Hello all, <br><br>I recently acquired a Lisa 2 (Macintosh XL) with the 2/5 motherboard, old IO board with the coprocessor socket and battery pack and 800k Floppy ROM, CPU board with ROM's dated 1985 and 2 x 512k RAM cards.&nbsp; The problem is, it won't start. The motherboard was badly corroded but I cleaned the corrosion with vinegar and alcohol and it looks decent now, I could not find any broken circuits.<br><br>What I already tested:<br>- Power supply is OK (+5V standby voltage present, replaced all electrolytic capacitors) <br>- on the COP421 chip I can measure the power button signal when I press the power button but the state of pin 24 remains the same<br>- i can "force" start the power supply by applying 5V on the ON pin of the COP421 (pin 24).<br>- the power supply starts with no problems, correct voltages present on the I/O board<br><br>- I can only get a grey picture&nbsp; with some horizontal lines but no sound and no video<br>- unfortunately I have no other boards to switch out for testing.<br><br>- does anybody have a clue where to start digging for reparing this lisa?<br>

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