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Thread: Schematics

  1. #1

    Default Schematics

    Hi all,

    Does anybody here have access to (and could you provide me with) schematics for an Alesis ProLinear 820 DSP monitor? These powered speakers are no longer in production and I had one fail. I've searched on-line to no avail.

    I did contact Alesis who replied that I need to take it to an authorized service center (the nearest of which is nearly 200 miles away). I have local service technicians who can fix anything if they have a schematic (and access to any proprietary parts that may be inside, of course).

    These boxes apparently either didn't sell well or are not failing often (I'm guessing the former) and people are hanging on the them, as I can't find any used on eBay.

    Thanks!
    Richard
    Green Valley Recording
    My cats have nine lives; my life has nine cats.

  2. #2
    Join Date
    Jul 2006
    Location
    SF Bay Area
    Posts
    1,016

    Default Re: Schematics

    Quote Originally Posted by Richard Rupert View Post
    Hi all,

    Does anybody here have access to (and could you provide me with) schematics for an Alesis ProLinear 820 DSP monitor? These powered speakers are no longer in production and I had one fail. I've searched on-line to no avail.

    I did contact Alesis who replied that I need to take it to an authorized service center (the nearest of which is nearly 200 miles away). I have local service technicians who can fix anything if they have a schematic (and access to any proprietary parts that may be inside, of course).

    These boxes apparently either didn't sell well or are not failing often (I'm guessing the former) and people are hanging on the them, as I can't find any used on eBay.

    Thanks!
    Here is an entire replacement PCB board
    http://www.instrumentalparts.com/9-79-0326.html
    ---------------------------------------
    Philip G.

  3. #3

    Default Re: Schematics

    Quote Originally Posted by cgrafx View Post
    Here is an entire replacement PCB board
    http://www.instrumentalparts.com/9-79-0326.html
    Thank you for that Philip. However, it would be nice to know if the problem is actually on that board rather than buying it at $139 and potentially finding out it's not where the problem lies. I saw that they have the power assembly also, for $145, but it's out of stock. The problem could be in either of these boards... or neither... the unit has a DSP control circuit that may be the culprit too. I really need a schematic.

    Thanks very much for the link though... if one of the local technicians can determine that the issue is in the board they have in stock, I'll have a place to get it. I have a friend who's an electrical engineer and may be able to suss out something...
    Richard
    Green Valley Recording
    My cats have nine lives; my life has nine cats.

  4. #4
    Join Date
    Jul 2006
    Location
    SF Bay Area
    Posts
    1,016

    Default Re: Schematics

    Quote Originally Posted by Richard Rupert View Post
    Thank you for that Philip. However, it would be nice to know if the problem is actually on that board rather than buying it at $139 and potentially finding out it's not where the problem lies. I saw that they have the power assembly also, for $145, but it's out of stock. The problem could be in either of these boards... or neither... the unit has a DSP control circuit that may be the culprit too. I really need a schematic.

    Thanks very much for the link though... if one of the local technicians can determine that the issue is in the board they have in stock, I'll have a place to get it. I have a friend who's an electrical engineer and may be able to suss out something...
    I've ordered schematics from Alesis in the past. Generally you just need to have some way to indicate your qualified to do the service work.

    On the other hand, I assume the monitor is out of warranty so I'm not sure what difference it would make to them.
    ---------------------------------------
    Philip G.

  5. #5

    Default Re: Schematics

    Quote Originally Posted by cgrafx View Post
    I've ordered schematics from Alesis in the past. Generally you just need to have some way to indicate your qualified to do the service work.
    I requested the schematics through their web support address. In my message I indicated that I have a qualified service technician at my disposal who could fix the box with proper schematics. I've gotten the same message from two respondents, and the message is: "Alesis does not publish product schematics. For any service inquiries outside of warranty, you can contact an authorized Alesis service center. Here's the US/Canada list:" (the list includes 3 places in the U.S. -none in my state- and 3 in Canada).

    On the other hand, I assume the monitor is out of warranty so I'm not sure what difference it would make to them.
    My thoughts exactly; the monitors are well out of warranty. Not only that, but they're no longer made and I don't understand why they're keeping the repair information so close to the chest.
    Richard
    Green Valley Recording
    My cats have nine lives; my life has nine cats.

