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1. paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:08 JST paulrickards

   COPS 421 emulator board complete. This will go in the IO board and control keyboard and soft power functions.

   #AppleLisaClone #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:06 JST paulrickards

     in reply to

     It’s been a while since the last #AppleLisaClone update, but I’ve been busy behind the scenes.

     First, the W27C512 to 6309 PROM adapters came in and they seem to work just as well as the hand built versions, just smaller.

     #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:06 JST paulrickards

     in reply to

     Next, I designed a board to plug into the #AppleLisaClone motherboard that breaks out the keyboard jack, power switch, power LED, and floppy drives. This powers on the Lisa as expected!

     #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:06 JST paulrickards

     in reply to

     Finally, I obtained a bare 2MB SunRem RAM card and the parts to build it up. It uses 8x256K parity SIMMs.

     #AppleLisaClone #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:06 JST paulrickards

     in reply to

     • DosFox

     So when you combine all of these things together, the #AppleLisaClone has shown the first stable screen and begins to do the self test!! Signs of life! This is a huge step forward.

     Many thanks to @DosFox for the guidance along the way!

     #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:07 JST paulrickards

     in reply to

     Plugging in the IO board into the motherboard, the PSU doesn't automatically turn on. But this is good, because it's soft power!

     However, grounding the /PWRSW line on the motherboard floppy connector does not turn on the system. Hmmm.

     #AppleLisaClone #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:07 JST paulrickards

     in reply to

     The COP421 emulator is powered by +5v standby to manage time of day and soft power functions. At the PSU, it measures 5.3v. At the COP421 emu, it measures 4.7v. This is still in range of the COP402 (4.5 - 6.3v). My PSU delivers 1.8A of +5v standby.

     #AppleLisaClone #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:07 JST paulrickards

     in reply to

     Probing pins 1 and 2 of the COP402 (which are the clock pins) I'm getting just high and no pulsing. Does the issue lie with the COP402 microcontroller or with the crystal circuit (which is on the IO board)?

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:07 JST paulrickards

     in reply to

     Some progress on the #AppleLisaClone today.

     -Received a new COP402 processor to replace the COP402M (microchannel version).

     -Replaced the two new W65C22N with real MOS 6522 chips (from a 1541 floppy drive!)

     -Replaced a 74HC132 with a proper 74LS132 (IO board clock).

     With that, soft power now works the way it should!

     Next problem: it gives a single beep at startup with a scrambled screen (see video). Fault: CPU or RAM?

     #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:08 JST paulrickards

     in reply to

     With that and a few missing chips later, the IO board is complete with two emulator boards 😅

     #AppleLisaClone #RetroComputing

   • paulrickards (paulrickards@mastodon.social)'s status on Monday, 23-Oct-2023 10:39:08 JST paulrickards

     in reply to

     • DosFox
     • Jason P 🌈

     With the help of @DosFox I’ve been able to test the PSU, motherboard, and CPU cards (sans IO and RAM). It’s not much, but this flickering screen of a grid like pattern is exactly what is seen from their rig in the same state. And the scan converter I’m using detects the right sync rates of 22.73Khz @ 60hz (which are the rates @compu85 got using a projector). So this is promising!

     #AppleLisaClone #RetroComputing