A600 - joystick error

[kris2222]

Hi!

A strange problem appeared - when I push joystick up, it randomly goes diagonally (for about a second, sooner or later) up/left, then back to up.

The problem persists on all joysticks, regardless if I have extra memory plugged in or not.

What might be the cause?

Thanks for help in advance!

[kris2222]

Thanks, is it possible to replace them?

[kris2222]

I noticed that 74LS157 has been replaced, looks like in a clumsy way. Does it have something to do with joystick/ mouse controls?

Here are the photos, click an then click again to view whole size.

[kris2222]

Thanks a lot for the feedback.

I'm gonna buy a multimeter, check the patterns and maybe replace the chip for this one:

http://sklep.slawmir.com.pl/product_info.php?products_id=45229

What makes you think it is a wrong chip?