  6. #6

    Default Re: Schematics

    Looking at the PCB, it appears to be just the amplifier. (I could be mistaken...) I wonder if there's a separate power supply, which would be the more likely culprit if the entire thing is dead.

    Have you opened it up and looked inside at all? Do you get any indication that it's getting power (i.e. an LED indicator)? Some power supply PCB's have a small buss fuse mounted right to the board. Could it be as simple as a blown fuse?

    Fortunately, it didn't look like there were any SMT components, so it should be easy to fix if your engineer buddy can find the problem.

  7. #7

    Default Re: Schematics

    Quote Originally Posted by CurtZHP View Post
    Looking at the PCB, it appears to be just the amplifier. (I could be mistaken...) I wonder if there's a separate power supply, which would be the more likely culprit if the entire thing is dead.

    Have you opened it up and looked inside at all? Do you get any indication that it's getting power (i.e. an LED indicator)? Some power supply PCB's have a small buss fuse mounted right to the board. Could it be as simple as a blown fuse?

    Fortunately, it didn't look like there were any SMT components, so it should be easy to fix if your engineer buddy can find the problem.
    Yes... I've opened the box a couple times. There are two boards inside. One board looks like it may be a power supply/DSP component board and the other looks like it's the power amplifier. I could see no obvious problems, e.g. burned or bulged caps or smoked resistors (there was no smoke on failure), and found no fuses. There is no odd smell either. And it's definitely getting power, as there is a DSP LCD at the top of the box that indicates which emulation the box is pursuing.

    Here are links to the two boards:
    http://www.instrumentalparts.com/9-79-0326.html
    http://www.instrumentalparts.com/9-79-0294.html

    Here's a link to a picture of the box... you can see the LCD at the top:
    http://www.alesis.com/prolinear820dsp
    Richard
    Green Valley Recording
    My cats have nine lives; my life has nine cats.

  8. #8

    Default Re: Schematics

    So it's getting juice and the DSP is working, but no sound, right?

    Another easy thing to check...
    There's going to be a few wires going from the PS/DSP board to the amplifier. I'm assuming a ground, a positive voltage rail, and a negative voltage rail. You could check with a meter to see if the amp is getting power itself. Perhaps one rail took a dump.

    Anything with a DSP usually has a separate 5VDC supply for that, which would explain why that part still works.

    I suggest this because of a piece of gear at the TV station where I work. It did the same thing. Front panel display and firmware worked, but it wouldn't pass a signal. No visible signs of destruction, but checking supply voltages revealed a missing -12VDC rail. (+12 and +5 rails were healthy.)

  9. #9

    Default Re: Schematics

    Quote Originally Posted by CurtZHP View Post
    So it's getting juice and the DSP is working, but no sound, right?

    Another easy thing to check...
    There's going to be a few wires going from the PS/DSP board to the amplifier. I'm assuming a ground, a positive voltage rail, and a negative voltage rail. You could check with a meter to see if the amp is getting power itself. Perhaps one rail took a dump.

    Anything with a DSP usually has a separate 5VDC supply for that, which would explain why that part still works.

    I suggest this because of a piece of gear at the TV station where I work. It did the same thing. Front panel display and firmware worked, but it wouldn't pass a signal. No visible signs of destruction, but checking supply voltages revealed a missing -12VDC rail. (+12 and +5 rails were healthy.)
    Correct; DSP is working but there's no sound. Thank you for these tips, Curt. I'll definitely check for PS issues (or my electrical engineer friend will). This is a good tip for a place to start. Thanks again!!!

    I'd still love to have schematics though, if only for future reference... are there no Alesis service guys here on the forum who could help me out?
    Richard
    Green Valley Recording
    My cats have nine lives; my life has nine cats.

  10. #10

    Default Re: Schematics

    Another thing to keep in mind...
    When checking those voltages, check at the amp end of the wires. A bad pin on a connector can give you fits. I've had it happen myself. I'd checked the voltages at the P/S end and seen all healthy voltages and assumed the supply was good (it was), but the real problem was that it still wasn't getting to the board.

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