[sdiy] Alpha Juno battery replacement

[Richie Burnett]

Were you able to see the underside of the battery?  Mine looked absolutely 
fine from the top but was green and crusty on the bottom and had started 
leaking battery juice towards the PCB!

That voltage sounds low, Adam.  Mine was still measuring nearly 3.3, and is 
actually still brightly illuminating a red LED on the bench beside me after 
3 days!  (I wanted to run it down before throwing it in battery recycling.)

-Richie,



-----Original Message----- 
From: Adam (synthDIY)
Sent: Friday, September 4, 2026 7:20 AM
To: Richie Burnett
Cc: synth-diy mailing list
Subject: Re: [sdiy] Alpha Juno battery replacement

Thanks for the heads up Richie!

Just opened my MKS-50.
Battery looks OK
Measures 2.9 volts.
I think it's the original, soldered in, which means I must have never seen a 
low battery warning since I've owned it since the 90s, because I always 
replace these with holders!

Plenty of room for a holder in the chassis, off the board.

A










> On 2 Sep 2026, at 05:58, Richie Burnett <rburnett at richieburnett.co.uk> 
> wrote:
>
> Just changed the battery in my Roland Alpha Juno 2 that was likely 40 
> years old!  The old Sanyo CR2032 coin cell looked fine from the top (+) 
> side, measured 3.295v and hadn't shown any battery warning message on the 
> synth's display.  In fact it's terminal voltage was higher than my brand 
> new Panasonic CR2032s that both measured 3.278v.  However, when I 
> de-soldered it the hidden underside was covered in tiny crystals and green 
> crud (>.<) Looks like I got there just in time!  So, don't wait for the 
> low battery message, or visible corrosion, and don't wait for 40 years 
> before changing it!!!
>
> For anyone with an Alpha or MKS-50 there's an excellent step-by-step guide 
> here:
>
> https://llamamusic.com/mks50/MKS-50_battery_replacement.html
>
> -Richie,
>
>
> -- 
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