XL keyboard works 100% but power LED is dead...

[Level42]

Any hints on what can make an XL keyboard work 100% but not the power LED ?

Yes I understand all the basics like interrupted tracks/circuits...possible LED dying (rare) but maybe some of you already have expereienced this and know a common source for the issue ?

I'm positive the flex is inserted correctly, I cleaned the contacts with alchohol and all keys work in the self test.

 

Must say that I have used the test-PCB with the little switches for the common keys a few times on both boards I experienced this with...could the contacts become bent in too much because of this ? I have a keyboard that is only the flex, no resistor PCB on it so the socket for the flex might be widened because of the use of the test-PCB ?

[Andromeda Stardust]

The original red led in my nes died a decade ago but the console continued to operate. For most folks, the led not working is a sign that the console has bit the dust or receiving no power, but not in my case. I eventually replaced it with an obnoxious bright blue led, before later settling for a cool 405nm violet that I could live with.

 

That said, power leds are cheap to replace with a bit of solder know how. It can be fun to change the colir as well or keep it stock. Green is a fun color, and if you get the limey style, it's still period tech as they've had green leds for decades. Just avoid those high intensity blues...

[flashjazzcat]

Sometimes the track is scraped away by the LED legs directly under the point of contact (on Mylar keyboards) or a dry solder joint has cracked on the console key board of AWC/Alps PCB. Some conductive paint should do the trick on a Mylar board, although replacing the LED (which is not difficult, even if it's soldered in) would be the first troubleshooting step.

[+kheller2]

Using jumper wires from 5v to the LED legs directly (observing polarity) would be my first test.

[Sugarland]

Yes I'd test the LED by applying voltage directly to it first, unplugging it from the mobo first.

[xrbrevin]

take the opportunity to fit a unique colour replacement?

or mod-in a bi-coloured one to indicate mod switch position? (e.g. OS ROM etc)

[NISMOPC]

My 1200XL that I recently received had poor soldering at the PCB which caused a bad connection to the LED legs. I re-soldered the legs and it worked.