o Emphasize that boards with HC input chips are likely problematic

README.md

@@ -399,9 +399,16 @@ If you encounter this, try these things
    - Make sure to have as short as possible flat-cables connecting your
      Raspberry Pi with the LED panel.
 
-   - Use an adapter board with a bus-driver that acts as level shifter between
-     3.3V and 5V. You can find [active adapter PCBs](./adapter/) in a
-     subdirectory of this project.
+   - In particular if the chips close to the input of the LED panel
+     read 74HC245 instead of 74HCT245 or 74AHCT245, then this board will not
+     work properly with 3.3V inputs coming from the Pi.
+     Use an [adapter board](./adapter/active-3) with a bus-driver that acts as
+     level shifter between 3.3V and 5V.
+     (In any case, it is always a good idea to use the level shifters).
+
+   - A temporary hack to make HC245 inputs work with the 3.3V levels is to
+     supply only like 4V to the LED panel. But the colors will be off, so not
+     really useable as long-term solution.
 
    - If you can't implement the above things, or still have problems, you can
      slow down the GPIO writing a bit. This will of course reduce the

adapter/active-3/README.md

@@ -8,14 +8,14 @@ Adapter PCB to support up to 3 panels
    * Open source KiCAD PCB EDA format.
    * (not very pretty layout, was just lazy and let the auto-router do it).
    * BOM:
-     - 4x HCT245 in 20-SOIC (7.5mm package)
+     - 4x 74HCT245 or 74AHCT245 in 20-SOIC, 7.5mm package.
      - 4x 100nF ceramic capacitor (0805 package)
      - 1x 10kOhm resistor (0805 package)
      - 3x 16pin IDC (=2x8) male receptible to connect the panels.
      - 1x 40pin female connector to connect to the RPi.
    * The FAB files are provided as [active3-rpi-hub75-adapter-fab.zip](./active3-rpi-hub75-adapter-fab.zip)
 
-The board is also [shared on OSH Park][osh-active3].
+The board is also [shared on OSH Park][osh-active3] (not affiliated).
 
 ![Preview][rendering]
 ![Real World][real-world]

adapter/passive-3/README.md

@@ -11,7 +11,7 @@ Adapter PCB to support up to 3 panels
    * (not very pretty layout, was just lazy and let the auto-router do it).
    * The FAB files are provided as [passive3-rpi-hub75-adapter-fab.zip](./passive3-rpi-hub75-adapter-fab.zip)
 
-This board is [shared on OSH Park][osh-passive3].
+This board is [shared on OSH Park][osh-passive3] (not affiliated).
 
 ![Preview][rendering]
 

adapter/passive-rpi1/README.md

@@ -9,7 +9,7 @@ Adapter PCB to connect to Rasbperry Pi1
    * (not very pretty layout, was just lazy and let the auto-router do it).
    * The FAB files are provided as [passive-rpi-hub75-adapter-fab.zip](./passive-rpi-hub75-adapter-fab.zip)
 
-This board is [shared on OSH Park][osh-passive-rpi].
+This board is [shared on OSH Park][osh-passive-rpi] (not affiliated)
 
 ![Preview][rendering]