AMB Laboratories DIY Audio

[KMorgan]

Hi All

First post. Hope you can help.

I've built a y2 DAC. However, I'm posting this here as I have a problem with the USB side of things which is, of course, on the y1 board.

When I connect my DAC by USB I get a message saying that the device is being installed, but then I get this

"USB Device Not Recognised. One of the USB devices attached to this computer has mulfunctioned, and Windows does not recognise it. For assitance in solving this problem, click this message."

This message appears whatever USB port I use, and on both my Vista Home Premium desktop and my XP laptop. Any advice on where to start fiddling would be appreciated. It's not causing me any problems as I use the optical-in. However, it's a nuisance to know that something aint quite right.

Thanks v much

Keith

[amb]

First, make sure you used the correct part for U2U (what does the markings on it say?).
Second, make sure you used all the correct value resistors/caps in all positions.
Third, check/reflow your solder joints around U1U and U2U, and the USB connector.
Are the voltages at the 3.3V checkpoints correct?

[KMorgan]

First, make sure you used the correct part for U2U (what does the markings on it say?).
Second, make sure you used all the correct value resistors/caps in all positions.
Third, check/reflow your solder joints around U1U and U2U, and the USB connector.
Are the voltages at the 3.3V checkpoints correct?

Thanks for the prompt reply.

All the voltages were as advertised when checked. Regards the other suggestions it will have to wait until tomorrow night (Monday, UK) before I can sit down and have a look. The other y1 and y2 parts of the DAC all seem to work correctly using optical and coax, so I'm assuming the fault must lie on the USB board?

I'll post back when the checks are done.

Thanks again

Keith

p.s. y2 related, but I have to trace down an intermittent connection somewhere on the y2 board (or inter-board connectors). Occasionally the sound drops off from the y2 output (both channels). Giving the DAC a tap brings the music back.

[KMorgan]

Two Steps Forward

Well, having reflowed some of the joints the DAC was recognised by my laptop. I even managed to play music. Yippee!

One Step Back

I then turned my attention to the intermittent music problem. I've managed to make this much worse At the mo I can't get any music out of the thing at all except on the rare occasions when I happen to twist/tap the boards in just the right way (y2 you see, I know... wrong forum ) I'm going to replace the pins and recepticles and see if that helps.

Anyway, even though this intermittent music problem is frustrating, at least I know I have a fully functional DAC in there somewhere.

Cheers for now

Keith

[MisterX]

Do you still get voltage at the 3.3 and 4.75 test points when the Y2 portion stops working?

[KMorgan]

MisterX

I'll be visiting this problem again on Wed night. I'll check what you suggest and report back.

Keith

[KMorgan]

Things just getting worse.

I've gone from everything working, except "USB device not recognised"/intermittent sound from y2, to USB working with y2 very intermittent, and now to big problems with 3.3v supply and nothing working.

I'm just a bit frustrated. I've also got too much on over the next few days to spend the necessary time trying to resolve it. Thanks for your help so far guys. Next week I'll detail all I have done, and the results. I'll start a new thread in the y2 section at that time. The first thing I'll do is draw 1cm squares on the boards and systematically check solder joints and continuity.

Cheers

Keith

[rocket_sled]

My Y1-usb lite is not recognised when plugged in the PC. This was built a while ago and was working fine until now.

I am unable to get a reading on the 5V VCC & 3.3V test points, 5VBUS is ok.

For testing can i use an external 3.3V supply and connect it to the 3.3V test point and check if the DAC is recognised (I do not have an extra U3U IC with me) ?

[amb]

My Y1-usb lite is not recognised when plugged in the PC. This was built a while ago and was working fine until now.

I am unable to get a reading on the 5V VCC & 3.3V test points, 5VBUS is ok.

Did you test with the two board sections mated? Or separated? If separated, you need to put a jumper across VCC and VBUS at J2U in order for VCC to get power.

For testing can i use an external 3.3V supply and connect it to the 3.3V test point and check if the DAC is recognised (I do not have an extra U3U IC with me) ?

Since you have no voltage at VCC, then there is no voltage going into U3U, so that's unlikely to be your problem anyway.

[MisterX]

I suppose the point being to find out what other replacement parts you will need to order?
Yeah, the use of an alternate 3.3 volt power source would help in that situation.

Edit: Whoops, sorry Ti snuck a reply in there while I was typoing.