Not So Flexible After 20 Years

[Visitor]

I was asked if I would take a look at this guy's hearing aid dehumidifier. It had been intermittent and finally stopped working completely. I checked the tactile "start" switch in the top for operation and cracked solder joints, then opened up the base to look at the circuit board. A couple big transistors to turn on the fan and germicidal bulb caught my eye as being possible suspects....

Then I noticed the flex cable between the circuit board in the base and the circuit board with the switch in the lid. No need to look any further! Whimpy cable didn't hold up to 90° bends twice a day for 20 years!

Cables like this don't seem to exist these days. Digikey has part numbers for some that would work, but no stock.

I took the easy way out and soldered in headers and used some Dupont jumper cables. I think that will last as long as it matters, and easy enough to fix if it does not.

 

[Pommie]

this guy's hearing aid dehumidifier.

Should that be steriliser?

Mike.

 

[Visitor]

It's both actually.

 

[Pommie]

I'm not sure I wanted to know about sweaty hearing aides.

Mike.

 

[Visitor]

I tend to agree with you!

 

[gophert]

Digikey has part numbers for some that would work, but no stock.

For cut-to-order bits at Digikey, the quantity listed is often zero but lead-time to replenish stock is usually one day. But it sounds like you made it work with on-hand bits. Nice work.

 

[Visitor]

I think that decent stranded wire should work as well as the solid conductors of the flex strips. If not, it's almost trivial to replace the jumpers now.

I could have used a piece of ribbon cable, but it's always such a pain in the butt to solder ribbon cables to boards.

 

[Visitor]

The headers worked out nicely.

 

[rjenkinsgb]

If you want to restore it with the original type of cable, we have a reel in stock - I'll put a piece in the post if its of use.

 

[Visitor]

Thank you for the offer! That's ok. I suspect my solution will serve the purpose for as long as the device will be used.