Sinclair ZX80 / ZX81 / Z88 Forums

Thanks again for your prompt replies. Mark, that EPROM compatibility image is brilliant! It proves that one doesn't need Photoshop or Visio skills to create a very useful diagram. Moggy, your offer is greatly appreciated. I wonder if the programmer you have is the one described here: A "very-scottis...

Thanks for the feedback, Mark, Moggy. @Moggy: the programmer doesn't look very complicated, do you have the schematic? Will you be happy to share the code? Many years ago - more than I'd like to admit - I remember when "the guy" who sold me a ZX Spectrum clone ( the Romanian HC 85 ) for which my par...

I have a very simple EEPROM Programmer witch which I programmed the 28C256 EEPROM for the Harlequin. I would like to replace that ROM with a 27128 or 27C128, but I cannot program it with the programmer I have. I have two questions: 1) can a ZX Spectrum be used to program EPROMs? 2) I know about the ...

Got the EEPROM on eBay, so it wouldn't surprise me if this is not a genuine ATMEL chip.

This is the feature I am using in the programmer:

Mark, what a shame there is no "Thanks" button implemented in the forum's platform. I knew the differences bewtween all types of ROMs; what i didn't know was that some of the EEPROMs (like the one in my Harlequin) could be written while being part of a system , and not only when inserted in a progra...

I hope everyone agree, the EEPROM are Read Only Memeories. Fact. As mentioned at the beginning of this thread, I had some issues with putting my Harlequin 48K into service. It works fine now. But!.. I'm curios, and I like to find out "what would happen if". I am using a 28256 EEPROM, with both halve...

Hello, If I don't want to use the internal speaker (audio will be routed via the RGB connector to the TV's speaker, using the SCART input), am I correct in assuming I don't need to solder the follwoing components: - Transistor Q5 (BC548) - Diode D9 (1N4148) - Resistor R47 (22K) - Capacitor C34 (0.1u...

Hello,

Can anyone explain me how this ZX Spectrum 48K (issue 4A), in such a poor condition, no accessories and untested, could fetch so much money?

1024MAK wrote: ↑Tue Jan 04, 2022 4:49 pm
Your link is incorrectly formed

Mark

Ooops. Edited.

Thanks for the info, zx-heinz.

In my circumstances, I don't think it will work, though. Acording to the data-sheet, the voltage for erasing the W27C512 EEPROM is +14V and for programming is +12V. My very basic EEPROM programer, knows +5V only.