Posts tagged "electronics"

Dead KORG microKEY, Part 2: Noobface McHamfists Desolders His First SMD

Fri 17 June 2016

J-Link and microKEY plugged into breadboard

Oh God. Oh God. I've been putting this one off, but the stuff has arrived. I can't back down now!

A brief résumé of what happened in Part 1: this great little KORG microKEY MIDI controller stopped powering up for reasons unknown. By wiring it up to a J-Link debug probe, we found that the CPU was still alive and kicking, yet somehow the computer was receiving garbled USB messages. As this keyboard has a built-in USB hub, the stab-in-the-dark diagnosis was that the chip responsible (a Genesys GL850G) had gone bad and needed replacing. Unfortunately, the chip is a 28-pin 10mm*8mm surface mounted design, and our bumbling hero has never before soldered an SMD component, much less reworked a board!

To properly capture the fear of someone doing surface-mount rework for the first time, everything in this piece was written minutes after happening.

Article continues here! KEEP READING, YOU

J-Link Detective Squad: Dead KORG microKEY-37

Sun 08 November 2015

Korg microKEY-37

I love the KORG microKEY 37. It's an excellent entry-level MIDI controller that fits unobtrusively on your desk, great for impromptu jamming when you should be focused on something boring like "tax" or "finding a new house before eviction day". The keys feel pretty soft, as they use rubber domes instead of metal springs, but the velocity response is excellent. I highly recommend it, as it's one of those products which basically lives forever and delivers year after year of good service.

I bring this up because back in about February, my KORG microKEY 37 stopped turning on. The unit would no longer connect via USB; each time it would give up at different points during the initial handshake, with dmesg spewing a number of unhappy messages. Here's one attempt at plugging the device in.

[Sun Sep 27 06:00:56 2015] usb 3-1: new full-speed USB device number 17 using xhci_hcd
[Sun Sep 27 06:00:56 2015] usb 3-1: device descriptor read/64, error -71
[Sun Sep 27 06:00:57 2015] xhci_hcd 0000:00:14.0: Setup ERROR: setup context command for slot 16.
[Sun Sep 27 06:00:57 2015] usb 3-1: hub failed to enable device, error -22
[Sun Sep 27 06:00:57 2015] usb 3-1: new full-speed USB device number 18 using xhci_hcd
[Sun Sep 27 06:00:57 2015] usb 3-1: device descriptor read/64, error -71
[Sun Sep 27 06:00:57 2015] xhci_hcd 0000:00:14.0: Setup ERROR: setup context command for slot 17.
[Sun Sep 27 06:00:57 2015] usb 3-1: hub failed to enable device, error -22
[Sun Sep 27 06:00:57 2015] usb 3-1: new high-speed USB device number 19 using xhci_hcd
[Sun Sep 27 06:00:57 2015] usb 3-1: Device not responding to setup address.
[Sun Sep 27 06:00:57 2015] usb 3-1: Device not responding to setup address.
[Sun Sep 27 06:00:58 2015] usb 3-1: device not accepting address 19, error -71
[Sun Sep 27 06:00:58 2015] usb 3-1: new full-speed USB device number 20 using xhci_hcd
[Sun Sep 27 06:00:58 2015] usb 3-1: Device not responding to setup address.
[Sun Sep 27 06:00:58 2015] usb 3-1: Device not responding to setup address.
[Sun Sep 27 06:00:58 2015] usb 3-1: device not accepting address 20, error -71
[Sun Sep 27 06:00:58 2015] usb usb3-port1: unable to enumerate USB device

Oh snap! I'm torn on what to do... buying a replacement is doable, but this one was limited edition and a replacement wouldn't be the same cool colour scheme! Maybe there's a clue to what went wrong inside the unit?

Article continues here! KEEP READING, YOU