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Kai Robinson

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Everything posted by Kai Robinson

  1. ....aaand there's a short circuit between the power planes in all the board revisions. CANCEL YOUR BUILDS, DESOLDER. I'll send out another batch of boards FFS - its only on the split power plane at the back - can't locate it...c8 links to gnd and power, and even without a capacitor in, the planes are linked.
  2. So - as the title explains, this is designed to save as many Mac SE's as possible. So many have died thanks to the stupid PRAM battery on the board, and with the SE being a 2-layer PCB with just through hole components, it's actually one of the easiest to save. So - how do you reproduce a PCB? First, get a Mac SE PCB - in my case a 'dead' board from eBay for €29 - thanks, random spanish man! Then, you get to work desoldering. Literally EVERYTHING. Not a single component must remain! However, 30 year old solder and my ZD-915 desoldering station caused a handful of through holes to just pull out of the board, or some traces would come up with it. I found that pre-heating the joint, with a little flux (AmTech RMA-223), would make the solder melt a lot cleaner when you use the ZD-915 desoldering gun. You must use a lot of heat, on these boards. For those joints that have been corroded, you must flood the area with flux, heat from both sides, then try and move the pin using a soldering iron (i find 420 degrees C suitable, with a standard flat tip) before trying to use the desoldering gun. Sometimes it won't always come out of the joint, in which case reflood with flux, and attack it with desolder braid. I use 2.0mm GootWick, which is fantastic stuff (thanks to Louis Rossmann for the recommendation). As part of this process, I made a list of the parts that you need to save, and the ones that you can ditch. Obviously, all the custom Apple ones are a must - the rest are either still available, or are available as new-old-stock or pulls. So - here's what you need to save: SIMM Sockets - IMPOSSIBLE TO GET - desoldering these needs HEAT as there are a lot of connections to the ground plane. Pre-heat the joints, maybe add a dab of proper Kester 63/37 eutectic LEADED solder (none of that RoHS crap), flood with flux. PDS Socket - Amphenol/AMP/AVX DIN-41612 3-row, 96-pin connector (Style-C) - Available new, but still worth reclaiming as sifting through the minute variations of parts is an arse... Inductors - probably easy enough to get new ones, but ehhh, they don't really break, and they fit fine. AM26LS30's - NLA, only available as NoS or Reclaimed AM26LS32's - Available new, but still worth reclaiming MC3488A - NLA, only available as NoS or Reclaimed RTC Chip - Custom Chip - maybe possible to clone using pin-compatible ATTiny85 ADB Chip - Apple branded PIC16CR54 - maybe possible to re-produce/clone GLU Chip - Apple branded PAL16L8 - maybe possible to re-produce/clone BBE Chip - Custom Chip NCR5830/AM58C30 SCSI Chip - NLA, only available as NoS or Reclaimed WIM/SWIM Floppy Chip - Custom Chip Hi & Lo ROM Chips - Toshiba TC531000CP MASK ROM's - Reclaim & reuse, but these are the same pinout as 27C512, but adds A16 in place of VPP pin - you can use 27C1001's on an adapter - doug brown made a similar setup with a built in ROM disk for the Mac Plus. 74LS245 - Available new, but still worth reclaiming - replace with CY74FCT245ATPC or CD74FCT245E 74F257 - Available new, but still worth reclaiming - replace with CD74ACT257E DB19 Connector - NLA, only available as NoS or Reclaimed. These are a bastard to get out cause the lugs are soldered. I found that pre-heating the joint first, filled with flux, then pressing hard into the pad with the desoldering gun, waiting til you see the solder go molten, you can often schlorp out the majority of the solder and then tidy up with wick afterwards. Passives - REPLACE ALL - use high tolerance metal film resistors & nichicon or panasonic electrolytics. Maybe try and save the PLCC Socket if you can. remove it cleanly - sometimes the pins pull out but they can be put back in if you're careful. Once you've saved all those parts, it's time to get scanning! 800 to 1200dpi on your scanner. If your scanner bed cant quite fit the whole thing on, scan one side, then rotate 180 degrees, scan, flip the image, then you can merge the images in photoshop. My scanner clips about 5mm off, so i use this method. There will be a part 2 to follow...but any questions so far?
  3. Here's the patch around in the latest board rev.
  4. @cheesestraws @PowerMac_G4 - I HAVE DISCOVERED A TRACE ISSUE! Look here - you'll see i've connected stuff that has no business being connected. I accidentally pistook a trace going into a pad - turns out that i'd actually shoved the trace out the way while desoldering. I just verified against other SE boards - see the original, and the fix. Can cut the trace and patch direct with a bodge wire
  5. Also - upon further signal inspection the 338-6523 is NOT likely to be a 6523 TPI as originally thought - the pins match up to the 6522 config instead, some obfuscation on Apple's part but would make the most sense since the 6522 is used in everything else, and there's nothing being used on what should be Port C, IRQ is connected to the other IRQ pins, R/W connected to R/W etc. I'd love to be able to edit my original post. At least that means one less custom chip to use - you can indeed use a brand new WDC 65C22N instead.
