Nord User Forum

My faithful NE2 has died on me, no LEDs, no display, no sound. Short story first, i tried the test program (Program 1+3+5 from the service manual). And voila, display is active, but it only shows first one dash (-), then the second dash, and then it goes black again. No more tests are run and no response but buttons (shift + up / down). I can't find anything in the service manual about dashes, only the usual E7 etc.
Tried to connect USB to both a Mac and Windows machine to update firmware, but not detected in system profiler or device manager.

Before I ran the test program, I started with tracing power. All rails on the power board seems to be solid (3.3V, +/-5V, +/-12V). Could it be some bad electrolytic capacitor on the main board that holds down the voltage somewhere? Or does the dashes indicate that something is wrong with the flash, OS, bootloader?
Since USB isn't discovered, is MIDI a more "direct" route to firmware update the microcontroller?

Any help is appreciated.

I am afraid it can be something more serious that just the power supply (which you may anyway check to ensure all voltages are being rpoperly generated) and OS update can only be done via USB afaik.

You may check in NE2 service manual if there is any way to boot it in an "Update mode" rather than in "Test mode", but if there is a PSU or other HW issue it may not work as well (even if existing).

I've sort of ruled out the power supply, since I see all output voltages (10pin ribbon cable) to be within spec (3.3V, +/- 5V and +/-12V). My first thought was one or more power rails (most likely 3.3 or 5V, as 12V is probably amp section) can't handle to large number of LEDs (which in total will consume considerate current) and the power dips at power up so the microcontroller goes into some limbo mode (brown out voltage).
I'll hook each power rail up to an oscilloscope and check. Hopefully it gives me some hint.

Oscilloscope showed next to no ripple on either rails, nor any dips or brownouts at power up. Hunt continues.

After power, check resets, then clocks.

The device SP705CU (U27) is a reset supervisor chip.
Use ESD-safe practices when probing the circuit boards.

You might want to check out the Troubleshooting section of:
https://www.nxp.com/docs/en/application ... 332TUT.pdf

You seem familiar with electronics, but if you need help please ask.
Good luck!

Edit: Added link to M68331 document

Thanks. Yes, I forgot to write it. Since the Nords seemed to be plagued by faulty memory, I checked their reset. Pin 1 of SP705CU is briefly low (reset) at power up, then goes high. I'll check reset_0 and reset_1 signals later tonight.

Does anyone know if the test program (program 1+3+5 at power up), is affected by a failed OS? Does it check OS integrity at test start?
In the service manual it says the test program is residing on chip U17, which is M27C1001 (one time programmable or UV erasable), so it is impossible to be overwritten during a OS update.

Also, the USB is going to a PDIUSBD12. Is this chip programmed/configured at every power up by the micro controller, or is the PDIUSBD12 programmed once at the factory (or OS update) to be a stand-alone USB-interface? If the latter, I don't understand why my computer doesn't detect the NE2. If the PDIUSBD12 needs to be configured at every power-up, I understand (since the micro controller probably doesn't work correct on my board).

okwestern wrote:Also, the USB is going to a PDIUSBD12. Is this chip programmed/configured at every power up by the micro controller, or is the PDIUSBD12 programmed once at the factory (or OS update) to be a stand-alone USB-interface? If the latter, I don't understand why my computer doesn't detect the NE2. If the PDIUSBD12 needs to be configured at every power-up, I understand (since the micro controller probably doesn't work correct on my board).

The PDIUSBD12 Data sheet says:
6.6 SoftConnect
The connection to the USB is accomplished by bringing D+ (for high-speed USB
device) HIGH through a 1.5 kΩ pull-up resistor. In the PDIUSBD12, the 1.5 kΩ pull-up
resistor is integrated on-chip and is not connected to V CC by default. The connection
is established through a command sent by the external/system microcontroller. This
allows the system microcontroller to complete its initialization sequence before
deciding to establish connection to the USB. Re-initialization of the USB bus
connection can also be performed without requiring to pull out the cable.

--So it appears that the M68331 must be running and configure the USB for it to enumerate on the host PC.

True. I just finished probing the test connector (which happens to be a standard BDM connector - background debug mode). Sadly I don't have the interface, so I just probed each:
TP2:
1 (!DS): 0v
2 (!BERR): 4.95v
3 (GND): 0v
4 (!BKTP): 4.95v
5 (GND): 0v
6 (!FREEZE): 0v
7 (!RESET): 4.16v
8 (IFETCH): 4.95v
9 (+5V): 5v
10 (IPIPE): 4.95v

Any clues here?

I've now looked at the signals, and at boot CSBOOT should pulse 5 or 9 times (16 or 8-bits port), but it keeps pulsing forever. This could be due to a corrupt OS image, or MCU not being able to read flash memory, or execute the program. I see the RESET should be pulled up with 820R, but the NE2 by design has 10k. Quite weak compared to the datasheet recommendation.
TP2 FETCH and IPIPE (serial data in/out) pulses at a high frequecy.

Just tried to update OS over MIDI, but the OS updater says it can't find any synth. I'm using Steinberg UR22 as USB->MIDI and Windows 7.
I can't get into "update mode" when I press PROGRAM 1 + PROGRAM 5 at power-up. It should show "rd" or "--", but it shows nothing.
Any clues?