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RH-10 Battery Charging Problem

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Kona702

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Hello Ev1,

I have about 4 batteries (all bought within the last year brand new) They all arrived dead and I could only get two to charge, one I had to play with for a bit to get it to start charging. It seems on VERYDEAD batteries that the RH-10 has a very tough time charging them. Any suggestions on how to get the other two to start charging? I have managed to get one of them to make the RH-10 display the charging screen for about 1 minute, then it goes blank and stops. I am currently sitting here and pressing the "stop/charge" button every minute hoping that it will start charging on its own. I will let you know if I have any success.

I would be much appreciative if someone would have any tips on how to get the other battery to even begin charging.

Please help and Thank You!!!

Sean

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Sorry to be so brusque but I really am in a rush tonight. Try googling (forget using the search function here) MZ-R91 and NiMH and battery and site:sonyinsider.com.

The best solution for the recalcitrant batteries seems to be one of these MD recorders. They're typically not expensive. There may be other ways, including readjustment of the charging parameters for the RH(9)10.

Hope this helps

Stephen

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Thanks for the reply and I appreciate it!!

Sorry...I thought you were referring to a particular thread...

I briefly looked through the article and I guess I'm not the only one with this issue.

I saw several posts about people doing "service manual adjustments" on other models to increase the charging voltage due to this problem. Is this complicated, and can I do it with the RH-10?

Thanks for your always useful help,

Sean

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YESSSS!!! I figured it out...

I saw a trick someone posted (can't find it now) that if you attach a AA with the piggyback battery connecter with the dead NIMH battery in it and use it till its dead, the battery should charge. What I did was attach a AA to it and set it to record in HI-LP so the battery would definitely die. After about 2 hrs the unit died and I detached the AA piggyback. Then I hit play and the previous DEAD NIMH batter actually got a small charge from the AA. Now it is charging flawlessly!!!! Thanks to whomever posted that trick, I cant find the post again to thank you there!!

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At first sight what that sounds like is that the AA is pumping up the power supply just a little bit.. equivalent to my tweaking of the voltages. Jim, r u there, care to comment on the electronics of the above machinations? I presume the AA is an alkaline, not NiMH!!!!!!!!

Any solution is a good solution when you're stuck :)

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At first sight what that sounds like is that the AA is pumping up the power supply just a little bit.. equivalent to my tweaking of the voltages. Jim, r u there, care to comment on the electronics of the above machinations? I presume the AA is an alkaline, not NiMH!!!!!!!!

Any solution is a good solution when you're stuck :)

I'm not too sure about this. I have been giving the MZ-N710 charging problem a lot of thought recently, and come up with a possible chink of light.

If you recall, we discussed N710's tending to dislike charging gumsticks. We had several thoughts, the most obvious being that the battery contacts *must* be clean and free of corrosion or tarnish. That doesn't solve all problems though. Then the idea was that leaving it in a charging cradle for a while helped, especially if connected to a high-current bench prower supply. Also there was the voltage settings too low, as in the difference between Malay/Japan factories. Each little thing seemed to cure some units, but not others. Plus there was the idea, as above, that boosting it with an AA add-on case would help.

Recently I have been experimenting again, specifically with the N710, as there are some units that just will not cooperate (initially) even when several of these 'tricks' are performed. So I sat down with the circuit diagram and had a real good look. I now have a suspicion that all - or most - of these solutions may have been a sheer fluke, and the actual problem is the charge current detection circuitry. This idea came to me after a particularly bad example starting working fine after having the back case removed. Previously it would either not charge at all (nothing appeared on the screen), started charging and stopped again within seconds, or simply charged the battery to an early stop, perhaps just a third of the potential battery capacity.

I believe it to be caused by the charge current detect resistor. This has to be a small value, otherwise it would drop too much voltage and consume a lot of power, turning it into heat. The resistor within the N710 is 0.022 ohms. Yes - just one fiftieth of an ohm, not much higher then the resistance in a short length of wire! I suspect that a bad joint, perhaps just a hairline crack in the soldering, is increasing the ohmic value and thus dropping a greater voltage than it should. The result could be that internal battery resistance is misread, or current miscalculated, or the final battery voltage detected too early.

Now the resistor is found on the lower edge of the circuit board, where a lot of flexing is possibly going to occur due to power plugs being inserted/removed, being placed on a charging and stand and - possibly - when an add-on battery box is screwed on to the unit.