  6. For the RTxCA and RTxCB it states in the datasheet:
  7. The pins are connected as such: 1 i0 to NC 2 i1 to pb6 on 6523 3 i2 to irq on 53c80 4 i3 to wrdata on IWM/SWIM 5 i4 to /enbl1 on IWM/SWIM 6 i5 to pa4 on 6523 7 i6 to 16M output from osc 8 i7 to pa3 on 6523 9 i8 to /RTxCB on 85C30 & BBU pin 40 10 GND 11 i9 to /OE (Pulled LOW through R12) 12 o0 to /RTxCA on 85C30 13 o1 to Output A on 26LS32 - U4C 14 o2 to /IPL0 on BBU 15 o3 to /ENABLE on Lower Drive via filter 16 o4 to /ENABLE on Upper Drive via filter 17 o5 to FLOPPY_WR on all drives 18 o6 to NC 19 o7 to fclk on IWM/SWIM & BBU pin 44 20 VCC
  8. O1 is OutA is an INPUT FROM 26LS32, at least.
  9. Hmm - OE is permanently pulled low via R12 (150Ohm) - doesn't connect to anything else. With the HAL/PAL16L8 - if OE ever goes HIGH, then everything is disabled.
  10. Here you go. The pin assignments are as the PALASM: /* Dedicated input pins */ pin 1 = I0; /* NC*/ pin 2 = PB6; /* PB6 */ pin 3 = IRQ; /* IRQ */ pin 4 = WRDATA; /* WRDATA */ pin 5 = ENBL1; /* /ENBL1 */ pin 6 = PA4; /* PA4 */ pin 7 = CLK; /* CLK INPUT*/ pin 8 = PA3; /* PA3 */ pin 9 = RTxCB; /* /RTxCB */ pin 11 = OE; /* OE */ /* Programmable output pins */ pin 12 = RTxCA; /* Combinatorial output */ pin 13 = OutA; /* Fixed high output w/ output enable */ pin 14 = IPL0; /* Combinatorial output w/ output enable */ pin 15 = ENABLE_L; /* Combinatorial output */ pin 16 = ENABLE_U; /* Combinatorial output */ pin 17 = FLOPPY_WR; /* Combinatorial output */ pin 18 = B6; /* Fixed high output w/ output enable */ pin 19 = FCLK; /* Combinatorial output w/ output enable - FCLK on BBU Pin 44 */ glu.bin
  11. Yah, it's odd - i've literally buzzed everywhere - I0 is just N/C, completely. Not sure why FCLK is so mental, either.
  12. For salvaged parts - Dual Wipe probably make more sense, but for stuff that was socketed already, like the ROMs, definitely turned pin all the way!
  13. Hmm - want to take a crack at the .bin i extracted?
  14. So yeah - you can read the contents as a .bin file while you tell the minipro 'yes, it's totally a rom', and then you parse it using the PAL analysis tool here: https://web.archive.org/web/20160124105239/http://dreamjam.co.uk/emuviews/pal/index.html
  15. And here comes the OE equations... It opens fine in Notepad++ but yeah, you can see they're...nutty. glu_(1).txt
  16. Yeah - using an adapter you can read them as if they were a 27C020 ROM
  17. Name HAL16L8; PartNo ; Date 2020-07-13; Revision 0.1a; Designer Kai Robinson; Company ; Assembly ; Location United Kingdom; Device g16v8a; /* Dedicated input pins */ pin 1 = I0; pin 2 = PB6; pin 3 = IRQ; pin 4 = WRDATA; pin 5 = ENBL1; pin 6 = PA4; pin 7 = CLK; pin 8 = PA3; pin 9 = RTxCB; pin 11 = OE; /* Programmable output pins */ pin 12 = RTxCA; pin 13 = OutA; pin 14 = IPL0; pin 15 = ENABLE_L; pin 16 = ENABLE_U; pin 17 = FLOPPY_WR; pin 18 = B6; pin 19 = FCLK; /* Output equations */ !FCLK = CLK & !OE; B6 = 'b'1; !FLOPPY_WR = WRDATA; !ENABLE_U = !ENBL1 & !PA4; !ENABLE_L = !ENBL1 & PA4; !IPL0 = !PB6 & IRQ; OutA = 'b'1; !RTxCA = !PA3 & !RTxCB & !OutA # PA3 & !RTxCB & !OutA # !PA3 & RTxCB & !OutA # PA3 & !RTxCB & OutA; That's what i pulled out of the GLU so far...makes sense, but the OE is a MESS. There must be a way to reduce them, but WinCUPL just crashes constantly.
  18. To be fair - there's no reason you can't use an FPGA with more pins than the PLCC layout - you can just not use the PLCC socket and use a standard BGA or TQFP part - like the ReAGNUS: https://www.exxoshost.co.uk/forum/viewtopic.php?t=2828 Also - the chips that should probably be concentrated on first, would be the ADB Chip (the PIC16CR54) and the GLU logic chip (PAL16L8). I have the equations but the OE list is insane...
  19. BTW - this is the finished board, i was so busy doing it, i forgot to post it
  20. There's 0v reading on the output of the PSU for anything - I think its the power switch thats broken, seeing as there was a fizzing noise coming from it...
  21. I got all excited....plugged it in and...the PSU is dead in my SE chassis
  22. Just finishing the last bodge wires now... Solid core wire sheath is a pain to work with...!
  23. Mostly a combination of the Macintosh Classic schematic (a cost reduced SE that also uses the same BBU), and backtracing pins on the board. Sprint has this wonderful 'test' feature - click on any pin of the BBU, and you can see exactly where it goes. I'll send you the sprint layout file if you like, you can take a look yourself.
  24. @quorten You may find this useful: https://docs.google.com/spreadsheets/d/19KZSWZ_Px0TnwkSoki0VuATfsSeL1rhe9WXxzEwFZL4/edit?usp=sharing Also, you'll have to make the second schematic page from scratch, seeing as there seems to be none on the internet.
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