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SD-1/32 still losing its memory

2012-11-27 by Christian Brunschen

Hi all,

you might recall that I was having an issue where my SD-1/32 suddenly started losing the contents of its usually-battery-backed RAM when powered off. I replaced the battery (putting in a battery holder to make future battery swaps easier too, but that didn't help. So I figured the culprit might be the capacitor that is supposed to smooth the transition of power from power supply to battery and vice versa – and today I replaced that capacitor. Alas, that did not have the curative effect I was hoping for - when powered off, the RAM contents still disappear. Yes, I put the battery back in the battery holder. Without the battery, the keyboard complains loudly that the battery level is too low; but with the battery in place, no such complaint – everything looks like it should be working ... but it isn't.

I'm a bit stumped. Of course this doesn't make the SD-1/32 impossible to use, but it does mean that everything has to be saved to and then reloaded from floppy disk whenever I want to do anything ... which is rather annoying, and considering the age of the drive and the floppies as well, is perhaps not ideal in that respect either. (Of course, that aspect can be addressed by replacing the floppy drive with a floppy emulator, but still.)

Does anyone here have any other thoughts or ideas about what might be the cause of this behaviour (that the RAM fails to keep its contents when the power is turned off)?

Best wishes,

// Christian

Re: [Ensoniq-VFX-SD] SD-1/32 still losing its memory

2012-11-28 by Adriano Camocardi

Hi Chistian, I don't have the hystory of your procedure on your SD-1, so let´s start of the first dot. The battery that you used have the same voltage and current that the original battery of the SD-1? If it don9;t have the same value probably it is the problem. So the battery need to suply the voltage and current RAM memory during the power-off.

I hope this can help you.

Best Regards.

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2012/11/27 Christian Brunschen <cb@...>

Hi all,

you might recall that I was having an issue where my SD-1/32 suddenly started losing the contents of its usually-battery-backed RAM when powered off. I replaced the battery (putting in a battery holder to make future battery swaps easier too, but that didn't help. So I figured the culprit might be the capacitor that is supposed to smooth the transition of power from power supply to battery and vice versa – and today I replaced that capacitor. Alas, that did not have the curative effect I was hoping for - when powered off, the RAM contents still disappear. Yes, I put the battery back in the battery holder. Without the battery, the keyboard complains loudly that the battery level is too low; but with the battery in place, no such complaint – everything looks like it should be working ... but it isn't.

I'm a bit stumped. Of course this doesn't make the SD-1/32 impossible to use, but it does mean that everything has to be saved to and then reloaded from floppy disk whenever I want to do anything ... which is rather annoying, and considering the age of the drive and the floppies as well, is perhaps not ideal in that respect either. (Of course, that aspect can be addressed by replacing the floppy drive with a floppy emulator, but still.)

Does anyone here have any other thoughts or ideas about what might be the cause of this behaviour (that the RAM fails to keep its contents when the power is turned off)?

Best wishes,

Re: [Ensoniq-VFX-SD] SD-1/32 still losing its memory

2012-11-28 by Christian Brunschen

On 28 Nov 2012, at 00:11, Adriano Camocardi wrote:

Hi Chistian, I don't have the hystory of your procedure on your SD-1, so let´s start of the first dot. The battery that you used have the same voltage and current that the original battery of the SD-1? If it don't have the same value probably it is the problem. So the battery need to suply the voltage and current RAM memory during the power-off.
I hope this can help you.

It's the exact same type of battery as it should be - a Lithium cell, 4V, 2/3AA size. Even the same manufacturer (Panasonic). Also, the problem started while the original battery was still soldered in place - and the analog tests actually gave a pretty good voltage reading. So it's unlikely to be the battery.

Since it also isn't the capacitor .... my thinking is going in the direction of the power supply.

Best Regards.

