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[smariotti]

Originally Posted by JimS

According to the service manual, EMI401 is a noise filter listed as 100pf. On the actual schematic, its drawn as a resistor with an extra lead going to ground... I'm assuming that's a 100pf capacitor to ground. It says 4.7 next to it, but no multiplier... In any case, the 5v to both joystick ports goes through it, so if you've got the 5v on the ports, I'd say EMI401 is OK.

That's interesting, as on the motherboard it's clearly a 1/4 watt resistor. There are three holes at the site of EMI401 on the silkscreen, though the resistor just connects between two of them.

[smariotti]

Well, that fixed it!

I replaced the charred resistor with a closely matching (1.1 Ohm) resistor from my parts box and voila! Mouse works again like a charm.

What was misleading is that the burned resistor still read approx 1 Ohm impedance across it, even though it was "bad."

Here's the newly soldered resistor that got my mouse back in action.

[JimS]

Originally Posted by smariotti

Well, that fixed it!

I replaced the charred resistor with a closely matching (1.1 Ohm) resistor from my parts box and voila! Mouse works again like a charm.

What was misleading is that the burned resistor still read approx 1 Ohm impedance across it, even though it was "bad."

Here's the newly soldered resistor that got my mouse back in action.

Interesting....
They're always changing stuff like that from one batch to the next. Glad to hear you got it working again.

[amigaloco]

I have exactly the same problem (original post) with the mouse port in an A4000 MoBo. Does anybody knows someone to trust the repair of my MoBo within Europe? I don't want to incur in extreme postage costs...