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

[brianw]

I recommend:

#1) leaving it alone until it fails. I've never seen a 2032 leak.

#2) replacing with an identical BR2032 with the correctly-spaced legs for this PCB, assuming that you have plenty of experience with soldering vintage gear without damaging things like the pads. The worst thing is starting with a working synth and ending up with one that doesn't work, due to mysterious soldering issues.

In particular, I recommend against modifying the Matrix 6 with either a battery holder or wire extensions. The single worst thing I've found when buying used synths is a battery flopping around and damaging other rare components because someone failed to replace the battery with the original configuration. These modifications are always worse than the original, or a replacement that's identical to the original.

Note that if you're finding BR2032 battery cells that don't fit the Matrix 6, then you need to keep looking. Go to a manufacturer site like Panasonic, and search their product category. Once you have confirmed the measurements of the pin spacings, look for an exact match in their catalog. From there, you'll have a specific product number to search for.

Case in point: I recently repaired an Ensoniq ESQ1. Searching the usual distributor sites, I couldn't quite find the right battery, or at least there didn't seem to be any guarantee about the pin spacings. After I looked in a battery manufacturer catalog and got an actual part number, it was really easy to find a distributor with parts in stock, cheap. This wasn't a 2032 battery, by the way, but the process of finding an appropriate part number works the same.

Brian Willoughby


On Aug 7, 2022, at 9:07 AM, John Speth wrote:
> Regarding soldering, I've faced that problem in the past. I've had good luck with preparing a battery by soldering red/black pigtails to the battery, wrapping it in heat shrink tubing, then soldering the pigtails to the board after snipping (no heat) the old battery out. Then figure out some way to anchor the battery (tie-wraps, etc) if necessary. It also makes it easier to replace the battery again 30 years later :)
> 
> I think the key when working on old fragile boards is to take every precaution to avoid heating the board due to soldering. The pigtails provide a measure of soldering heat isolation. Soldering the wires to the battery requires a hot iron and flux.
> 
> JJS
> 
> On 8/7/2022 7:33 AM, Jean-Pierre Desrochers wrote:
>> 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)
>> <image002.jpg>
>> 
>> 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 ?
>> <image004.jpg>
>> 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