ZX MAX 128 ZX Spectrum Clone Build

Building another Brand New ZX Spectrum for the charity fundraising. This time a Don Superfo designed ZX MAX 128, a much neater and less cluttered version using a CPLD to replace all the logic from the Harlequin version.
It wasn't all plain sailing with chip programming issues and problems with fake CPLD's
Thanks to Julian for donating the board and various components.
And thanks to ‪@NLKMediaGroup‬ for donating the case and all the other components, also for piecing together the BOM into something even an idiot like me could follow!
Thanks to Chris who volunteers at the RMC cave for providing another flight case.
And thanks to Bobbus64 for donating the DivMMC.
You're all amazing.
This very special ZX Spectrum will be auctioned for charity on the 16th of September 2023 to raise money for the Befriending Scheme
Just Giving Page for The Befriending Scheme
www.justgiving.com/page/moref...
www.morefunmakingit.co.uk/cha...
Upcoming live stream link!
Live Stream PART ONE!
kzbin.infoPfF5H2jWBfQ?...
List of contributors -
Donators -
Neal - ‪@NLKMediaGroup‬
Fergus - / ferguslogan
Lee Smith - ‪@leesmithsworkshop‬
Rudy - ‪@RudysRetroIntel‬
Arcadesy - / arcadesy
MikeDX - / themikedx
Julian Brown
Bobbus74 - / bobbus74
Devzine - / devzine_pl and t.co/YiVw1daaYP
Charles - ‪@RetroTeaTime‬
Taz - / tazfaedodge
Nigel - ‪@NigelsWorkbench‬
Ginger Hippy Gaming - ‪@gingerhippygaming7962‬
James - / ghost82uk
Chris from the Cave
Retro Krazy - ‪@RetroKrazy‬
Contributors -
Rees - ‪@ctrlaltrees‬
TechMadeEasy - ‪@TechMadeEasyUK‬
Retrograde Scene - ‪@RetrogradeScene‬
RetrobitsTV - ‪@retrobitstv‬
Steve’s Tech Shed - ‪@StevesTechShed‬
Timberwolf - ‪@TimberwolfK‬
CRG - ‪@CRG‬
The Retro Channel - ‪@TheRetroChannel‬
Live Stream Guests (in order of appearance)
Rose Tinted Spectrum - ‪@RoseTintedSpectrum‬
The Retro Channel - ‪@TheRetroChannel‬
Mr Lurch’s Things - ‪@MrLurchsThings‬
Lee Smith’s Workshop - ‪@leesmithsworkshop‬
Jan Beta - ‪@JanBeta‬
Gouldfish - ‪@GouldFishOnGames‬
CRG - ‪@CRG‬
RMC The Cave - ‪@RMCRetro‬
This Week In Retro - ‪@ThisWeekinRetro‬ (Dave)
RetroBitsTV - ‪@retrobitstv‬
Adrians Digital Basement - ‪@adriansdigitalbasement‬
SECOND CHANNEL!
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Discord Channel
/ discord
More Fun Website
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[@RoyLake]

it's mine, all mine! :D

[@MoreFunMakingIt]

And now it works too! :D

[@RoyLake]

@@MoreFunMakingIt That it does :)

[@RudysRetroIntel]

Excellent donation to a great cause. Lots of learning on this one. Thanks for sharing

[@MoreFunMakingIt]

Glad you enjoyed it Rudy!

[@bobbus_74]

Well done for pushing through and getting it sorted, Lee. I would have launched it at the wall. 😄

[@MoreFunMakingIt]

Thanks mate! There were a few moments I came close!

[@LongyFromCork]

Great video, and a great cause. A frustrating journey, but you got there, and I'm sure there's greater enjoyment to be got from getting it working, the round about way. When everything goes to plan, you learn little. When things go wrong, you learn lots. Best of luck with the auction.

[@MoreFunMakingIt]

I always say you learn more from mistakes. And I learn fast because of all the mistakes!

[@ConTanidis]

There's more than enough for all. If only more could offer like you and change this needy scheme we live in.

