I'm struggling with an MV1FZS board. Here are the symptoms and the tests performed:
- Errors: NeoDiag shows "VRAM UNWRITABLE". UniBios reports "Memory Card error".
- RAM: Both VRAM chips have been replaced, swapped, and verified with an external RAM tester (they are 100% working).
- Control Signals: Using the oscilloscope, I verified that /OE and /CS signals are pulsing correctly during the boot/diag sequence.
- The Issue (/WE): The Write Enable signal (/WE) remains STUCK HIGH (5V).
- Oscilloscope findings: * On NEO-C1 Pin 9 (LSPWE Out), I see the signal dropping to 0V for a very brief moment at startup/reset, but then it immediately stays high.
- I see the exact same behavior on LSPC2 Pin 173 (LSPWE In). The pulse reaches the LSPC2, but it's not "active" enough to allow writing.