Fobbed Off! Which replacement receiver?!

My key fobs both stopped working a couple of weeks ago. Looked online here, there and everywhere.

Bought new fob batteries: no difference. Found 4-digit code and performed 5-minute key ceremony. Door opened. Opened bonnet. Removed car battery earth. Removed headlining (I have no sunroofs but there's condensation under the roof metal). Removed receiver from under headlining. Cleaned obvious corrosion with cocktail stick. Put back. Success!

Next day: back to not working. Receiver removed. Cleaned receiver circuit with PCB cleaner and soft toothbrush and placed on radiator. Put back. Success.

Next day: back to not working. Grrr!!!

There's a metal box on the circuit board which means that part of the circuit can't be cleaned. Time to replace the receiver.

But... which model receiver to replace it with? Googling the numbers on the receiver box and circuit comes up with nothing.

My 1998 S-Reg Disco 2 must be one of the earliest. Below are some pictures of the box and circuit board.

Will the replacement be plug-n-play, or will I need to faff about with diagnostic stuff (which I don't have and don't understand!)?

How will I know the new receiver is going to work on the right radio frequency?

Thanks, chaps!

maybe you didnt google well something even if the part number is superceded Let me google that for you

it's plug and play

The metal box houses the UHF transmitter. It will work as long as you keep it dry but if moisture gets in there all sorts of things happen to the frequency and the sensitivity.

If your car is that wet, maybe time to sort that out first.

Peter

jimspearman said:

There's a metal box on the circuit board which means that part of the circuit can't be cleaned. Time to replace the receiver.

Click to expand...

If you've got PCB cleaner in the house and an otherwise busted receiver, you can go one step further...

I carefully cut off the screening can along 3 sides, folded it back and cleaned out all the corrosion under it with a toothbrush and isopropyl alcohol, then soldered the 3 sides back down. That was last winter, and it's been running perfectly since. I expected it might only be temporary but the range is still better than when I got the car!

If you've nothing to lose, it might be worth a shot!

sierrafery said:

maybe you didnt google well something even if the part number is superceded Let me google that for you

it's plug and play

Click to expand...

:lol:

Thanks!!!

Yes, I found your advice (lots of it), but the bits about MHz threw me. No numbers on the box label, or circuit or any component, gives any clues about this. The only number which might be (on the label of the box of mine) says “251.8”…?

So, it’s safe to assume that YWY000080 replaced YWY100140 and they don’t come in any of the wrong frequencies?

listerdiesel said:

The metal box houses the UHF transmitter. It will work as long as you keep it dry but if moisture gets in there all sorts of things happen to the frequency and the sensitivity.

If your car is that wet, maybe time to sort that out first.


Peter

Click to expand...

Yes, that’s exactly the bit I can’t clean…

Thought about placing the receiver in a bag with some silica gel.

rolinger said:

If you've got PCB cleaner in the house and an otherwise busted receiver, you can go one step further...

I carefully cut off the screening can along 3 sides, folded it back and cleaned out all the corrosion under it with a toothbrush and isopropyl alcohol, then soldered the 3 sides back down. That was last winter, and it's been running perfectly since. I expected it might only be temporary but the range is still better than when I got the car!

If you've nothing to lose, it might be worth a shot!

Click to expand...

Got to be worth a try!

jimspearman said:

.....
So, it’s safe to assume that YWY000080 replaced YWY100140 and they don’t come in any of the wrong frequencies?

....

Click to expand...

it's the same, even with a bit improved range, for the other frequency it's different part number

sierrafery said:

it's the same, even with a bit improved range, for the other frequency it's different part number

Click to expand...

Gottit! Magic - thanks very much!

rolinger said:

If you've got PCB cleaner in the house and an otherwise busted receiver, you can go one step further...

I carefully cut off the screening can along 3 sides, folded it back and cleaned out all the corrosion under it with a toothbrush and isopropyl alcohol, then soldered the 3 sides back down. That was last winter, and it's been running perfectly since. I expected it might only be temporary but the range is still better than when I got the car!

If you've nothing to lose, it might be worth a shot!

Click to expand...

This has worked (so far!).

I couldn't unsolder the metal box as it needed lots of points heating and releasing at once. I tried cutting off those parts of the solder standing proud, but it still wouldn't budge.

I used wire cutters to nip off the box on three sides, then lifted and cleaned with PCB cleaner and toothbrush. I bent the box back but couldn't (so didn't) solder back in place. It seems the box is not part of the circuit, or mission-critical.

Will leave off the rear side interior panels in case I need to order and fit a new one in the coming weeks.

Thanks, again! :clap2:

jimspearman said:

This has worked (so far!).

I couldn't unsolder the metal box as it needed lots of points heating and releasing at once. I tried cutting off those parts of the solder standing proud, but it still wouldn't budge.

Click to expand...

Not surprised, without a solder reflow station it would be very hard to get it off without destroying the contents. That's why I suggested cutting

I used wire cutters to nip off the box on three sides, then lifted and cleaned with PCB cleaner and toothbrush. I bent the box back but couldn't (so didn't) solder back in place. It seems the box is not part of the circuit, or mission-critical.

Click to expand...

Well done! The box isn't part of the circuit but is shielding to stop noise and interference from getting in where it shouldn't. It's usually called a 'shielding can' or 'screening can'.

It's worth refitting it if you possibly can, even if it looks untidy as long as it's electrically connected at all the original points (simplistically, it's the size of the gaps that determines how much interference gets in). It may work perfectly without it, or you might find a parking space beside a street light, car or other radio transmitter or electrically noisy equipment and find you can't unlock.

But I guess even if it just tides you over until you get a replacement, it's easy enough to swap it out later!

Glad to help, thanks for coming back with the progress report.