ZX Spectrum ROM chip identification

[Skeet]

Hi,
This is my first post on here. I recently started repairing and restoring ZX Spectrums and ZX81s. I want to copy some ROMs to EPROMs with my XGecu programmer, but I am struggling to find the ROM chip identification numbers to let the programmer know what chip is in the programmer to copy. Most of my ROMs don't have the actual chip type printed on them just the Sinclair or Amstrad serial number.
They are not even identified on the schematics either.
The toastrack ROM does have the actual chip number on though, so I have been able to read and save this ROM.
Does anyone know where I can find the actual ROM chip identification numbers for Sinclair and potentially other ROM chips?
Is there a database for this?
Any help would be most appreciated.

[1024MAK]

Most ZX80, ZX81 and ZX Spectrum computers made for Sinclair Research (or under the earlier company names) use mask ROM chips. So they won't have a number that your programmer will recognise.

The binaries of these ROMs are widely available online anyway. And are also available in many emulators.

For the ZX81, you want the last version from Sinclair, as the two earlier versions have a bug. Or better off, the rewritten version called the "Big bang" ROM. I'm sure Moggy will be along soon to provide more details and a link...
Oh, and a 2764 is the replacement EPROM type you need, but as it's a slightly different pin out, some extra wiring alterations are needed. The pin compatible EPROM chips are extremely hard to find now and not many programmers support them.

If you do want to read a ZX Spectrum 16K/48K/+ ROM, it's equivalent to a 23128. Which is similar to a 27128 but with an extra chip select on pin 1.
Hence with some programmers you may need to manually make set up changes.
And due to this, there needs to be a change on the PCB.

Mark

[Skeet]

Thanks Mark, that's really helpful.

[Moggy]

Thanks for intro Mark glad to help where I can.

@Skeet.

Whilst I cannot help with the Spectrum ROMs I can for the ZX81.

For the 81 I use a veritable old stager, as mentioned by Mark, in the form or the 2764 EPROM. This requires a 21volt programming voltage which some modern programmers balk at but the later CMOS 2c764 EPROM only requires 12/12.5/13 volts (depending on manufacturer) so should be OK with modern kit.
The Re-wiring consists of two pins lifted and two wires soldered as per picture.

As for the image I personally swear by and use only the Big Bang ROM image which gives roughly a double speed increase with BASIC,faster PRINT and CLS and also gets rid of the annoying screen flicker when using PAUSE and after using SCROLL.

The thread for said ROM can be found here..

viewtopic.php?f=5&t=2986&hilit=zx81x2

Hope this is of use to you.

[1024MAK]

Thanks Mark, that's really helpful.

If you have more questions, want more details or want further help, I'm happy to help.

Mark

[Skeet]

Thanks for intro Mark glad to help where I can.

@Skeet.

Whilst I cannot help with the Spectrum ROMs I can for the ZX81.

For the 81 I use a veritable old stager, as mentioned by Mark, in the form or the 2764 EPROM. This requires a 21volt programming voltage which some modern programmers balk at but the later CMOS 2c764 EPROM only requires 12/12.5/13 volts (depending on manufacturer) so should be OK with modern kit.
The Re-wiring consists of two pins lifted and two wires soldered as per picture.

As for the image I personally swear by and use only the Big Bang ROM image which gives roughly a double speed increase with BASIC,faster PRINT and CLS and also gets rid of the annoying screen flicker when using PAUSE and after using SCROLL.

The thread for said ROM can be found here..

viewtopic.php?f=5&t=2986&hilit=zx81x2

Hope this is of use to you.

Thanks Moggy, that's super helpful.