ZX Spectrum 48k

Here you will find all kinds of fixes for 48K spectrum, I'm going to add information on how to lower the power cumpstion of the spectrum. Many of this things is needed for the spectrum laptop.

ZX Spectrum 48k Issue 3B 0,575A 9,85V = 5,66W Changes: Gain: Regulator 2576T-5 0,400A 10,20V = 4,08W 1,58W CPU Z80C 6Mhz 0,335A 10,42V = 3,49W 0,59W Upper 32K SRAM D43256BCZ-70LL 0,270A 10,64V = 2,87W 0,62W 64kx1 (8 chips) videoram 0,213A 10,70V = 2,28W 0,59W Gave noice on picture, would need some fix for this problem. 64kx4 (2 chips) videoram 0,182A 10,84V = 1,97W I only had 16kx4 chips but they refresh is A0-A7, does not work, and I had no 64kx4 left but should give same result. ULA chip uses appr. 0,68W My laptop Spectrum with 7" LCD uses appr. 7W, it has the regulator and the upper 32k ram fix. Spectrum & LCD uses both appr. 3,5W each.

A SIMPLE VIDEO OUTPUT

This fix is for ZX Spectrum 16/48/48+ only.
And as shown in pic the modulator lid is off I have done a composite videofix and a really simple one with a 16v 100uF cap.

PICTURE QUALITY FIX

This fix is for ZX Spectrum 16/48/48+ only.
If you having alot noice(shadows), shows alot in red and cyan then this fix might be what you are looking for, this doesn't fix the flicker.
videofix before/after 7MB in WMV format


REPLACING TO A COOLER REGULATOR

This fix is for ZX Spectrum 16/48/48+/128k

32K ram replacement/expansion

This fix is for ZX Spectrum 16/48/48+
On the 32k ram chip bend up pin 1,20,27 all others are soldered to rom chip.

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VIDEO OUTPUT

This fix is for ZX Spectrum 16/48/48+ only.
If you remove the pcb in the modulator box you can then build this videofix in the box, all signals are avaiable in it.
This converts the high impedance videosignal to ~75 Ohm standard video.
Use right klick to save the image.




S-VIDEO OUTPUT

This fix is for ZX Spectrum 16/48/48+ only.
First pic is the video and the second is s-video.
It's hard to see the differences on the pictures, the colors seems to be better and a sharper text ;-).
Description:
Locate C65 and loosen the end that goes to TR2, now this is Chrominance (- end of C65 cap)the color signal solder it to pin 2 on s-video socket.
The Luminance (B/W video) signal is taken from input to modulator (wire nearest main board corner) and soldered to pin 3 on s-video socket.
Pin 1 & 4 on s-video socket is soldered to ground.(GND,same as modulator) The modulator can be removed.
It doesn't take away the flickering since signals are in the same way.
The TV doesn't have to decode the color signal from video so it's 1 stage less in TV and this enhances the picture a little bit.