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Motu 828 MKII Main Out jack noise

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Motu 828 MKII Main Out jack noise

Postby christianmurphy » Sun Mar 11, 2012 8:14 pm

Picked up a 2nd hand Motu 828 MKii, as it was a bargain cause it had a few things wrong with it. Was wondering if anyone could help with fixing them!

First, the main out jacks are completely faded and scratched around them from lots of blind plugging in and out, which doesn't bother me, but the right channel creates random blasts of a really soft white noise type of sound. It's not dangerous or hugely irritating, but noticeable when listening quietly. So first up looking to open it up and replace them. Left ones fine but worried it might go as the right one has.

Secondly, a couple of the push/twist knobs have snapped off. They're still usable with nimble fingers, but would be handy to change them if possible!

Really just looking for advice on where to get the replacement parts (if possible), and how tough it is to do it!

Christian.
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Re: Motu 828 MKII Main Out jack noise

Postby Ris of Serig » Sun Mar 11, 2012 10:41 pm

Musictrack are the UK distibutors for MOTU stuff.

There's a repairs page here on their website:
Musictrack - Repairs

HTH

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Re: Motu 828 MKII Main Out jack noise

Postby christianmurphy » Mon Mar 12, 2012 12:05 am

Thanks, but it appears they don't distribute ANY parts, and have a fixed charge of £110. Bit steep for one jack socket that would take all of 10 minutes to disassemble/solder/reassemble!

Any idea where I could pick up a jack socket that would work?
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Re: Motu 828 MKII Main Out jack noise

Postby The Elf » Mon Mar 12, 2012 8:52 am

christianmurphy wrote:the right channel creates random blasts of a really soft white noise type of sound.
That doesn't suggest a simple jack socket replacement to me. It might be worth paying that repair charge.
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Re: Motu 828 MKII Main Out jack noise

Postby Hugh Robjohns » Mon Mar 12, 2012 9:41 am

Yes, random blasts of white noise sounds like a digital problem rather than a mechanical contact issue, and the kind of physical abuse that would snap knobs off may well have damaged the printed circuit board too.

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Re: Motu 828 MKII Main Out jack noise

Postby christianmurphy » Mon Mar 12, 2012 12:18 pm

I think I might be describing it badly. 'Blasts' might be the wrong word. It's more random soft noise, doesn't sound like a digital thing to me as it still plays perfectly, and only comes out of one of the jacks, and it's the jack the looks particularly battered. Although you lot will almost certainly know more than me! Even if it's not it could definitely use replacing and would much rather have a crack with a 3 quid part then send it off. I paid less for the whole unit than the repair cost! (actually still a bargain I think because the left main out jack is the only thing that doesn't actually work properly, rest is just cosmetic).

Would the jack have to be a specific part or could I potentially fit a neutrik part for example?
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Re: Motu 828 MKII Main Out jack noise

Postby Hugh Robjohns » Mon Mar 12, 2012 1:08 pm

So you think it sounds like a failing jack connection? If so, replacing the socket could help... but it might be worth cleaning it first with deoxit or similar.

You'll have to dismantle the unit to see what kind of socket has been used, but it's probably a direct pcb solder version, so an identical part will really be needed to fit the same board space. On the other hand, if there is sufficient space, I'm sure alternative bodge solutions could be found...

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Re: Motu 828 MKII Main Out jack noise

Postby christianmurphy » Mon Mar 12, 2012 1:50 pm

http://www.flickr.com/photos/niobite/6278139639/sizes/l/in/photostream/

Top left, would be on the bottom row of jacks on the main PCB. In that case I'll take it apart, take the jack out and find something from neutrik that resembles it most - I've done some PCB soldering in interfaces before so (fingers crossed), should be okay!

Cheers
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Re: Motu 828 MKII Main Out jack noise

Postby ef37a » Mon Mar 12, 2012 3:21 pm

Ooo! A gutshot of a MOTU!
And not hugely impressed? It does not seem to me that those jacks are bolted onto the back panel? Hence the eventual failure.

They are also stacked pairs and 5 mins Googling found nothing like them, certainly Neutrik have nothing (they do stacked jack but the chances of the pin footprint matching?).

If the £110 is for a replacement pcb, and it bloody well should be, and the repair carries a 90day warranty then I would say that was fair. If I had my way ALL equipment would have such boards made available for a "service exchange". Much greener and creates jobs locally.

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Re: Motu 828 MKII Main Out jack noise

Postby Hugh Robjohns » Mon Mar 12, 2012 3:38 pm

ef37a wrote:They are also stacked pairs...

Are you sure? Doesn't look that way to me. Looks like more like a set on the main board, and a second set on the raised daughter board.

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Re: Motu 828 MKII Main Out jack noise

Postby christianmurphy » Mon Mar 12, 2012 3:45 pm

Hugh Robjohns wrote:
ef37a wrote:They are also stacked pairs...

