Marantz PMD 671 frying batteries ?

[Edwin2]

Hi, is there anyone out there, knowing a real solution for the frying batteries from
a PMD 671 from Marantz?

Since it was new, it is frying the batteries. I already measured over 70 degrees C !!
The batts are 2500 mAh, NiMh. The menu is set to NiMh.

From a radiostation in the Netherlands, I already got the advice to set the menu to
NiCad. I already did, and placed new batteries, bcs the others were fried to death!
But I don`t have experience with that yet.

The machine also starts charging EVERYtime you switch the machine off, even
when the batts are charged !!

I THINK I have to build a separate chargingcircuit into the machine, and set the
pmd to Alkaline in the menu.

Anyone else with a good Idea ?

Thanks in advance,

Edwin

PS: Marantz will not repair this, I already tried that.
To get it repaired by them, I think I have to sue them.... :-(

 

[Nigel Goodwin]

Well you haven't filled your location in, so we've no idea where you might be, but assuming it's under warranty there should be no problem - presumably it is designed for using and charging MiMh batteries?.

 

[Edwin2]

I am in the Netherlands, it has been away once, but nothing changed, and now
they will not do anything against it.

Yes, in the menu you can choose between Alkaline, NiCad, and NiMh.

There are 2 faults in this system:
1: It starts full charging everytime you switch off the recorder. (when used on mains)
Even if the batteries are already fully charged.

2: It never stops charging

Kind regards,

Edwin

PS: The radiostation I mentioned, has the same problems.

 

[Nigel Goodwin]

Eitrher it's faulty, or designed incorrectly - in either case the manufacturer is liable and should sort it. By messing with it yourself you invalidate any warranty.

 

[Edwin2]

I know re warranty, but at least I get it solved, and can still use the recorder.
If I sent it back all the time, I don`t have a recorder, (and no income!!) and it
keeps coming back with the same fault. :-(

Never a MARANTZ again for me !

Kind regards,

Edwin

 

[AllVol]

I have no personal knowledge about this machine other than their website.

Have you tried a different wallwart power supply? There could possibly be a problem there, with it supplying more than the recommended 15 vdc.

 

[Edwin2]

Hi, thanks for thinking along.

Yes, psu gives 15 Vdc.

I am studying the diagram now, but if it makes any sense, I don`t know; bcs I am not the
only one with the problem.

The charging should start/stop independent to the use of the recoder on the external supply.
Now the charging seems to stop when the rec is switched on, and the chg starts from the
beginning, when the rec is switched off.

I cannot imagine, that a transistor is blown into a shortcircuit, bcs that would be too
coincidental with other machines with the same problem.

So I don`t think it is a hardwarefault.
But the problem can be solved with other hardware. (a separate chg-circuit )

Kind regards,

Edwin

 

[Nigel Goodwin]

Why not post the relevent part of the schematic?.

 

[Edwin2]

It is too big. To get a sharp picture, you need to zoom in until you have only a few transistors
on the screen.

I am charging now, with the menu set to NiCad instead of NiMH, and waiting what happens.
Aehh... the batteries in it now are new.

But I`ll try to put the diagram here. I hope it is of any use.

Kind regards,

Edwin

 

[Edwin2]

New info:

The advice, to set the system to NiCad, even when NiMh are used, is of no use
either. The batteries still get hot, and the recorder keeps charging.

MARANTZ CANNOT BUILD A CHARGINGSYSTEM IN THEIR EQUIPMENT,
AND ARE FRYING YOUR BATTERIES !
NEVER BUY A MARANTZ THAT WORKS ON BATTERIES !!

It has already cost me a set of batteries.
I will need to build an own chargingcircuit myself. I will be able to, but how many
owners are ?
Yes, Marantz knows where to find me, again, it is in the Netherlands, so they
can contact me if they want to solve the problem.
But I am sure, they are too arrogant to do that.

Kind regards,

Edwin

 

[Nigel Goodwin]

Well your circuit doesn't display, I should try posting it again, without a silly long file name.

