Help please - Hearing aid housing issue

RCF · September 11, 2022, 8:14pm

@BeLo Thank you for the suggestion. Interestingly that was my thinking too. I’ve had a similar experience with a battery in a blackberry tablet. The battery would get too low and the charge circuit decided it couldn’t recognize a battery. I did pulsed charging and eventually got enough charge into the battery that the charge circuit was happy. With that in mind I’ve done similar with the hearing aid in it’s charge case. Rocking it into charge until lights go red, the rock out of connection and repeat. Hundreds of times. Hoping that a trickle gets through until the charge circuit comes on. But that hasn’t been successful. Might be that it will take a thousand times vs hundreds or might not work at all with the HA charge circuit. Any thoughts on that ? When I took it apart I wasn’t in a destructive mood and was still trying to recover it gracefully. But that was well over a year ago and I’ve moved on so perhaps it’s time to get a bit more aggressive. I may try to determine the voltage and get enough charge on cell that it wakes up the charge circuit, assuming that is the issue. But it is all tightly sealed and I’ll need to figure out how to expose the battery terminals and also figure out if 5v can be applied while it’s still in the circuit hearing aid circuit, assuming is 3.5v battery.

@pvc Regarding the black cover, what the image shows is how it was when I removed the shell. Black cover on one side, clear on the other. Both appear to have copper wire lacquer coated and going from memory I think soldered directly to the cell on either side (but I didn’t look under the black cover). I may take apart again and be a bit less concerned about it surviving. If I do, I will take images again and report any findings.

BeLo · September 11, 2022, 8:32pm

If the cut out is in effect then no charge should be getting through so I don’t think that would work but I do understand the logic and have done similar things in the past myself. That sort of thing stands more chance of working with a NiMh or NiCd battery but trial and error with LiPo batteries has led me to using my ‘jump start’ method when faced with this problem.

I do quite a bit of repair, refurbishing and making and have used this method quite a lot on everything from a 100mAh single cell all the way to a 4000mAh cell in a 4S drone battery. It works more often than not but a big caveat is that the resurrected battery will have a reduced capacity generally related to how deeply discharged it was and for how long. A battery reading 0.5v left in a drawer for a year will probably only have 20% of its original capacity, if that, once brought back to life.

Also the low voltage cut outs are there for a reason as recharging a damaged battery could cause a fire. Given the low amount of energy stored in these small batteries I doubt that they would do that but whether you want a damaged Lithium battery resting on your ear is up to you and your tolerance for risk!

The max voltage of the battery will be 4.2v so the circuit shouldn’t care about 5v but droping down to 4v is safer.

RCF · September 11, 2022, 8:43pm

@BeLo Excellent distinction between battery chemistry and charge circuits. I think you are correct and I wasted my time. Live and learn

When I got the set they were used and arrived partially charged. I put the case on charge and both aids went into normal yellow/orange charge color. Several hours later one was green and the other red. That how they have stayed. One charges and the other doesn’t so it might be a bad battery. Possible that it had discharged too far and too long before I rec’d them. Since then if I’ve purchased a used set I’ve asked to an image of green charge lights.

Thank you for the education. I guess ideally I learn how to replace the actual battery and hope it’s an off-the-shelf type. But there is not a lot of room as you can see in the images and battery seems wired into the device and sealed as opposed to a snap in type cell. Makes some design sense and serviceability was probably not high on the engineering checklist.

Best regards and thank you for sharing your knowledge and expertise.

tenkan · September 11, 2022, 10:02pm

Have you managed to find the actual dimensions, are the Phonak the same size as the Oticon batteries, as in similar to the size 13 battery?

pvc · September 11, 2022, 10:20pm

No I don’t know much about Phonak Lion batteries and I don’t have access to any Phonak hearing aids.

RCF · September 12, 2022, 3:32am

@tenkan Thank you for the civil response and suggestions.

This incident occurred around early summer of 2020. They were still under warranty at the time but only for the original purchaser, at least that was what both Phonak and the selling audiologist told me. The eBay seller provided the receipts. But I found the audiologist and family were close and I didn’t feel right pursing through that audiologist.

I think the warranty is still valid and I could check in Target as you note. If I recall correctly the date of mfg was 2020 and believe the warranty was three years. I rec’d them early in the pandemic, life was anything but routine and I put them away. The only reason they came up in this dialog is someone was having problems with a shell not closing and I recalled I had taken some images. I thought that sharing the images might possibly be helpful. I was late to that party.

Wish the battery was more accessible but I’m sure the engineering team had a reason for integrating so tightly. It appears literally hard-wired into the hearing aid. Perhaps the guts are simply swapped when a battery is replaced by the mfg.

