Patches and discussion for Ensoniq VFX family

I have a strange problem with my SD-1/32.

I bought it used on eBay a couple of years ago; when I received it, it still had sequences and such in memory, showing that the battery was fine. Indeed, the analog tests (Preset + Compare) showed the same thing.

Then, a few months ago, when I started it and tried to look at the sequences in memory it told me 'The Sequencer must be Loaded' – in other words, it had completely forgotten the contents of its battery-backed memory. However, it was not complaining about a low voltage level from the battery.

So I figured it might be that the battery was coming loose when the keyboard was cooling off, or something similar. Anyway, I just today replaced the battery with a battery holder and a fresh battery; and the same thing still happens: battery level us shown as '142' on the analog checks page, there's no low-battery-voltage warning, everything seems to work while the keyboard is mains-powered ... but once it's powered off, the sequencer OS and the internal-RAM sounds are forgotten.

I've also checked - while the keyboard was off - the battery voltage (3.04V), the voltage drop across the diode to the right of the battery (0.04V) and the voltage at the power supply pin of the SRAM chips just below the battery (2.99 - 3.00V) – all of which appears to indicate that power is being supplied, and correctly, and as expected.

Had this been a VFX-SD or SD-1 where I had replaced the SRAM chips, those would have been my next suspicion - but on the SD-1/32, these are soldered in place, so there's no potential issue with sockets or similar.

So I am a bit .... lost. This isn't a crippling problem - after all, I can save-and-reload everything - but that's not really ideal and uses the floppy drive a lot. Any suggestions, thoughts, advice would be greatly appreciated.

Best wishes,

// Christian Brunschen