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kpatz

A6 Andromeda Repair, Battery Replacement, with pics

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For those with out-of-warranty Andromedas, here's how to get inside your beast to do repairs, and how to replace the backup battery, if it should become necessary down the road.

 

Usual disclaimers apply. Don't attempt this if you aren't experienced with soldering. Unplug the power cord before you start, and take care not to zap anything with static electricity. Ground yourself if you can. Keep toddlers, cats, dogs, gerbils, etc. away. And so forth.

 

Remove the marked screws from the back of the A6.

a6_repair1.jpg

 

Remove the marked screws from the back of the A6.

a6_repair2.jpg

 

Unscrew the nuts from the foot pedal jacks, to allow the main board to be removed.

a6_repair3.jpg

 

Remove the marked screws from the bottom of the A6. There are some screws that I didn't mark, these hold the keybed in and don't need to be removed (unless you need to remove the keybed).

a6_repair4.jpg

 

Remove the marked screws from the bottom of the A6.

a6_repair5.jpg

 

Lift the top cover off, and set it behind as shown.

a6_repair6.jpg

 

Here's the main board, which contains the digital stuff (CPU, memory, ADC/DAC, DSP for effects, etc.)

a6_repair7.jpg

 

Here's the analog ASIC board, containing the VCOs, VCAs, and VCFs.

a6_repair8.jpg

 

Disconnect all the cables from the main board (ribbon cables, aftertouch connector, and power connector).

a6_repair9.jpg

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Remove 8 silver screws holding the main board in, and carefully lift out the main board.

a6_repair10.jpg

 

Here's the battery. It will need to be unsoldered from the board. Use desoldering braid or a solder sucker.

a6_repair11.jpg

 

The battery holder I got only has 1 positive pin, instead of 2 like the original, so I installed a jumper.

a6_repair12.jpg

 

Here's the battery holder, installed. Turns out on my A6, the problem wasn't the battery itself, but a diode was installed incorrectly. I discovered and repaired that later on.

a6_repair13.jpg

 

Reinstall the board into the synth, put the screws back in, and then plug in the connectors.

a6_repair14.jpg

 

Here's another shot of the diode that was installed backwards on my A6. This prevented the battery power from reaching the SRAM chip, causing my A6 to lose its settings when powered down.

a6_repair16.jpg

 

I unsoldered the diode, and reinstalled it in the correct direction.

a6_repair17.jpg

 

Once you're finished inside, put the synth back together in the reverse order as taking it apart. Carefully lower the top cover onto the bottom cover, and replace all the screws. Replace the nuts on the footswitch jacks. Plug 'er in, do a hard reset (if necessary, if the memory is lost), and give 'er a test!

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Nice work !

 

You're a brave man. I've done that to numerous sub 300 dollar synths, but I dunno about a 2700 dollar one......

 

I wonder if it was the factory, or if someone had been there before you ?

 

Anyway, again, good work.

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I seriously didn't know there was a battery in the A6. I quite like the RAM card.

 

Unless they are using FLASH RAM (CF or eq), any piece of gear that stores patches - synth, FX, guitar modeler - uses a battery to retain RAM memory with the power off. Even the A6 RAM card has a battery.

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Can't know unless you've seen it, or have schematics.

 

I've noticed, though, that some FLASH using gear will pop up a brief message that says, "writing, please do not power-off unit" when I do something that needs to write to FLASH. My Motif Rack does this, for example.

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I kind of expected the insides of the A6 to look a bit more 'cluttered' considering what this monster machine is capable of. I saw the pic of all the boards and was like, "that's the Andromeda, huh?" But it does make sense that it looks that way since it's a modern design using ASICs and such.

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I kind of expected the insides of the A6 to look a bit more 'cluttered' considering what this monster machine is capable of. I saw the pic of all the boards and was like, "that's the Andromeda, huh?" But it does make sense that it looks that way since it's a modern design using ASICs and such.

 

Yeah, I agree. Seeing how clean it looked inside for some reason made me feel a bit better about letting it go. That's not a shot at the A6 by any means, but for example I let go of a Jupiter 4 or a RE-301 and after I saw the insides I was just :facepalm:

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a6_repair6.jpg

 

 

This is a classical Oberheim PCB layout. Personally my favorite ever. So simple to maintain and service, totally opposite to some Japanese synths i serviced. When you open a Jupiter 8, first thing to do is to take a 2 hour break to clean up your mind, then you can proceed.

