Midi controller / DAC interface not recognised (Device descriptor request failed).

I have an EKS XP10 midi controller with a Burr Brown DAC. When plugging in the controller it isn't being recognised by Windows.

I have two more of the same controllers. Only this one has this problem.

I have checked and confirm there is steady 5v across legs 1 and 4 of USB socket on the underside of the board. Also 3v across data pins 2 and 3.

I have checked and confirm there is steady 5v across legs 1 and 4 of USB socket on the underside of the board. Also 3v across data pins 2 and 3. On the good boards the voltage across pins 2 and 3 is 2.7 volts.

I have also checked the voltage between ground and various testing points on the board and they seem to be the same, except across the two silver contacts at the top left of the board, with L10 written next to them.. On the bad board at that spot there are two components with 472 written on them, which look like green painted capacitors to me, but soldered on the other side of the board (the side without the components on it). The voltage across them is 0.26 volts.

On the good boards, the components at that spot are 800 ohm resistors soldered on the component side of the board and have 0.5 volts across them.

The chips have had the codes scratched off them. Apparently manufacturers do this sometimes so their products can't be reversed engineered.

If this is a chip problem, for example whichever chip responds to the device descriptor request, I have a solder reflow station and can try and reflow them.

Hi,
the green items are inductors, for noise or interference suppression. They appear to be in the L9 & L10 positions on the board. They do not appear to be directly involved in the USB part, possibly they are filters for the audio I/O side?

The data lines from the USB socket appear to go to a 28 pin IC [U2] on the opposite side of the board.

I'm guessing that could be an FT232R or equivalent, a USB to serial converter?
Have a look at the data sheet & see if the power and USB data connections go to the appropriate pins?

That's what the PC driver should be seeing and configuring so if it has all the correct voltages, it could well be faulty.
If the voltages are wrong, look at the power interconnections.

FOund something. Two of the legs on that chip, which are not connected on the good boards, have a short. THere appears to be exposed metal under there between them. NOt sure why as I didnt think there should be track there.

Are they pins 11 and 12?

Yes, pins 10 and 11. From that better image, the other pins do not appear to match the FT232.

Can you examine the device properties for in device manager with one of the working ones - in Details & select Hardware IDs?
That may help pin down the exact IC type they use?

AudioDevice on USB Bus 2.8.45
MEDIA\PGUSBMM3ADAPTER\9&2094A6B5&0&ID01

I have noticed the device details change when I uninstall the current driver, from Ploytech, which supports the DAC in the controller ( Burr Brown 2702).

I'll reboot and get the other Hardware ID too, which appears when the Plotech driver isn't installed.

Without a driver installed:

Burr-Brown USB Audio Codec 2702 (commercial 2.8.45)
USB\VID_08BB&PID_2702&REV_0100

My bad those two legs are in parallel on the other two boards as well. Must have been some film or something on them.I scratched a little with the probes and they are connected.

Califauna said:

those two legs are in parallel on the other two boards as well

Click to expand...

Drat...

I was hoping the problem was a revised board version that needed a different driver; that's not all that unusual, it's happened with some Tascam interfaces etc.

I spent a couple of hours last night trying to find more info on these units or other drivers, but the information is extremely rare.
The makers site was replicated by the internet archive before they went out of business - but for whatever reason the driver downloads were behind a login system so were not archived..

Do you have one of the original driver CDs for the units? Is the "Ploytech" driver the original or another that happens to work?

Thanks for looking into this.

I have the manufacturer's (EKS) drivers installer files downloaded.

The Ploytech driver is designed for various popular interfaces. One of them which is supported is the Burr Brown 2702. I use that driver usually because it is designed to allow shared mode use of the device.

I can upload them if it helps.

The Boards all say 'EKS XP10 V1.14' on the component side and on the other side:

STD-1
94V-0
4405

OK!
Do you get any different results re. the units being recognised, if you use the original EXS driver?

And just a thought - are you using the same USB socket on the computer for every test? Some USB device drivers do not work properly with certain USB controllers, particularly USB3 ones. A lot of PCs have two or three different sets of USB sockets working from different controllers.

No I have tried with various ports and with both drivers. On two PCs as well.

Nirsoft USBdevview doesn't seem to provide anything beyond windows device manager. Its listed as unknown device with failed device descriptor and loading the BADDEVICE.Dev.NT driver.

In windows is it possible to manually associate a device with a driver and a device description, on the offchance that it could work even with this chip failing, if that is the cause?

I'd guess the DAC IC has failed.
That appears to be the one near the centre of the board, between C37 & C56?

