I bought my Yamanha DX7 with this problem.
INTERNAL MEMORY presets had scrambled named and wouldn't play any sound.
Reading the different threads on the web, I figured this was due to the battery although the
BATTERY CHECK showed 4.3V.
Before I attempted to change the battery, I first reloaded the INTERNAL MEMORY with sounds.
Hereafter the steps found on http://bobbyblues.recup.ch
Set your DX7
MIDI CH=1i.e. Use the data entry slider or button
8again then set
SYS INFO AVAILwith button
INTERNAL MEMORY PROTECTthen set to
Soundbank transfer to your DX7
Used a Macbook Pro + SysEx Librarian with a Cahaya Midi USB Interface 5 Pin Din Plug Cable for PC/Mac
- Run your SysEx transfers program on your computer and load or open (depending on the program you are using) the SysEx file you want to transfer
- Choose "SysEx send" (or the appropriate option) on your SysEx transfers program
- You must then see
MIDI RECEIVEDon your DX7/TX7 display (transfer is OK)
This operation restored my internal memory, but the next day the presets were gone again and the label were scrambled.
The battery still showing 4.3V
So I decided to attempt the battery change.
I ordered a 3V - CR2032 solder pin for Yamaha DX7 found on eBay.
I followed the instruction found on the NEGATRON BLOG
On my first attempt, I soldered the battery to 2 wires instead of directly soldering to the board, in order to allow the operation to be easier the next time if needed.
I closed DX7 but I didn't do the
BATTERY CHECK, so I don't know if showed correct.
I loaded the new presets (using MIDI/USB interface) and all looked fined. I turned ON/OFF the DX7 + un/plugged it and checked the
INTERNAL MEMORY and the presets were there.
I thought I had resolved it but an hour later the presets were scrambled again. i.e. No sound.
The battery change didn't help.
BATTERY CHECK showed 4.3V ??? instead of 3V.
I read further and the first comment of the blog page, Kevin described my issue.
BATTERY CHECK showing 4.5V instead of 3V.
That's when I decided to give my soldering another go. Interestingly Kevin says:
the trace coming off of the positive terminal of the battery that was supposed to connect to the next component had a gap in it in this kind of shape: —||—
I had also noticed that and I had bridged the battery pin to the diode...
On my second attempt, I removed the mainboard again and this time, I added more solder to look like on the picture on the blog
Closed the DX7, powered it and
BATTERY CHECK showed 3V!!! YEAH!
...BUT the next day, I switched on my DX7 to my disappointment, the internal memory is corrupt again and to my surprise
BATTERY CHECK showed 4.3V ???
Why would the
BATTERY CHECK show 3V after replacement and 4.3V the next day?
Any pointers of what may be happening?
A minute ago the
BATTERY CHECK was showing 3V again.
I touched my wires and it fluctuated!
Looks like it might be my soldering or bad wires.
I removed the battery completely
BATTERY CHECK showed 4.3V!
Wired it again and it's now showing 3V. Let's see if that keeps the memory overnight.