[@M0UAW_IO83]

There's a lot of 'NOS' CPLDs which are actually genuine but have had the JTAG lockout enabled so they need to be 'unlocked' before they can be reprogrammed or even recognised by a JTAG programmer so it's entirely possible that the 'fakes' you have are real but just locked. You can't unlock them with a JTAG programmer, you need a 'proper' programmer like Dataman 48UXP or similar. The 74HC04 is the active portion of the clock oscillator, could have been replaced by a canned oscillator module I guess, but it's an absolute classic design.

[@MoreFunMakingIt]

I found this out after recording this video. Apparently there's a way to unlock them by applying 12v to the right pin, but in order to do this you need to isolate the CPLD from the rest of the components on the board. I'll try this if I get another board to build in the future

[@M0UAW_IO83]

I've got a few 100% genuine parts which came from old projects and products, I also have a Dataman 48XP programmer, I need to hack together the parallel programmer interface and see if I can get it to talk to them but I'd be interested to try one or two of the 'fakes' if you felt like experimenting?

[@MoreFunMakingIt]

@@M0UAW_IO83 they don't belong to me, but I can ask the owner Julian? Best contact through email or other social media, KZbin comments regularly disappear

[@kyorin6526]

Good job. That successful programming moment would have gotten an "F***-yeah!" from the guy that does TheRetroChannel :o)

[@MoreFunMakingIt]

Love Mark's reactions. A very genuine guy

[@TheRetroChannel]

​@@MoreFunMakingItAww 😊

[@Chriva]

The HC04' is likely involved in feedback and signal shaping of the crystal oscillator signal. :) Something that is needed for the CPLD (and other processing chips) to function

[@MoreFunMakingIt]

Thanks! I'll try to remember that 😁

[@jaycee1980]

The 74HC04 is used to form a Pierce oscillator with the crystal. This is pretty much the standard crystal oscillator circuit used in digital electronics today.

[@mogwaay]

Wow, what a palava you had with the CPLD, looks like fakes are a big issue with those chips. Sorry i couldn't help much when you reached out, id never used that series before. Ive since learned about the mostly compatible Microchip ATF15x series chips which are much cheaper new and im looking at using them in my future projects. Cheers!

[@MoreFunMakingIt]

Good luck with the new chips. Hope they don't suffer the same shortages

[@fhunter1test]

For CPLD - there is 'detect chain' button in Quartus, that inquires - what CPLD (or CPLDs) is connected to the programmer. By the looks of the error - internal JTAG ID did not match the one for which this file was compiled. (though my FPGA/CPLD skills are more than a bit rusty - I haven't done anything for more than a few years).

[@MoreFunMakingIt]

Yup, did that and it correctly identified the chip. But then refused to program it. I now believe they've been programmed and the JTAG line is no longer available. There's a way to reset them but I'll leave that to an expert

[@fhunter1test]

@@MoreFunMakingIt If it identified the chip - then it should program it. Lines and interface are the same for detect and for programming. (if I am not mistaken)

[@bruno_tapez]

Great auction items and very well presented. Thank you very much for your contribution. Hoping that one day there will be another auction for charity and that that ZX Max 128k will be repeated (and if it can be in the same color). If so, you have a guaranteed bidder (Me). All the best.

[@MoreFunMakingIt]

Thank you!

[@bruno_tapez]

@@MoreFunMakingIt 👍

[@thebyteattic]

The parts are probably not fake; just previously programmed and locked (for IP protection) by an OEM. Once the corresponding product is thrown away, scammers harvest the boards and remove the PLCC parts from their sockets, selling them as NOS. But since they were locked before, they can't be reprogrammed.

[@MoreFunMakingIt]

Yeah, I think you are right. I read somewhere you can unlock them by applying 12v to the JTAG line, but I would need another board to do this. If it works it will be very handy as there are a bunch of chips on my workbench like this!

[@WhatHoSnorkers]

Looks gorgeous that. All those chips made me nervous! So much soldering!

[@MoreFunMakingIt]

I only get hungry around lots of chips

[@deang5622]

Chips are easy to solder once you have done two pins.

[@colinmalcolm1211]

Hi again Lee. I was hoping you could point out a place a place to get the schematic for a toastrack 4s board. I have them for everything else but not the 4s. The problem is there is no C79 listed and I would like to know which way round it goes? also tr4 oriantation

[@MoreFunMakingIt]

Hi Colin. The best thing I can suggest is joining my discord. Its very difficult to hold a conversation in youtube comments. For one thing I only get notifications (sometimes) for the first message. All replies usually are lost in the void. I think I know what you're asking but there are a couple of things I need to know first, so discord would be the place for that. You should find a link in the description of most of my recent videos.

