[Scarebird]

I have a vintage Alpine 7502, fully functional except for the button lights. It seems they ran the LED's in series and one is burned out. My "google-fu" here has not found any suitable replacements.

Does anybody have a source or a shop that would repair this affordably?

Web pic of what it looks like when running

[ID67goat]

Not sure if you checked out sites like Mouser? Lots of choices, hopefully you can find a match.

It kind of looks Ike the LED fits into a socket that is soldered to the board….can you pull the LED out?

https://www.mouser.com/c/optoelectro...%20color=Green

[Scarebird]

well, 2 things were discovered:

1. they have a proprietary green paint on them

2. they were fixed soldered, and fragile.

[Stuart]

You could try googling the model number of the head unit, like "alpine 7502 schematic". Sometimes that will turn up a schematic that someone has posted, along with part numbers for the components. It's worth a shot.

It's old enough that chances are the LED is discontinued, but if it could lead you to a spec sheet you may be able to compare the characteristics to something newer that will work. If you get that far, try Mouser, Digi-Key or Parts Express, one of them may have something suitable.

[Scarebird]

I have looked at Digikey and Mouser; none of the offerings look anything like the unit mounted.

More research.

[Bill Hanlon]

It costs $13, but would this help? https://www.analogalley.com/osccart/...roducts_id=842

If the LEDs are in series and one is "burned out" neither should light up. Is that what is happening? If so, you could probably replace the bad LED with just about any green LED. Is the mounting important?

[Scarebird]

yes, neither will light.

The inner LED is dead. They are a special shorter unit, nest in the button plastic.

[dataway]

First thing I'd do is assemble the unit and get a voltage off the traces for the LEDs to see what you need to look for voltage wise.

There are literally thousands and thousands of different LED configurations available. Start with voltage, then color, then .... anything that will fit in the available space with leads that will reach the original solder points. Looks like you have a decent amount of room between the cover and circuit board ... lots of "bar" and flat LEDs available these days.

It does look like there is a "holder" or mount there for the LEDs, they aren't bare LEDS soldered to the board ... Alpine was a big enough outfit that the holder or mount is probably a proprietary part that went away many years ago. But heck, being LEDs, just about anything the right color and voltage that you can stuff in there would work.

This place looks like they have some parts for the 7502

https://www.pacparts.com/catalog/par...NE/MODEL/7502/

Is the burn out section called the "pre-set" buttons? If so they list a "pre-set lamp"

[dataway]

On second look it doesn't appear that the part is available anymore.

I guarantee that there is a forum somewhere that has a solution for that problem.

[Scarebird]

I ordered some of these "R2D2" looking LED's from Amazon:

https://www.amazon.com/dp/B09C8FPTJW...t_details&th=1

They arrived and fired up the soldering iron and using solder wick removed the defective LED. I took one of the replacement and sanded it down in a belt sander to a height that would fit. I soldered it in and tested - it worked but it's mate did not. mnnh.

So out came the solder wick again to remove the other LED - bit of a fight. Another replacement was sanded, but the circuit board for some damn reason would not take the solder! A minor wisp of smoke came from the main display: uh-oh...

I said to hell with it, reassembled the radio and tested it in the car the next day - no issues other than the light not working.

Some days best to leave well enough alone.

[dataway]

Yep, sounds like short of sending it out to be repaired (I'm sure someone does this) you are probably better off.

I was astounded at the prices they get for used working 7502 units. Around $250 and up.
Not sure how easy it is to replace the whole board ... but that's always an option if you find one cheap and the display still works.