The Epson QX-10 is a sleek looking design from the early 80's. It is from the tail end of the CP/M Era and it's a really neat looking machine. My experience with the QX-10 started when a friend was demonstrating his at a local Retro meet up hosted by Free Geek. It turns out he had a second machine in need of repair and since he's already got a very nice one, I was able to acquire that second machine from him, thanks again, Steve!
I started working on this in the Fall of 2025 when I acquired the machine. There was no cable included to attach the custom CRT to the base unit. This cable brings both power and signals from the base unit to the CRT and so it's difficult to begin testing without that. There is a replacement cable avaliable online, so I ordered one of those. With the cable installed I could see that the machine was powering up to the "Insert Diskette" prompt. This is a very good sign because it means that the processor is running and whatever diagnostic checks are built into the ROM are passing.
As with most CP/M machines that don't have a hard drive the A drive is used constantly to boot and run the machine, so the A drive often needs special attention. This machine was no exception. The floppy drives were manufactured by Epson themselves. In order to maintain the sleek form factor of the machine they made these drives 1/3 height, not a standard 1/2 heigh drive, so these can not be easily replaced. Knowing this I took my time removing the drives and cleaning and lubricating the mechanisms. They were so jammed that I could not even insert or remove floppy disks from the mechanism. With the floppy drives working, I could move on to the next phase of the repairs.
I made some floppy boot disks using my flux disk imaging setup that I've discussed before, but unfortunately my normal workflow did not work because these machines have a very unusual disk geometry so the first round of disks I created were not able to boot the machine properly. But I did get far enough to type characters in to the screen and this is when I noticed the next challenge, the keyboard was not working.
This keyboard, the Epson Q603A, is a special one designed for the word processing software called ValDocs. There is some good information on Deskthority about the keyboard. This is a foam and foil keyboard, so I was not concerned because I've repaired several foam and foil boards over the years using the replacement kit from TexElec. However, sadly, this board used a prototype switch with a much lower profile of foam and the normal replacement pads would cause the switches to remain pressed all the time. I emailed TexElec about this and I was very happy to learn that they were already working on a low profile foam pad. I got a set of these and installed them and the keyboard is working again as expected, one more step closer to getting this machine back on the road.
At this point because of my problems getting booted up and not have known good boot disks I stalled out on the project and set it aside. But within a few weeks I saw a relevant post on the Vintage Computer Federation forums where I hang out, so I chimed in on there. I received some great feedback about my disk imaging problem from one of the members there and I was able to create some new boot disks using a different starting point. These boot disks worked and I could see that the Epson was fully booting up into an operating system.
Unfortunately, as often happens with Retro Computers, just when we think a project is ending, something else broke. The CRT display starting rolling and I couldn't get the video to stabilize. This CRT has only one adjustment for brightness on the outside so I took the case off to get inside. I went through all the potentiometers on the circuit board and put Deoxit Fader Lube on them and cycled them back and forth. I also did a careful inspection. I was not able to identify anything wrong. After plugging everything back in it started working again. I think there may be an intermittent connection with one of the sync signals so I'm going to try to isolate that to the Monitor side or the Computer side and maybe reflow the solder joints on those circuit boards.
But for now, the machine boots and runs, and it's time for me to explore one of the last and most modern looking of the CP/M machines. I'm really glad to have this machine in the collection as it very much has the look of the era it came from...
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