---
title: "A Temporary Setback"
id: "25402"
type: "post"
slug: "a-temporary-setback"
published_at: "2020-06-10T17:25:27+00:00"
modified_at: "2023-01-18T17:32:59+00:00"
url: "http://localhost/blog/a-temporary-setback/"
markdown_url: "http://localhost/blog/a-temporary-setback.md"
excerpt: "In testing my latest iteration of an RGB to SVIDEO/composite board, I managed to toast my 2068. Symptoms point to fried RAM chips, according to an article on DIY fixes to the 2068, so I’ve ordered replacements. The circuit boards..."
taxonomy_category:
  - "Blog"
---

In testing my latest iteration of an [RGB to SVIDEO/composite board](/timex-sinclair/a-small-update-on-video/)
, I managed to toast my 2068. Symptoms point to fried RAM chips, [according to an article on DIY fixes to the 2068](/article/a-broken-2068-fix-it-yourself/)
, so I’ve ordered replacements.

The circuit boards above, from left to right, are a buffered 2068 expansion bus, an attempt to make a SD card based file storage solution and a board that will bypass the internal ROM (home and EXROM).

### Buffered Expansion

I have several projects I want to hook up to my 2068 and I don’t particularly feel like making them all feed-through, like the old devices made for Timex computers. Instead, I’ve made an expansion board that allows for “cards” to plug in.

The first version I made is just straight through: there’s no buffering of any of the signals. The problem with that approach is almost every expansion card would need its own signal buffering.

Based on [some work by Charles Bothner](/article/ts-2068-with-unlimited-ram-capability-2/)
, I have fully buffered the address and data busses, along with a few other signals.

The address bus is one way; the data bus is bi-directional, driven by the /RD line.

### SD Card file storage

I don’t have the patience for tape that I used to, so I’m working on a device that’ll use the commands built-in to the 2068 to save/load to SD cards. It has a [Teensy 3.5](https://www.pjrc.com/store/teensy35.html)
 to do all the heavy lifting.

I’m calling it the 2065[bis](https://www.wiki.travellerrpg.com/Bis)
.

### ROM Bypass

[Bill Pedersen](/tag/william-j-pedersen/)
 did a lot of research and work to improve the 2068. If you read his articles, you’ll see he was really enthusiastic about getting the 2068 to a state where it delivered on its potential.

One of those areas was a ROM bypass tool to facilitate developing correct Home and EXROM images. Larry Crawford worked with Bill on some of his projects and this is a PCB from one of them. It allows [bypassing the internal ROMs and using static RAM and EPROMs](/article/rom-exrom-bypass-board-for-external-eproms/)
.

As soon as I get my 2068 back in working order, I’ll be able to test boards and start working on these projects again.

### Tags

[Blog](/category/blog/)

### People

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### About The Author

[David Anderson](/author/david/)
I'm a big fan of the Timex/Sinclair computers: my first was the TS 1000. I love building things for my TS 2068 and sharing them with others on this site and andertone.com.