I been looking for a replacement for a while, but the contacts don't look right?

Don't worry about that, the contacts inside the players matches the battery contacts. Don't forget that this AIWA battery is not a standard battery, it is an exclusive type so no commercial factory will manufacture them.

Old news and non-voltage regulated. Fry your grail AIWAs at your own risk.

Typical cheap China bodged crap.

 Sorry, I Just woke up from a long hibernation...

So... it's bad news! oh boy....we're back to the storyboard...

Hi members,

I also have a question concering these recargable batteries.

I have at least 15 of them; some of them look brand new but they are all DEAD and do not take a charge.

Is there any way to bring them back to life or can they be just used as paperwheight?

I have seen on the bay these batteries in the original package and they have never been used. Would they take a charge or are they also dried up and worthless?

Thanks for any response.

Paperweight my friend, a museum piece!

Paperweights the lot of them > you may as well stick them all together and use thusly. Even ones un-opened will be dead now > keep those as curiousities. Sadly lead acid batteries need to be constantly topped up to 2.0V to maintain their life, otherwise their lifespan quickly degrades. Not the ideal thing to use in something like a walkman where a user would drain a lead acid battery close to flat, forget to charge the battery for a few days and then charge it... rinse... repeat... kill battery.

Your only hope is that someone makes a caddy with voltage regulation for those gumstick type NiMH batteries with separate NiMH charger to top them up, if you want to utilise the internal battery slot in AIWA units.

It is possible to shrink down the original voltage circuitry found inside the external AA battery pack to incorporate it into a PB-4 adapter to use with 2 NiMH mini gumstick batteries, but the PB-5 is more of a challenge for space.

^ Given time, I might be able to rustle one up for the PB-4, but that is currently a low priority project for me.

Not necessarily paperweight. Car batteries work in a similar way and can be revived. The problem with the lead acid batteries is that the acid crystallizes on the cells inside the battery and thus preventing the acid (that hasn't crystallized yet) from being in contact with the cells. Once this happens, the battery cannot be charged anymore and the rest of the acid crystallizes as well. Constant current chargers only heat up the battery but don't charge it. I am not an expert in electronics but the solution to this problem would be to design a pulse charger that would charge the battery at higher current than it was designed for and at higher voltage (10-20% higher than the nominal battery voltage should be enough). The impulses should be at 5 second interval. This would shatter the crystals and acid would become liquid again.

Depending on the battery construction, it might be possible to dismantle it completely, melt the crystallized acid and after cleaning with strong alkaline, refill it and seal it back again.

My UPS battery died a few years ago. Since UPS devices are not exactly cheap or easy to get, so I removed the acid seals on the top and poured battery acid. Works ever since. But like I said, I'm no expert by any means. 

Dear all,

what is the story with Nickel-Cadium batteries: Sony NC-&WM, Panasonic RP-BP62 etc.

Do they need to be recharged regularly or can they languish in the drawer for years without going dead?

How long should they be recharged?

How do you know when they are fully recharged?

I have a couple which I recharged too long whereby they ballooned and couldn't fit in the compartment anymore. More paperwheight.

Why can they not be adopted to replace the PB-4?

Thanks for any reply

Virtually all rechargeable batteries will fail if not looked after properly. Over time NiCD and NiMH will lose their ability to store as much charge as when they were first bought.

Some rechargeable batteries do increase slightly in volume when fully charged and will shrink back to original size so long as there is damage due to over stretching of the external packaging. If they have increased massively in size, then it is likely you have over charged the battery.

How long it takes to charge a battery depends on a number of factors. Eg battery capacity, amount of charge applied, battery type.

Get a good delta voltage based gumstick battery charger and a digital multimeter to check the voltage. NiMH batteries that have completed their charging cycle will measure approximately 1.4V <- although this is no indication it is at optimium capacity, and subsequent charge and discharge cycles may be required before it does.

The Sony and Panasonic gumstick batteries although of similar physical shape are not the same in many ways to a PB-4 or PB-S5. For a start the battery terminals are at opposite ends on these as opposed them both being on the same end for the AIWA batteries. Also they are of different chemical type ie NiCD/NiMH and lead acid type, therefore there are different voltages too.

It is not recommended to pair two half sized NiMH gumstick together to double the voltage and directly connect to an AIWA as the voltage regulation circuitry is located within the external battery pack. Some people are happy to over rule this risk, but personally I do not see the point in spending a lot of time, money and energy trying to collect rare AIWA just to shorten their lives because I wanted the convenience of no external battery pack with a bodged solution.

*PLOP,

How can a dry cell fry a Walkman?  You can't get a voltage spike and these units are designed for a 1.2 battery that will drop off in voltage after awhile.

Most of the rest are 1.2V But no, the AIWAs are designed for 2V operation so you would need two batteries in series.

A fully charged NiMH cell measures ~1.42V, so two of those together would take the voltage up to nearly 2.9V. Given that standard non-rechargeable cells are ~1.5V and since AIWA took the time and trouble to design in a voltage regulation circuit to moderate the voltage down from ~3.0V closer to 2V would you want to take the risk?

