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Circuitbenders Forum => Drum machines => Circuitbending discussion => Roland & Boss => Topic started by: nochtanseenspecht on July 25, 2011, 08:42:05 PM

Title: 626 memory required voltage
Post by: nochtanseenspecht on July 25, 2011, 08:42:05 PM

greetz,
anyone knows if it would be possible to maintain the memory of the tr626 with a voltage lower than 9V dc ?

i ask because i have here a 626 with a spoiled battery compartment, so i need to put in something small,
just enough V to maintain the memory, and not enough V to make it run and suck the battery.

( like in my cz101, i use 6 V to keep memory, to little to make it start up

ok thanx, david

Title: Re: 626 memory required voltage
Post by: Gordonjcp on July 26, 2011, 01:43:04 PM

The memory IC requires 5V or so.  Have a look at how other synths manage to do battery backup.  You're going to need a diode in there to stop the rest of the machine trying to run off the backup battery.

Title: Re: 626 memory required voltage
Post by: nochtanseenspecht on July 26, 2011, 09:05:29 PM

ah Gordon, i was hoping you reply  :) thanks !
maybe it is wise to attach  something direct to the memory IC, like 2 2032's in series..

Title: Re: 626 memory required voltage
Post by: Circuitbenders on July 29, 2011, 11:43:38 AM

I attempted this on a DR110 after doing some research on how you install a battery backup into a TR606. The only problem was it it seemed to need at least 2.5v or so to keep the memory alive and the voltage drop across the diode meant that the CR2032 battery i was using couldn't supply enough power. At least thats what appeared to be happening, i could be reading the DR110 schematic completely wrong.

Without the diode its as Gordon says, the unit was trying to run from the battery and flattened it in a day or so.

Back to the drawing board for that one i think............