#Arkive PD: Replace internal clock battery GM5

[prairiedog]

Unfortunately it didn't fix the problem :-(, probably due to my soldering skills! More on that later. I documented my procedure - this may be useful for anyone attempting any kind of GM5 repair in the future.

The original issue was that every time the main battery was removed and reinserted the time would be lost and I would be prompted to set the data and time. So the internal rechargable battery needed replacing.

I'm thinking of selling the GM5 so it would be nice to be in full working order.

There are a few places selling ML-421 batteries but not with the solder tags.

I tried to order from Aliexpress, waited ages then it was cancelled for some reason. I wasn't convinced of the quality anyway. So I sourced a genuine ML-421S/DN from mouser.co.uk. At £1.45 each they were cheap but with Fedex shipping from US plus all the extra charges it was closer to £20, so I ordered 3 batteries just in case.


Mouser.co.uk batteries

I found a copy of the service manual. It's on my google drive, hopfully accessible here:

https://drive.google.com/file/d/1RBYMln-W6drsZpFGgWifW-96HKlJ4D-7/view?usp=sharing

So, with a bit of spare time after Christmas I tackled it. I followed steps 1-3 of the disassembly procedure on page 40 of the manual.

I used a Philips 00 screwdriver for all the screws and there were no issues. Not all screws are the same size so use a system to track where the screws belong.

I have a cheap amazon soldering iron https://amzn.eu/d/4YEnWPB and practised my skills on an old PCB from a dead gadget. I'm no expert and I've soldered a few things in the past with clumsy but successful results. But I found I was managing fine with my practice PCB.

1. Remove battery and card.

2. Remove 6 case screws, one on each side under the strap loops, and four on the base. Around the tripod mount, only the two near the LCD should be removed.


6 screws

3. Remove hotshoe cover and the hotshoe spring (flat metal springy plate). The instructions show prying it off with a flat bladed screwdriver with arrows to lift and slide at the same time. The screwdriver caused some marking on the case and the spring wouldn't budge. Once I used a pointed tool (a board pin in my case, but a toothpick etc would work well) to lift the spring, it slid out with no effort at all. One of those things you only discover with trial and error.


lift the spring with a pointy tool (green) and the spring will slide out easily.

There are four screws under the spring that should be removed.

4. Remove eye cup. Once I realised which part had to slide, it was fairly easy to use both thumbs to wiggle it forward.


Only the top bit slides so don't try and push the whole protruding eyepiece

5. Pry open the case

I used hands mostly, with a little help from a spudger tool.

This was easy.



6. Remove rear cover

As you tilt the rear case assembly (with tthe LCD) back you will see there are three ribbon cables that need removal. From now on all the connectors are a bit different so I won't go into the details but they are fragile and a lot of care needs to be taken removing them.

With these three removed the rear case assembly can be set aside.


3 flex cables connecting the rear assembly to the PCB

7. Access the rear of the PCB

The biggest pain is that the battery is on the far side of the main PCB. Remove the three screws (circled red) and seven cables (circled blue)


Flex fun

The main PCB is still held by the soldered speaker wires (circled red) and a cable behind the PCB (circled blue)


Pesky things keeping PCB in place.

I had no appetite to desolder the speaker wires, though in retrospect it might have been OK. So I lifted the PCB enough to detach the cable from the connector and tilt the PCB back.

You can now see the released flex connector (blue) and the speaker wires (red - still atached) and the pesky battery (yellow)


Dark side of the PCB

8. Replace battery

I desoldered the battery tags with the help of some desoldering tape.

I tested the voltage of the old and new batteries and they were dead and approx 3V as expected.

I held the new battery in place with one of those little plastic clamps and attempted soldering under a "helping hands" magnifier. This was where the fun began - I really struggled to get the solder to stick. I tried different solders, different temperatures etc but it was tough. Like, I mentioned before, my practice on an old PCB was fine so I'm not sure of the issue here. Eventually I got blobs in place and the voltage seemed OK when I tested on the tabs.

