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    #1

    MOTU Traveler mk2 and power supply

    I've had this thing in for a couple weeks, gotta wait for the firewire controller IC to arrive. For any of you who aren't familiar with this, it's a realtime firewire DSP, mixer and mic/instrument preamp. It costs ~$900 nowadays, when this one was bought 5 years ago it was $3k. And it was a factory refurb to begin with, so it isn't exactly a cheap device.

    Failure cause is a common one for this model. The owner borrowed it to someone who plugged the firewire cable in backwards, frying the controller. I have some other suspicions about this (as plugging the firewire in backwards swaps the +30v supply with ground, something which shouldn't cause a failure, since the controller IC is 3.3v so obviously powered by a regulator and protected by diodes).

    But what's shocking is that i found the main filter cap bulged and leaking, which is an Elna 35v 1000uF, no mention of low ESR anywhere. Somebody should tell them that Elna doesn't make SMPS caps. The other caps are from Nichicon and Meritek. They look okay but NONE of them are properly pushed into the board and they wiggle around. Nice job guys.

    I was bored today so i also took apart the power supply because it was buzzing and whining. What i found inside horrified me. I bet this didn't cost more than $0.50 to make. Caps are all Jun Fu, with the primary side cap leaking. Since the cap inside the device itself is gone, i'll also test the secondary caps, they could very well have gone open. There is NO CONTROLLER IC, it's a self-oscillating flyback with optocoupler feedback. Oh yeah and THE MOV IS MISSING. Is this a power supply for a $3k device??? Jeez.

    And don't let me get into what caused the failure in the first place - the bottom of the Firewire ports isn't soldered to the board, which allows the aluminum guard to split apart. Everybody i asked about this told me "no way it was plugged in reverse, it's foolproof!" but i was surprised about how easy it actually is to plug the cable the wrong way around in this thing. This is an unacceptable design fail. And all it would take to fix would've been a blob of solder.

    Sorry for the pic quality btw, i forgot where i put my camera.

    Edit: Primary cap tests OPEN. I threw it on the scope just for fun, and... 200mV p-p 50Hz ripple, 300mV p-p switching ripple and 600mV p-p high frequency ringing, most likely from the transistor switching spike. Those numbers are with the power supply UNLOADED. And consider that it actually goes thru a pi filter. I think this can truly be called "made by HongKongFlyApart, LLC".

    Edit 2: The 600mV spikes were coming from my cellphone charger nearby. I unplugged that and now there is "just" 400mV. Doesn't make it less bad however.
    Attached Files
    Last edited by dood; 10-20-2010, 11:25 AM. Reason: Cut out duplicate text as requestion by OP
    Originally posted by PeteS in CA
    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
    A working TV? How boring!
    Tags: None
    #2
    Re: MOTU Traveler mk2 and power supply

    Looks like a slightly better version of a cheap external HDD PSU.

    Comment

      #3
      Re: MOTU Traveler mk2 and power supply

      some things are just wiser to be kept analog - no way would a pre-amp & mixer with a reasonable number of inputs cost even a thousand if it wasnt digital.

      how many input channels does this box have?

      Comment

        #4
        Re: MOTU Traveler mk2 and power supply

        Originally posted by stj View Post
        how many input channels does this box have?
        Four mike preamps and two stereo line inputs or four mono. It also has random crap such as optical, ADAT and MIDI. It's a 1U unit after all, there's a limit on how much you can squeeze into one rack space. I like the part where they say "24-bit 192kHz analog". Analog is analog, duh. That it has 192k ADCs and DACs, well that's a totally different story. Here is how it looks in its entirety.

        Oh yeah and it's got some horrendous opamps too. NJM4850s. At least they aren't 4558s, but 800nV of input noise??? The good ol' TL072 has 18nV and it isn't anywhere near "good". There are also NJM2115s, those don't even have published noise specs! At least the mike preamp is decent, it uses PGA2500s. Oh yeah and the DACs. They are made by AKM (Asahi Kasei), those are good.

        But as for the price... well if it were $400, maybe it would be worth it. At $1k in my part of the world ($900 in the US like i said above), um, no. And it sure as hell wasn't worth $3k even five years ago. However, i will give it a spin once i get it fixed, just to see what it's about.

        Btw, thanks to dood for cutting out the duplicate text.
        Originally posted by PeteS in CA
        Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
        A working TV? How boring!

        Comment

          #5
          Re: MOTU Traveler mk2 and power supply

          Why woulda phone charger cause more ripple?
          What is this hgkongflyapart joke that i am missing?

