A1200 Joystick Port "Up" direction not working

[thgill]

Posted this over at Amibay, but thought someone here might have so insight as well.


I recently received a mint condition A1200 and last night I discovered that the Joystick "Up" direction doesn't work on Port #2. Mouse and both buttons work fine on the first port.


All other directions including the fire button work fine. While I have had plenty of Amiga's over the years, this is the first time I ran into a controller port issue.

So far things I have done:

1. Tried multiple known good working controllers. All have the same issue.

2. Checked solder points on the bottom of the motherboard on the Joystick port. Everything looks good and using my multimeter continuity is fine between the pins and the solder points on the bottom of the DB9 socket.

3. Checked the A1200 schematics and tested for continuity between Pin 1 of the Joystick port (which should be the 'up' direction) and pin 10 of U34. Nothing. However the other pins also don't buzz up to U34 and they all work fine, so this fact might not be relevant.

4. Tried a different power supply. Same thing.




Not sure what else to do at this point. After doing some googling, it seems weird that its just one direction having the issue.



The A1200 board is a 1D4 revision with a 4gb CF card on the IDE bus. No accelerator in it currently (waiting on a Blizz 1220 to be delivered). Machine is otherwise stock. Modded micro-atx psu for power.


Thoughts or suggestions?

[Toni Wilen]

According to schematics there are low ohm resistors (located inside those Exxx-protection components) between joystick port pins and U34. Use resistor measuring setting instead of continuity setting.

It is near guaranteed to be either connection problem between joystick port pin and U34, damaged E365 or damaged U34.

[thgill]

Stupid question, but how can I tell exactly which one is E365?

They are all clustered together closely and its near impossible to read the silk screening and discern which is which.

[thgill]

i think I have identified E365 and I think its the issue.


I believe one side of it is not soldered down correctly and isn't making contact with the pad.


Time to break out the iron and see if I can fix the little sonofa....

[thgill]

Thanks Toni!

All sorted.

Found a microfracture between the solder pad and one side of E365. Quick usage of the soldering iron and its working fine now.


Seems like it was from the factory like this. Original seller claims to have never had an issue with the joystick, I however doubt this. Unless he never pushed up on the stick.