I was so absorbed in this I have no photos of the process.

9. Reassembly

Everything in reverse. The biggest hassle was getting the ribbon cables back into the connectors - first the one on the back side of the PCB then all the others. They spring all over the place and it takes a lot of patience to get them in place and clamped. But I got there in the end.

10. Conclusion

The camera is reassembled and is now fully functional except for the original problem. It was left overnight with the main battery in, so if the internal battery was going to charge it would have. As soon as the main battery is removed the time is lost. :-(

I could have fried the battery, but the voltage measured OK in place on the PCB. I suspect I just didn't get the contact needed when soldering.

Maybe I'll try again in the future when I have a spare afternoon but hopefully this post will be of use to others whether they attempt a battery replacement or some other repair in the future.

 

[glassoholic]

Wow... I wish I had your skills, perseverance and bravery.

 

[tedolf]

I wonder if this is the same body as the Leica C type 112?

Tedolph

 

[Peadingle]

In my old Canon S3, the battery was accessible from the main battery compartment. It should be like that on all cameras rather than having to disassemble the camera.

 

[Eric Nepean]

I’m an electronics engineer with a fair bit of prototyping experience; I’ve also taken a MIL SPEC soldering course.

At a guess I’d say your problem is due to a cold solder joint. You can check for this by measuring the voltage between the metal tab and the battery surface, it should be 0V, if you’ve made a cold solder joint it will be closer to the battery voltage.

How to get around this

The soldering kit you’ve got looks pretty decent, with two caveats. First, the solder included is lead free solder, which is more difficult to use successfully, especially for a beginner. Second, there’s no flux included in kit, except possibly in the solder wick.

When soldering, the main obstacle is that metal surfaces are covered with a thin layer of oxide, unless the surface has been freshly cut or abraded. The oxide reforms rapidly when the metal becomes hot. Solder is unable to penetrate an oxide layer.

An electrically conductive solder joint won’t form unless the solder has intimate contact with the metal surfaces, and the solder penetrates into the metal. For this to happen both metal surfaces have to be above solder melting temperature, and there must be no oxide layer.

The typical way around this is to add “Flux” which “eats” the oxide layer. You do have to be careful not to overheat the flux causing it to burn.

The challenge with lead free solder is that it melts at a higher temperature, and the flux it requires creates fumes which are harmful to your lungs.

The fumes from flux for lead tin solder are much less harmful, the vapours don’t contain lead.

I recommend a small roll of 63/37 or 60/40 Tin-Lead Rosin core solder, and perhaps a small container of rosin flux, to be applied with a small brush. Use it for electronic repairs, not for anything to do with drinking water. The temperature of the iron should be set to 700F/370C ( as opposed to 750F/400C for lead free).

First prepare the materials to be joined, remove any obvious oxide and old solder, fix in position, and apply a small dab of flux. After the iron is hot, clean the tip with a bit of abrasive, the apply flux and solder so the tip is bright and shiny. Then apply the tip to the joint, apply the solder to the tip so the liquid solder touches the joint. Wait for the joining metals to come to temperature, the solder will flow freely over the joint, add a little more solder now. Remove the iron and let cool.

If the joint does not get hot enough for the solder to flow, don’t increase your iron temperature more than a little, instead use a bigger thicker tip to increase heat flow to the joint, and check that your tip is clean and well wetted with solder.

A successful joint has an easily recognized appearance , the solder is bright and silvery, and the solder merges into the metal gradually.

--

Cheers
Eric

 

[prairiedog]

Hi Eric,

I can't tell you how much it means to receive such a lengthy and informative reply. You have some fantastic advice that I didn't glean from the web/youtube so this is invaluable.

The adafruit link is good and I immediately realised I ended up with a cold joint, as you suggested. I also recognise I was initially getting residue of burnt flux (too high temperature) so was cleaning up with some rubbing alcohol and gentle scraping.