 

[Edwin2]

Hi Nigel,

I am very sorry, but I can open the diagram from the forum.
And the name is not made by me.
I called it: 671pwrcct.gif, the rest is made by the forum.

But I think there can not be made any change in the original circuit,
to solve this problem.
It must be a softwareproblem. And that is in the controller.
So I might need to build my own chargingcircuit.

Stupid Idea, to leave halve of the development of a product
to the customers/users.

Kind regards,

Edwin

 

[audioguru]

Marantz audio equipment was the best available in the 70's.
Then it was sold to Superscope, then to Philips and it wasn't as good any more.
Then a Japanese company bought it and also owns Denon, McIntosh labs and Boston Acoustics. I guess this hi-fi company doesn't care anymore.

My Creative MP3 player and HP digital camera came out with firmware updates to fix problems with their battery chargers.

 

[Edwin2]

Hi,

yes, mine had a firmwareupdate too, as it was away to fix two problems.
One inputamplifier I think it was, and the frying of the batteries.

But it still doesn`t stop charging.

And as it came back, I could not read the CF-cards anymore on the pmd.
Yes, new recorded ones worked, but the previously recorded cards were unreadable.

Well, I`ll build my own chargingcct for it.

Regards,

Edwin

 

[Gary in CA]

Mine's about 3 years old.

This is from page 54 of the manual:

"AA size rechargeable Ni-Cd or Ni-MH batteries can be used in the supplied battery holder, but they cannot be recharged with the PMD671's built in charger."

The 2.2 ampere Marantz charger is for AC operation or recharging one of the welded battery packs, RB1100 Ni-Cd or RB1651 Ni-MH only.

Charging spring-held 8xAA batteries is usually 500-600 mA maximum or they get way hot and soften the springs.

 

[Edwin2]

It is 30 years ago, that NiCad batteries were 700 mAh !
They are now over 2,5 Ah !

So, that cannot be a reason for frying batteries.
And the build-in batteries are also soldered together.
Marantz cannot expect users needing a solderingiron for charging the batteries.

A few weeks ago, I found out, that after the batts were realy flat, they were not `fryed`
by charging.

Meaning: It is a stupid chargingcircuit that just charges a certain time, without any
batterycontrol.
This methode can only be used at a chargecurrent of 1/10 C

Kind regards,

Edwin

 

[sdean7855]

I don't know if this is of interest to you, but what I did was to buy the components to make a 15VDC battery pack that takes D cells...battery holders, a fuse and a cable with the right end to plug into the 671. It lasts and lasts. I've gotten disgusted with the self-discharging and long recharge times of the rechargeable...this solves that...and Alkaline D cells aren't all that expensive. It *is* a bit heavy and about half the size of 671 itself.

 

[audioguru]

Ni-MH cells have replaced Ni-Cad cells for years.
Ni-MH cells have 4 times the capacity of Ni-Cad cells.
Modern Ni-MH cells hold a charge much longer (6 months or more) than Ni-Cad cells.

 

[Edwin2]

@ sdean7855:

Why not build a small box under the PMD 671 ?
`under` means when the machine is vertical, like hanging on its belt.
Then you take 8x C cells, or some like them but a bit shorter.
They are 3,5 Ah; use those with soldertags.
Drill two 4,5 mm holes in the bottom, glue two pieces of 4mm/5mm
pertinax at the inside of the machine, after tapping M4 thread in it.
Now you can screw the external box onto the machine.
Extra advantage is, that you can mount another plug, without destroying
the machinecase. Maybe use a 270 degerees DIN-plug ?
You can use the plug also for DC-powering, and charging the batteries.
But now the charging is independent of the on/off-switching of the PMD.
AND you (the circuit) can stop charging before frying the batts.

Do you have an original batterypack from PMD ?
On the bottom end of the PMD are some contacts too.
Can you measure what is happening there ?
I think it could be a build-in NTC or PTC.
Please measure the resistance on the contacts, and blow over it with a
hairdryer, (NOT up to 70 degrees please !!! ;-) ) and watch what happens.
(Resistance going up or down)

Thanks in advance!

Kind rergards,

Edwin