Best regards and pleased we can have dialog.

tenkan · September 12, 2022, 7:05am

Yes I’ve come across this before, I find it hard to believe, it should of course be the HAs that have the warranty, so what I’ve been able to do in the past, is send directly to Phonak and have had them repaired on a few occasions, I’ve also sent through an audiologist clinic HAs that were brought on eBay and originally from the VA, Phonak repaired these as well, so I would definitely give it a try, as it stands the M50 is unusable in it’s present state.

Yeah I’m thinking it was more then “we don’t want people doing DIY” on a battery swap, but I don’t think they’d replace the circuit and chassis as well every time they needed to change the battery out, it can’t be as hard as it looks, we engineers don’t make things that hard to replace (well, we try not to, he he) Phonak would anticipate that they would be replacing a few batteries, so they’d make it easy for the tech department to do the swap out, there’s no way they’d want them to be tied up for to long doing it, could well be that black plastic cover and battery plus wire connection is one piece, as in comes away from the rest of the chassis in some way?

Vigilo · September 12, 2022, 8:35am

Apologies for the late response (been on holiday/vacation) for the Boleros I took apart I needed to remove all three pins, and then it came apart ok.

Possibly each version of the HAs is different as designs change through the years

RCF · September 13, 2022, 3:55am

I think you may be on the right track with this. When I had it apart I was looking for a way to either take a voltage read on the battery or apply some power to try to wake up the charge circuit. There was no way to do that was obvious to me. Might have to revisit it with the black cap as a target of interest. I don’t think it was just a pop off. From memory it was held together with what appeared to be like a clear heat shrink plastic. But that memory is from a.long time ago so might not be real accurate. It is also possible what I see as a soldered wire is actually attached to a battery casing which would make sense from a serviceability perspective…

Good ideas, thank you !

sterei · September 13, 2022, 4:27am

I don’t think so. Some time ago I made a CT-scan of my Paradise. It looks more like the wire is welded to the battery. But the other side of the cable seems to be soldered to a PCB.

mami2529 · September 13, 2022, 10:20am

Aw that’s gorgeous! this is a rare chance to see what inside these wonderful devices for the sake of curiosity.

Too bad, there no microphone ports show! I want to see that too but I think you may already re-assemble and closed.

Thanks for showing what the inside.

RCF · September 13, 2022, 3:02pm

That is an amazing image. How are you able to place a hearing aid in a CT-Scanner ? The only ones I know of are medical and not something one could easily get time on for a hearing aid.

Looking at your images it appears as if the two parts slide together. As if they hold the battery inside. That would be consistent what I see that appears to me as something akin to heat shrink plastic around the parts of the battery cell. Also would fit with @tenkan thoughts of the battery being accessible. I added colors the what appear to be the two sides of what is maybe a battery cell holder, shrink wrapped to hold securely ? I don’t know how to interpret you image fully. Are those the actually battery cell walls and the internal material not imaged, or perhaps the entire battery is not shown in image ?

Very interesting for sure and I would love to know how you did this.

Attaching image with colors added to show what looks like two sides sliding together, though that may just be battery construction. Out of my area of knowledge.

PS I haven’t been here for years so I don’t know the etiquette and culture. Should this be moved to a separate thread. Lots of dialog about the HA internals that would probably be valuable for some future reference.

Looking closer, the area under the red circle would imply this is actually the battery cell walls you’ve imageD ?

pvc · September 13, 2022, 4:18pm

HMm; Maybe??

Desolder Wire #1
Desolder Wire #2
Rotate the entire (battery and battery case) counter clockwise and remove

Then with both wires (+/-) disconnected from the (hearing aid charge circuit) you could apply the voltage necessary to try jump-starting a lifeless battery.

And maybe new replacement batteries come with wires already attached so that you can just resolder to the PCB.

sterei · September 13, 2022, 7:14pm

I think you are right, this could really be worth a separate thread.
Today I can’t but tomorrow or next weekend latest I will do so.
Or somebody else can start it…
I will provide more information regarding industrial CT-Scan more pictures.
I will also try to make the data downloadable from a cloud server. (lots of data I’m afraid)

lilliegin · March 22, 2023, 5:43pm

Are you in the U.S. or UK. I am in Valencia CA and need ebay Hearing Aids (Oticon OPN1’s) programmed to my Audiogram from Kaiser Permanente medical my KS 9.0 left HA got damaged and Costco or the Manufacturer of the HAs will repair out of warranty hearing aids - plus the KS 9’s or KS 10’s are not sold anymore. (dlangfor).