Spectrum Next - Issue 3 and 4 boards and casing

[@SwainyAtRetroAsylum]

Looks good. Reminds me that I need to change the battery in my Next.

[@paulklasmann1218]

Why was the RAM changed to be one chip that's a BGA? If it fails it will be a much more difficult component to replace, if not impossible for most folk. Off course the FPGA is a BGA but they rarely fail. I'd have preferred more accessible RAM, especially with the rubbish lead free solder used nowadays. In any case, I'm looking forward to delivery of my two Nexts. Thanks for showing the assembly.

[@SpectrumNextStuff]

kzbin.info/www/bejne/Y6KXd42eoa2Sibs explained around 16:10

[@lostcarpark]

Would it be possible to put the connector for the ribbon cable on the bottom of the board? If there's enough clearance from the case bottom, it would make assembly easier, as the ribbon could be attached after the boards are screwed down. It would also mean that the daughterboard wouldn't need to be unscrewed every time the main board is removed.

[@SpectrumNextStuff]

Clearance is tight with respect to the main board and the bottom case. I’ll get an answer :)

[@SpectrumNextStuff]

2.75mm clearance apparently, so not much.

[@lostcarpark]

@@SpectrumNextStuff Thanks for the informative response! So how tall is the new ribbon connector? Very hard to figure out from the video. And just curious, was the idea of putting the connector on the bottom of the board considered?

[@SpectrumNextStuff]

@@lostcarpark FFC connector is 2mm tall I believe so it might give 0.75 of breathing space :) There were never any plan to move this. The connector has been on top prior to the issue 2 becoming a thing, perhaps 2016 or earlier. With the previous connector type having such a large profile it would not have been possible then. Even up to the issue 2e (issue 3) we used the larger type. It was only based on results of emc testing and such that our board design bureau changed the parts. We do not design the Next board any more although we feed back on their decisions and have requested a number of improvements (deferring to their knowledge of how best to implement them). Ultimately it isn’t necessary to move the part as they will be assembled in a very capable factory and their QC incorporates testing button actuation and streaming capability from the SD card etc.

[@SpectrumNextStuff]

Actually, just had a look at the right part this time, 2.55mm so 0.2mm free

[@clangerbasher]

Where is the project now? Is Kickstarter 2 still open? Will there be a third one?

[@SpectrumNextStuff]

You’d be best off having a read of KS update 17 and 18 to get where things are up to. www.kickstarter.com/projects/spectrumnext/zx-spectrum-next-issue-2/posts/3408549 no idea on another KS yet

[@clangerbasher]

@@SpectrumNextStuff Thank you.

[@wetwareerror9511]

Does thus mean that we cannot connect an extra sd card reader ?

[@SpectrumNextStuff]

It's no different from the previous board types, just a different type of connector for the daughterboard. I'm not sure what kind of device you're currently using though or how it connects.

[@intrepidis1]

I feel like it would be safer to connect the ZIF cable to the main board, screw that down, then bend the ZIF cable over to connect the daughter board.

[@SpectrumNextStuff]

It’s a pita that way. The cable is too short to present much when you bend it around the main board to present it to the daughterboard.

[@RichardHallas]

I’m disappointed to see the change of connector. Why do this? There must be some overwhelming advantage, because it’s a vastly more fiddly replacement for what was previously a very convenient connector, and it renders the new board incompatible with anything designed for the existing socket type. In future, too, it’ll mean that anyone offering add-ons that use this socket will need to offer two connector types (e.g. the in-development DB+ project) for KS1 vs KS2 Nexts. I thought one of the mission-critical objectives of the KS2 Nexts was for them to be indistinguishable to users from KS1 ones, and this seems like a very incompatible change, albeit one that affects only a small minority of users. Regardless, I just don’t like the fiddly and fragile new connector type. It’d be interesting to know why this change was felt to be necessary.

[@paige.landers]

It was an RF noise thing during the certification process. Know I saw an update about it at some point but it doesn't appear to be in either of the relevant KS2 updates so must've been on the FB group.

[@RichardHallas]

@@paige.landers Oh, right - thanks. I do follow the KS and FB updates quite closely, but I'd missed that. A valid reason, then - but a bit of a pity nevertheless.

[@spinnetti]

I'd prefer no daughter board at all - why can't it be just a single board? Would eliminate both connectors and the ribbon.

[@RichardHallas]

@@spinnetti I think it must be recognised that the design is essentially 'historical' now. I.e. The KS2 boards are physically compatible with the KS1 boards, which in turn were designed to go into original Spectrum cases (as indeed many have). You could certainly argue that if the KS2 boards were ONLY EVER going to go into proper Next cases, and not other third party (or original) Spectrum cases, then everything could indeed have been put onto a single board, and you wouldn't have needed a second pair of optional joystick ports in an alternative position, either. However, I believe I'm right in saying that the KS2 board was originally going to be offered on its own, caseless, as happened with the KS1 boards. As such, the daughterboard would have needed to be kept optional and the alternative pair of joystick ports retained. Later, of course, it was decided that KS2 machines would be offered ONLY as part of full, cased computers, so the need to retain compatibility with the original Spectrum form factor was lost, but only at an advanced stage. I guess this is one reason why the wifi card has been moved to its new position on the right-hand edge, where it would fail to fit inside an original Spectrum case (I imagine a slot would now need to be cut so that it poked out of the side!). But presumably more drastic modifications to the main board wouldn't have been justifiable economically. Besides, there's at least one third party expansion project underway that will replace the daughterboard with a more powerful version that has extra functionality, so it's potentially a useful thing to be able to swap out in any case. Anyway, this is just informed guesswork on my part - I can't speak on behalf of the Next team - but I think the underlying message is: look at the history. The Next was designed to be compatible with (i.e. fit inside) the original rubber-key Spectrum case, and although that's no longer a requirement for the KS2 Next, designing a whole new circuit board to integrate the separate daughterboard was probably neither worth doing in itself nor financially justifiable.

[@paige.landers]

@@spinnetti In addition to what @Richard Hallas said, eliminating the daughterboard would necessitate a new case design for the KS2 machines and that's WAY beyond the scope of the project. The case was probably the single biggest investment of both time and money from the first Kickstarter and KS2 was intended from the start to use the existing injection molds.