Reviving the Yamaha DX7s, part 2

[Note: this is Part 2 of our saga.  You may want to start with Part 1]

So I finally had time tonight to look at the DX7s.  I was planning on spending a bunch of time tonight working with my new Presonus Firepod, but that didn’t work out as I had hoped.  Presonus sent me the unit, but no power adapter (even though there was even a tag on the box from the factory that said “include power adapter before shipping”)!  I’ve emailed Presonus customer support about it, and based on my dealings with them so far, I expect we’ll be able to work something out.   It just means I have to wait even longer to use it.

Anyway, I used the “free time” tonight to spend time with my daughter and to fix the “Change Battery” message on the DX7s.  I was mostly successful (at fixing the keyboard – spending time with Lily is always fun).  I took the keyboard apart again and reflowed the solder on the battery and double-checked everything again, and turned it on…

…and still got Change Battery!.  Crap.  But I had a hunch.  What if the battery is really fine, and it’s sort of like on some cars how the Change Oil light isn’t always reset when you get your oil changed?  So I made a voice (and said to myself “oh yeah.. I almost forgot.. this thing sounds awesome!”), named it something obviously not from Yamaha’s factory (’17h Pad 01′)  and then turned off the keyboard.  I turned it back on right away (and got the Change Battery notice again), but when I pressed Voice -> 1, my voice came up!  So it IS remembering patches again (when the battery is really dead, the memory gets “corrupted” by junk, so if you try to recall your saved voices, it might now say ‘v4$.87&_21ZxZ’ or something as equally meaningful instead of whatever you had saved it as).

I thought maybe I could just dump the factory voices back on over MIDI.  So I hooked it up to my music PC and turned on the computer, and while it was trying to boot, I heard a *click* *CHUNK* *CHUNK* *CHUNK*.  Crap.  Now I need a new hard drive, but this really has nothing to do with my DX7s.. So.. what else can I try?

More digging turns up the “Test Mode” procedure for the DX7s:   Hold down voice buttons 16 and 32 simultaneously while you power on the keyboard.   It will then boot up to a “test mode” that tests each individual part of the keyboard and then re-initializes it at the end.  All of the factory voices are still gone (they’re not stored in ROM on the synth, only RAM), but it gets rid of any outstanding error messages (Like “Change Battery!”).  As a side note, the test procedure on mine showed the battery at 5.0V, which is perfect.   So I started stepping through the different parts (by repeatedly pressing the YES/+1 key), and it tested the oscillators, the display, the tone generator, and then got to the Pitch Bend test (PB 50 on the display).  Remember from Part 1 of this saga that I had taken off the pitch wheel and reattached it?  Apparently I didn’t align something right when I put it back on.  The PB 50 on the display indicates that the pitch wheel is centered between 0 and 100 (makes sense, right?  Pitch wheels are spring loaded to return to center).  So if I move it down the numbers should go below 50, and if I move it up, above 50.  The problem is that when I move mine, it seems to be stuck between 99 and 91.  Like I said, something doesn’t seem to be aligned correctly.  And the diagnostic routine won’t get past this part as the PB doesn’t test OK.  So now I get to take the bottom off the synth again and take a look at the pitch wheel.

Tomorrow.  Now, I go get some sleep.

[The Saga Concludes in Part 3]

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