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Installing a New Battery in a Yamaha DX7
Posted on September 26th, 2009 6 commentsI recently had the chance to replace the battery in a Yamaha DX7 Synthesizer. The manual for the DX7 states that the battery should last for 3 to 5 years and it was well past that time. I first thought that I could just run down to Walgreens and pick up a “button” style battery and pop it in but after poking around on the Web, I found out that the DX7 uses a special kind of CR2032 battery with solder leads mounted on it. I found a suitable battery through Mouser (part number 614-CR2032FH-MFR). To replace the battery you basically have to take the whole synth apart, but Yamaha tries to make the procedure as painless as possible.
I found some very helpful instructions through Dave Benson’s DX7 Page (also archived here) for replacing the battery. These instructions were spot-on!
There were a couple of things I noticed while disassembling the synth.
1. The connector labeled C6 on the main board is not connected to anything.
2. The main board was a little difficult to remove from the chassis after all screws and connectors were out. There are two tabs that are used to mount keyboard. You have to angle the main board between these tabs and the back of the chassis to lift the board out. Be careful when doing this!
3. To remove the old battery, I used a solder sucker to get rid of most of the old solder which makes it easier for the old battery to pry up and out.
4. The battery evidently had been replaced before. There was a service sticker from some repair shop on the back of the unit. The trace between the battery’s positive lead and the next component (which is a diode) had been severed. I had to solder in a short jumper over the trace to fix it.Overall, replacing the battery was not a difficult task but somewhat time consuming. Have fun!
You can click on the images below to get a larger image:
Yamaha DX7 open with keyboard in place
Yamaha DX7 close-up of connector C6
Yamaha DX7 open with keyboard removed
Yamaha DX7 main board
Yamaha DX7 solder side of main board near battery
6 responses to “ Installing a New Battery in a Yamaha DX7 ”
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Kevin May 15th, 2010 at 18:57
Thank you so much for this info!
I have been trying to replace the battery in my second-hand DX7 mk1 for the past 3 days. I have read just about every page on the internet in English and Japanese, including this one, time and time again. No matter how many times I tried to redo the battery I was getting a strange battery reading of 4.5V in the Function>Battery Test screen for what is in fact a 3V battery. The internal memory would be OK for about 30 minutes and then slowly start to corrupt until everything was lost.
I was ready to give up and assume it was a deeper motherboard issue until I read this again and decided I would take a look at the underside of my DX7’s motherboard and compare it to yours. What I found was that 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: —||—
The two separated vertical/parallel solder spots looked clean and square with no evidence of tampering, so I had been assuming that it came that way from the factory, but when I really looked close I noticed, “Hey, this positive terminal isn’t connecting to ANYTHING right now on either side of the board!” It was being separated by that otherwise professional-looking gap. Figuring I had nothing left to lose, I put a small bit of solder over the top to bridge the two, and VOILA - when I turned on the DX7 the battery reading was at a sensible 3.0v and my memory stays in tact now!
I have no idea how my motherboard ended up that way. I don’t know what that portion of the board looked like out of the factory because I don’t have another DX7 to compare it to, but I can only assume that the battery was changed before in an attempt to repair the unit and someone made a mistake.
I cannot thank you enough for taking the time to write this information up. I had given up on this keyboard and thought that it would become a mere conversation piece in my living room. Information on these keyboards is so scarce, so I really appreciate your willingness to share this. You have made my week. Cheers!!
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I remember that that area around the battery definitely showed signs that people in the past had been poking around there. I’m curious if a cutter or a pair of pliers got out of control and cut the trace (cleanly!) ..
Thanks a lot for sharing your experience!!
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Frank Vella July 21st, 2010 at 08:18
Thank You for sharing the pictures are a great
help. I feel I can attemt this project now. I’m still am not sure about one thing. The internal sounds when the battery is off the board. This is a used unit I just bought,and I
do not have a back up card of origional sounds,and not sure how to back this up.
Will you please comment on this.
Thank you for your time.
Frank -
Hey Bob,
My DX7 doesn’t start up anymore and I’m considering to change the internal battery. I’m not sure if you will answer this but I’ll give it a try anyway. I live in the UK and Mouser doesn’t ship that recommended battery there. Do you by any chance know if this battery would work?
http://www.batterymarket.co.uk/2-x-panasonic-cr2032-lithium-batteries-p-679.html
Regards,
Aron
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@Frank Vella
You may want to look at dumping the sounds via MIDI. I actually was able to do a SYSEX dump of the original sounds by using MIDIOX http://www.midiox.com/ running on my PC. Take a look at Dave Benson’s DX7 Page at the link in the main post.
-bob
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@Aron
I don’t think that one will work “out of the box”… The CR2032 battery that the DX7 needs has solder leads mounted to it. Take a look at Mouser’s catalog page
http://www.mouser.com/catalog/catalogUSD/641/2074.pdf
(It’s figure “G”) You just might be able to (carefully) solder your own leads to a regular CR2032 battery with a little work!-bob
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