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Reverse Engineering the Macintosh SE PCB & Custom Chips for 1:1 reproduction
Posted by: JustG on 2020-07-16 23:12:49 I am so glad I found this forum. All of these projects amaze me and I love seeing an idea come to reality.
Posted by: LaPorta on 2020-07-16 23:45:30 Perhaps we can find a US-based supplier to crank some out here as well. An incredible job!
Posted by: Kai Robinson on 2020-07-17 07:04:07 After a full inspection of the boards, i can say the following: JLCPCB have done a fantastic job, for the money. The silkscreen on both layers is sharp and better quality than PCBWay for sure. Everything fits - although the holes in the prototype may be a little tight for reusing some parts - thankfully most of the parts that need to be reused are to be socketed anyway, so not really too much of an issue - although the SIMM socket pads were 1.4mm x 0.72mm, so i've made them and all the other DIP socketed parts a touch larger, at 1.6 x 0.8mm to make for a better fit, especially if reusing parts. The pads for the rear I/O, such as the ADB/Serial and the metal support bracket are a tight fit and i missed out excluding the pads on the underside from the solder mask, so i've already re-done the sockets from scratch to give a 0.25mm larger surface area (track width from 0.25mm to 0.50mm as they're 'drawn' and then infilled with an exclusion zone), as modern PCB's are very, very accurate and incredibly fine, compared to ones from the 1980's. Now the biggest fear i had was hole alignment. Fear not - for all the holes line up bang on! Literally, 1:1 is what i was aiming for, and i assumed i may be out by about 2-3mm in some places, but from the measurements, 1mm difference at best - In addition, all the rear IO ports are PERFECTLY ALIGNED. I'm going to start building these up on Monday/Tuesday next week as i have family commitments and a well earned barbecue to host. I need to get some parts from a US supplier of SIMM & PGA sockets - would someone mind being a middleman for that?
Posted by: pax on 2020-07-17 12:57:55 Beautiful!
Posted by: Kai Robinson on 2020-07-22 21:39:49 It's been a while since i last posted - just having time to myself has been nice. So - i'm missing the capacitors, a 53c80 SCSI chip and the SIMM sockets (my old ones may not fit in the holes) but here's how it looks built up so far... Still need a middleman for the parts from phoenix electronics, if someone wants to volunteer?
Posted by: blusnowkitty on 2020-07-22 22:41:35 This'll be a fun project and I might have to get in on a board or two. Both my SEs sit in the corner gathering dust because they have bum SIMM sockets. Stupid brittle plastic clips.
Posted by: Kai Robinson on 2020-07-22 23:14:05 @blusnowkitty Well - you can get some new sockets from Phoenix Electronics - i linked them earlier in the thread - but you're welcome to sacrifice an SE to the cause 😉
Posted by: techknight on 2020-07-22 23:31:27 I love the fact that you put everything in sockets 🙂
Posted by: Kai Robinson on 2020-07-22 23:34:12 I love the fact that you put everything in sockets 🙂 Well, makes it easier to swap out stuff - especially during the prototype stage - i even socketed the oscillator 😀
Posted by: techknight on 2020-07-22 23:34:48 True, plus it makes it easier to test chips that may be dead or not from other boards.
Posted by: Torbar on 2020-07-23 08:37:32 If you're still looking for a US based middleman for the parts from phoenix, shoot me a DM, I can help out
Posted by: jimjimx on 2020-07-23 08:48:10 Are these FS yet? What’s the cost?
Posted by: Kai Robinson on 2020-07-23 17:23:06 @Torbar - yes please, theres about $50 of parts i'd like, obviously willing to pay extra for your time and shipping, obviously. Need some PGA68 sockets too as well as a glut of the 30-pin SIMM sockets. @jimjimx - Not yet, this is the prototype stage, the prototype boards i just had made are in need of bodge wires for VCC and GND for the I/O ports, but that's been fixed, along with the silkscreen, in the latest board revision. If the prototypes are a success, i'll produce, and sell for about £30 (GBP) per board, to recoup development costs and board production costs. I'll do a limited run of boards at OSHPark for those who want the glass black finish and clear soldermask (so you can see bare copper on black), but otherwise will be a standard run of boards in either green, purple, blue or matte black....
Posted by: Kai Robinson on 2020-07-25 05:59:21 OK - can someone else with an SE logic board take a photo of the text on the side of C19 - need to know if it's a 10nf Cap, or something larger - Also, is C67 (above the BBU, and to the right of the uppermost 74F257) populated at all or just blank pins?
Posted by: cheesestraws on 2020-07-25 06:43:24 I can't get good enough light right now for a photo, if nobody has provided one by tomorrow I'll have another go with more light.