          Comment

            #6
            Re: MOTU Traveler mk2 and power supply

            Most likely because the cellphone charger has zero shielding and it couples noise everywhere.

            As for the hongkongflyapart joke, i think it was Toasty who first coined it.
            Originally posted by PeteS in CA
            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
            A working TV? How boring!

            Comment

              #7
              Re: MOTU Traveler mk2 and power supply

              The ICs arrived today. However i didn't find any SMD flux, and messed the first chip up by trying to tin the pins with soldering iron, which made a lot of unremovable solder bridges. Luckily i had ordered three chips.

              I then decided to practice on a fried video card which had the same format of chip (64-pin 0.5mm pitch). I unsoldered it with my hot air gun, and thought about what i could use as flux to put it back. Then my eyes fell on my can of solid flux, and a piece of flux had just cracked off inside. "Wait a second, what if i..." So i broke off another even smaller piece of flux out of that, put it in the middle of the chip location, and melted it with the hot air gun till it became one large thin flux puddle. I then placed the chip back onto the board, heated everything up, then used the tip of a small screwdriver to push the chip into the solder. Magic!

              "Okay, lemme see if i can repeat that." Flux puddle, check. Out goes the TSB41AB2 from the antistatic bag. Alignment, check. Heat, check. Screwdriver, check. Chip pushed in, double check. Power on.

              Hot damn. It works!!!! I also have found my camera so will post hires pics of the whole job. Edit: I put my UT60E on the SYSCLK pin (49.152MHz) and it reads 49.13M. On a meter that's rated for 10MHz. Someone mentioned that it can't possibly be accurate at that freq, well, take this. Pics tomorrow.
              Last edited by Th3_uN1Qu3; 10-21-2010, 02:50 PM.
              Originally posted by PeteS in CA
              Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
              A working TV? How boring!

              Comment

                #8
                Re: MOTU Traveler mk2 and power supply

                chips come from the factory pre-tinned.

                btw, i tin used chips using an iron & lead-free solder.
                i can tin a tsop flash that way with no bridges every time!

                Comment

                  #9
                  Re: MOTU Traveler mk2 and power supply

                  I can solder a flash without a hot air gun. But a flash only has pins on TWO sides...
                  Originally posted by PeteS in CA
                  Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                  A working TV? How boring!

                  Comment

                    #10
                    Re: MOTU Traveler mk2 and power supply

                    Ok but what does hongkongflyapart really mean?

                    Comment

                      #11
                      Re: MOTU Traveler mk2 and power supply

                      Nothing, it's just a joke. Read it 3 more times and you'll get it. Btw, the transformer was given some SMPS Shut Up(tm) treatment, and it's now so quiet i thought i broke it.

                      But darn this thing runs hot. After an hour of use, the new mains filter cap comes in at 55C at the top, while the heatsink of the switching transistor which is in its immediate vicinity reads 83C. Considering that this is with the power supply open, and its lid has absolutely NO venting slits, it's scary. No doubt the main cap is going to fail again in a couple years. I left the Jun Fus on the secondary alone, they tested good and have this weird form factor that i could not find readily available around here.

                      I haven't gotten around to changing the Elna cap on the main board, but the thing works fine as it is. Most likely because pretty much EVERYTHING has vregs, vregs and more vregs. The device itself barely breaks a sweat, so the only thing that killed that cap is definitely its high ESR. At least let's give them credit for engineering the device to work even if it's bad.
                      Last edited by Th3_uN1Qu3; 10-21-2010, 10:06 PM.
                      Originally posted by PeteS in CA
                      Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                      A working TV? How boring!

                      Comment

                        #12
                        Re: MOTU Traveler mk2 and power supply

                        the mains cap getting hot is a bit strange.
                        what diodes/rectifier dies it use?
                        maybe the diodes are slow or poor.

                        Comment

                          #13
                          Re: MOTU Traveler mk2 and power supply

                          well it sounds like theyre getting hot because of the nearby heatsink not because they theselves are getting hot

                          Comment

                            #14
                            Re: MOTU Traveler mk2 and power supply

                            Yup, shovenose hit the nail on the head. Anyway... as it turns out everything would work BUT the firewire connectivity. Yup, the only pins which didn't get soldered properly were the firewire data pins...

                            I removed the firewire IC once again and tinned the pads with lead solder, then went for broke. Aka heat it till you're afraid that the IC will start melting. Device detected. Success! Upon a closer inspection the Elna cap is actually fine, i thought it was leaking electrolyte but it's simply a darker spot in the top, it doesn't scrape off like electrolyte would. It also tested good for ESR. I still don't like it but i'm supposed to remove each and every screw to get the board off, and i'm not gonna do that.

