New build ZX Spectrum 48k?

[MrClump]

I have one of these puppies coming from Italy, for no other reason than, well why not?

It's just begging to be populated and I'm trying to decide whether to go down the route of scavenging parts from non-functional Speccies or doing the whole thing completely brand new, components, case, the works. I already have a Nebula from Retroleum, and could get a new coil from Mutant Caterpillar, after that other than the rom I guess it's all pretty easy to source. If a little costly!

[rimmeruk]

I was looking at one these boards a few months back as it looked like a fun project to build one from scratch with complete new components.
Would look great inside transparent case with all new color matching resistors.

You do know it is an exact copy of the original board, so placing used components from an original board doesn't sound like a great idea
I thought the whole point of this board was to populate it with new components, apart from the Z80 and ULA chip. Although I think there is a modern ULA replacement and some new old stock Z80's floating around.

Unsoldering old components, especially some that have been on the board since the 80's, are far more likely to suffer heat damage from the desoldering and then resoldering process.

[MrClump]

It's 99% a complete copy of the original board, with a few minor tweaks; improvements on lower ram decoupling to help with jailbars, polarity protection on the PSU input for if someone plugs in a centre positive PSU.

But yet, I think brand new is definately the way to go, especially as I already have a new ULA. I think a clear case would look very nice indeed.

[1024MAK]

The CMOS Z80 is still in production (and is compatible), so the only real difficult items are:

• The ULA,
• The DRAM chips
• The LM1889 colour encoder chip
• The ‘coil’.

Mark

[rimmeruk]

I'd not put those 4116 DRAM chips in that board unless they were socketed and I had a large bag of them for backup.
There are the modern ram chips now and a smd ram addon board that populates the slots on Retroleums website.

[MrClump]

I'd not put those 4116 DRAM chips in that board unless they were socketed and I had a large bag of them for backup.
There are the modern ram chips now and a smd ram addon board that populates the slots on Retroleums website.

I have a lower ram replacement board sitting on the bookshelf unused that I bought from the Joulespercolomb chap a little while back. I could put in 4116s and have the modern replacement in reserve for when they inevitably die. Everything that can be socketed will be. Although it's going to be a new build, I would like to try and keep it as authentic as I can.

The PCB hasn't even arrived yet, and I am getting excited about this project. Mrs Clump is NOT going to be happy about many, many hours that are going to be spent tinkering in the garage on this!

[rimmeruk]

Well I went to order mine from a UK seller on heebey but there was a back order in place, so guess it will take several weeks to arrive if they are being manufactured in china. Out of curiosity, how much did you pay for your board ?

Oh dear, poor Mrs Clump takng 2nd place to the spectrum, I guess it's better than spending hours in the pub

[MrClump]

Well I went to order mine from a UK seller on heebey but there was a back order in place, so guess it will take several weeks to arrive if they are being manufactured in china. Out of curiosity, how much did you pay for your board ?

I never answered this! I got mine direct from the guy in Italy who is behind the whole thing, his name is Andrea Vavassori, you'll find him in the Spectrum For Everyone group on Facebook. I paid €28 including delivery to the UK, an absolute steal if you ask me.

Since my last post, my 4v PCB has arrived, and it really is a lovely thing indeed, very high quality. I also have all the components on their way from Mouser and a few others. I've also got all the harder to source bits such as a new coil from Mutant Caterpillar and a Nebula ULA from Retroleum, although I plan to put a vLA82 in it. It's going to be built with 100% new parts. The only thing I am currently undecided on is the video output; obviously, I am not going to put a modulator in it but not sure whether to go with just composite or get one of the S-Video modulator replacements. Maybe I can work it so it has both.

If you come to get one yourself I've produced a spreadsheet of the BOM with what I think are the required components with manufacturer's and Farnell/Mouser order codes. Took me ages!

[vanpeebles]

Some of this overlaps my low power 6a thread. I'm waiting online for new ula, upper and lower ram modules, and pondering the s video from zxrenew.

[MrClump]

Some of this overlaps my low power 6a thread. I'm waiting online for new ula, upper and lower ram modules, and pondering the s video from zxrenew.

That's what I've been looking at too, I'm guessing if you also pick up the same connections for a composite socket, so long as you don't connect both at the same time it might just work with the choice of either.

[vanpeebles]

I liked the look of removing the modulator all together