Posted by: Kai Robinson on 2020-07-25 07:06:54 Bar the 50pin IDC, PRAM battery, the electrolytic capacitors (finding axial ones is a pain), one transistor, one resistor and the ferrite bead....we are t-minus 4 days to launch! Getting the SIMM sockets back in was a pain due to the slightly bent pins, but after the requisite blood sacrifice was made both went in without much trouble. Blood for the blood god, I guess....?
Posted by: Kai Robinson on 2020-07-27 00:37:39 Revised BOM here: * Partlist from file: MacintoshSE.lay6" / 26/07/2020 00:32:29 * * Name Value * C1 100nF C2 100nF C3 100nF C4 33uF 16v C5 33 pF C6 100nF C7 100nF C8 100nF C9 100nF C10 100nF C11 33uF 16v C12 100nF C13 33uF 16v C15 100nF C16 33uF 16v C17 100nF C18 33pF C19 10pF C20 100nF C21 100nF C22 100nF C23 100nF C24 100nF C25 100nF C26 33uF 16v C27 100nF C28 100nF C29 100nF C30 100nF C31 100nF C32 33uF 16v C33 100nF C34 33uF 16v C35 100nF C36 1uF 16v C37 33uF 16v C38 33uF 16v C39 100nF C40 68pF C41 100nF C42 100nF C43 100nF C44 100nF C45 100nF C46 100nF C47 100nF C48 100nF C49 100nF C50 100nF C51 100nF C52 100nF C53 100nF C54 100nF C55 100nF C56 100nF C57 100nF C58 100nF C59 100nF C60 100nF C61 100nF C62 33uF 16v C63 100nF C64 100nF C65 100nF C66 100nF C67 100nF CR1 1N4150 CR2 1N4150 CR3 1N4150 J1 EAR Kobiconn 161-3520-EX J2 SERIAL TE 5749268-1 J3 SERIAL TE 5749268-1 J4 EXT SCSI Amphenol L77SDB25S1ACH4R J5 INT SCSI Molex 87831-5019 J6 EXT FLOPPY J7 UPPER DRIVE Molex 87831-5920 J8 LOWER DRIVE Molex 87831-5920 J9 ADB TE 5749181-1 J10 ADB TE 5749181-1 J11 Speaker J12 MAIN Molex 39-28-1143 J13 PDS TE 5535032-4 J14 SIMM PE Connectors HWS9229 J15 SIMM PE Connectors HWS9229 J16 1x3 HEADER L1 33uH L2 33uH L3 33uH L4 Ferrite Bead Q1 2N3904 R1 10k R2 10 R3 47 R4 47 R5 560k R6 10 R7 10 R8 1.2k R9 47 R10 47 R11 1k R12 150 R13 1k R14 470 R15 1k R16 3.3k R17 10k R18 1k R19 10 R20 75 R21 3.3k R22 47 R23 47 R24 47 R25 47 R26 3.3k R27 3.3k R28 47 R29 47 R30 47 R31 10k R32A 47 R33A 47 R34 10k R35 150 R36 150 R37 39 R38 39 R39A 47 R40A 47 R41 3.3k R42 39 R43 3.3k R44 3.3k R45 3.3k R46 3.3k R47 3.3k R48 3.3k RP1 39 4610X-102-390LF RP2 39 4610X-102-390LF U1C SND U2C 26LS30 U2E 74ACT257 U2F 74ACT257 U3C 26LS32 U4B FILTER U4C 26LS32 U4D MC3488A U4E BBU U5D 85C30 SCC U6B 58C30 SCSI U6D ROM HIGH U7D ROM LOW U7E MC68000 U8B FILTER U8D SWIM U9D GLU U10C ADB U10D 16 Mhz Clock U11A FILTER U11B FILTER U11B FILTER U11C RTC U11D Rockwell 338-6523 TPI U11F 74FCT245 U12F 74FCT245 Y1 32.768 KHz
Posted by: tt on 2020-07-27 15:43:36 @Kai Robinson Wow this is such an interesting take on PCB repair. I have this strange urge of wanting to transplant components off an old working board to a new one, which I know makes no sense. If you need help with buying parts in the USA, let me know. I am interested in buying some simm sockets to repair some on a board but I'm not sure if they are 1-up or multi-up ATM.
Posted by: cheesestraws on 2020-08-01 00:17:09 @Kai Robinson R25 on your BOM above you have marked as a 47Ω, but on the three boards I have here out of machines, it's 560Ω (see photo attached). Mind sanity checking me to make sure I'm not going mad?
Posted by: Kai Robinson on 2020-08-01 01:09:58 You are indeed correct, it is 560Ohm, and that was on the list i have noted down - I could have sworn i amended the BOM correctly above...
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