I initially tried a spot of super glue to hold the battery in place while I soldered, before I used the plastic clamp. I think some of the glue residue may not have helped either!

One of the criticisms of the iron was that temerature control is not accurate, not surprising for cheap kit. But I did experiment with various temperatures.

I note your comment on a bigger tip - I started with the finest tip and stepped up to the next one and got better results.

You've given me confidence to try again, armed with alternative solder, flux and your advice!

Thanks.

 

[cba_melbourne]

Thank you very much for the disassembly description and pictures. One day I may have to do that too. I already did on a GM1, there the battery is under the top cover. But then, I regard myself as an expert soldering artist, with over 50 years experience in industry

It could well be you cooked the new battery. You have to solder very fast, to prevent overheating the whole battery. Re-chargeable Lithium batteries like these do not respond kindly to heat.

Soldering requires skill and lots of practice. It is not something you can learn in a couple hours. It takes more like several weeks full time, to develop the most basic skills. Before you feel confident at soldering, I would suggest bringing the board and the battery to a radio repair shop (if they still exist in your town) and let them do it for a small fee. Wrap it in aluminium foil to prevent damage to static charge until there.

The soldering kit you have there is incredibly cheap, but I think it is perfectly fine for the task. Don't use lead-free solder, it is much easier to work with ordinary old 40/60 rosin cored radio solder. Especially if inexperienced at soldering.

First thing, properly "wet" the new solder iron tip with tin. Without this first step, you can achieve absolutely nothing - zero. If tin "pearls" form on the tip, it is not properly wetted yet. Avoid excessive temperature, as this quickly "burns" the tin (makes it look matte) and hard to work with. Set the soldering iron to around 270C.

I suggest to first tin the tips of the battery lugs. Only after these are "wetted" with tin (nice and shiny), solder to the board.

Then, that is a multilayer board with lots of copper layers inside, so it takes quite some heat and time. First remove the existing solder drops, they are very likely lead-free solder and do not mix well with radio solder. Then add two nice drops radio solder. Let cool.

Finally hold the battery in place, and just melt the two solder drops on the board onto the wetted battery terminals. Work fast, don't overheat the battery, dont burn the solder, it should be just two shiny drops of solder. If they look matte you overheated. If not confident, clip dome tweezers or pliers to the battery to help it stay cool in the process.

It sounds all so easy. I remember some 50 years ago I had to train factory workers at soldering. That was easy two layer boards back then, by far not as demanding as today. Yet it took several weeks until the most taltented were capable of reliably producing clean solder joints. And many never learned it no matter how hard we tried, and had to be transferred elsewhere to do another job.

 

[Eric Nepean]

Hi Eric,

I can't tell you how much it means to receive such a lengthy and informative reply. You have some fantastic advice that I didn't glean from the web/youtube so this is invaluable.

The adafruit link is good and I immediately realised I ended up with a cold joint, as you suggested. I also recognise I was initially getting residue of burnt flux (too high temperature) so was cleaning up with some rubbing alcohol and gentle scraping.

I initially tried a spot of super glue to hold the battery in place while I soldered, before I used the plastic clamp. I think some of the glue residue may not have helped either!

One of the criticisms of the iron was that temerature control is not accurate, not surprising for cheap kit. But I did experiment with various temperatures.

I note your comment on a bigger tip - I started with the finest tip and stepped up to the next one and got better results.

You've given me confidence to try again, armed with alternative solder, flux and your advice!

Thanks.

Hi PrairieDog, you’re quite welcome.

A few more comments that have come to mind:

1) You can make the soldering even easier by pre “tinning” the battery surface - applying flux and solder so that surface of the battery that you wish to solder to is already covered with solder making a good bond with the underlying metal. You would do this with the battery on bench top, not mounted in the circuit board.

2) In order for the circuit to work, both terminals of the battery must make good electrical contact with their respective connections. I can’t see from the photos how the other battery terminal makes contact - I get the impression that the other terminal is the other face of the battery, and that it is pressed down on a conductor by that metal tab above, acting as a spring. If my guesses are correct this leads to possible complications.

