Jump to content


  • Content Count

  • Joined

  • Last visited

Everything posted by powermax

  1. Yes, the B version is indeed much cleaner! The map image looks great while the downloaded jpg shows a long horizontal stripe of black pixels. Looks like something went wrong during stitching...
  2. I rotated the die image 90° clockwise and opened it in Inkscape. Pin 1 could be easily found because it's marked with "1" I then annotated all pads with the corresponding pin numbers and type. The power rails ("VSS" and "VDD") could be easily spotted. All other pins except three ones could be classified to be either input (red "I") or I/O pins (blue). I believe that pads 2-4 are there for testing purposes as described in chapter 7 "Testability". It looks like they were never connected to anything. The overall chip structure seems to match the description in the alrea
  3. Thank you! Is there any way to download the die shot from the map viewer? I'm eager to run degate on it.
  4. Yes. Next step would be to set up degate to locate all internal cells as well as find all power connections... There are unused pins that appear as blank pads.
  5. It looks like our BBU is a standard VTI gate array of type VGC1900 as indicated by the markings on the silicon die. VTI Gate Array databook (can be downloaded here) specifies its properties as follows: number of internal cells: 1288 number of input-only cells: 35 number of I/O cells: 58 number of power pins: 8 number of testability pins: 3 Pins total: 104 The above databook explains the exact topology of this gate array. Figure 2-3 on page 17 shows the anatomy of an internal cell of this chip as it was implemented in silicon. Have fun
  6. What's about giving degate (https://degate.org) a try? I personally didn't play with it yet so I can't say how well it performs for real-world use cases. By the look of things it was designed to semi-automatically identify common building blocks of ICs in die images. Considering the amount of gates in the said BBU reversing it manually may take a lifetime. Any tool that aids in speeding up such a task is highly appreciated IMHO...
  7. Thank you a lot, @MrFahrenheit It indeed works as you described. It looks like my restoration job was a success. I'm really happy now.
  8. Okay, let's get back on track. I would like to know if someone owning a PowerMac 6100 can play back audio CDs using the internal speaker. I'm going to check next if I can record CD audio with an audio recording software. The Sound control panel allows to select "Audio CD" as sound input device.
  9. Yes, I have the audio wire installed. Can it be a driver related issue?
  10. Yes, I did. I attached headphones to it. I hear alert sounds but no CD sound.
  11. I haven't tried it yet. The drive doesn't have any audio jack. It only has a connector marked "Audio out". It's rather difficult to attach a regular speaker to it without a special cable.
  12. Fellow Macintosh enthusiasts, I recently recapped an old CD-ROM drive in my Macintosh 6100/60 AV. It seems to work fine reading all CDs/CD-Rs I put in. When I insert an audio CD, the drive seems to play it back but I hear no sound. All controls in the Apple CD player including starting/stopping of playback, jumping between tracks as well as ejecting work flawlessly. The audio cable between the CD-ROM drive and the motherboard is attached. The internal speaker is confirmed to work either - I hear the startup bong as well as alert sounds. Volume control also w
  13. @LaPorta I always do an incremental recap replacing caps one by one while double-checking every change and ensuring that everything is installed and soldered properly. I also thoroughly clean the board along the way. I've also learned it the hard way by sacrificing one power supply and one PowerMacintosh board.
  14. I'd pull out the PSU, disconnect all devices attached to it and check the voltages then. What part number do you see on the PSU? It's sometimes possible to find the schematics for some PSUs used in the old Apple machines. BTW, I successfully fixed and recapped an ASTEC PSU in my PowerMac 6100 three years ago...
  15. Thanks a lot for this helpful guide! FYI, my Sony CDU561-25 has a bigger board with the spindle motor attached to it instead of that small board (see the attached pictures). That's probably due to the fact that my drive is an internal one that comes with the PowerMacintosh 6100/60Av. I'm somewhat reluctant to take out this bigger board. I don't want to damage the spindle motor...
  16. I'm recapping a Sony CDU-561-25 as well. One only needs to remove six screws and the cables on the side in order to take it apart. I also can share photos of the whole process. Be careful to not damage the surrounding components when removing the stock caps. Pay a special attention to NOT touch the small trimpots on the controller board (laser adjustment). I don't know what happens otherwise. The drive will presumably become unusable. I saw this guide too but I want to point out that the replacement tantalum caps recommended there aren't properly derated.
  17. @LaPorta I'm late to the party. I hope you haven't destroyed it yet I'm currently recapping a 300i drive taken out of my PowerMacintosh 6100. It's easily torn down. What manufacturer and part number do you see? Mine is a Sony CDU-561-25 caddy loading CD-ROM drive.
  18. @Kai Robinson I don't want to make any pressure but is there any chance for us to follow such a decapping session someday? I find the idea super exciting
  19. @Kai Robinson Are the higher resolution images of the ADB chip die available? I'd like to attempt to reverse engineer its firmware (I have some experience with reversing ADB devices. You can look at my current work on reversing and documenting the Apple(extended) II Keyboards here)
  20. You need to simulate the CUDA communication protocol to achieve that. The whole task boils down to programming a FSM. It is surely doable and was modeled in software several times. How easy it's going to be depends on the hacker's skills
  21. The default polling rate for the ADB bus is 11 ms = 1/90. It's usually set during MacOS startup by issuing the CUDA_SET_AUTOPOLL_RATE (0x14) command to CUDA. CUDA is responsible for polling the ADB bus at the specified rate. It's called autopolling in the MacOS jargon. Autopolling is started and stopped using the CUDA_START_STOP_AUTOPOLL(0x1) pseudo command. The polling algorithm in the CUDA firmware differentiates between the most recently used device (MRU device) and the least recently used device (LRU device). By default, the MRU device is the mouse while the LRU device is assumed
  22. There are several reasons why a Mac doesn't power on. I usually use some sort of incremental search for the source of failure starting with very simple diagnostics like a visual check. What does happen when you power on the machine? Do you hear any noise (PSU fan spinning, HDD spinning and clicking)?
  • Create New...