Are you sure? Doesn't look that way to me. Looks like more like a set on the main board, and a second set on the raised daughter board.

hugh

I believe you are correct Hugh. This is an image from a MkI but looks like it would be the same design:

http://pics.studiorepair.com/Motu/828/slides/Motu_828_PCB_Jacks__STUDIOREPAIR_08031001_0703096163.JPG
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Re: Motu 828 MKII Main Out jack noise

Postby ef37a » Mon Mar 12, 2012 4:28 pm

christianmurphy wrote:
Hugh Robjohns wrote:
ef37a wrote:They are also stacked pairs...

Are you sure? Doesn't look that way to me. Looks like more like a set on the main board, and a second set on the raised daughter board.

hugh

I believe you are correct Hugh. This is an image from a MkI but looks like it would be the same design:

http://pics.studiorepair.com/Motu/828/slides/Motu_828_PCB_Jacks__STUDIOREPAIR_08031001_0703096163.JPG

I stand corrected, trick of the light!. Still not bolted to the back panel tho'! Poor do in my view and I don't think Neutrik do them. And those pots are a bit naff as well!

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Re: Motu 828 MKII Main Out jack noise

Postby Hugh Robjohns » Mon Mar 12, 2012 5:22 pm

You're right, mechanical integrity would be better if the pots were bolted to the back panel... but it's built to a budget and that's the kind of compromise that is to be expected.

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Re: Motu 828 MKII Main Out jack noise

Postby christianmurphy » Mon Mar 12, 2012 9:27 pm

UGH. Took it apart and looks like it's gonna be a pain to do! Seems two of the pins are at the rear and one at the front of the jack.

Here's the idea - Get a couple of Neutrik slimline jacks, and mount it 90° to how it would usually mount, and use some wire (like the thin bendy but kinda strong wires on a guitar cap), to stretch round from the PCB up to the connectors. Will look like a serious bodge, but if I can get the right wire and spot a bit of glue when it's in, it should hold it's place pretty well I imagine.

What's the best way to figure out what the PCB points will be in relation to pins 1 2 and 3 on the new jack?

I will definitely post pics of this
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Re: Motu 828 MKII Main Out jack noise

Postby ef37a » Mon Mar 12, 2012 10:05 pm

If you can find an exact replacement jack the way to proceed is to destroy the existing jack carefully with side cutters until you just have individual pins left then heat those up one at a time and GENTLY pull them out.Clean holes with WICK not a sucker! Almost certain to be Pb free solder and so if you are not up to speed with that stuff, kitwise and experience, put everything back and pay up!

If I were servicing those boards I would make a form tool up out of brass stock but not worth it for a one off.

Yes, you could fit another jack type and wire off but that might compromise noise and possibly stability. Again, IMHO if you cannot get the right part, forget it.

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Re: Motu 828 MKII Main Out jack noise

Postby ef37a » Tue Mar 13, 2012 8:44 am

Hugh Robjohns wrote:You're right, mechanical integrity would be better if the pots were bolted to the back panel... but it's built to a budget and that's the kind of compromise that is to be expected.

Hugh

The stuff I came from was "built to a budget" but it was not cut that near to the bone!

I would expect it of Bellringer and Phonic but MOTU?

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Re: Motu 828 MKII Main Out jack noise

Postby Adam Inglis » Mon Mar 19, 2012 3:29 am

When I had to get my MkII repaired, I spoke to the local tech, who told me no schematics are ever supplied, it basically goes back to the distributor who returns the unit to to MOTU and obtains a replacement for a certain fee (which wasn't exorbitant).

Doesn't bode well for future repairs though.
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Re: Motu 828 MKII Main Out jack noise

Postby ef37a » Mon Mar 19, 2012 7:11 am

Adam Inglis wrote:When I had to get my MkII repaired, I spoke to the local tech, who told me no schematics are ever supplied, it basically goes back to the distributor who returns the unit to to MOTU and obtains a replacement for a certain fee (which wasn't exorbitant).

Doesn't bode well for future repairs though.

The consumer has no one but himself to blame for such a situation IMHO. He has been chasing the lowest possible price for decades since Retail Price Maintainance was abolished and the "pile 'em high, sell it cheap Magnet" stores emerged. It costs a great deal of money to equip a workshop and good technicians deserve a decent wage. Then, when kit is out of warranty Joe P does not want to pay more than a tenner for service. A good example of this is the almost total abscence of any in house service backup in music instrument stores.

We see many consumer programmes such as "cowboy builders" but we never see the firms that struggle and go to the wall because customer won't pay for a good job, want it "vatfree" or just don't pay up promptly at the job finish or at all!

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Re: Motu 828 MKII Main Out jack noise

Postby Hugh Robjohns » Mon Mar 19, 2012 9:29 am

Quite so!

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