If it won't communicate, there is nothing you can do to force it.

Can you see if the USB data lines connect to pins 6 & 7 on that IC?

yes looks like it . https://pdf1.alldatasheet.pl/datasheet-pdf/view/56839/BURR-BROWN/PCM2702.html

rjenkinsgb said:

I'd guess the DAC IC has failed.
That appears to be the one near the centre of the board, between C37 & C56?

If it won't communicate, there is nothing you can do to force it.

Can you see if the USB data lines connect to pins 6 & 7 on that IC?

Click to expand...

yes looks like it . https://pdf1.alldatasheet.pl/datasheet-pdf/view/56839/BURR-BROWN/PCM2702.html

I checked and 6 and 7 go to legs 21 and 22 on the presumed UART chip. From there I can't see. There is 1300 or so ohms between legs 6 and 7 and the USB port data pins.

Regarding the jogwheel, the pins are 1 to 5 right to left looking from the component side of the board. Pins 4 and 1 (5v and Ground) have direct track connection with legs 10, 11, 15, 16, 25, and 28 on the presumed UART chip U2. Pins 2 and 5 (Index and B) go down to two test holes by R66, which then go left and down to test holes between r61 and r75 (via test holes connecting track on both sides).

In Nirsoft Devview I get this:

==================================================
Device Name : Burr-Brown Japan PCM2702
Description : USB Audio Device
Device Type : Audio
Connected : Yes
Safe To Unplug : Yes
Disabled : No
USB Hub : No
Drive Letter :
Serial Number :
Created Date : 7/25/2020 12:50:51 AM
Last Plug/Unplug Date: 7/25/2020 12:50:51 AM
VendorID : 08bb
ProductID : 2702
Firmware Revision : 1.00
USB Class : 01
USB SubClass : 01
USB Protocol : 00
Hub / Port :
Computer Name : DESKTOP-42V9VIS
Vendor Name :
Product Name :
ParentId Prefix :
Service Name : usbaudio
Service Description: @wdma_usb.inf,%USBAudio.SvcDesc%;USB Audio Driver (WDM)
Driver Filename : usbaudio.sys
Device Class :
Device Mfg : (Generic USB Audio)
Friendly Name : Burr-Brown Japan PCM2702
Power : 0 mA
USB Version : 1.00
Driver Description: USB Audio Device
Driver Version : 10.0.18362.1
Driver InfSection : USBAudio
Driver InfPath : wdma_usb.inf
Instance ID : USB\VID_08BB&PID_2702&MI_00\9&2094a6b5&3&0000
Capabilities : SilentInstall, SurpriseRemovalOK
==================================================

==================================================
Device Name : Burr-Brown Japan PCM2702
Description : USB Composite Device
Device Type : Unknown
Connected : Yes
Safe To Unplug : Yes
Disabled : No
USB Hub : No
Drive Letter :
Serial Number :
Created Date : 7/25/2020 12:50:51 AM
Last Plug/Unplug Date: 7/25/2020 12:50:51 AM
VendorID : 08bb
ProductID : 2702
Firmware Revision : 1.00
USB Class : 00
USB SubClass : 00
USB Protocol : 00
Hub / Port :
Computer Name : DESKTOP-42V9VIS
Vendor Name :
Product Name :
ParentId Prefix : 9&2094a6b5&3
Service Name : usbccgp
Service Description: @usb.inf,%GenericParent.SvcDesc%;Microsoft USB Generic Parent Driver
Driver Filename : usbccgp.sys
Device Class :
Device Mfg : (Standard USB Host Controller)
Friendly Name :
Power : 0 mA
USB Version : 1.00
Driver Description: USB Composite Device
Driver Version : 10.0.18362.693
Driver InfSection : Composite.Dev.NT
Driver InfPath : usb.inf
Instance ID : USB\VID_08BB&PID_2702\8&889cc25&0&4
Capabilities : Removable, SurpriseRemovalOK
==================================================


Also, it installs the following in ' software devices' in Windows device manager:

EKS Midi Driver
SWD\MMDEVAPI\MIDII_E83C0101.P_0004

Photos of a chip with something almost legible.

The surface on that IC looks rough in the closeup - has it been inked over rather than sanded? A wipe with alcohol may reveal more.

The PCM2702 does not appear to include a serial port so the unit must have another USB interface device internally to provide that part of the setup.

You could really do with a scope so you can see what is happening on the data lines!

I got that text come up by using a dremmel to polish a little. I tried alcohol and cleaning before that.