Jeff wrote: ↑Sun May 14, 2023 10:04 pm
This is maybe just the contrast potentiometer. Have you checked it ?
ehhh... that was it!

Thank You!
after turning up the contrast in the LCD, there was reading again. it still did not see the SDcard. i measured around the working board and compared voltages on the SDcard socket. pin #1 had no voltage on it, i traced the track on the PCB with the help of the PCB layout pictures and measured that there was a broken track between SCcard socket pin #1 and R9. the track on the bottom side from the hole was OK, but in the top side something happened to the track under the SDcard socket. i fixed it with a thin wire through another hole. after this it was reading the SDcard. i watched a few Amiga trackloading demos, they loaded OK, but

there were new isses...
at the end of the loading process (when the demo finished) there was a constant and loud piping noise from the speaker (btw its speaker sounds quite differently compared to the other one, just out of curiosity i changed the PIC - one has new (1.8.2.40) FW the other has 1.6.0.0 - and it sounded the same as before). the piping stayed until new floppy operation... there is also a constant soft sizzling noise and i can hear the LEDs blinking

when loading up the Fileselector with FW 1.8.2.40 it stops loading with:
ERROR: LBA Change Test Failed ! Write Issue ?
and on the LCD: LBA00000002 08
with FW 1.6.0.0 it loads OK. (on the working board it load OK with both FWs, from the same SDcard)
what could be causing this? i used the same SDcard as with the other one, on the working one Fileselector loads without errors.
i checked in Workbench and i can write to the disk even when Fileselector does not load...
thank You for Your patience!