Zx spectrum +2a comp mod

For experts to discuss very technical stuff and newbies to ask why the Spectrum they bought off ebay doesn't work.
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thefa11_guy
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Zx spectrum +2a comp mod

Post by thefa11_guy » Fri Aug 10, 2018 9:15 am

Hi guys,

I've recently been given a near perfect in box +2a. I was thinking of modding to output composite but I have a question.

The real easy mod of cutting the power and bypassing the RF modulator is only ever shown on the spectrum. Not the +2a. My question is, can this method be used on this board or is it not capable?

I apologise if this as been covered. Spent the last hour hunting the forum but I may have missed it.
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1024MAK
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Re: Zx spectrum +2a comp mod

Post by 1024MAK » Fri Aug 10, 2018 1:31 pm

Most Europeans use the RGB/Monitor socket and a suitable SCART lead. RGB via SCART produces a far better picture than composite video.

There is information somewhere over on World of Spectrum forums, but it is more involved than the modification on the 16K/48K/plus models due to the sound being mixed in and totally different composite video circuitry.

Mark
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Ast A. Moore
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Re: Zx spectrum +2a comp mod

Post by Ast A. Moore » Fri Aug 10, 2018 6:03 pm

What the guys above said: you’d be far better off hooking the Speccy up to the TV using the RGB signals. Either purchase a ready-made cable (overpriced), or make your own (cheap and dead easy).

Depending on your TV, you may or may not need to modify the Spectrum—one resistor value needs to be changed. That’s regardless of whether you decide to buy a cable or make your own.
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Every man should plant a tree, build a house, and write a ZX Spectrum game.

Author of A Yankee in Iraq, a 50 fps shoot-’em-up—the first game to utilize the floating bus on the +2A/+3,
and zasm Z80 Assembler syntax highlighter.

thefa11_guy
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Re: Zx spectrum +2a comp mod

Post by thefa11_guy » Fri Aug 10, 2018 8:13 pm

Cheers guys

I can honestly say I've never touched a spectrum til a stripped this one to give a thorough clean. I found some info on the web that that this has a built in speaker but I sure as hell didn't see one during my teardown. I'm assuming therefore that I have to use the 3.5mm socket to carry audio.
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chequered flag
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Re: Zx spectrum +2a comp mod

Post by chequered flag » Fri Aug 10, 2018 8:56 pm

No speaker in any 128K model.
The RGB port provides mono sound and it is connected to SCART.

Some casual technical information:
http://www.dataserve-retro.co.uk/conten ... /d200.html
https://spectrumforeveryone.com/technical/
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1024MAK
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Re: Zx spectrum +2a comp mod

Post by 1024MAK » Sat Aug 11, 2018 5:12 pm

Audio output is also available on the Tape/Sound 3.5mm jack socket.

Mark
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