Power LED not working Lynx II

[Alexs]

Hi,

 

I have a Lynx II with a Power LED that is not working, can I replace it? Does anybody know which part I would require

 

 

Thanks in advance

[7800fan]

Depends on why it's not working. If the buttons all are working, that rules out loose connector issue. You could take the Lynx apart (check for sticky on taking it apart all the way to controller board) and using a meter check the diode (positive probe on right side toward button A and B, negative side toward control pad). If you don't see a light and the meter doesn't get a reading, it may be burned out or the tape holding the leads to the circuit membrane have come loose. If they do light up, check the connector. LED negative is on pin 1 (left side when the control panel is up and connector is pointing down). LED positive uses the same 5v source that all button shares.

 

If you can't find a problem with the connector, LED checks out, and all then it could be the LED control circuit may have gone bad. From pin 1, it goes through 1k resistor and a transistor that turns it on and also flashes when battery is low. I'd have to look at schematic to see what else can go wrong but 99% of the time the problem is in the connector.

 

Replacing it is not easy:

 

I replaced mine using a size 3528 SMD LED soldered in between the legs of the old LED. The original LED uses obsolete "subminature axial LED" package and finding cheap source of such LED was hard. I found one source but it was minimum 15, costs $20 plus shipping. Screw it, a lot of 10 SMD LED from eBay was under $3 shipped. So what I did was to carefully snip out the old LED while leaving as much of the leads as possble, positioned the SMD LED (with correct polarity), soldered it in place.

[Alexs]

Thanks 7800fan for the comprehensive reply

I opened her up and the tape was securely in place, buttons work fine and connector has no issues. I have another lynx with a working LED so I will try it's membrane on this lynx to rule out of it is the LED control circuit. (the only other issue with this lynx is that I get sound through only one earphone [mono]) maybe that is related? Failing caps?

 

If it turns out to be the LED then I will try and solder on a new one like you did