Add like 10-100nF caps from TxD+ to GND (serial) and TxD- to GND (serial). Don't see why that wouldn't work, unless the PIC power consumption is > 1 mA
@jmac they are not used much. The controller blink them after initialization and that's about it.
IIRC, the one under Power is actually "Num lock" and the other one is "Scroll lock". Like on a real Mac, these LEDs are not very useful.
You can make them blink with something like ADB Express...
@Phipli that was for me. Thanks again :)
I ended up building a prototype with the schematics from MacGarden. It didn't work, but may be an error on my part (not working = not visible by software)
Then someone provided me a real (working) one, and the schematics don't match, different ICs, PIN...
Yes, as most of the SCSI upgrades. Some board asked for Plus ROMs, others had patched 64k ROMs in other way or another.
The Beck-Tech MacMEGABYTES used a second set of ROMs to patch the 64k ROMs
The 64k ROM assumes that the max RAM possible is 512. Since video and sound buffers are at the top of memory, this can't work
The 68k ROM make the CPU writes at the top of 512kB of RAM, and your logic board video/sound circuit reads at the top of 1024kB of RAM
Missing keys, broken case mostly. Can you see your keyboard with ADBParser ?
The three LEDs flashing the first time is a good sign. It means the controller is alive.
The LED trick I've seen it fail with working keyboards, don't know why. I will go with either your matrix is fully dead, or it's...
Thanks ! I didn't have a blank bracket around but that's a good idea !
The "someone" is me. Don't bother, I found the resistors values. I did this project using your previous pictures, so thanks a lot !
Some measurements and subjective remarks. This has been benchmarked against a Quadra 650 board (Wombat). I did it to double check something wasn't broken with the daughter board
Output levels
The last notch on the PAS16 Control Panel volume is an overdrive, 100% volume is last position minus...
Thanks a lot ! I would keep the box, the card is more valuable this way, but you do you :)
The gerbers files and design has been released on GitHub here
Will try to release the measurements this week-end as well
Build log
First remove bracket. Then desolder C101, C110 and the HD26 connector
In my case C101 was dead, the card needed a recap anyway
Assembling the daughter board
This requires soldering all three jacks, both Molex connectors and both capacitors. Everything CMS can be assembled by your...