ZX80 with red LED?

Discussions about Sinclair ZX80 and ZX81 Hardware
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ZX79
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Joined: Wed Apr 06, 2016 9:36 pm

ZX80 with red LED?

Post by ZX79 »

Hi,

A well known auction site is listing a ZX80 with a red LED on the upper front panel. Although I presume it is a non standard post sale modification, did any version of the ZX80 come with a LED?

Not that I intend to modify mine, is there a source describing possible ZX80 modifications?

Thanks.

H
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1024MAK
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Re: ZX80 with red LED?

Post by 1024MAK »

Until the sale to Amstrad, none of the ZX computer range had any LEDs fitted.

So just to be 100% clear, Sinclair never fitted LEDs to the ZX80, the ZX81, the ZX Spectrum, the ZX Spectrum+ or the ZX Spectrum+ 128k. Also, none of the PSUs supplied with these computers had LEDs.

And yes, sometimes owners added a "power on" LED (with series resister). Either connected to the +9V DC supply, the +5V DC supply.

One fairly common upgrade for the ZX80 was to replace the ZX80 ROM chip with the "new" ZX81 ROM. Note that as it turned out, this was the first ZX81 ROM and had the well known maths bug.

Some ZX80 owners mounted both ROM chips, one piggy backed on top of the other, and had a switch so they could switch between them while power was off.

Also sometimes you will see switches for switching the +9V DC input on/off.

In later years, certainly for ZX81 and ZX Spectrum 16k/48k models, composite video modifications started to appear.

Recently I removed the existing PCB from the modulator in a ZX80 that I had been asked to repair, and fitted one of Pokemon's ZX8-CCB modules (provides an improved composite video signal that is more compatible with modern displays).

There are some pictures showing my ZX80 after I removed the piggy back ROM arrangement (due to some of the wires going to the switch having broken off, which prevented it from working) in this thread ;)

Mark
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