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Please help! Schiit Modi 2 not being recognized anymore by Windows?

rjp

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May 15, 2020
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#81
UPDATE: Fixed Permanently!

I had the same issue, and applying heat to the chip identified a few pages back (CM6631 Audio processor) always made the DAC recognizable to my PC for a while until it cooled down. Well, I replaced the chip and now my Modi works perfectly!

The part was only 5.75 and is a simple fix if you know how to solder tiny stuff. There are some videos online showing how to do this sort of thing at home, but it definitely requires some experience and a lighted magnifying viewer. It has 100 pins, and can be done with small soldering iron or heat gun. I got the part here:

https://www.semiconductorstore.com/..._medium=InvoiceLine&utm_campaign=InvoiceEmail

Screen Shot 2020-07-27 at 10.30.01 AM.png
 
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#82
I had the same issue, and applying heat to the chip identified a few pages back (CM6631 Audio processor) always made the DAC recognizable to my PC for a while until it cooled down
Interesting, although i've got a Modi (v1) and it's internals are sparse in comparison to the Modi 2. Only about 3 chips, each with 4-8 pins. Same problem but on another chip? EDIT: stupid me forgot there's an underside to the PCB, and there it is, CM6631A.

Seems like they had a major quality issue at one point and it's across multiple products and generations.

Interestingly i'm still seeing a lot of recommendations for these products, and even posts of users willing to buy another after they've had one or more fail. Obviously people like these products, and for good reason. Maybe i'm just unlucky, but i've rarely had any devices fail on me, and for that reason i'd be very hesitant to buy another Modi.
 
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rjp

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#83
Interesting, although i've got a Modi (v1) and it's internals are sparse in comparison to the Modi 2. Only about 3 chips, each with 4-8 pins. Same problem but on another chip? EDIT: stupid me forgot there's an underside to the PCB, and there it is, CM6631A.

Seems like they had a major quality issue at one point and it's across multiple products and generations.

Interestingly i'm still seeing a lot of recommendations for these products, and even posts of users willing to buy another after they've had one or more fail. Obviously people like these products, and for good reason. Maybe i'm just unlucky, but i've rarely had any devices fail on me, and for that reason i'd be very hesitant to buy another Modi.
I wonder if the issue was with the quality of the CM6631A chip supplier or the Modi circuit itself. So far mine is still working perfectly since I replaced the chip. So it could have been a bad run of ICs or possibly the Modi circuit stresses the chip beyond normal limits somehow?
In any event, it is great to have it working again. It really is a nice sounding DAC.
 

t.gaze

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Sep 24, 2020
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#84
Hello All,

I found this thread a couple months ago, and have used the heat trick to connect to the Modi every time I restart windows. I think rjp is correct that its the USB Audio chip that has failed somehow. The heat must elevate the voltage or disconnect part of the IC to reset it somehow. I don't think reflowing the board would work, it probably takes replacing the IC.

A friend suggested using an optical Toslink cable to bypass the USB interface.

It worked!

I think I will try to replace the CM6631A at some point, but for now a $5 easy fix is getting an optical cable!

Thank you everyone that has contributed to this thread! You aren't alone!
 

ed1727

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Sep 27, 2020
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#86
Hello All,

I found this thread a couple months ago, and have used the heat trick to connect to the Modi every time I restart windows. I think rjp is correct that its the USB Audio chip that has failed somehow. The heat must elevate the voltage or disconnect part of the IC to reset it somehow. I don't think reflowing the board would work, it probably takes replacing the IC.

A friend suggested using an optical Toslink cable to bypass the USB interface.

It worked!

I think I will try to replace the CM6631A at some point, but for now a $5 easy fix is getting an optical cable!

Thank you everyone that has contributed to this thread! You aren't alone!
t.gaze
Are you using the Modi 2? I don't have any optical inputs. Hairdryer method work, how stupid!
 

Kradziej

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Oct 9, 2020
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#88
Registered to post that I also successfully fixed unrecognized issue by replacing CM6631A. At first I thought it cant be an IC problem, tried to heat up 3.3V LDO and it worked! So I replaced LDO but problem still persisted. You really only need a little heat to resurrect that pesky audio processor. Ordered 2 ICs from aliexpress, soldered "new" one and finally modi no longer blocks my computer from POSTing (also recognized in windows as a bonus).

