[sdiy] Oberheim Matrix 6 ---- 3.6v Lithium battery replacement.. or not ?

[Mike Bryant]

Depends how much reverse leakage D7 has :-)

But yes in the past we often put a 2,2M resistor across D7 to keep it topped up.


From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Jean-Pierre Desrochers
Sent: 07 August 2022 16:29
To: Synth-diy at synth-diy.org
Subject: Re: [sdiy] Oberheim Matrix 6 ---- 3.6v Lithium battery replacement.. or not ?

Sorry.. my mistake.. The shown circuit do not try to charge the battery at all..
Sorry again. So the battery that is in this Matrix is a very good one still !

De : Synth-diy <synth-diy-bounces at synth-diy.org> De la part de Jean-Pierre Desrochers
Envoyé : 7 août 2022 11:22
À : 'Mike Bryant' <mbryant at futurehorizons.com>
Cc : Synth-diy at synth-diy.org
Objet : [Polluriel détecté] Re: [sdiy] Oberheim Matrix 6 ---- 3.6v Lithium battery replacement.. or not ?
Importance : Faible

This is what the schematic shows..
Yes there is a ‘recharge type’ circuit that helps the battery for long term..

[cid:image001.png at 01D8AA7C.2B3882A0]

De : Mike Bryant <mbryant at futurehorizons.com<mailto:mbryant at futurehorizons.com>>
Envoyé : 7 août 2022 11:16
À : Jean-Pierre Desrochers <jpdesroc at oricom.ca<mailto:jpdesroc at oricom.ca>>; Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
Objet : RE: [sdiy] Oberheim Matrix 6 ---- 3.6v Lithium battery replacement.. or not ?


I’d leave it alone if it’s still working fine.  On designs back then we often used to leak a few uA into the battery whilst the unit was powered up which kept them living for much longer.  Don’t know if this keyboard has that but if so it would explain the long life.




From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf Of Jean-Pierre Desrochers
Sent: 07 August 2022 15:33
To: Synth-diy at synth-diy.org<mailto:Synth-diy at synth-diy.org>
Subject: [sdiy] Oberheim Matrix 6 ---- 3.6v Lithium battery replacement.. or not ?


Hi all,

A friend of mine brought me a working Oberheim Matrix 6 keyboard
that he was worried about the inner memory lithium battery (BR2032)
being about to die.. and to replace it.

Well after a quick check the battery was still in pretty good physical condition (no leakage)

[cid:image002.jpg at 01D8AA7C.2B3882A0]

and was showing a strong 3.23v on its terminal (AC unconnected)

So.. In this situation I’m wondering if this lithium cell should be replaced or not.
I know this keyboard is at least 30-40 years old and many of the coin
batteries of these vintage keyboards need to be replaced, but..
And on replacement I thought about soldering a coin battery socket
on the PCB pads BUT the battery placement on the PCB
is very close to some IC’s as shown on the picture and
would need the socket to be raised a little to avoid these IC’s.. I don’t like that.
I could also buy a coin battery with PCB legs too like this one
but again, replacement or not ?

[cid:image003.jpg at 01D8AA7C.2B3882A0]

I don’t know the year of manufacture of this Matrix but here are
the serial number and BIOS number.

SN: 7622661

BIOS: M6R 2.13



Your opinions are very welcomed.
Cheers !
Jean-Pierre
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