Some Compact Flash (CF) to IDE adaptors fail to light up the drive activity LED, I was wondering why…
I took a board and removed some components and did some measurements, and I discovered that the BOTH base pins of the NPN transistors are connected to ground. Huh?! That means that the transistors won’t switch at no circumstance!
If my measurement are correct, the components are connected as the schematic above.
1 = VCC / 5V
2 = GND
3 = DASP_CF
4 = DASP_IDE (on Commodore Amiga called _IDE_LED)
1AM. = 3904 / NPN Transistor
Amiga schematic (A600/A1200)
How to fix
To fix this there must be a connection between the CF card DASP_CF signal and the DASP_IDE signal. If you take a look at Q1 & Q2 in the schematic you see that the Emiter (1) of Q1 is connected to DASP_CF (3), and the Collector (3) of Q2 is connected to DASP_IDE (4). So to fix the activity LED make a bridge between those two pins, see image below.
Fix mentioned on forums
On many forums you see people fix it like this:
You just can fix it like I showed it, save a wire 🙂
Known boards with this problem
- CF-IDE44/2.0mm ADAPTOR V.B1