There is no markings explanation in datasheet but I'm guessing numbers like 1801 and 1322 are in YYWW format, if so then I replaced fairly recent batch with old one. I wonder which batch may have issues, if ICs break across different batches then I doubt its IC fault...
 

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dhkimboa

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Oct 12, 2020
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#89
UPDATE: Fixed Permanently!

I had the same issue, and applying heat to the chip identified a few pages back (CM6631 Audio processor) always made the DAC recognizable to my PC for a while until it cooled down. Well, I replaced the chip and now my Modi works perfectly!

The part was only 5.75 and is a simple fix if you know how to solder tiny stuff. There are some videos online showing how to do this sort of thing at home, but it definitely requires some experience and a lighted magnifying viewer. It has 100 pins, and can be done with small soldering iron or heat gun. I got the part here:

https://www.semiconductorstore.com/..._medium=InvoiceLine&utm_campaign=InvoiceEmail

View attachment 75387
did you get this for modi 2? is it the same part for modi 3?

i have a modi 2 with this problem I'd like to replace this part as well ~~
thanks for reading me
 
Joined
Mar 1, 2020
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#93
Holy shit. My Modi 2 stopped being picked up this morning, so I stumbled into this thread and the hair dryer trick worked for me too. The music sounds so much warmer now!

What's the most cost-efficient replacement to get as backup in case it fails?
 
Joined
Apr 14, 2021
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#95
A possible $3 brute-force hack/"fix" that's been working for a while.
OK, so I also registered to post about this issue. Thanks to others for posting the temporary workaround (heat) to get these problem C-Media USB 2.0 audio chips recognized again.

I acquired a Schiit Modi 2 with this very problem that was waaayyy out of warranty. Not recognized until I heat up the C-Media chip a couple mins w/a hair dryer. Most certainly not a "solution" because every time you shut down the computer or DAC you've got to unscrew lid, apply heat, then Yay! DAC is recognized (again).

BTW this is not limited to Schiit DACs using these C-Media USB audio chips (e.g. CM6631A)... Other DACs using it can experience this problem, e.g. some Emotiva units - "I can tell you that failure of the C-Media chip is one of the more common faults we see in the DC-1. It doesn't go by batches or anything like that - that particular chip just seems to be more prone to failure than many other components."

Anyway, I've built several amps & headamps but never worked w/SMD. I could certainly order a new C-Media chip (~ $13 shipped?), buy a hot air re-work station (decent ones $50?) OR ChipQuick SMD1 removal kit ($16), plus a bevel solder tip ($12) and give it a go. And maybe I will if/when this $3 hack stops working...

For now I'm using this $3, possibly temporary but working for a while now, solution - a $3 shipped eBay Chinese "5.5*4CM 5V Carbon Fiber Heating Pad Hand Warmer USB" small USB heating pad. So far this had been "fixing" the problem for over a week now. I power the double-faced tape-attached heater pad for < 2 mins (through phone charger) and then bing! the Modi DAC is recognized, disconnect the USB warmer, and the DAC works for the whole day (until I shutdown).

Steps I used:
1 - Confirmed USB not recognized problem was the frigging C-Media USB audio chip... A hair dryer on low applied to it for a minute or two made it magically recognized.
2 - Ordered a USB heat pad like referenced above. Waited a couple weeks for it to arrive. Tested it by plugging into USB phone charger (not your PC/Mac), it got warm.
3 - Used strong double-faced tape, the type with a blue peel layer on the outside, to attach heat pad to frigging C-Media USB audio chip.
4 - Passed its wire out the back & was able to somewhat tighten the Modi 2 DAC's lid screws.
5 - For me, I power the heat pad for ~ 2 mins from an iPhone charger and voila! - the Modi is recognized & works well for the day.

Photos or it didn't happen:
the bugger:
schiit_modi_dac_fixhack_ - 1.jpg
the smallest USB warmer I could find... Is actually smaller than it looks here:
schiit_modi_dac_fixhack_ - 2.jpg
USB warmer attached, its USB wire out middle-back & screws tightened lightly:
schiit_modi_dac_fixhack_ - 3.jpg
Booted Mac not seeing DAC yet...
schiit_modi_dac_fixhack_mac_ - 1.jpg
After 2 mins powering heater:
schiit_modi_dac_fixhack_mac_ - 2.jpg
Unplug USB heater, DAC working well until next reboot.
Wild that a "fix" they use for diesel engines, block heaters, would have application for an IC:)
 
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