Memotech Hardware Repairs

System RAM

After Video RAM (VRAM) faults, probably the most common computer failures, and certainly some of the most difficult to diagnose, are associated with the system RAM in the MTX. Apart from the (relatively rare) occurrence of actual DRAM component failures, there have a number of self induced problems where people, myself included, have attempted to upgrade an MTX500 (32kb) to an MTX512 (64kb) by removing the 32k DRAMs and replacing them with 64kb ones.

There does not appear to be any technical reason why the 32kb DRAMs cannot be replaced with 64kb ones. From a practical perspective, the only difficulty is that, apart from the MTX512S2 (which has 256kb of RAM anyway), the RAM is soldered directly to the board. As the replacement involves unsoldering and soldering components on the computer board, the obvious potential cause of failed upgrades is damage to the board - either breaking tracks or causing short circuits.

Both Andy (see here) and myself (see here) have tried and failed to successfully complete this upgrade, but have had the luxury of being able to fall back on Andy's MTX Memory Card to recover the situation and complete the upgrade. Since my MTX was working again using the memory card, I had not spent a lot of time trying to understand/fix the upgrade problem.

However, Martin Allcorn has now successfully upgraded an MTX500 to 64kb of RAM by swapping out the onboard DRAM, now that the concept has been proven to work, I intend to revisit my failed upgrade and see if I can repeat Martin's success. In the meantime, you can read about Martin's successful, if somewhat time-consuming diagnosis and upgrade, along with other experiences, by following the links on this page.

By Replacing the On-board RAM

RAM Repair / Upgrade - Diagnose and Repair an MTX512 RAM Fault (Martin Allcorn)

RAM Repair / Upgrade - Turn a MTX500 into a MTX512 (Dave)

Using Andy's Replacement Memory Card

RAM Repair / Upgrade - Turn a MTX500 into a MTX512 (Andy)

RAM Repair / Upgrade - Turn a MTX500 into a MTX512 (Dave)

RAM Repair - Diagnose and Repair an MTX512 RAM Fault (Mark Kinsey)

Spare Parts

The Memotech MTX is now over 30 years old and many of its components are obsolete, it is still possible to obtain most components but they seem to be getting more expensive as they become rarer. I have a very limited quantity of a few components available should you be interested in sourcing them from the UK at, what I believe to be, reasonable prices

See here for details