Defender question

flex

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All of the buttons stopped working. When I powered the game the very first time, the reverse button didn't work. I traced the wires back to the small printed circuit board and wiggled the ribbon cable and it stated working but I am not having any luck this time. Also, when I go through the game diagnostic check it shows the buttons are not recognized. I think that maybe the pcb might be bad? I am lost as to what to do now. Any suggestions?
 

check your ground is connected tight and clean. the ground from a button traced back might lead you to a problem.

check the board you wiggled for cold solder joints or disconnected wire from the connector.

somewhere there is a ground problem and you just need to find it.
 
The board you wiggled is the I/O board. Use a DMM or continuity tester and test the board for connection to ground. Then pull the cables that go to the control panel and check the header pins for corrossion. Clean them if necessary. Plug the cables back in. If that doesnt work you will need to test for ground breaks in the cables. The following diagram shows the pinouts:

attachment.php


Clip one lead of your DMM to pin 10 (the one marked GND) of the second connector and the other to any of the labelled pins on the second connector. If you don't get connectivity throught the wires, there is a break that you need to find. So trace the ground wire first.

If you do get connectivity than it may be the i/o card.

ken
 

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Hi all - i have a similar problem... Sometimes when I start my defender, it will work perfectly for a while and then Auto UP, Up And Fire get stuck (I can see thats its these three through the Diagnostic mode) and the rest of the buttons play fine. Sometimes I dont get the probelm at all. I replaced the connectors to new molex connectors that go to the widget board and reflowed the headers on it.

I tried the test where you put the connector on gnd (pin 10, 1st connector) and try to get continuity on the other labled pins on the second connector. I dont get any continuity. I can trace the ground through the control pnel - no wire breaks and each button links to their specifc pin - no problem.

What next?

Thanks,
Pat
 
If it is an intermittent issue, it may be the ribbon connector. When you see the buttons are "stuck", put the game into the switch test and try wiggling the ribbon cable on the I/O card. Usually it is at the CPU connnector side.

The other possibility is that one or more of the logic chips on the I/O card are going bad. Here is a link to a thread that includes direction on using a logic probe to check the logic chips on the I/O card: http://forums.arcade-museum.com/showthread.php?t=119119


ken
 
If it is an intermittent issue, it may be the ribbon connector. When you see the buttons are "stuck", put the game into the switch test and try wiggling the ribbon cable on the I/O card. Usually it is at the CPU connnector side.

Definitely is the ribbon cable. Touch it and they go on and off stuck. So do I just need to reflow the headers on the CPU connector side?

Thanks,
Pat
 
It is probably not the headers. It is the !#$$@#@ plastic terminator. The plastic terminators are IDC type connectors (Insulation Displacement Connectors). Basically each wire gets pushed into a connector. The connectors look like a U where the inside of the U is like a knife blade. As the wire is pushed down the insulation is cut (displaced) and the wire contacts the metal. Sounds great except that the wires wiggle and expand and contract with temperature and eventually will work their way up until they don't connect anymore.

To fix this, you need to recompress the wire back down into the metal connectors. There are two ways to do this. The best way, if you have a vise, is to put two pieces of cloth over the faces of the vise and gently but firmly squeeze the top and bottom of the CPU board terminator so that the wires are pressed back into the connectors. To do the I/O connector side you need 2 small blocks of wood over the face of the vice and carefully squeeze the top and bottom of the connector to press the wires into the connectors.

If you don't have a vise, you can do the same thing with a pair of pliers. I have found channel locks work best becuase you can adjust the faces of the pliers to be the same thickness as the terminators so the faces of the prilers are parallel when they start to compress the plastic. Again firm but gentle. Don't really squeeze or you can break the plastic. With pliers, you need to squeeze and then move down the terminator. It is better to do several passes across the length of the terminator then to try mashing it in one sqeeze (that's a good way to break the terminator). If you do break the CPU side, you can get replacements from Fry's. If you break the I/O card side, that is not good. I don't know where to find those terminators.

It's late and hopefully this makes sense otherwise I can try explaining it tomorrow, after I get some sleep.

ken
 
OK , i think I got this... so the ribbon cable doesnt need any adjustment, its really just pushing the wires on the terminators back in on the CPU and I/O side?

In other words, a replacement ribbon cable wouldnt do the trick...?

Thanks Ken,
Pat

Why do you specify cloth for CPU and wood for I/O, just curious..
 
If you use cloth on the I/O side you run the risk of the pins on the bottom of the card going through the cloth and breaking the solder joints on the bottom or top of the circuit board. If that happens, it is a mess. With wood (as long as you don't use a piece of oak) the pins will push their way into the woodand it wirll cradle the back of the I/O board so there is a firm surface to press the top down on.

As for replacements, if you look at the I/O board side, the connectors are laid out in a diagonal row of four pattern. I have never found a source for those connectors, so you need to very carefully squeeze the top without breaking it. The CPU side is a different story. You can get those connectors all over the place, the even have them at Fry's. So if you break the CPU end, it is easy to get a replacement.

ken
 
Thanks. That was the link I was trying to find. The pictures tell the story much better than my words.

ken
 
If you do break the CPU side, you can get replacements from Fry's. If you break the I/O card side, that is not good. I don't know where to find those terminators.

Bob Roberts sells the ribbon cables with connectors attached. He doesn't sell the connectors separately, but he told me they cost only a few dollars less than what he's charging for the whole thing, so it's not really a big deal anyway. Andre at Arcade Solutions also sells the ribbons and connectors.
 
You're welcome. The key to using the vise is to take it slow. If you crack the top piece on the ROM or I/O board size, you will probably need to replace the whole connector.

ken
 
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