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Dave H.
 
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Default Alesis AI3 schematic, anyone?

Hi folks,
I recently picked up a damaged AI3 ("Mk2", 24-bit version) for a very
low price, now need to repair where it was dropped on the dustcap in the
ADAT input, with physical damage to the PC board - does anyone have a
schematic for this beastie (even just the bit relating to the ADAT IO
driver/buffer chip U1, optical TX and RX would be a real help), or is anyone
willing to pop the hood and take a look (with a loupe, they're SMDs!) at
what the chip (U1) should be and the values (or printed codes) of the tiny
SM caps close by?

Thanks for looking,
Dave H.
(The engineer formerly known as Homeless)


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Mike Rivers
 
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Default Alesis AI3 schematic, anyone?


Dave H. wrote:

I recently picked up a damaged AI3 ("Mk2", 24-bit version) for a very
low price, now need to repair where it was dropped on the dustcap in the
ADAT input, with physical damage to the PC board - does anyone have a
schematic for this beastie (even just the bit relating to the ADAT IO
driver/buffer chip U1, optical TX and RX would be a real help)


If you have enough damage to the board to require replacement of some
parts, you probably have internal damage to the board and just
replacing the chips won't fix it.

Have you ever replaced a surface-mount IC? It takes some special tools
and techniques. If you're really up to making a repair, I'm sure a
phone call to Alesis (and a lot of patience) will get you what you need
to know. An alternate approach is to call Wavefront Semiconductor, tell
them that you have an AI3 with a crunched ADAT optical driver and
receiver and ask what a suitable replacement would be. You might even
be able to con them out of a free sample since you probably can't buy
those things one at a time.

Real people don't have schematics of this sort of gear. And most of the
time, you can't identify a surface mounted component part visually.
Good luck. You may have to consider yourself lucky that you didn't pay
much for it.

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Dave H.
 
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Default Alesis AI3 schematic, anyone?


"Mike Rivers" wrote...



If you have enough damage to the board to require replacement of some
parts, you probably have internal damage to the board and just
replacing the chips won't fix it.

Have you ever replaced a surface-mount IC? It takes some special tools
and techniques. If you're really up to making a repair, I'm sure a
phone call to Alesis (and a lot of patience) will get you what you need
to know. An alternate approach is to call Wavefront Semiconductor, tell
them that you have an AI3 with a crunched ADAT optical driver and
receiver and ask what a suitable replacement would be. You might even
be able to con them out of a free sample since you probably can't buy
those things one at a time.

Real people don't have schematics of this sort of gear. And most of the
time, you can't identify a surface mounted component part visually.
Good luck. You may have to consider yourself lucky that you didn't pay
much for it.


Well, yes, I've repaired SMT boards before, fault-finding to component
level, have the lab at work to borrow out of hours, and the parts are almost
certainly available - the optical RX is a standard SPDIF/ADAT TOSLink
component used in lot of digital audio gear and available for £6UK (about
$10US), the bufer chip will be a standard part (nobody would be dumb enough
to have one manufactured soleley for 'em!) and apart from a couple of torn
but (I think, after a close inspection) repairable IC pads, the board's in
good shape! The guy I bought it from had a quote of $200 for the repair
(with labour at $75/hour) but doesn't need it any more, having upgraded to a
much more expensive interface, so using my own time it'll probably cost less
than $50 in parts, making the total under $100 and a few hours of my time -
reasonable, really!

Some folks do have schematics for their gear - I have them for most of the
old MXR gear I have, some of the Yamaha kit, quite a lot of the Roland
kit... but then, I'm a geek and an engineer of the Dwarvish persuasion. Too
many people are frightened of opening up equipment, largely due to ignorance
of safety (both their and the equipement's), but it's generaly not rocket
science )

Dave H.
(The engineer formerly known as Homeless)


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Dave H.
 
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Default Alesis AI3 schematic, anyone?


"Preben Friis" wrote...

Maybe this will be of some help:
http://www.wavefrontsemi.com/index.php?id=11,10,0,0,1,0

Wavefront Semiconductors was previously Alesis Semiconductor.


Thanks, it points me to the driver chips, although I suspect these are
further back into the circuit than the one that's been peeled off the board!
The pin-count on these are higher (20-pin rather than the 16-pin that it
looks like is missing), so I suspect it'll be a buffer chip that's missing.
IT'd really help if someone could take a maginfying glass and read the part
code off U1, just behind the ADAT IO!

Best regards,
Dave H.
(The engineer formerly known as Homeless)


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Mike Rivers
 
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Default Alesis AI3 schematic, anyone?


Dave H. wrote:

Well, yes, I've repaired SMT boards before, fault-finding to component
level, have the lab at work to borrow out of hours


Well, excuse me, but sometimes, particulary when we don't know you
around here (I'm reading your message in rec.audio.pro) you need to say
that. People who barely know which end of a soldering iron ask about
schematics and think that fixing a complex piece of modern gear is like
replacing a charred resistor in a guitar amp.

The guy I bought it from had a quote of $200 for the repair
(with labour at $75/hour)


using my own time it'll probably cost less
than $50 in parts, making the total under $100 and a few hours of my time -
reasonable, really!


If you say so. I'd probalby go ahead and spend the $200, let someone
else chase down the parts and take the risk of damaging it. Your
choice, clearly, and I won't argue with someone who has plenty of time.


Some folks do have schematics for their gear - I have them for most of the
old MXR gear I have, some of the Yamaha kit, quite a lot of the Roland
kit...


Times have changed. With a lot of this stuff, you need to sign a
development partner agreement or be signed up as an authorized service
station in order to see a schematic. Competitors, you know . . And
companies like Alesis just don't sell much to people who are inclined
to, and equipped to do their own repairs.

Too
many people are frightened of opening up equipment, largely due to ignorance
of safety (both their and the equipement's)


And well they should.

but it's generaly not rocket science )


To a rocket scientist, no.

Good luck on your quest.

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