Minstrel ROM Cart

Name: Minstrel ROM Cart
SKU: 40215
Price: 30.00 USD
Availability: InStock

An 8K or 16K ROM replacement cartridge for Minstrel Expansion Bus, Minstrel 2,3,ZX81 or TS1000

Designed by Tynemouth Software in United Kingdom

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2025-10-10T08:29:13.396Z-Minstrel ROM Cart on Minstrel 3.jpg

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2025-10-10T08:29:13.396Z-Minstrel ROM Cart with ROM.jpg

2025-10-10T08:29:13.396Z-Minstrel ROM Cart on Minstrel Expansion Bus on Minstrel 3 zoom.jpg

2025-10-10T08:33:56.722Z-Minstrel Expansion Bus with Minstrel ROM cart and Minstrel ZXpand on TS1000.jpg

2025-10-10T08:33:56.722Z-Minstrel ZXpand K.jpg

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An 8K or 16K ROM replacement cartridge for Minstrel Expansion Bus, Minstrel 2,3,ZX81 or TS1000

What is it? This is a ROM replacement cartridge for Minstrel Expansion Bus which can be used with the Minstrel 2 and Minstrel 3, and with an edge connector or Minstrel Expansion Bus backplane with a …

What is it?

This is a ROM replacement cartridge for Minstrel Expansion Bus which can be used with the Minstrel 2 and Minstrel 3, and with an edge connector or Minstrel Expansion Bus backplane with a ZX81 or TS1000.

It replace the internal 8K ROM at $0000-$1FFF with one of up to 8 x 8K ROM images on the cartridge (jumper selectable).

It can also replace a further 8K from $2000-$3FFF to make a 16K block, with up to 4 x 16K ROM images on the cartridge. If there is RAM at this location (as there is on the Minstrel 3), it will be disabled, reducing the system RAM to 24K.

What makes it special?

The ROM in the ZX81 is used for two things. Firstly it provides the built in operation system and BASIC language, but also contains the character set used by the display circuitry. The ROM cart only replaces the former functionality, the character set is still read from the internal ROM chip. This leaves an extra 512 bytes of code space from $1E00-1FFF which can be used to make small modifications to the ZX81 ROM such as added extra keywords etc.

ROM chips that are supported include most 28 pin ROMs and EEPROMs

27C64/27C128/27C256/27C512
28C64/28C256
W27C512

Why did you make it?

I wanted a way to try out alternate system ROMs and diagnostic ROMs.

It can be used to load three of the four TS1510 ROM cartridges (not Flight Sim), by using 16K mode and making ROM images with the TS1500 ROM from $0000-$1FFF and the TS1510 cartridge ROM from $2000-$3FFF).

It can also use used to host the Minstrel ZXpand ROM on a ZX81 or TS1000 that has a suitable internal RAM upgrade. Allowing the Minstrel ZXpand to be used on those machines.

[Minstrel ZXpand] (https://www.tindie.com/products/tynemouth/minstrel-zxpand/)
[ZX81 internal 16K upgrade] (http://blog.tynemouthsoftware.co.uk/2017/10/zx81-internal-16k-ram-reversible-version.html)

Limitations

The ROM cartridge replaces the internal ROM, so only full OS or utility ROMs can be used

The character set is still read from the internal ROM chip, so ROM such as HFORTH or ASZMIC which have a different character set will not work.

See this blog post for more information on writing your own ROMs.

Minimal ZX81 Compute and Display Code

The ZX80 is missing the /ROM_CS pin on the edge connector, so it is not suitable for use with a ZX80 without modification. The Minstrel 2 does not have this limitation.

What options are there?

This is available as a kit or assembled, and can be installed directly into the Minstrel Expansion Bus slot on a Minstrel 2 or 3, or into one of the slots on the Minstrel Expansion Bus backplane (which would allow it to be used with a ZX80, ZX81 or TS1000)

What other modules are available

Currently the following modules are available, more are being added. Let me know if you have any ideas or requests.

4 port Backplane
4 port Powered Backplane
Minstrel Joystick
Minstrel Input Monitor
Minstrel ROM Cart
Minstrel ZXpand
ZX IO by David Stephenson (www.zx81keyboardadventure.com))

What it not included

No other Minstrel Expansion Bus cards or backplanes, or any of the Minstrel or ZX81 computers are included. No ROM chip is included.

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Tracked shipping is recommended on international orders. Parcel will include full value declaration and may be liable to additional delays, tariffs or customs fees upon arrival. Please be aware of this before ordering, there is nothing I can do about it.