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Batteries seem to have a four year life in Andromedas.


Back up those patches!

Actually, the battery should last much longer than that. The factory battery is slightly larger than a CR2032, and static RAM takes very little power to maintain. The Samsung SRAM chip in the A6 can retain data down to 2 volts or so, so the battery can be drained down to 2.2 volts and you'll still be ok (fresh lithiums are around 3.2-3.3 volts).

 

Synth batteries should last longer than PC motherboard batteries, since PC motherboards have a real-time clock on them the battery maintains. As is evidenced by Juno and DX synths that have 20+ year old batteries that are still good.

 

I just replaced my battery because I thought it was the cause of my memory problems. Turns out it was the diode. In fact, with the diode installed backwards, the battery was getting "charged" when the synth was on. Precisely what the diode is there to prevent. It's a good thing the battery didn't leak or something.

 

What's interesting about the RAM card I got with mine, is there's no "battery compartment" in it. When its battery goes dead, I guess you just have to toss the card. I wonder if the card's battery gets charged when it's plugged in with the synth on.

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Dammit, when I see stuff like this, I wish I had better electronics skills. :cry:

 

At work, Websense is flagging your site as "malicious" (hence no pretty electronics pictures for me). Thanks to PhPoxy, I can see that it's because you hacked your own site. :)

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I just replaced my battery because I thought it was the cause of my memory problems. Turns out it was the diode. In fact, with the diode installed backwards, the battery was getting "charged" when the synth was on. Precisely what the diode is there to prevent. It's a good thing the battery didn't leak or something.

 

 

Pretty amazing that you even spotted that as un-assuming as it is... Nice work :)

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Thanks for reminding me that I haven't updated my site in eons...

 

Can you see pretty electronics pictures through PhPoxy? I fixed the "hack" months ago, how often do you guys update your web(non)sense?

 

As for the diode, it took some tracing with a voltmeter to figure out what was going on (if i had schematics, it would have been a piece of cake). I saw 3+ volts at the battery, and

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As for the diode, it took some tracing with a voltmeter to figure out what was going on (if i had schematics, it would have been a piece of cake).

 

 

Heh, well, more than I would have been able to figure out! :p

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Wow, congrats kpatz!

This also makes me wish I had better electronic skills. I could have never found this. In fact, I have a D550 that needs fixin' and I won't have it fixed because it will probably cost more than the thing is worth. So unless I acquire some skills, it has died its painful death and is no more :cry:

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Thanks for reminding me that I haven't updated my site in eons...

Can you see pretty electronics pictures through PhPoxy? I fixed the "hack" months ago, how often do you guys update your web(non)sense?

 

Yeah, loading this thread through the PhPoxy program shows the pictures.

 

To change the Websense category back to "personal", you have to mail them. (As described at the end of this article.)

 

I hate web filtering software.

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I do not own an A6, but I always appreciate this kind of post. Nice pictures.

Also, nice job spotting the backwards revolving anticlockwise rotation of the 3 3 3 diode!

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I don't know what's worse, companies that make web filtering software or those who use said web filtering software.

 

I'm glad the place I work for isn't like that. Nothing like saying "we don't trust our own employees to use their best judgment, we should hire a 3rd party vendor to pass on that judgment for them"...

 

I want filters in my synths, not on the web...

 

Plus, it was April when I fixed the "hack" problem, so surely they should have updated their filter since then???

 

P.S. I emailed Websense, hopefully they'll respond.

 

What's your issue with the D-550 CR?

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Congratulations, I always admire people who can sort out their synths.

 

Dammit, when I see stuff like this, I wish I had better electronics skills.

 

Same here, but there is a simple (although tedious) solution to this - the local library :-) Sooner or later I'll go this route, I don't want to sell my synths when they stop working any more.

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What's your issue with the D-550 CR?

 

The issue is *probably* the OP amps. What happens is, on one channel, I get more noise than sound. The sound is there most of the time, but I get a constant crackling noise like what you get when you mess with an audio cable that has the solder fallen off

So I tried to use it as a mono synth, turning off the effects, but when I recorded it to tape, everything sounded like crap compared to what I did with the Fusion. I mean, really muddy, not much high end. Meaning, the channel that does work, also has something going on that makes it sound bad, so it could be needing a rewiring or it could also be the op-amps.

I was told that to change the OP amps alone would cost more than the D-550 is worth, and that still might not be the problem.

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