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Bolacore

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  1. Bolacore

    Radius SE 2.1 ROM Dump

    The only other part would be getting the GAL equations, as it has a handful of them on the board. Apart from that, you could probably figure it out if you had the time and clone it, although I'd imagine you could greatly simplify it with an FPGA.
  2. Bolacore

    Radius SE 2.1 ROM Dump

    Hello, just wanted to share I've uploaded the v2.1 ROMs for the Radius 16/25 accelerator for the SE. I've not found another copy online, so hopefully this helps someone who wants to run Sys 7.1/7.0 on their SE with Radius card. Link: https://www.macintoshrepository.org/27255-radius-se-accelerator-2-1-roms
  3. I recently picked up an LC that had a TDK power supply with lots of leaky caps. When powered on one of the big TO220 diodes would get red hot. The back side of the power supply is all black as well, presumably from being run when shorted. I've replaced all the caps, resoldered all the joints on the low voltage side, and now it longer heats up, but just clicks. If I put the output on a scope it rises and falls with the clicks, but all 3 rails hit the right voltage before the click. Does it once every 1.5s or so. Under load it does it every ~1s and the output sags down to a couple volts. Not really sure what else to replace on this, as I can't find any schematics for it. Any ideas on what to try next?
  4. What do you mean? The drive passed the test in Apple Personal Diagnostics, as well as the bad block test. May very well be going bad though, it is from 1990 after all. I have a SCSI2SD showing up sometime soon, so will probably switch to that at some point.
  5. Just to update, I finally found one program that seemed to work: SCSI Specialist. Initialised the drive, and I can now install Sys 7.1 without issue. No idea why the others didn't work
  6. If it helps, I fixed a Mac Classic recently with the exact same error. In my case, it was the 74LS174 - a few of it's pins had corroded from bad caps and were no longer making contact. That little chip generates the timing for the CAS PAL in the corner of the board, and if it's not working, you'll see half (or all) the data bus not working very well. Pulled the chip on mine, cleaned the board, and put the chip back on. Booted right up after. Looking at your board, it looks the same as my did before I repaired it.
  7. I recently got my Macintosh Classic up and going again after recapping (analogue + logic). It passes the Apple Personal Diagnostics tests on the long RAM test, logic board test, and floppy test. It has it's original 40MB SCSI drive, and already had Sys 7.0.1 on it that worked just fine. I wanted to reinstall it fresh with Sys 7.1, so I started up Disk Tools from the Sys 7.1 disk set, and ran Initialize on Apple HD SC Setup. It ran for about a minute, and then bombed with an illegal instruction error. Every time I now try I get the same issue, and can't format the drive. I've tried with Disk Tools from 6.0.8, 7.0, 7.1, and 7.5.3, all fail with generally the same error a minute in. I've also tried Lido 7 which also fails with an illegal instruction. Not sure what to do now, as I can't understand why it keeps bombing on me. Is the issue with the drive, or is something else possibly at fault here? Thanks in advance for the help
  8. Hello, I've picked up a Macintosh SE that was said to have a broken CRT, and did not power on at all. Indeed if I powered it on with everything connected, the 5V rail seemed dead and only 0.5V was on the +12V rail. Since I had them on hand, I replaced all the electrolytic caps on the analog board and inside the Sony CR44 supply. I put the Sony power supply on a load after and it seems to be able to put out the rated current on all rails. Powered it up with just the analog board, plus CRT + yoke boards connected and the fan spun up and I saw 5.6V on the 5V line and 11V on the 12V line. However, if I connect the logic board, the fan no longer spins and I get the same really low voltage levels as before. Nothing seems to get hot though - if I look at the logic board after 10 mins with a thermal camera everything is cold, and everything on the analog board is too. There's a short somewhere (I'm assuming), but I cannot seem to find it. If I measure the resistance at the analog board of the voltage rails everything seems fine. The logic board seems fine too, although it's 5V line measures 110 ohms at the J12 connector. I'm not quite sure where to start, as it's not obvious to me which piece is at fault. Has anyone else seen this behaviour before? Thanks in advance
  9. Bolacore

    Macintosh Classic - low beep with garbled screen

    Is there a compatible chip? I see it's Motorola branded, and I've found other ICs from them that were RTCs + SRAM. If not, I'll try the trading post here seeing if someone has a spare. As well, do you know what the screen should look like without the ROM installed? Should it be blank, or actually display lines/rectangles like mine does?
  10. Bolacore

    Macintosh Classic - low beep with garbled screen

    Ah that's good to know then, I wasn't sure if that was an extra ROM for the built in System 6. I'm wondering if I've just killed the ROM and it's resulting in garbage on the bus, hence the garbled screen with it in. I can't seem to find replacements, so will try an find an EPROM that's pin compatible. Can't find any replacement for the RTC. Will just keep going under the assumption it isn't needed. I believe it's I2C, so, would be surprised if it didn't work at all without it, but I could be wrong. And that's the one, I hadn't heard anything about what it's for. Glad to know it's for testing.
  11. Hello, I'm repairing a Macintosh Classic I picked up with battery damage. When I received it, it was totally dead (0V from the power supply on all rails), and it's battery had leaked on it's board. It has it's original SCSI drive and RAM expansion card with dual SIMMs. I've since repaired it's power supply (4.95v for 5V supply, 11.82 for 12V supply), cleaned up the board, replaced all caps, and have been trying to get it to boot. Despite the battery leakage, the board seems in good shape, and the only loss was the RTC IC (UA2 on my board) since it's leads fell off, and what I presume are the two FETs to charge the lithium battery. Both have been removed from the board. The entire area around the 68000 and VIA check out just fine if I follow them according to the schematics. However, when powering it up I get a screen with random artifacts on it, and a low pitch loud beep from it's speaker after a few seconds. It then sounds like it attempts to read the floppy, then stops after a few seconds. 10 seconds later this repeats with another beep, and more floppy noise. I can't really find anything describing what this low pitch chime might be. Not sure if it's actually intentional or some fault on the board still. Does anyone know what it means? Is it an error code? Video of the bootup + sounds: https://photos.app.goo.gl/kyN9d6Rxwcb1Vb5V7 As well, had a few questions on replacement parts as well - Can the Classic boot without it's RTC IC (UA2 on the board)? As mentioned, I pulled it from the board due to corrosion. Can the Classic boot without it's ROM (UE1 on the board)? I have a 40-pin ROM and the board has a 42-pin socket. During repairs I had the ROM off by one pin and it got quite toasty, so I presume it's dead. If I pull it, the screen produces rectangles on the screen with no beeps, with it the screen is totally garbled but it does chime. What is the PCB finger connector at the bottom of the board for? Not too relevant, just curious. My schematic doesn't mention what it's for. Thanks in advance!
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