To be honest, I have not proved this to my satisfaction yet. I am still waiting on finding units with the same problem, and going straight to this resistor and resoldering the pads. If this cures it instantly, for several machines consecutively, (and taking into account that some units may have other problems besides), I may be willing to claim success. But the jury is still out.

Jim

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Having taken a closer look at the RH10's service manual, it appears the chrging circuitry in this model is a lot more sophisticated than the N710. Indeed it has to be, as charging can be done from 3v power supply or 5v USB supply. The same suspect resistor does not exist.

What is very surprising to me is that according to the schematic, the external AA battery is, literally, just strapped across the internal gumstick. That seems a bit odd, with one being 1.5v and the latter 1.2v, so maybe there is something in what both Sean and Stephen suggest - that inserting a good quality AA 'Duracell' will kick a recalcitrant gumstick into life.

Another oddity - the SM gives the gumstick as the NH-14WM (black/orange). But I was sure Hi-MD units were only ever shipped with the NH-10WM (grey/orange)?

One hour later - done a round of service manual checks and it seems the charging circuit I am describing only exists in the N510/520, N710/NF810 and N910 (interesting as I have seen an N910 having exact same problems). So I was jumping the gun to think the N710 tests I had been performing applied here. So yes - Sean's observations are true - probably.

Jim

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I dont mean the 3.7V rechargable 1047? batteries but the disposable lithium batterys that are 1.5v or 1.6v rathr than the lower 1.4v 1.5V when new.

Energiser brand does them.

Sadly i only have AAA and no AA to test if it works.

BTW just charged my RH10 with a MZN1 3V charger 500ma.

(I couldnt find the RH10 genuine charger so dont know the current it outputs)

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I dont mean the 3.7V rechargable 1047? batteries but the disposable lithium batterys that are 1.5v or 1.6v rathr than the lower 1.4v 1.5V when new.

Energiser brand does them.

Sadly i only have AAA and no AA to test if it works.

BTW just charged my RH10 with a MZN1 3V charger 500ma.

(I couldnt find the RH10 genuine charger so dont know the current it outputs)

Using the 500mA charger rather than the 1A that comes with the unit, you can get away with it. I wouldn't try recording in Hi-MD mode with the AC-ES305 (AC-MZR55?) that came with the MZ-N1 though, especially if the internal battery is also flat. You may get record errors, which could ultimately lead to making a nice expensive 1GB disc into a coaster. But that does beg the question, why is it allowable to power the unit off the USB line when the theoretical maximum current down that is also 500mA? In fact I have come across USB sockets that purport to provide full spec power on the 5v USB line but fail miserably. Personally I never rely on USB outputs for power, always prefering separate supplies.

Jim

(must update by listening list at some point !!)

V V V V V

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  • 2 weeks later...

Having taken a closer look at the RH10's service manual, it appears the chrging circuitry in this model is a lot more sophisticated than the N710. Indeed it has to be, as charging can be done from 3v power supply or 5v USB supply. The same suspect resistor does not exist.

What is very surprising to me is that according to the schematic, the external AA battery is, literally, just strapped across the internal gumstick. That seems a bit odd, with one being 1.5v and the latter 1.2v, so maybe there is something in what both Sean and Stephen suggest - that inserting a good quality AA 'Duracell' will kick a recalcitrant gumstick into life.

Jim

Jim,

It definitely works. I have done this twice on two different horribly drained NH-14WM batteries and it has worked. I had tried EVERYTHING to get these to start charging, I was a millisecond away from giving up. BUT!! Like you said Jim, the gumstick and external piggyback charger are on a series circuit, so when the unit is powered on the AA supplies about 1.4 volts to the gumstick. It seems that this was enough to give the gumstick a tiny charge so the RH-10's charging circuit would recognize that the battery was inserted and begin the full charging process.

My take on the reason that the batteries wouldn't charge is because the RH-10's circuit must rely on a current from the battery to recognize that one is even inserted and begin to charge it. If the battery has absolutely NO JUICE, then the RH-10 probably "thinks" that there is no battery even in the chamber. What do you think Jim and Stephen? Does this sound viable?

Also...on the RH-10...the usb only "trickle charges" the gumstick. It never charges it more than about halfway (no idea why...kinda stupid IMO). You have to plug the unit into the 3V adapter to charge it fully.

Sean

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