Enterprise 64 – repairs and modding

… or Egyptian adventure

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Story

For the past few days, I am battling a sinuses infection and I cannot work in my garage so I’ve decided to write some blog posts. This is going to be another “old story” post. I took pics for this post back in mid-2020 🙂

The story is quite usual, a friend of mine asked me to search for a specific computer for him – Enterprise 64.

After reading some forum posts on Polish and Hungarian forums, I’ve found out, that these computers were popular in UK, Hungary, and Egypt. I was surprised to find NOS units in Egypt. Well, at least according to the eBay seller. The problem was that shipping costs were kinda high. Sachy/Lamers came up with an idea and suggested that some folks from the local retro community might want to have such a machine so we could order more computers and split shipping costs. He was obviously right and that significantly lowered shipping costs per person.


A couple of weeks later four machines showed up, YAY! 🙂

EP64 #1

In general, these computers were in very good shape, however, they needed cleaning as some weird polymer reaction was visible on a joypad. Below, is the first machine that I’ve worked on.

Apart from that, there were loose parts rattling inside. The plan was to disassemble it, clean and check what was wrong with loose parts before powering it on. It turned out that the copper heatsink got loose inside one of the machines.

Fortunately, that weird gooey came off nicely.

Now, I could move on to testing but first I needed a proper A/V cable. Obviously, I had to make it myself as it is not a standard one.

EP64 uses an edge connector for video output so I had to improvise a bit. I’ve cut an old PC ISA connector into pieces and cleaned them afterward.

Fits nicely.

I’ve also 3D printed some cases for these handmade connectors.

I’ve found schematics for this cable on one of the Hungarian websites. Here it is just in case you need it.

I’ve connected the video cable and it worked right away!

The first machine was ready. I will get back to it later and now let’s fix the second unit.

EP64 #2

It wasn’t that easy with the second machine. It required cleaning and some electronic fixing. It was missing a joy cap and a side connector cover but these were easily 3D printed 😉

Unfortunately, this EP64 produced garbled video output.

After researching this issue, I’ve figured out that one of the transistors is to blame. I’ve ordered a replacement transistor – BC337 – which is a standard bipolar NPN transistor. Replacing it, fixed the issue.

Fixing a broken keyboard membrane was next on the list. It became very brittle because of its age so first I had to cut it. However, after cutting it, I had to extend it somehow because it was simply too short to reach the connector on the motherboard. I’ve decided to desolder the original connector and extend it with a ribbon wire. I’ve also added an additional piece of plastic to the membrane to strengthen it.

That fixed the keyboard problems.

Upgrades

I’ve started looking for upgrades on Hungarian Enterprise 64 forums. By the way, these forums rock! Very informative source. It quickly turned out that one of the guys still manufactures various add-ons. Funnily enough, it also turned out that he is my fellow countryman who is also a member of speccy.pl community. Pear, as it is his nick, created several cool expansions. I’ve contacted him and ordered some of them. I don’t have links to every single mod though.

  • EnterMice – PS/2 mouse and joystick interface
  • EXDOS – Floppy drive interface
  • BusBridge
  • IsBasic cartridge
  • ZX Spectrum emulator card
  • RAM expansion card – orginal

Add-ons came in quickly and some with nice 3D printed cases.

IsBasic cart worked right away.

I’ve 3D printed a case for EXDOS and added a GOTEK drive to it which I’ve modded with an OLED display.

I’ve also 3D printed a case for the joystick interface and loaded some games to test it.

Next, I’ve connected a ZX Spectrum emulator card via a BusBridge. Unfortunately, as I’ve quickly found out, it requires more RAM, so I had to install a RAM card first.

It all worked nicely. However, I must add that Pear helped me a lot with his suggestions via emails. Thank you, buddy!

The end

This is all I’ve for now. However, our Brazilian friend donated a very nice Enterprise 128 machine that I will be working on soon. Hopefully, it won’t have to wait another two years for its own blog post 😉

2 thoughts on “Enterprise 64 – repairs and modding

  1. Speaking of Brazilian, I suspect that the injection molds for the Enterprise key caps were reused for the Sharp HB 8000 – Hotbit MSX computer

  2. Great post! I wonder what is the schematics of that ZX emulator. It looks like only glue logic and the ROM with Basic. Am I right? The post could use some little table with hardware info of the Enterprise at the beginning tho. Best regards! 🙂

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