Notices by paulrickards (paulrickards@mastodon.social), page 3

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

#AppleLisaClone #RetroComputing

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

#AppleLisaClone #RetroComputing

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

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)?

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

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

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

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

#AppleLisaClone #RetroComputing

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

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

Ok, display sorted out, now to the next big hurdle. The #AppleLisaClone is throwing a error 45 which is a “bus error” and it happens as soon as RAM is being tested. So, @DosFox and I suspect the issue lies on the new RAM board.

I’ve tested the SIMMs in a Mac Iix and they work. I’ve also pulled all of the TTL chips and they tested good on the Chip Tester Pro.

Kinda stuck at this point. Having another RAM card would be very useful now.

Ideas?

#RetroComputing

Hey that’s not bad looking! There’s a dizzying number of settings in RGB2HDMI so it takes a lot of time trying things, back tracking, etc.

This is a repurposed iPad LCD with an external driver. I think it’ll make a fine display for the #AppleLisaClone.

#RetroComputing

This is curious: @iconicbits also has a SunRem 2MB card that hasn’t worked either. And combined with an Apple 512K card, was also able to produce an error 45.

https://mastodon.social/@iconicbits/111131652337404316

When I bought the ICs for the SunRem 2MB card, I missed the fact the top two chips (highlighted in yellow) are supposed to be 74LS373. Instead I stuffed 73S373 chips (note S vs LS) just like the bottom three (highlighted in red).

I finally got the LS parts and swapped those in.

Much to my surprise the card now seems to work perfectly, at least with MacWorks! 🎉✨

Thanks to @iconicbits for reminding me!

#AppleLisaClone #RetroComputing

A pile of boards and parts have started to arrive for the Lisa Clone! Still more parts to arrive.. #AppleLisaClone #RetroComputing

Anyone have a Lisa RAM card they'd want to sell me? (hopefully better than the current eBay listing of $229.)

(Thx for a boost!)

#RetroComputing #VintageComputing #AppleLisa #VintageMac #VintageApple

Well, I just placed orders for boards and parts to build a new Lisa 2/5 around my existing Lisa CPU card, the only part of a Lisa I’ve ever owned.

I would never have thought this was possible if it weren’t for the work of @DosFox who recently built the first new Lisa since 1986! Thanks for the inspiration!

I’ll continue this thread as parts roll in. I may ask (beg) if folks have some parts in your bins! 😀

#RetroComputing #VintageComputing #AppleLisa #AppleLisaClone

Since the minimum order for PCBs was 5 and I only need one, I’ll have 4 boards each of the Apple Lisa motherboard, IO board, LisATX board, and diagnostic/riser cards to sell. I’m in USA. Send me a DM if interested!

Can I use a Mac 128k/Plus mouse (DB-9) on a Lisa 2/5 (DB-9)? I'm hoping they're the same mouse inside, despite differing button sizes and labels on the bottom.

*Edit: The consensus is yes you can!

#RetroComputing

6504 from 1989 reporting for Lisa duty 😃

#RetroComputing