gorf optical joystick goes up

KazooBR

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I was playing Gorf and my ship started drifting upward. I had this problem when I first put it back together but rotating the center grommet solved it for a while. Now, it takes a lot of movement to get it to go down and doesn't stay.

I reflowed virtually all the pins including the optos and connector pins. I cleaned the optos though they were relatively clean from the recent rebuild.

I'm guessing an opto is bad but don't want to move it to another spot to confirm ... too much soldering and I'm guessing I might need to move all 4 to be sure. Is there another way? If not, I'm willing to replace the two on the up/down axis with new ones if they are available. Anyone know where I could get a couple?

thanks!
 
I remember buying those optos at Radio Shack 10yrs ago to fix one. I'm guessing they don't sell those anymore..heh
 
I'd also like to know a little more exactly what I'm looking for. I've seen where replacement parts came from pinball parts but I don't know if there is some tolerance/spec that I need ... or are these generic and any old opto will do?

Thanks
 
You can confirm it's a bad opto by removing the opto board from the bottom of the stick, and flipping it up (leaving it attached). In this position, the ship should not move at all (none of the stick's "tabs" are in the gates). If it still drifts up, then that opto is bad.

The part is not critical - last one of these I fixed I used an opto gate scavenged from a printer

-Ian
 
Did that last night and it still goes up so I guess I've confirmed it. Can you tell me how I know which one is bad on that axis? When I push the joystick forward the ship is supposed to go up ... so does that mean the forward opto is the bad one? I guess I don't know if the joystick tab blocks the opto which triggers action ... or if it unblocks and triggers action.

I was just gonna change one, test and then change the other since I wasn't sure how to troubleshoot. :confused: But, with all this help maybe I can be a little more precise.
 
I can not recall if the opto in question has its view blocked or opened when triggered. I think its opened. That is when you push a direction the opto responsible for that direction has a cut out in the plate that passes through it land between its halves. Wither way, just pop the CP, look at what they look like with the stick centered, push the bad direction and see which one of the four is in a different configuration.

In your case of up being messed up my bet its the opto closest to the front of the game with the CP on.
 
The joystick tab breaks the opto beam to trigger it. With the board flipped up and off the stick assembly, nothing should be breaking any beams, and none will be triggered. Use a piece of cardboard in between the optos to trigger them manually to test.

-Ian
 
Can check them with a cellphone too... put it in movie mode and look at the optos. You should be able to see the light from them in the cellphone.

If you see a light in all of them, save one... then you know that one is bad.

It's a quick and dirty test... sometimes it works, sometimes is doesn't. Just depends on if you can get the right angle to see.
 
Can check them with a cellphone too... put it in movie mode and look at the optos. You should be able to see the light from them in the cellphone.

If you see a light in all of them, save one... then you know that one is bad.

It's a quick and dirty test... sometimes it works, sometimes is doesn't. Just depends on if you can get the right angle to see.

I used to work on alot of TV's and that was a good test when the remotes were not working. For some reason I recall it only working with black and white cameras.
 
I used to work on alot of TV's and that was a good test when the remotes were not working. For some reason I recall it only working with black and white cameras.

It'll work on pretty much any camera without an IR filter. Cell phone cams are usually too small to bother with putting that filter in there. Some webcams too. And even if they have that filter in there, you can take them out in 15 mins or so.
 
I knew about this trick for remote controls but never stopped to think about it for optos!!! Awesome tip.

Here's what a good one looks like. I confirmed my bad one (which is not an original anyway) by this method.

BTW: My new iPhone 4 didn't work but my older Canon SD300 camera did.
 

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update: I found the H21A3 optos on ebay for 1.90 from a seller called mind-tek. They had to ship from Thailand so that took a couple weeks ... but arrived without any issues.

Put the part in and it works. The mounting holes are *slightly* different so you'd need to drill out just a little of the pcb but it felt very secure just soldered in so I left it alone.

Gorf is back to life!
 
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