Amiga 600 game port up and left not working

[frasbo]

Hi.. hoping someone can help me. So I have an amiga 600 which has been recapped and has been working fine for a few years now. Today I went to play it and noticed that the left and up aren't working on the joystick. I tried a sega mega drive gamepad and same behaviour.

I took the amiga apart and checked all the pins on the game port have continuity with a multimeter and they all appeared fine. Checked all the caps and resisters close to the game port and I'm finding a connection for each of the pins so they all appear ok. I cleaned all the board with some IPA and and a light brush and now I notice that if I push up-left on the joystick this works but still to movement if I individually press left or up.

Any ideas?

[frasbo]

Thank you I will try this all out. Much appreciated.

Ive ordered a parallel 2 port joy stick adapter off ebay in the mean time - do you know if this will get round the issue? Or will this also use the CIA?

Also is it easy to replace CIA chip with just a solder iron? Or will I need hot air station etc...

[frasbo]

Many many thanks for such a detailed responce. This will give me a great way to troubleshoot the issue.

Thanks again - I will update once I get time to try this out.

[frasbo]

No not got the 1MB ram expansion but thank you for responding.

[frasbo]

Just to give an update on this issue;

So I ordered the U34 chip from ebay (from a seller in Italy) - I managed to remove the chip with a soldering iron without ripping the pads (I don't have access to Hot Air Station) by flooding the chips pins with solder, wicking up the solder and slowly lifting each pin. I replaced the chip but the behaviour still persisted with up and left not working on the joystick.

So in my frustration I attempted to repeat the process as I received 5 chips from Italy but this time I ripped about half the pads the chip sat on - I attempted to retrace these and a put a new U34 back on - at this point it was a total mess and now the mouse only half worked and only fire worked.

So I had to send off my Amiga 600 to Luke at Retro Six for repair (Cost me £60) - who I can't recommend enough (Guys is a Wizard with this stuff!)

He posted a tik tok video of the repair on the retro six tick tok page (also his facebook page) of him repairing my mess.

He also mentioned to me that the resistor on the MV1 line (68R termination resistors) had burned out which he said is starting to be very common.

Hope this helps someone!

Thanks for the help from the previous people who replied.