It's your choice if you want to wire up two fully charged NiMH cell and pop them into your AIWA, then go ahead. I can't stop you, but don't say 'if only I had known' if the unit stops working and you are left with an unrepairable paperweight.

Thank you for the info on the AIWA rechargeables.  I'm sure I'm not the only one that didn't know they take 2 batteries and I didn't want to assume this. I opened up my own Panasonic and found a 1.2 volt battery and didn't see how that could be a problem.  Now that we are talking higher voltages x2 I would do some checking before I used them.

Whilst I am not sure whether to call you courageous, insane or foolish to sacrifice a really rare, valuable and working PX1000 to this experiment, I hate to tell you however that back in August 2010 I already made this experiment on a junked JX707. So I know it is 'possible' to power a unit with two NiMH batteries in series and this is not major news to me.

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If you feel that you want to continue in this venture then that is your business. I do not feel comfortable however that it is hailed a complete success without pointing out the risks.

There are no simple 'resistors' inside the AAA battery pack. If you read the rest of the above thread you will discover there is a complex voltage regulating circuit inside. If you have the AAA battery pack and put in a freshly charged pair of NiMH batteries into the pack and measure the voltage it will measure ~2.3V. If you drain them for an hour or so, they will STILL measure ~2.3V. Eventually the voltage from the pair of batteries will drop low enough that the circuit is not able to sustain this voltage of ~2.3V and the unit ceases to be powered.

I am very close to miniturising this circuit to fitting inside the space occupied by a PB-4 battery (slightly more space than that for a PB-S5A).

I don't feel it is a matter of arguing the point to win it, but rather informing those out there who are unaware so that they don't fall into the likely pitfalls.

Yes, your unit will 'work' for a time, but for how long? Taking your example of overclocking CPUs further, people do overclock them and they increase the voltage to aid stability. But did you know that increasing the voltage does two things : it increases the heat produced (probably a non-issue for a walkman at these low voltages), but more importantly it can encourage the growth of dendrites within semi-conductor components. This a phenomenon known in the CPU overclocking scene, and when those dendrites grow too long they short out circuits. People in the overclocking community know that when they overclock and up the voltage on their CPUs they are making a balanced pay off for having extra speed over a shorter life span for their CPU. So your PX1000 may not stop working instantly today, but at some point down the line it very likely will.

There are safer options to getting your PX1000 to run, and I can understand your excitement to have it working and also being portable too. Whilst being hard to find, AAA battery packs for the PX1000 are available if you look around. They are definitely a lot more easier and cheaper to find than another PX1000 and I can tell you from personal experience.

At the end of the day most of us are here because we like retro electronics and we want to enjoy them.

Did you try to back to life original battery? Lead -acid a specific and dont like a full disharge as Ni-Mh accums. I red a lot of literature about lead-acid batteries without liquid electrolite (this type used in Aiwa, sorry i could not translate it correctly in english)/ If somebody read russiuan i will send links to articles. 

Briefly:

Do not try to charge old battery directly in the Aiwa device. It will destroy battery 100%. Too many gas H2 will be emmissed and safety (??? do not know english word) will be opened. 

There are two ways to restore battery from bad condition:

1) Charge by special impulce current. Positive impulse with 2,2V  with special fronts of impulse and negative impulses with low voltage. Required to develope spesial charging device. In the internet there are Diagrams for 12V batteries but I did not find for 2V small batteries. If somebody want to create special charging device - write me exchanger@inbox.ru I will give you additional info

2) Charge by 0,1-0,05 current. For example, for PB-5S with 600mAhg capacity charge by 30 mA in 20 Hours. Then make a breake in 20 hours and measure voltage.  Less then 1,8 - charge again by same current. 2V and more - charge in Aiva playr as usual. This method prevent emission of H2 gas and solve sulfates (? english word?) in the battery.

How to charge? A lot of diagrams in internet for power adapters with stabilized current (not stabilized voltage!) LM317 for example could be used.

I have a new PB-4S new but produced in 121995 . It could be used for my JX-707 and I will try to restory it soon. Now the voltage is 0,125V - so looks fully died. Viktor

Sorry, did not understand what you mean. My idea was to restore old lead-acid batteries. I read this forom and see: all experiments were unssessful because people tried to charge old batteriees in Aiwa devices. And kill them.  Old batteries should be charged by ... 0?05C  see my post. 

It's not just a simple resistor in the AAA battery clip. Do not run the PX1000 off 3vdc, you will burn it out. Yes devices have a tolerance level and can run safely within that range, but the different circuits also feed off that rail, and chances of electromigration of a IC's, ultimately results in failure of the affected IC which is high as you are running it at it limits, in short you will shorten it lifespan, just won't risk a PX1000.

@Pawel

Battery regulator is that from an AIWA external battery pack.

Best to remove batteries to charge them with proper NiMH charger.