Vintage Synth Explorer Forums

I have finally changed the battery in my DX7. I am experiencing a strange problem, however. The battery check display shows a healthy 4.4V and I can load my sounds back in via sysex without any problems. However, if I switch the DX7 off for about one minute or more, the sounds and their names disappear completely, the master tuning goes flat, the MIDI In channel and bank number change to 0 (I have a hardware upgrade). If I only switch it off for say, 10 seconds, it works fine.

Any ideas what causes this? I haven't yet checked the hardware upgrade connections.

Gilles

Your battery isn't working properly. The battery should read around 3.0-3.3V when new. 4.4V means it's not reading the battery's voltage. Did you solder-in a new battery or did you install a holder? Did you install the battery in the correct direction? Check with a voltmeter.

a guess:
do you have the Angel City upgrade? if so IIRC it has it's OWN battery....which may be dead.

My upgrade is the Sycologic MEX V.2 or something like that. You can see a photo of it in the synth guts thread. It doesn't appear to have its own battery. I did install a battery holder but I should perhaps have followed the advice given to me by another forum member and soldered the battery on directly.

looking at the schematic, i think there might be a problem with the connection from the battery to the board. the voltage from the battery is not getting to the RAM, and the battery display is reading the voltage from the power supply to the RAM - not the actual cell voltage.

(edited to correct stupidity)

I see... I must admit my soldering skills were never very good. I will look into this.