Classicamiga Forum Retro Edition
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Thread: ZX Spectrum - just finish repairing a ZX 48K
Tiago 09:38 20th August 2012
some weeks ago i started to repair a ZX 48K. It had no image, sound or whatever.
I Started with a new IC 7805 (tension regulator), and some image appear, but a lot o squares and stripes.
I got some advice, and transistors TR4 and TR5 had to be changed, so i bought ZTX653 (TR4) and
ZRX753 (TR5), desolder the old ones, and solder the new ones, and, howwww, a nice new ZX48k.

Here is a video of the ZX48K, loading a small text that i put in the tape.

Zx is cool, i am now playing around images. i will post a video later of a photo on the screen of the zx.
Harrison 09:45 20th August 2012
Nice one. That brings back memories watching the video. I never owned a Spectrum at the time and instead bought an Amstrad CPC, but my friend had a 48K spectrum and we used to play loads of games on it. He then got the +3 with the disc drive.
Tiago 11:14 20th August 2012
I am reading some stuff. Amaizing how they did in 48K.
I did another video, this one i was able to put the logo from my magazine on a tape in a real ZX.
it was amazing to see it render on screen, it's a 256192 image with +/- 7kb that i did on pee cee, then
converted to wav and finnely recorded in real tape.

chek it out.
another test i was able to put my photo avatar on it, a lot of noise and wrong pixel colors, but it worked!
Harrison 12:03 20th August 2012
Great. What did you use to make the image to load and render?

I used to love the 8bit tape loading screens as they drew and slowly revealed themselves.

Did you know you don't even need to use a real tape player any more? A lot of people just connect the audio out from a PC and play sampled audio of the tape loaders from the PC to load the software into the Spectrum.
Tiago 13:28 20th August 2012
Yes you can connect a MP3 !!
But the old tape recorder has.... is different, is the real thing.
I did all the stuff in Pee Cee. I did the image in photoshop, converted it to 256192 then
with some software converted from jpg to *.SCR (zx file).
After i run 2 command prompt programs still in Pee Cee that put the image and the syntax to load it in a one peace in a *.TAP file that you can run on a emulator. Then i converted to WAV sound file that i used to record to the real tape.
But the programs in PC do it all automatically, i didn't understand all the steps, i will try to learn how to do it, all in ZX.
Harrison 13:51 20th August 2012
I'm really tempted to give that a go just to see play around with it under emulation.

I've never kept up with the Spectrum retro scene much, probably because I never owned a real one. I think most people tend to focus on the systems they owned growing up. I do however know there is a large community for the Spectrum, and they are still creating stuff for it. I've seen a few Youtube videos of demoscene productions on the Speccy and they have managed to perform graphical effects far beyond anything considered possible back in the 80's. Same is true for the C64 and CPC computers though. Some of the productions produced in recent years are really impressive.

We must start some threads to explore the demoscene on each of these platforms. Should be interesting.
Tiago 23:33 21st August 2012
Another work with the ZX48K
This time a photo of my avatar in G+
i found very cool this render, for his age, the graphics are fine.
I bit difficult to get the best result, in the end i pic this one:

Harrison 01:06 22nd August 2012

The Spectrum did produce the nicest results in black and white. It had issues in colour due to its colour clash issues.

Have you had any issues loading from tape? I remember we used to have loads... tape volume not quite right, or the audio cable getting knocked during loading. Are you considering getting a 3" disc drive for it? Or even upgrading to a Spectrum +3. Have you looked at the QL?
Tiago 09:44 22nd August 2012
I don't haev any issue from tape. It works just like it did 25 or more years ago. It was a good tape loader, and still is. Loading and/or recording without any problem. I just had to find the correct volume setup, +/- 7/10 and then all software so far works using that value.
Funny was that, when i wanted to recod to tape, i didn't remember that cassetes have something like diskettes, at the bottom, but reversed. There is a hole, that if it's open, you can't record, if it is closed, you can. Many original cassetes came with that closed, so that you could not record on top of that.
I had to put a bit of duck tape to close it. Before that, when i pressed the record, the button would not go down, i had to press that little witch down manualy, then i realize it was a simple mecanism, the switch didn't go down because the hole in cassete was not closed, so it would no press the swith. So simple

Getting a disc drive, no. I tend to get the things i had, or i liked back in the days, here in Portugal, the ZX48K
dominate the scene, disc drives were not common. And i really enjoy the feeling of the tape.

The QL, well i never saw one in my life...

and about the video, the original photo had color, it's a normal photo taken with that camera you see, Nikon D70. It was taken in a mirror. I had to convert it to the zx screen resolution. I try to put it in 256 color, even in 16 color, but the colors would mess it all, so that when i convert to zx, it was a bit mix of colors. back and white the same thing. the only convertion, that it would keep a photo feeling was dithering. To keep the color in a pc convertion to zx, the original photo must not have many colors, and you have to do a lot of work to reduce colors mantaining a good aspect. A bit hard
Harrison 10:17 22nd August 2012
The problem with colour clash on the spectrum meant only certain colours could be placed next to each other. Put the wrong colours and you get a third ghost colour between them.

This problem was easily seen in sprite based games when the player sprite moved over background graphics and would change colour. Quite annoying.

One thing that was nice owning an Amstrad CPC was that most Spectrum games were directly ported. They looked very similar but didn't have the colour issues. The only annoying thing was that developers got lazy and tended to just do Spectrum ports for the CPC. It meant the CPC abilities never looked much better than the Spectrum's, whereas then developed natively it could do much more.

I never know the Spectrum was so popular in Portugal. What were the best selling games?
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