Best wishes,

// Christian

2012/11/27 Christian Brunschen <cb@...>
Hi all,

you might recall that I was having an issue where my SD-1/32 suddenly started losing the contents of its usually-battery-backed RAM when powered off. I replaced the battery (putting in a battery holder to make future battery swaps easier too, but that didn't help. So I figured the culprit might be the capacitor that is supposed to smooth the transition of power from power supply to battery and vice versa – and today I replaced that capacitor. Alas, that did not have the curative effect I was hoping for - when powered off, the RAM contents still disappear. Yes, I put the battery back in the battery holder. Without the battery, the keyboard complains loudly that the battery level is too low; but with the battery in place, no such complaint – everything looks like it should be working ... but it isn't.

I'm a bit stumped. Of course this doesn't make the SD-1/32 impossible to use, but it does mean that everything has to be saved to and then reloaded from floppy disk whenever I want to do anything ... which is rather annoying, and considering the age of the drive and the floppies as well, is perhaps not ideal in that respect either. (Of course, that aspect can be addressed by replacing the floppy drive with a floppy emulator, but still.)

Does anyone here have any other thoughts or ideas about what might be the cause of this behaviour (that the RAM fails to keep its contents when the power is turned off)?

Best wishes,

Re: [Ensoniq-VFX-SD] SD-1/32 still losing its memory

2012-11-28 by Bob S.

I don't have the schematic but from past experience, some of the battery backed circuits used a diode to isolate the battery from the power supply. When the power supply is turned off, the diode becomes forward biased and the battery can now supply voltage to the chip. If the diode is open or not making connection, the battery voltage will not get tot he memory and all power is lost to the chip on power off. See if there is a diode....

Bob

El Segundo, CA

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----- Original Message -----

From: Christian Brunschen

To: Ensoniq-VFX-SD@yahoogroups.com

Sent: Tuesday, November 27, 2012 16:15

Subject: Re: [Ensoniq-VFX-SD] SD-1/32 still losing its memory

On 28 Nov 2012, at 00:11, Adriano Camocardi wrote:

Hi Chistian, I don't have the hystory of your procedure on your SD-1, so let´s start of the first dot. The battery that you used have the same voltage and current that the original battery of the SD-1? If it don't have the same value probably it is the problem. So the battery need to suply the voltage and current RAM memory during the power-off.

I hope this can help you.

It's the exact same type of battery as it should be - a Lithium cell, 4V, 2/3AA size. Even the same manufacturer (Panasonic). Also, the problem started while the original battery was still soldered in place - and the analog tests actually gave a pretty good voltage reading. So it's unlikely to be the battery.

Since it also isn't the capacitor .... my thinking is going in the direction of the power supply.

Best Regards.

Best wishes,

// Christian

2012/11/27 Christian Brunschen ;<cb@...>

Hi all,

you might recall that I was having an issue where my SD-1/32 suddenly started losing the contents of its usually-battery-backed RAM when powered off. I replaced the battery (putting in a battery holder to make future battery swaps easier too, but that didn't help. So I figured the culprit might be the capacitor that is supposed to smooth the transition of power from power supply to battery and vice versa – and today I replaced that capacitor. Alas, that did not have the curative effect I was hoping for - when powered off, the RAM contents still disappear. Yes, I put the battery back in the battery holder. Without the battery, the keyboard complains loudly that the battery level is too low; but with the battery in place, no such complaint – everything looks like it should be working ... but it isn't.

I'm a bit stumped. Of course this doesn't make the SD-1/32 impossible to use, but it does mean that everything has to be saved to and then reloaded from floppy disk whenever I want to do anything ... which is rather annoying, and considering the age of the drive and the floppies as well, is perhaps not ideal in that respect either. (Of course, that aspect can be addressed by replacing the floppy drive with a floppy emulator, but still.)

Does anyone here have any other thoughts or ideas about what might be the cause of this behaviour (that the RAM fails to keep its contents when the power is turned off)?

Best wishes,

Patches and discussion for Ensoniq VFX family

SD-1/32 still losing its memory

SD-1/32 still losing its memory

Re: [Ensoniq-VFX-SD] SD-1/32 still losing its memory

Re: [Ensoniq-VFX-SD] SD-1/32 still losing its memory

Re: [Ensoniq-VFX-SD] SD-1/32 still losing its memory

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