Search found 374 matches

by 1024MAK
Sun Jun 16, 2019 1:03 am
Forum: Hardware
Topic: New and need help
Replies: 2
Views: 164

Re: New and need help

The normal colours are the less bright shades. The more intense colours are the bright colours. In BASIC to get a bright colour, use BRIGHT 1. The way that the machine generates the BRIGHT colours, it mixes the red / green / blue video signals with the BRIGHT signal. The way in which this is done fo...
by 1024MAK
Sat Jun 08, 2019 12:34 pm
Forum: Hardware
Topic: Trying to fix my ZxSpectrum+
Replies: 31
Views: 996

Re: Trying to fix my ZxSpectrum+

As far as I know, there are no drawings showing the track layout for ZX Spectrum 16K / 48K / plus boards. There is a pin-out of the 4116 (or equivalent) DRAM chips over on Sinclair ZX World . All the pins with the same name on each chip are linked together and then go to various places (see the sche...
by 1024MAK
Fri Jun 07, 2019 11:29 am
Forum: Hardware
Topic: Trying to fix my ZxSpectrum+
Replies: 31
Views: 996

Re: Trying to fix my ZxSpectrum+

While we are on the subject of repairs to old computers, unless you have a lot of experience and have good quality desoldering equipment, often with most components and chips, the PCB is more valuable than the component or chip. So it’s a good idea to use a method which is as kind to the PCB (board)...
by 1024MAK
Fri Jun 07, 2019 11:11 am
Forum: Hardware
Topic: Trying to fix my ZxSpectrum+
Replies: 31
Views: 996

Re: Trying to fix my ZxSpectrum+

Note that before fitting any sockets or components, recheck your work, at least TWICE. Use a good multimeter on the continuity range to prove that every pin on every chip/component is connected to everywhere it needs to go. Not just to the next nearby chip or component. I suggest you print out a sch...
by 1024MAK
Fri Jun 07, 2019 8:33 am
Forum: Hardware
Topic: Trying to fix my ZxSpectrum+
Replies: 31
Views: 996

Re: Trying to fix my ZxSpectrum+

Just to add to what Muttley Black posted. When I am replacing missing / broken tracks, I use “5A fuse wire”. This is uninsulated tinned copper wire that has a diameter of 0.2 mm. In the U.K. it is sold in electrical stores on a cardboard card. Or you can extract the strands from insulated flexible s...
by 1024MAK
Fri Jun 07, 2019 7:47 am
Forum: Hardware
Topic: Learn vintage electronic / computer engineering at 2019.
Replies: 24
Views: 919

Re: Learn vintage electronic / computer engineering at 2019.

Thank you for the treasure! You have an opinion about the “Electronic Principles” book, by Albert Malvino? Yes, as I understand it, it is a very good book. I don’t have a copy myself. But I think I did see a copy in my local library back in the 1980s. You don’t need to spend money on the latest edi...
by 1024MAK
Fri Jun 07, 2019 7:37 am
Forum: Hardware
Topic: Learn vintage electronic / computer engineering at 2019.
Replies: 24
Views: 919

Re: Learn vintage electronic / computer engineering at 2019.

in terms of general computing, which includes how home computers work, there is also the part work magazine “The Home Computer Course” which was followed by the “The Home Computer Advanced Course”. They covered the mainstream U.K. home computers, which of course included the ZX Spectrum :D Mark
by 1024MAK
Thu Jun 06, 2019 2:09 pm
Forum: Hardware
Topic: Trying to fix my ZxSpectrum+
Replies: 31
Views: 996

Re: Trying to fix my ZxSpectrum+

No. TR4 (which was a ZTX650) should be replaced with ZTX651 transistor or a ZTX653 transistor. All these are NPN type. TR5 (which was a ZTX213) can be replaced with a ZTX751 transistor. Although many small signal TO92 cased PNP transistors will also work in this position, but the pin-out of the legs...
by 1024MAK
Thu Jun 06, 2019 1:58 pm
Forum: Hardware
Topic: Learn vintage electronic / computer engineering at 2019.
Replies: 24
Views: 919

Re: Learn vintage electronic / computer engineering at 2019.

Thanks for that :D They also are available from other places, for example eBay. Search for “5v 7805 lm2596 dc converter”. Some time ago I was asked about books to learn more about electronics. One book I found very useful, but is not really a beginners book, rather an intermediate level book, is “In...
by 1024MAK
Fri May 31, 2019 7:14 pm
Forum: Other Retro Stuff
Topic: BBC Microcomputer just arrived!
Replies: 7
Views: 327

Re: BBC Microcomputer just arrived!

ZxSpence wrote:
Fri May 31, 2019 7:04 pm
You could club a hippo to death with one blow using that.
The Master 128 is even bigger :lol:

Mark