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We have now reached the first major milestone! This: Now it might not look like much but this techstep now has none of the original programmed parts installed. The main micro and all 3 PAL's have been replaced verifying that all the dumps are good! Work can now properly start on stage 2 :)

I think both me and @Kai Robinson have considered the IIsi and IIci but they are 6 layer boards so require completely redrawing like @Bolle did with the SE/30 rather than just tracing. I'll defiantly be looking at them in the future though if someone doesn't beat me to it My next board (after...

Just had the V1.1 IIcx booting for the first time last night :) Needs a couple of small patches but the design is 99% done

That's exactly what my breakout board dose :) (Well would do, if more than 4MB worked in the onboard bank) My intention is to replace the onboard bank with another SIMM or additional RAM on another module and completely ignore the onboard bank

If you ever feel like patching the LCIII ROM to recognize more than 4Mb it's internal bank I would love to get the LCIII booting with 16MB in the internal bank :)

Provisional version of the new DC in board is done: This comprises of a lithium battery charger, battery protection IC and associated dual mosfet and two boost regulators (+5v and +9V) This board can in theory be fitted to a original techstep however the +5V regulator should be omitted in this...

I thought they where 27C16's not 64's, need to have a look at my SE/30 board now..... Either way it doesn't really matter as the 28C64 will work fine to replace either :)

That 4 slot riser is very intersting, i'm guessing that PAL is generating additional RAS signals for the extra simms Given the marking of that chip (CE16V8) i'm guessing it's a PALCE16V8, hopefully it isn't protected as it might be hard to extract the code from it if it is

Me and @jajan547 are currently working on creating a replica of the Apple Techstep This will be a functional and (mostly) electrical clone of the original but will not be a exact 1:1 copy as the design will be optimised where changes can be made to make the board easier or cheaper to assemble...

Are those sanded or have they been painted over? it might be worth trying a little IPA on them Edit: Looking at the pictures I would guess U8 is the only PAL on there, looking very closely at the picture @Kai Robinson posted I *Think* its marked as a TIBPAL16R4 so hopefully this is unprotected...

Yep ROM's are socketed If someone whats to have a go at modifying it that would be really cool, software is not my expertise.... I tried 0/8/16MB, 0MB gives death chimes anything else works but only 4MB is seen

And a couple of things I have discovered while playing around: The LCIII needs the onboard RAM bank to be present otherwise it produces chimes of death (even with SIMMS in either or both of the other slots) and secondly that onboard bank is limited to 4MB, if you install more it simply doesn't...

Board layout, gerbers and scans are now on GitHub: https://github.com/max234252/MacLCII_Reloaded As with my other designs these are provided under a non-commercial licence but if you are a repairer and want to offer transplant services (or have any other commercial use in mind) please contact me

Very interesting, That seems a very good way to go and is more closer to what I was originally thinking about doing Those Simms are had to get over here but I can easily get hold of 4mx4 DRAM IC's so could just design a similar simm assuming there is enough space in the LC case

Almost, two 32MB's and one 16MB. the top slot only has one RAS line connected to it so will only work with single rank SIMMS which due to the ammount of address lines available is limited to 16MB (32's have two ranks of 16MB each on them)

And the breakout SIMM and triple riser have been sent off to JLCPCB While i'm waiting for them I'll probably draw up a "direct riser" design too

I think if we are going that route I would be tempted to have a slot cut on the board, if it was the right width you should be able to get the correct angle on the simms without having to cut them Also I got some new 32MB SIMMS today and can confirm for anyone having doubts that 68MB 100% works:

Probably! :) My liking of this approach is for a couple of reasons though, it's more flexible as what's on the end of the cable could be a breakout board as pictured above or it could just be a RAM card with all the RAM soldered on it (Which I like as angled 72pin sim slots are extreamly hard...

I was thinking, why stop at two simms when you can have three! The top slot replaces the onboard bank and would only support single rank simms (Dual rank ones will likely just show as half their capacity) Really this is just a development stop gap, It's the quickest design I could think of to...

Interesting, I hadn't thought of doing it that way...... I'll need to do some measuring to be sure weather or not that would fit I suspect the floppy and power connectors might get in the way of the backwards facing simm's but i'll need to double check that