3) if that metal tab over the battery is acting as a spring, you must take care not to accidentally melt the solder that holds it in place, else it may lose it position and no longer press on the battery. I have occasionally done this by putting an elastic around the handles of a small pair of pliers, and clamping those between where the soldering iron is applied and the solder joint which is not supposed to melt.

4) If the super glue got onto the gold plated conductor pad which connects to the other side (other terminal) of the battery, I fear you are in deep water indeed. If you used super glue gell you may be ok but liquid super glue has a strong tendency to wick. If its got onto the contact under the battery it may be very difficult to remove without damaging the contact - any abrasion may remove the gold plating leading to unreliable connections as the copper oxidises. It is possible that acetone may dissolve the super glue, but it may also affect the conductor adhesion (and will probably dissolve the green solder resist - which will be messy)

If I was faced with superglue on the battery contact that I could not cleanly remove with a Qtip and some solvent, or if i ended up removing the gold plating, I might decide to live with no battery, or to use some 30 gauge insulated wire or some 5 thousands brass shim stock to connect directly from the other battery face to the circuit conductor. If I have to hold something in place a bit of tape often does the trick, in manufacturing we have been warned off of epoxies because the fumes can have a negative effect on other components. Unclear about super glue.

Circuit Board Construction: The circuit board you have there is very likely not just a two layer board with conductors only on top and bottom, it likely has 2 or more interior layers of conductors. You must be careful not to damage connections to the interior layers as that is really difficult to repair.

The conductors will be copper; conductors used for pressure contacts will be plated with a thin layer of gold eg 25 micro inches. you have to be careful to not abrade the gold plating as it is very thin and easily removed. Once the gold plating comes of the contacts, the connection will eventually fail as the copper oxidises.

The green “solder resist” coating is an insulating layer which protects the conductors from inadvertent shorting and also prevents solder from adhering in places where it should not during manufacture

--
Cheers
Eric

 

[Messier Object]

My approach Eric would be to solder some short insulated copper leads to the battery - less chance I think of cooking the battery and easier to check the battery voltage before connecting it to the PCB.

I’d put an insulating shrink sleeve on the battery before soldering its new leads to the PCB

Peter

 

[prairiedog]

Very welcome suggestions - thanks for taking the time and effort to reply. When I’ve practised more I’ll tackle the camera again.

 

[prairiedog]

Thanks again for even more great tips. I’m amazed at people’s willingness to share knowledge. I think the superglue was ok.. once wiped it dried and I could flake it off with a craft knife blade. The contacts on the board were little copper squares under the original solder blobs - I assume connecting to sandwiched conductors. Wish I had more photos but I got absorbed in the job!

it’ll probably be a while before I get more practice and decide whether to have another go!

 

[David Fell]

So I sourced a genuine ML-421S/DN from mouser.co.uk. At £1.45

Hi, this is a rechargeable cell, so as long as the main battery is kept charged this battery will work for many years, but if it is left discharged for a long time it will die and not recover, hence the clock resetting.

I have old M43 cameras (GF1) which I have diligently checked the main battery every 3-months and charge A/R and is working just fine along with GM1, FX37 & LX2 (2006) P&S all working well.

I suspect your battery maybe OK but may take a few days to charge or the circuitry around the cell is defective which killed the old battery and stopping the new one from functioning.

BR David

 

[Eric Nepean]

My approach Eric would be to solder some short insulated copper leads to the battery - less chance I think of cooking the battery and easier to check the battery voltage before connecting it to the PCB.

I’d put an insulating shrink sleeve on the battery before soldering its new leads to the PCB

Peter

Especially if ones soldering skills are weak

 

[Tom Caldwell]

Thanks for your detailed information on the pull down of the camera body. It seems that you managed to get the evf surround off fairly easily. This pressure fit part of the case disassembly can be awkward to get apart.

