Controller Diagnostics

[mortari]

I am trying to diagnose a wonky controller and am coming here in hopes of finding answers. Initially I just rebuilt it as my other one, but when I went to test, it could turn right and that was it. I have looked online and found a bit about the controller and how it is wired and functions. I have tested my cable for continuity, noting the 2 pins that don't have a wire connected. I am now diagnosing the PCB and have found my contacts have continuity, and am now trying to figure out how to see which buttons are registering at the base of the PCB where the wires join.

 

How do I test the board in a way that will allow me to see if there are bad spots in the diode chain? Will that be my best bet? I have reflowed most of the joints, and the board *looks* good, but am wondering if I should just do them all. Thanks in advance.

[Milli V]

I am trying to diagnose a wonky controller and am coming here in hopes of finding answers. Initially I just rebuilt it as my other one, but when I went to test, it could turn right and that was it. I have looked online and found a bit about the controller and how it is wired and functions. I have tested my cable for continuity, noting the 2 pins that don't have a wire connected. I am now diagnosing the PCB and have found my contacts have continuity, and am now trying to figure out how to see which buttons are registering at the base of the PCB where the wires join.

 

How do I test the board in a way that will allow me to see if there are bad spots in the diode chain? Will that be my best bet? I have reflowed most of the joints, and the board *looks* good, but am wondering if I should just do them all. Thanks in advance.

If you have an adam and smart basic write a little program to test it, thats what I have

 

Milli

[mortari]

Nope... just my CV.

[cdn2a]

The controllers are drop dead simple.

 

If you have a wiring diagram, thats all you need. **Note, most diagrams out there have the diodes labeled backwards**

 

Most multimeters have a diode tester, I've yet to see a diode go bad.

Most of the time, it's the "leaf" spring contacts or fire button that are having issues. I find cleaning them, etc usually works.

I tear a very small strip of 600 sand paper, and pull it through the connection, once up and once down.​

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The biggest issue is the cords. You say you tested it, I find most are broken right beside the rectangular block.

Most often it's an intermittent connection. It comes from them being yanked out of the socket by the cord.

The other big issue is the push on connection to the PCB, they usually oxidize, I usually add some solder and attach them directly to the board.

 

If you have a multimeter and a soldering iron, you can fix the controller.

 

The keypad?... it's another story. (then your into silver conductive pens, etc... )

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[coleconut]

 

Most multimeters have a diode tester, I've yet to see a diode go bad.

 

The keypad?... it's another story. (then your into silver conductive pens, etc... )

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I have been able to revive 99% of controllers except those with keypad issues. I toss them into a box pending further investigation.

But its my understanding that you cant reliably test a diode unless its removed (?) And I dont own a conductive pen (yet)

[cdn2a]

For a 100% test, yes it should be removed. However if it's shorted, or open you can find that with it in the circuit. Test each one of them, compare them to each other, both forwards and backwards, you then only need to pull the outliers.

 

For the pen, I find this one works well. It bonds to the mylar well. Using a flashlight from the back can show broken traces.

 

http://www.mgchemicals.com/products/prototyping-and-circuit-repair/pens/silver-conductive-8420-p

[mortari]

I have the board out and cannot see any bad solder joints, multimeter detects contact being made on all pads... other than the up contact bridge being cracked... I will need to replace or repair it I guess. Other than that, it could still be related to diodes I suppose huh? I have a few more controllers in the post... so maybe I can do some donor work.

[Milli V]

I have the board out and cannot see any bad solder joints, multimeter detects contact being made on all pads... other than the up contact bridge being cracked... I will need to replace or repair it I guess. Other than that, it could still be related to diodes I suppose huh? I have a few more controllers in the post... so maybe I can do some donor work.

 

Check for continuity in the actual wire too - it may be broken somewhere

[mortari]

I checked the cable, no dice. Maybe I should reassemble and try to make a list of functions that don't work or something... the first one was a dream to re-do, but this one is being a bit tricky.