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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: kris2222 on September 25, 2012, 10:20:15 AM

Title: A600 - joystick error
Post by: kris2222 on September 25, 2012, 10:20:15 AM

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!

Title: Re: A600 - joystick error
Post by: carvedeye on September 25, 2012, 10:32:02 AM

The CIA chips maybe?

Title: Re: A600 - joystick error
Post by: kris2222 on September 25, 2012, 10:40:26 AM

Thanks, is it possible to replace them?

Title: Re: A600 - joystick error
Post by: kris2222 on September 26, 2012, 12:30:52 PM

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.

(http://s13.postimage.org/8un7a93j7/IMAG0446.jpg) (http://postimage.org/image/8un7a93j7/)

(http://s13.postimage.org/y22oo8w0z/IMAG0448.jpg) (http://postimage.org/image/y22oo8w0z/)

(http://s13.postimage.org/5dpql0tur/IMAG0450.jpg) (http://postimage.org/image/5dpql0tur/)

Title: Re: A600 - joystick error
Post by: arttu80 on September 26, 2012, 06:56:34 PM

Oh boy. Yours LS-chip repair doesn't look very promising! Check with some basic multimeter that those traces aren't broken. Indeed this chip is important to your mouse/joy functions. Check picture below from Service Repair Manual...

(http://i10.aijaa.com/b/00341/10985578.jpg) (http://aijaa.com/JDjGK9)

Damn I got caught using widoze... :(

Afterall, is it even right chip installed there?

Title: Re: A600 - joystick error
Post by: kris2222 on September 27, 2012, 04:47:13 PM

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?

Title: Re: A600 - joystick error
Post by: arttu80 on September 27, 2012, 07:23:47 PM

Actually as I look at it more carefully, It seems id does read 74ls157, so it's the right chip. My mistake.