                            But here's the fun part. It works in the living room on both firewire ports on both laptops, but it will NOT work in my room on either of them. Also, if the case is touched while it's working, it'll crash the laptop. Whoever designed that power supply should shove it up his ass. It is definitely not my soldering at fault, as pushing on the board doesn't do anything, only touching the metal of the case crashes it.

                            Fortunately it can also be bus powered. As the owner uses a full-size PC for his work so he has 6-pin firewire with power, i'll tell him to power it by the firewire port whenever possible.
                            Originally posted by PeteS in CA
                            Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                            A working TV? How boring!

                            Comment

                              #15
                              Re: MOTU Traveler mk2 and power supply

                              Originally posted by Th3_uN1Qu3 View Post
                              But here's the fun part. It works in the living room on both firewire ports on both laptops, but it will NOT work in my room on either of them.
                              A lot of firewire audio interfaces are fussy about working with a certain firewire chipset.

                              TI chipsets seem to have the best overall compatibility.

                              Comment

                                #16
                                Re: MOTU Traveler mk2 and power supply

                                Well, guess it's time for the real facts. It's NOT the firewire controller that's causing all the trouble, it's the interface chip next to it which is a big ass mofo with no less than 144 pins. It chokes on firewire playback and does all kinds of nasty clicks and pops (that is, when it actually decides to recognize the computer). And yes it does respond to heat like i found out, but it'll work right for a few minutes at most. It's a Philips IC, forgot the model already but it's something i can't find for sale anywhere. The firewire controller i have replaced is simply "the middle man", its only special function is that it provides the 49.152MHz master clock.

                                Fortunately i've gotten the control software and the recording functions to work stable. The owner uses it to record mikes most often, so who gives a damn if it can't play sounds from the computer, it's not like he doesn't have other soundcards. One can route any of its analog inputs to the phones and monitor that way. Oh yeah and bar the room issue, now it works anywhere i put it.
                                Originally posted by PeteS in CA
                                Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                                A working TV? How boring!

                                Comment

                                  #17
                                  Re: MOTU Traveler mk2 and power supply

                                  Okay. I still dont get tue hkfa joke.

                                  On an differnt note, i actually was right about something! Yay!

                                  Why dont you drill a vent holemin the ps and add a fan?

                                  Comment

                                    #18
                                    Re: MOTU Traveler mk2 and power supply

                                    Originally posted by shovenose View Post
                                    Why dont you drill a vent holemin the ps and add a fan?
                                    If it were mine i would've probably done that. In fact, just drilling some holes would be enough.
                                    Originally posted by PeteS in CA
                                    Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                                    A working TV? How boring!

                                    Comment

                                      #19
                                      Re: MOTU Traveler mk2 and power supply

                                      Hello Th3_uN1Qu3,

                                      just come across this topic and I think maybe someone can help me!
                                      I'm repairing a Motu Traveler (I think Mk2, for sure it isn't a Mk3) that sometimes goes berzerk (i.e. strange noises on the outputs, like digital clicks, and front panel LEDs goin' mad)

                                      I'm trying replacing some caps, but no luck (btw, ESR on the original caps seems to be good)

                                      Do you have your Motu handy? 'Cause I've found a lot of ripple on the input (pin 1) and output (pin 2) of the 2 regulators near the MIDI port, and I'm wondering if you please can do some measures on your good one, just to compare with mine.

                                      Thank you a lot! Cheers
                                      - Marco
                                      Last edited by marcodassi; 10-23-2010, 08:32 AM.

                                      Comment

                                        #20
                                        Re: MOTU Traveler mk2 and power supply

                                        I'm sorry but i've handed it over today. The owner only really uses it for recording vocals, so he is content with how it works now. If you get ripple try powering it from the firewire bus not from its power brick, which is a piece of crap.

                                        But i'm quite sure ripple isn't your problem. Try tapping the PDI1394 chip (the big one next to the firewire controller, to the right and under the main DSP) with your finger while it's working. If it starts acting stupid when you do that, yours has the same problem as this one, and the chip has gone bad. It can't be soldering as i've reflowed it four times and got the same result. If you find a place where it can be ordered, let me know.

                                        Btw, does it work fine when it's not connected to the computer? If so, your problem is definitely related to that chip.
                                        Originally posted by PeteS in CA
                                        Remember that by the time consequences of a short-sighted decision are experienced, the idiot who made the bad decision may have already been promoted or moved on to a better job at another company.
                                        A working TV? How boring!

                                        Comment

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