[@TheFyend]

Is there a jumper for PAL/NTSC on this like with the standard Harlequin?

[@MoreFunMakingIt]

On the github page it says the outputs are composite and RGB PAL. So it looks like it might be PAL only. Might be an idea to ask Don Superfo himself.

[@dantootill]

Quartus bricked my C64 RGB mod board after I tried to reflash the FPGA with a later firmware. Just crapped out at 4%. I had to revert to an earlier version of the software (V18), which worked fine and I was able to bring it back from the dead. No idea why the later version (V21) just refused to work.

[@MoreFunMakingIt]

Yeah, similar here. Was warned from the start to use a specific version of Quartus

[@dantootill]

@@MoreFunMakingIt Bonkers isn't it? Intel never heard of backwards compatibility with products they haven't retired yet?

[@damouze]

I've read that Intel/Altera ATF150x chips are more or less drop-in replacements for the MAX7xxx chips. I'm curious to know how much of that is true, because I am working on some designs featuring ATF150x chips and WinCUPL is just straight up horrible.

[@MoreFunMakingIt]

You'll need to ask the experts. I get all my technical help from the clever people on my discord.

[@GouldFishOnGames]

Its a shame that the CPLD's were being a pain, but I guess you've now learned how to do it. and as such the expert that I will now turn to if I ever need to do it my self 🤣

[@MoreFunMakingIt]

Happy to help! But I'll have forgotten by then 🤣

[@colinturnbull2180]

Hello Lee. Fellow spectrum fixerupperer. Love your videos and good to know someone else makes the same mistakes I do. 😮 Can I ask you a question...? Where did you buy your modern psu with inline switch? Thanks.

[@MoreFunMakingIt]

Hey Colin! Thank you for the kind words. On my workbench I usually use a bench power supply and made up a lead with inline switch to suit spectrums. The ones I supplied with these new build machines were all bought from CPC. But they do come with incorrect polarity so needed new plugs fitted. The switch cab be bought from lots of places, but I recommend Retroleum if they have stock.

[@colinturnbull2180]

@MoreFunMakingIt Thanks Lee. Yeah I was meaning the ones you supplied in your charity event. Should have made that clearer. Thanks for the info. I'll go look up cpc.

[@MoreFunMakingIt]

@@colinturnbull2180 if I remember I'll dig out the link tomorrow when I'm at my PC. If I forget chase me down on discord or email. They're 9v 2A so you should find them easily

[@leesmithsworkshop]

this was so frustrating because I couldn't offer any help.

[@MoreFunMakingIt]

Got there in the end!

[@MikkyTee]

I've ordered one, but i cant seem to find info about the rgb cable, can you help? What did you use on that one..

[@MoreFunMakingIt]

It's a standard genesis 2/ mega drive 2 cable, but you need to remove the resistors and a cap from inside the scart end

[@MikkyTee]

@@MoreFunMakingIt many thanks lad ☺️

[@MikkyTee]

Me again, what psu do i need for this board, documentation is non-existent!

[@MoreFunMakingIt]

@@MikkyTee for this exact board any 9v PSU will work. It has a bridge rectifier built in so can take any polarity.

[@MikkyTee]

@@MoreFunMakingIt many thanks, sorry for the questions!

[@blackcountryme]

Harlequin with all the chips on looked like one of the Eastern European clones.

[@MoreFunMakingIt]

You're not the first person I heard say that!

[@RetroBytesUK]

Its annoying that a whole bunch of cplds stopped being made at the same time. Especially the 5v ones, there are a few projects I'd like to build but I'm now holding off until the people who created them have refactored them around a cpld you can actually still buy. I've never used the windows programming tools for cplds, so I've no idea how helpful it is when stuff goes wrong.

[@MoreFunMakingIt]

The rumour mill tells me things might be moving in a good direction soon!

[@DAVIDGREGORYKERR]

Could you not have got FPGAs/CPLDs from AMD as AMD owns Xilinx.

[@MoreFunMakingIt]

The chip was donated.