 

[prairiedog]

Once I realised which part of the eyepiece removed, it came off quite easily. I tried to capture that in the picture. I was surprised because I had read that it was hard.

 

[roneybr]

Hi, I thinking of change the internal battery of my GH5S with the same issue (need adjust clock everytime). Can you help me with the type of battery and supplier? I'm from Brasil and here I cant find one. I use Aliexpress too, but i just find others.

https://www.manualslib.com/manual/2088866/Panasonic-Dc-Gh5m-Series.html >>> Page 06 (ref n° B7501)

 

[cba_melbourne]

Hi, I thinking of change the internal battery of my GH5S with the same issue (need adjust clock everytime). Can you help me with the type of battery and supplier? I'm from Brasil and here I cant find one. I use Aliexpress too, but i just find others.

https://www.manualslib.com/manual/2088866/Panasonic-Dc-Gh5m-Series.html >>> Page 06 (ref n° B7501)

It's the same battery used in many other Panasonic cameras.

The Panasonic part number is N4ECY25Y0002

It's a rechargeable 3V Li-MnO2 button cell of 4.8mm diameter and 2.2mm tall, with solder tags

Here a link to a UK seller with picture:

https://fixpart.co.uk/product/panasonic-n4ecy25y0002-button-cell-battery-photo-camera

It is quite expensive if you buy it as a Panasonic spare part. It's actually a rip-off. The reason for the high price, is Panasonic attaches solder tags to it

****

The generic name for this battery is ML421, but you have to make sure you order an ML421 WITH SOLDER TAGS, because most you can buy are of course without solder tags

AliExpress has a pack of 10 waiting for you, with solder tags, for US$10 plus $1.89 postage. It's Japanese made cells, likely with the tags attached in China. I bought such a pack some 5 years ago from Aliexpress for my GM1, and it still works fine, hence I can recommend it:


Good Luck!

 

[roneybr]

Thank you! I just bought them. Thanks!

 

[roneybr]

They arrived! Much smaller than expected! Thanks again for the support!

 

[ChapelHillCody]

I have both a GM1 and a GM5. My GM5 hasn't had trouble keeping time when I change out batteries, but my GM1 needed the clock set every time the battery was removed.

So, I bought a bunch of those Panasonic ML-421S/DN Coin Cell Lithium Rechargeable batteries from Mouser, as they are slated to be discontinued. I just replaced the one in my GM1.

I have a lengthy video that walks you through the details of getting to the top P.C.B., which is much more work than it appears for the GM5. Here's the link to that video:

Thanks to this thread, I will do the same for my GM5 soon. In the GM1 video, I don't show unsoldering and then soldering-in the replacement battery on video; but I'll likely do that in the GM5 video. I repair a lot of electronics and found that a trivial task; but it might be more advanced than I thought for others.

These cameras are too good to let die on the shelf. Recently, I travelled to Australia with my GM1, GM5, and Sony RX100MK7. The GM's got the most use, as they simply took the best pictures, effortlessly I might add, with the array of lenses I have for them. The RX was best for blogging and some minor shots here and there. But for the best pictures, the GMs kicked butt.

I do have a few new batteries for these cameras on eBay here: https://www.ebay.com/itm/276948467403

Although you can still get those batteries on Mouser. Do not buy non-Panasonic batteries, because you really don't know what you're getting. These are lithium-ion rechargeable batteries that are recharged by the camera's battery; so unless you get the right kind of battery, it might work for a while but will not last. And the steps to replace that battery are something I'd rather do every 10 years.

If you follow the service manual, have a precision-tipped soldering iron (like a Weller Model #T0058770715 with a precision, round tip), and are a bit brave (at least with the GM1), I recommend replacing the battery as soon as you can. Use my video as a guide.

I'd also like to give a shout-out to Emily (https://www.microfournerds.com/) for her article on getting into Service Mode on these cameras. Also, her advice on lenses has been unparalleled except for my cousin who had an MFT and recommended the 14-140/3.5-5.6, which is almost permanently mounted on the GM5 now.