in to the Windows 10 computer yet. First I need to download some software, including a driver, before I attempt to connect the Zoom Floppy device. I browsed to the openCBM download site and downloaded the openCBM program for Windows. This is a command line program and requires using the PowerShell command line in Windows - unless I download a GUI. I downloaded the CBM Transfer GUI from a separate site. I also downloaded a USB driver helper named Zadig from their site. This allowed me to bypass the Windows driver problems that are associated with some legacy USB products and Windows 10.

After downloading and extracting the openCBM and GUI zip files I plugged in the Zoom Floppy to the Windows 10 computer. Windows said it installed the driver but it was not properly identified in Device Manager. To get the proper driver installed I ran the Zadig.exe program and let it do its thing. After it was done I checked the Device Manager again and this time the correct driver was installed. Next I ran the openCBM installer. The installer installed the openCBM files to C:\Program Files\opencbm. Next I ran the CBMxfer installer. This installer had the wrong default location for the openCBM software so I corrected the location to C:\Program Files\opencbm and let it run. When it was finished I had the cbmxfer.exe file in the C:\Program Files\opencbm folder. I right clicked on it and created a shortcut on the desktop and renamed it to Zoom Floppy GUI.

The final step for setting up openCBM and the Zoom Floppy device was to turn on the 1541 and see if openCBM finds the drive. I turned on the 1541 and then opened the CBMxfer GUI and clicked through the default preferences. The 1541 drive was identified! I put in my test diskette and did a directory and it listed my files! It works! So I now have the Zoom Floppy adapter setup and working. Now I can try to get some software that will run on the Plus/4 and transfer it to a disk in the 1541.

There is a lot of activity from the user community for this machine. A lot of software has been ported to work on the Plus/4. There are a few programs that were contemporary with the machine that can still be found. But most of the stuff available has come from the user community and it is shared at sites like “https://plus4world.powweb.com”.

One thing to watch for is that since the Plus/4 was more popular in places like Hungary than in the US a lot of the games will be supporting PAL video modes instead of NTSC.

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04/21/24

After reading several sites and watching videos on this machine it is clear that most people who have used this machine do not appreciate its built-in business software or its lack of compatibility with C64 games programs. Most games programs were created for the C16, this model's little brother with less memory. Some C64 games were “ported” but were limited to the C16 specs and did not take advantage of the better specs on this Plus/4.

There were a few games that were produced specifically for this Plus/4 but since the Plus/4 was backward compatible with the C16 most developers built their games for the C16 and knew that those same releases could be played also on the Plus/4. So, very little was produced specifically for the Plus/4. However, the built-in business programs could have made the difference had Commodore developed it further and promoted business features better. But by this time in Commodore’s history the management changed (Trammiel had left the company) and the Plus/4 was essentially abandoned as a failed system. It wasn’t until the user community started creating more software for this machine, and the C16, that this model started to reveal its potential.

If we were to transport ourselves back to 1984 and look again at this machine we might see it as a potential market leader for small business users. We should remember that the cost of buying a business oriented computer in those days was extremely high. The cost was between $3000 and $10000 and required learning either the CP/M or MS-DOS operating systems, or maybe a Tandy Unix or Apple OS. 

This computer had the potential to run office software and give the user an alternative to buying a “real” business computer system. Adding a disk drive and printer would bring the cost to maybe $800 or $900, and could be used with the family TV that most small business types would have already had at home. It would have compared very favorably to the Apple II or Tandy TRS-80 or CoCo at a lower cost. And remember, most “real” business computers at that time did not have color or games capability. Business computers were focused on text screens and printers only, not games. But this computer could easily be used “after hours” for family games, in full color. That would be a pretty attractive package for a small sole-proprietor raising a family.

In 1984 IBM and MS-DOS were beginning to become the “standard” for business users and CP/M computers were going out of fashion. By 1987 MS-DOS was the dominant system for business. But the cost to buy in was still at least $2000 and usually much more if purchased as a “turnkey” system. A lot of small mom-and-pop shops or sole-proprietors could not afford to spend that kind of money. If they had bought this machine, and if Commodore would have supported it with upgrades, then the small business person could have made a go of it for at least a few years. Eventually the prices for MS-DOS systems would come down. By 1990 the prices for computers had come down to under $1000. But in 1994 a small business owner would have done without a computer just because of the costs. Had Commodore not dropped the ball they may have had success in that market. And maybe the users of this computer would have “upgraded” to a MS-DOS computer made by Commodore.

But this is all a look backwards At the time maybe we couldn’t yet foresee that Microsoft would dominate the market with MS-DOS. In 1984 it wasn’t yet “decided” who would win the PC Wars and Commodore was still a player. Companies like NEC, Tandy, DEC, NorthStar and others were still trying to compete and grab their piece of the pie. But Commodore was still more interested in competing in the “home computer” and gaming systems markets. The landscape would soon be littered with failures in those markets, followed closely by the makers of so-called professional computers. In the end it doesn’t really matter. Commodore went down with everyone else as they all lost out to IBM and MicroSoft.

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04-22-24

Today I noticed that some games do not work without a joystick. I will need to get an adapter so I can use my C64 joystick. I have to be careful to get the right adapter so that I don’t risk damaging the TED chip.

I also noticed that I wasn’t getting any sound. I switched to using the RF video to the antenna input on the TV, using the TV/Game adapter from my CoCo2. When I tested the sound on that output it worked. So something was wrong with the RGB output, or the cable. I looked up the pinout and made sure the cable I was using was wired correctly. It appeared to be fine. I plugged it back into the RGB video port and I only attached the yellow RCA for video. It booted to the video screen just fine, as before. Then I started up Tetris, which has a big sound at the opening screen. Then I plugged in the white RCA plug and I got sound! I plugged in the red RCA plug and I also got sound. I plugged them both in and I still had sound. So, it appears that I didn’t have the cable attached correctly at first. Anyway, it’s working now. The sound is fine.

Now that I have tested this machine and verified it is working I am going to order some accessories. While I am waiting I am going to put it in the box and start checking out the VIC20.