You Make Robots Blog

Keeping Retro Computers Alive!

SD Solution

When I first started developing my own TZXduino PCB boards I was struggling to get it working with my Sharp MZ700 computer. Sometimes it worked and others not. I couldn’t put my finger on it, but then I put a scope on the output of the TZXduino device I purchased from the original guy who made them. I noticed a difference while playing around. I thought about this for a while and had read that LM386 needs to operate at 5v-18v and but really needs to operate higher than 6v to minimize drain. Most of the TZXDuino that were in the wild were driving the LM386 ( or AMP module) from the 5v pin on the Arduino thus allowing it to operate from the Arduino USB power. I noticed that with the drain of other components that only 3-4v was coming out of that pin and it occurred to me maybe that is the issue. So I factored that into the design of the PCB. Sometime later I found myself in a similar situation with certain ZX Spectrums. After digging about I found out some older models of the ULA chip can go a little deaf. In my own systems, I was fixing this issue by replacing the ULA. Fast forward and I decided to architect in the fix I had included for my Sharp MZ700 into my main PCB I use for all the other Retro Computers.. I’m calling it the Deaf Computer option. Now I cannot guarantee it will fix all your problems but Wayne over at Retro Robbins offered to test this theory out for me since he had a deaf Spectrum 128K+. Watch the first part of the video and decide for yourself.

Deaf Computer Test.

I’m going to run a regular prize draws so some lucky person can win one of my Retro Computer Devices.  Currently, the prize is a one-off translucent green Zxuitape for a ZX Spectrum 48K+ . All you have to do to enter is sign-up for our newsletter, and on the 15th of November 2020, I will randomly draw a winner. As long as the shipping doesn’t cost me more than £25 I’ll be shipping it to the winner. If it is more than £25 I’ll contact the winner first. To take part sign-up here:

If it doesn’t catch your eye ignore this post. Please bear in mind that there will be other devices up for grabs that might catch your eye, and if you have already registered for the newsletter, you are in the prize draw by default.

I realized very early on, that people wanting to update their TZXduino, MaxDuino, CASduino, or ArduiTape would struggle if they had no experience with the Arduino programming tool. So I built a FREE tool to do that for you in a way to give back to the Retro Community. Watch the video below and CLICK HERE if you want to download the tool.

Nice video from Wayne Robbins who is a big-time ZX Spectrum vlogger in which he shows off multiple ZXuitape models which allow you to load games on ZX Spectrums from SD card. He had an issue with one which I later identified as a problem with the SD card Wayne was using. Also Wayne referred to them as a TZXduino which is not technically true. ZXuitape uses the MaxDuino firmware which is far superior. Wayne is awesome in the community so I’ll let him off this once 😉 If you want to buy one for yourself CLICK HERE