Partially Solved: MZS-R5ST gone dark

[Zeugitai]

(Update: The portable unit was not seated properly in the deck. Incessant poking and pushing resulted in the seating of the rear corner of the MZ-R5ST into the MZS-R5ST deck and, voila, the power came on! I ended up just cleaning the old system batteries and putting them back in for the time being.)

[Original Issue:] I took my old faithful MZS-R5ST out of storage, plugged it in, ejected and reconnected the MZ-R5ST player unit, and the whole deck went dark. My heart sank and it hasn't come back. The unit was not misused or abused. On the contrary! However, it was stored for some time. It did light up when opened, and it did eject the player. Then...darkness. Pressing the power button, opening and closing the display lid, nothing.

[...]

[Remaining Issue:] The two internal rechargeable batteries are corroded.  They are Ni-Cd, 'AA', and according to the schematic in the service manual, page 61, 3v.  Does anyone know where to find these, or acceptable equivalents? I 'chatted' with Sony service today and was told these batteries are 3.7v. each. Nicd's are hard to find anymore. Will rechargeable batteries of 3.7v. and, perhaps, Li-Ion chemistry work as well?

Thanks!

 

[NGY]

Your old NiCd AA cells (1.2V nominal) are probably dead, after having spent such a long time in storage. This unit can take regular - AA size - alkaline batteries (1.5V nominal). If you have other gadgets that run on NiMh AA batteries (1.2V nominal), you can also try two of them.

[Zeugitai]

2 hours ago, NGY said:

Your old NiCd AA cells (1.2V nominal) are probably dead, after having spent such a long time in storage. This unit can take regular - AA size - alkaline batteries (1.5V nominal). If you have other gadgets that run on NiMh AA batteries (1.2V nominal), you can also try two of them.

Thanks.  To be clear, I am talking about the two _rechargeable_ Ni-Cd batteries that are nestled in the system board and require disassembly to reach.  As I recall, I bought this in Taiwan in 1997, or so.  It is a thing of beauty, and I always took care of it, and even stored it carefully. Nineteen years, however, take their toll regardless.

 I found the service manual on the Internet this morning, and on page 61, among the schematics, a note reads:

RECHAGEABLE

BATTERY (Nicd)

SIZE "AA" (IEC DESIGNATION R6)

2PCS 3V

Trouble is, batteries like these two are obsolete and even Sony does not have them in stock. My originals are corroded and need replacements.

 

[punkrockaddict]

The internal batteries for the timer are "nc-aa660ft"

seen these batteries ? I think most if not any 1,2V AA cell will do the Job

http://www.ebay.de/itm/Batterie-Telephone-sans-fil-pour-SONY-MZ-R5ST-/351516807256?hash=item51d808d058:g:pEYAAOSwPgxVSFGM

I´ll check my unit later.probably my batteries are drained out too.

But as i never used the timer function it didn´t happened to cause any problems.

[sfbp]

HUH?

Sony is right, 3.7V, this beast takes a LIP8. I have several, and an MZ-R5ST. No NiCads for me.

[NGY]

10 hours ago, Zeugitai said:

To be clear, I am talking about the two _rechargeable_ Ni-Cd batteries that are nestled in the system board and require disassembly to reach. 

...

 I found the service manual on the Internet this morning, and on page 61, among the schematics, a note reads:

RECHAGEABLE

BATTERY (Nicd)

SIZE "AA" (IEC DESIGNATION R6)

2PCS 3V

 

The internal NiCd batteries can be replaced with NiMH ones. The charging scheme is very similar of the two, the device would work with the replacements properly. Once you are about to replace them, make sure you buy the new NiMH AA cells with connecting leads welded onto them (example), as these batteries don't like soldering. Or you can simply use a two cell battery holder, if there is enough room.

As for the voltages: IEC R6 size (AA) NiCd or NiMH cells are 1.2V nominal, constrained by the chemistry. When fully charged, they show a ~1.5V voltage, so the two in series can reach the 3V noted in the SM. These cells cannot be replaced with lithium batteries, even with matching size/form (i.e., "14500") without changing the related circuitries, for the lithium cells being 3.7V nominal.

