Gregory's Serverbefore i can use the Apple IIe card, looks like i'll need to recap it. 😬
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66 comments
 @tubetime I like to think you have a stock room full of capacitors. @tubetime I recapped my SNES a few months ago to protect it. Unfortunately I think it has some problems with one of the ICs. Graphics are all weird. Also replaced the vreg even though the output from that looked fine.  I was having trouble because I was putting the *volume* image into the SCSI2SD rather than the *disk* image. turns out partition tables are important lol @tubetime Such a comforting boot screen. Diagnosing Extension conflicts not so much. I mean it's a large volume but should it really take an hour to mount? @tubetime wow I forgot all the partition options the Classic era disk formatting tools had. trying something else. unfortunately this didn't seem to work, I suspect the HFS partition needs to come before the ProDOS partitions. well this explains why it was hanging. there's probably some setting on the SCSI2SD that's not exactly right. @tubetime Seeing this is dredging up ancient memories of playing with not-new SCSI gear as a kid… staring at the baroque arrangement of peripherals, utterly confused as to why it wouldn’t just WORK. @kgutwin it's still a confusing mess when it comes to USB 3.0/3.1/Gen 1/Gen 2/3.2 Gen 1x2/2x2 and all the weird alternate mode issues. turns out this hang was caused by the SCSI2SD firmware, which was uhh shamefully out of date. with the latest version it works and i can partition the drive! it also turns out that MacOS wants to be the first data partition (i had the two ProDOS partitions first.) but it works now! @tubetime Memories of SE30s, Classics and a few Quadras in a graphics shop I worked at in 92. I used Filemaker Pro to manage work flow and create job tickets. Great relational database program. only had these poscaps hanging around. yes they're very fancy but they'll work. wow, it totally worked! is it an Apple IIe or is it a Performa 475? why not both! i figured out how to change the startup sound to "Quack" which makes me think of the Quapple (my Apple II ISA card that i cloned a while back) @natemartinsf it's super clean! also dang you're on mastodon too, i will follow you asap time to check the capacitors on the motherboard. there really aren't that many chips on it! I was also able to remove it without any tools. just bend some tabs and it slides right out. @tubetime copyright 1982 on the ROM--wow! @tubetime thanks! I think Apple added the expansion port on the Mac SE; I recall working on a prototype add-on for that port in 1989. I think the port used a conventional DIN 41612 connector; this one looks like a newer, extended version.  @tubetime Definitely a #Macintosh #mainboard: I've not seen and #PDS "slot" sockets anywhere else... i found a tech manual. this is a very clean design. most things are tidied up into the two big custom chips, MEMCjr and Prime Time. heh, they even put the bus sizing features in this chip. motorola removed that in the '040 (the '030 had it) and it caused innumerable problems for 68k computer designers. the Commodore folks solved this on their '040 Amiga CPU card by using a raft of ten (10) GALs, which burned a ton of power. @tubetime This post suggests power management. https://68kmla.org/bb/index.php?threads/where-to-find-341s0851-c-1990-apple-lciii-boot-issues.37152/ based on the pinout i think it's a 24C01 serial EEPROM, probably for a unique serial number or something. @tubetime that's 343S0120, often found alongside the customized 68HC05 Apple calls Egret (Cuda in later models) used for ADB, housekeeping tasks, PRAM, reset (and NMI) management, etc. IIRC '0120 serves as a power monitor, switching the HC05 to battery power when system power is cut. ...as seen here on a 630 DOS/LC580 board. yeah i'm wrong, this is a battery switchover circuit much like the MAX703. it provides voltage to the Cuda chip from the battery, and automatically switches to the 5V rail when power comes up. I've 3D printed a drive bracket for the Performa. it's designed to hold the SCSI2SD. it's a little loose but not a bad fit. I designed this based on photos of a real bracket, so the dimensions are probably slightly wrong today's status: i'm having issues with the joystick port. the machine thinks it is pegged to the lower right even when it is centered. the design is not an ADC. it uses a quad 555 timer with RC circuits composed of the external joystick resistance and 22nF capacitors. the Apple IIe just measures the time it takes to exceed the threshold. it's just barely pegged at 250 or so. 2.8ms. the resistance is 87.8K, so this RC curve implies a capacitance of 68nF. that can't be correct. inspecting the board reveals corrosion on the pins of an 'LS125, some of whose pins are wired into the joystick inputs (for some reason). i think the capacitor (already recapped C2) spilled electrolyte all over this area. i removed the 'ls125. there was definitely a puddle of electrolyte underneath (it crackled and fizzed during desoldering). note that the potentiometer connection (red arrow) is right next to a pin tied to ground (blue arrow). electrolyte is conductive, so maybe it was creating a leakage current. removing and cleaning the area helped quite a bit! it's not perfect so i think i have more cleaning to do. @tubetime I feel like that's the spiritual successor of the SE's BBU which turned a half dozen or so PALs into a single chip  @tubetime I wonder why a similar situation didn't cause problems in PC land when going from 8088 to 286 bus (and again from 286 to 386)? 8-bit ISA works (mostly) fine on newer machines. I wonder if this is a port-mapped I/O accommodation? I remember hearing- emphasis on _only hearing_- the 286 has some _slight_ incompatibilities when talking to 8-bit devices with an I/O port at an odd address. But most cards in practice didn't run into this. @tubetime Really clean! I love that they put legacy MOS 8bit VIA clones on chip, just like PC people had Intel 8bit chip clones in their Chipsets ☺️ @tubetime No, I was talking about the Show Time chip „set“. It integrates two VIAs and even a SWIM (Super Woz I… Machine) floppy controller. Apple IIe personality should feel at home 😄 @tubetime The Apple IIgs was the first to have this tool-less design. I don’t know why that is so. It made working on Apple products so nice. @tubetime Oooh that looks fun. Alas all I have in the classic mac world is a Mac SE with no slots. @tubetime @tubetime Yeah I've had mixed results with the SCSI2SD and random old hardware. A particularly weird one is suddenly the same one I've had forever stopped working on my Microvax. Used to work, now doesn't, no explanation. @tubetime better to discover through corrosion than explosion |
@tubetime Nah that's just some unmelted solder paste~ ;p