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Bad joystick chip (612197-1 7927). Any options for replacement?

Started by Pickaxe Brad!, June 09, 2022, 05:13:41 PM

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Pickaxe Brad!

Something must have happened to my O2 a couple months ago  because all of a sudden one of the joysticks was acting like the  ACTION button was permanently pressed.  Standard debugging had me swap joysticks' and eventually lead me to do a continuity test on the pins.  Sure enough, the fire pin was connected to ground (tested from the joystick port).  After unnecessarily desoldering the joystick connector, I removed what I think is the joystick chip (labeled 612197-1 7927). And I found the issue: the completely disconnected chip is pulling the pin to ground.

I'm happy-ish that I'm "close" to having fixed this issue, especially as desoldering is a new skill for me. But, before I press my luck to far and end up breaking something, I wanted to report my progress on this forum and see if I anyone knows of a place I can purchase a 612197-1 7927 chip and if I were to find one, would it be a drop-in replacement or does it need to be flashed or programmed somehow?

Any info/help is appreciated and it will prevent me from trying out crazy ideas like trying to use the outputs from the one good joystick chip and having it drive the second controller as well.  Probably a really bad idea I'm likely to try out if left to my own devices.  :D
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This IC could be a suitable replacement ( random shop, just for the IC description ).
There are a lot of these on eBay.

Or just buy a cheap, broken Videopac to cannibalize  :)

Programmers don't die.
They just gosub without return.

Pickaxe Brad!

Quote from: Xuul on June 10, 2022, 04:39:05 AM
Or just buy a cheap, broken Videopac to cannibalize  :)
I considered that, but I don't think I can desolder chips without breaking off a few pins.  I broke 5 getting this chip off.  :o

Many thanks for the info!  It looks like I'm only $5 away from fixing this system!
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How did this go?  I have a dead joystick port myself.  it's the joystick port on the right (looking at it from the back).  Which chip on the board is related to this? 

I think the issue happened when I unplugged a joystick.  the Odyssey 2 froze up and I think shortly after that it was non responsive.  A simple reset brought it back and it works fine if I use the joystick port on the left.. 

Also are there any fuses between the pins and the IC chip?  I was wondering what all of those flat brown discs are..  wondered if any of those might be pico fuses or something like that.. 

Pickaxe Brad!

Quote from: Caleb Garner on May 22, 2023, 11:12:16 AMHow did this go?

Well, a year later, this is still in-progress. After a delay of 3 months for the chip to arrive (bought off eBay from China), I discovered that I had damaged some of the traces on the board from my shoddy soldering skills.  I was going to have to run new wires and decided to look at it later...

...and then I never got back to it.

Your other post reminded me to find this and look at it again...but I haven't found the time yet.
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Totally know how that goes.  so there are no fuses between the IC and the DB9 port?  Which chips control which port?  I haven't opened my working O2 but I have a db9 version motherboard from my parts pile and the joystick ports are inside a metal case.  are the IC chips in there or are they somewhere else?  I wish this site made sharing images easier.  I like to think the DB9 and hardwired boards are basically the the some other than the ports so this image I hope can offer a reference of which chips are where.

Pickaxe Brad!

Yeah the metal shield is a frustrating thing to have to desolder just to look at anything.

The picture is basically the same as your version.  I will point out the minor differences below.

In the picture, the back edge of the board  has the power connector in the middle. The two white headers to the right of the power are for the joysticks (the DB9 version has the three additional pins going to ground) and if you follow the traces, they connect to the two 16-pin chips to the left.

I don't remember which one of the two controls which joystick, but it will be obvious if you look at the underside of the board.

I'm guessing the brown circles are the fuses you're asking about but they look different in my DB9 O2.
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I have good news. Replacing that chip did fix my dead joystick port.  I'm back in business baby!  that IC chip that was replaced isn't a rare one and can still be bought if not sourced from another O2 board (which is where I got mine from and thankfully worked)