Leaking batteries. A reminder, a warning.

[G6Tanuki]

I always set up recurring appointments in Outlook to remind me to change batteries.

Dead easy, and stops me forgetting about the battery in some obscure bit of gear only to find it flat and leakage damaged when I need it in a hurry.

Let technology take the responsibility of reminders....

[emeritus]

i have a Panasonic Zinc-Carbon flat battery in the old torch we keep in the kitchen. It's dated 10-2010. Just checked it and it measures 4.5V open circuit and provides a nice bright light. As its cells are in a plastic case, I guess it should be pretty leak-resistant. I still have the plastic case of a Duracell 4.5V flat battery that I was going to fit a 3xAA battery holder to when the Panasonic expired, but as it's still going strong, the Duracell mod is on the 'round tuit' pile.

[Chris55000]

Evening Symon!

. . . Regarding your N7118, now you've got the green verdigris off the copper print side of the PCB, it might be worth giving the copper–print side of the PCB a coat of circuit–board varnish afterwards to protect it!

. . .My policy with such equipment is to completely de–populate the PCB, wash it both sides in very hot soapy water and dry it in a hot–cupboard or on a radiator, scan it at high–resolution 300 D.P.I. black–and white, (both sides), reassemble the board with new resistors, electrolytics, small transistors, diodes, etc., (this was always recommended in "Television's" articles for major breakdowns of Sony TVs), replace old low–profile sockets with turned–pin ones, fit terminal–pins to protect the print from damage by external wiring breaking off (where possible), lacquer the copper side with circuit varnish, and finally (unless an equally good scan or original paper manual is available!) prepare a complete new Circuit Diagram on my sPlan 8, so it's preserved as far as possible against future damage by battery leakage, etc!

. . .Well done on resurrecting yours – I think it can go down in the "Success Stories" thread if you've tested it and it's all working OK!

Chris Williams

[Phil G4SPZ]

Originally Posted by The Philpott

I've noted that LED headlamps using AAA cells pull excessive current, rechargeable Li-Ion ones are preferable…

Hi Dave. I agree. I’ve tried standard rechargeable NiMH AAA cells in head torches but have been disappointed by their relatively short life. Do you have any recommendations for rechargeable Li-Ion drop-in replacements?

I am tending to use rechargeable cells more and more, especially in valuable equipment, as they’re less likely to leak.

[Phil G4SPZ]

I need to start putting date stickers on the front of equipment to remind me to change batteries before their expiry date. My greenhouse Sony portable needed attention for a crackly volume control, and I was shocked to find Sainsbury’s-branded alkaline C cells inside it, dated 2014… in perfect condition.

I can remember buying that radio at an NVCF just a couple of years ago… ahem, time flies faster as one gets older

[The Philpott]

Belated reply- Chris, i've only used AAA Lithium Metal disposables in my other head torches eg Energizer with reasonable results, but now AAA Lithium Ion rechargeables are available at 1.5v (how do they do that !?) i will undoubtedly get some if the price starts to get sensible..

Dave

[Phil G4SPZ]

Originally Posted by The Philpott

Lithium Ion rechargeables are available at 1.5v (how do they do that !?)

I think each cell contains an internal ‘boost/buck’ circuit which steps down the nominal 3.7 volts from the Li-Ion cell to 1.5 volts on discharge, and steps up the ~1.5 volt charging voltage to 4.2 volts with current limiting and overcharge protection.

[Refugee]

Those lithium 1.5 volt batteries sometimes cause radio interference from the converters.

[nicam49]

I'm just having a clear out and came across my daughter's 'My First Walkman' WM-3060 which got put away after the headphones broke. Much to my horror, the batteries were still in it after, what, 25 years..... but although flat, hadn't leaked at all. The make? Panasonic, made in Poland. think I'll be buying Panasonics instead of Duracell from now on.

[ex seismic]

And today I found two 24 year old Energiser Industrials in an instrument which also had not leaked.

[Philips210]

Whilst looking for a 12V wall wart for my external HDD drive reader, I stumbled across a Lexibook Countdown hand held electronic game. I remembered removing the leaking alkaline Duracells a while back but at the time I should have opened the game to check for problems.
It was only yesterday that I opened it up and there's a fair amount of damage. Much of the wiring is corroded and some SMD caps near the ceramic resonator have corroded pads. Although the solder mask on the PCB has come adrift in places, the actual tracks seem to have escaped problems. There are several corroded wire links on the board as well. All of the battery clips/springs have blue/green corrosion on them.

I stripped the unit completely including removing the LCD display and thoroughly washed everything. I'm not entirely confident it will be a successful result but I will try to revive it. It's probably not worth the effort but I don't like chucking out items that can be saved. Sorry, I should have taken some pics before I started but will post few of the progress if it works out OK.

Regards,
Symon

[The Philpott]

I agree Symon. If you can remove the source of the attack, many things can be retrieved successfully.

Nicam49- i've been cautiously recommending more recent Panasonic alkalines as TO DATE not a single one has puked. They are a little gutless by comparison with Duracell hand grenades, but i'm ok with that.

Dave

[Jon_G4MDC]

On a Sinclair calculator with corroded springs and contacts I was very pleased with the performance or ordinary Coke to remove the crystals. Use a small container and a little at a time. Refill when fizzing activity drops off.

[Philips210]

Originally Posted by Philips210

I stripped the unit completely including removing the LCD display and thoroughly washed everything. I'm not entirely confident it will be a successful result but I will try to revive it. It's probably not worth the effort but I don't like chucking out items that can be saved. Sorry, I should have taken some pics before I started but will post few of the progress if it works out OK.

As expected, I didn't succeed with this repair. The unit seems entirely lifeless with no display or anything. When I get five minutes I'll hook the 'scope up to the two osciillator circuits, one is by a ceramic resonator, the other runs from what looks like one of those miniature cylindrical watch crystals. I'm not happy with some of the surface mount caps in the oscillator circuits, they look suspect as far as corrosion is concerned. If I had another unit to compare with then I might be in with a chance of fixing it. I'll put it on one side, there are more pressing things to do at the moment.

Regards,
Symon

[Philips210]

A few pics attached of the Countdown game. I'm wondering if the corrosion has found its way under the chip on board epoxy. The tracks seem OK when the solder mask is scraped away so maybe it's alright. The repair (non repair) probably doesn't warrant any further time but I may come back to it at some stage.

Regards,
Symon

[stevehertz]

FWIW I'd just put a coat of any handy varnish/lacquer that you have around the house on those exposed tracks. If there is any remaining micro corrosion there it may stop it reigniting.

[factory]

No point in coating anything in it's current non-operational condition.
It possible some of those surface mount parts were resistors & the metal film has dissolved.

David

[Philips210]

That's a good point about the metal film resistors David. I'll try and find another board for comparison, and yes not much point lacquering the board at the moment but will do so if I can repair it.

Regards,
Symon

[GMB]

Originally Posted by Superscope

Something else worth checking are the RTC Batteries inside Laptops

I am today reminded of a similar theme, only worse. Another Racal Syncal-30P is on my bench. These ALWAYS have damage from the memory backup NiCd battery. The problem here is that being a military radio the box is hermetically sealed, thereby guaranteeing maximum damage from corrosive vapours from the battery.

But it gets worse this time....
The corrosion had spread as usual, damaging the PCB. But this time it managed to affect some resistors causing a tantalum capacitor to be out of specification - and it had protested in the way they always do. The resulting fire-ball had caused more damage than the battery could have managed by itself. First time I have encountered this.

So if you have a Syncal-30P (TRA931P) then strip it down now! (Only the "P" model is affected this way).