Mac Plus keyboard with poor connection

[nonzero]

I have a Macintosh Plus with an intermittently working keyboard. The keyboard works (all keys) when I tug the cord upward near the port on the keyboard. I've tried using another phone handset cord, and I get similar intermittent behavior. I've tried prying the 4 leads in the port up with a string to give it a bit more springiness, but it doesn't help. I'm guessing I'll have to open the keyboard and see if the port's solder joint is weak. Any tips on opening the keyboard and working inside it? Or any other possible cause for this symptom?

 

[trag]

When you write, "phone handset cord" you mean one for the Plus?  A standard phone handset cord is wired wrong and could damage your keyboard or Mac.

 

[nonzero]

I got one that follows the wiring of the original Mac Plus cord according to my continuity testing with a multimeter.

 

[GregorHouse]

I got one that follows the wiring of the original Mac Plus cord according to my continuity testing with a multimeter.

Are you sure both cables are specific for the Mac Plus? @trag is right here, you could damage both thing as wiring differs from a standard phone cord (Apple things). I can get a picture of my Mac Plus cable when I get home for you to compare

 

[nonzero]

It's coiled and looks about the same shade of gray as the keyboard, and everything else with the computer works. Also, the keyboard does consistently work with the cable tugged upward, as if something is not making contact properly without the added pressure.

 

[IlikeTech]

You might try bending the contacts in the keyboard connector to see if you can get them to make tighter contact.