(NiCd cells are also still available - search)

[sfbp]

Right. Sorry read that in a hurry. Characteristics of AA cells are fairly straightforward. You could even put in a normal alkaline AA except for the fact that it's real pain to have to replace when they run out.

[Zeugitai]

Thanks for the replies!

Those telephone batteries look right. 

Why would I need those tabs welded to the contacts?

[NGY]

3 minutes ago, Zeugitai said:

Why would I need those tabs welded to the contacts?

If the batteries are in sockets, then certainly there is no need for the tabs.

I have not yet seen the inside of this particular model, and assumed the batteries are soldered to the main board (like the back up cells in many different devices).

If you have some spare minutes, I would love to see a couple of good photos of the board.

[Zeugitai]

1 minute ago, NGY said:

If the batteries are in sockets, then certainly there is no need for the tabs.

I have not yet seen the inside of this particular model, and assumed the batteries are soldered to the main board (like the back up cells in many different devices).

If you have some spare minutes, I would love to see a couple of good photos of the board.

Oh!  I get it.  This board has battery "coffins" built into it with typical contacts and a spring inside of each.  I closed it up for now, but as soon as I get a pair of fresh batteries, I'll open it again and photograph and post the innards.

Thanks for the help!

[Nology]

I hate to bring up an old topic but I recently purchased an MZS-R5ST with the same battery issue so I figured I would share a photo of the internals with the bottom cover off. Can anyone here confirm which batteries do work with this unit? 

[sfbp]

I can see the corrosion from here. That's the most important thing that you will have to deal with.

[Nology]

The corrosion looks worse than it is. It's mostly on the top as shown and some on the bottom. Cleaning it up shouldn't be a problem. 

[sfbp]

I don't (of my own knowledge) know what NiCads look like when they go off (: But some expert out there will probably confirm that greenish colour is the Nickel, which indeed is the colour of most nickel salts eg NiS04 and NiCl2. So you need a rechargeable battery delivering the right voltage. Not sure if NiMH can be substituted as they will have different charging characteristics. Interesting that the power for the portable is Lithium, so the NiMH era was completely skipped by this machine.

[Nology]

I cleaned up all of the corrosion and found replacement internal batteries at a local battery shop. The same shop is rebuilding my dead LIP8 batteries as well. With the new batteries installed the unit now powers up but once I hit play, everything dies within a few seconds. I'm wondering if the the LIP8 battery needs to be in the portable unit for everything to work properly. 

Update:

The power supply sent with my unit is only 100ma and the factory power supply is 1.2A so that's clearly the issue. Now I just have to find the correct power supply here in the states. 

 

[sfbp]

Something like this should do the trick, I think. My unit is not using a special Sony charger.. anything should do.

https://www.ebay.com/itm/6V-DC-2-5A-2500mA-AC-Adapter-Wall-Home-Charger-Power-Supply-Cord-5-5mm-2-5mm/371702687591

[imkidd57]

Another bump to this very useful topic...

 

I had no idea that the R5ST had internal batteries, and this thread was a great alert to investigate!

 

My internal batteries had also leaked and corroded the terminals a bit, but it seemed to be all dry and crusted without obvious spread to circuit boards and components. Was reluctant to use water, which could spread it further but scraping with fine screwdriver, finer cleaning with fibreglass brush whilst holding the unit upside down, seemed to do the trick.

 

As for replacement batteries, I had a few old NiCad and NiMH size AA 1.2V which I had previously revived by charge/discharge. However they were mostly a bit too big in width or length to fit back in the unit; luckily there were 2 NiMH slightly smaller than the rest, which went in without too much force. Let's see what happens... I don't know how to ensure that any replacements ordered on-line would be the exact right size.

 

BTW the power supply is supposed to be 9V 1.2A, not 6V. My R5ST came with an original charger which gives the spec (see picture).

 

Also, before the recent event of swapping out the internal batteries, the unit went dead even with the original charger, and I thought it was toast. However I noticed the <reset> button on the underside of the case, and with the mains power connected, held it down for about 15s. Then the unit magically came back to life and was no trouble since then. No idea why it worked, but may be worth a try if anyone has a unit that seemingly fails.