Problem regarding to my Nord Lead 1

[filkry88]

Hello,
I recently bought a Lead 1 expanded with some kind of trouble. While turning on, the keyboard shows Pitch Bend Error, and after the boot the keybed doesnt trigger any sound. The keybed is functioning as it should, because turning Pelle's Mode allows keybed to work, and the sound is produced so as the pitch bend works as it should. It does sound weird however, I don't think that is how it should sound. After dismantling the front cover, I began to troubleshoot. I desoldered the pitch bend, the keyboard began to show that the instrument is a rack version.
While disconnecting the control panel PCB from the mainboard and turning the Nord on, this kind of trick allowed keybed to work as it should. The sound is a little too quiet and harsh, like it was connected to some kind of vintage distortion effect.
Does anyone know the solution to this problem? Did anyone experienced this?


Thanks in advance.

[pterm]

Sound issues with Nords often occur with an incorrect or malfunctioning pedal connected.
Try disconnecting any pedal.
Also, compare headphone output to the main L/R outputs - let us know if you hear a difference as that might point to a cause.

[filkry88]

Sound issues with Nords often occur with an incorrect or malfunctioning pedal connected.
Try disconnecting any pedal.
Also, compare headphone output to the main L/R outputs - let us know if you hear a difference as that might point to a cause.

there aren't any pedals connected. changing audio outputs does not make any difference.
I suspect the motherboard thinks it is a rack version because I disconnected the mod wheel and since the rack version doesn't have one the motherboard show the message as it should..
I wonder why does the control panel while connected to the main board is somehow turning off the keybed. Disconnecting the control panel "live" (while the instrument is turned on) the keybed goes alive instantly.

[filkry88]

I suspect the Lead 1 has similar circuitry to the NE2 whose schematics (and service manual) may be found online. This may help you:
NE2 Service Manual & Schematics

Please take the precaution of touching the metal chassis of your Nord before touching any circuitry with a finger or tool. This helps discharge any static electricity that might otherwise damage electronics.

The NE2 panel board has a resistor pair (R50, R51) for selecting between Rack and Normal modes. If you can find the corresponding components on your panel circuit board you ought to be able to trace the wiring and look for any anomaly. If you have a multimeter (Ohm meter mode) I recommend verifying the resistor values - sometimes resistors crack causing an open circuit. I expect that the motherboard "reads" these resistor settings at boot to determine its behaviour mode. If some issue exists, it selects the wrong mode. Disconnecting the panel causes the motherboard to select its default mode.

The distorted audio might indicate an issue with the power supply. Please compare the the NE2 power supply circuit schematic to the NL1 and if you have a multimeter (volt meter mode) measure the supply voltages to verify all operate correctly.

If you need help, please post pictures of the circuit boards and I can try to provide guidance.

[filkry88]

I suspect the Lead 1 has similar circuitry to the NE2 whose schematics (and service manual) may be found online. This may help you:
NE2 Service Manual & Schematics

Please take the precaution of touching the metal chassis of your Nord before touching any circuitry with a finger or tool. This helps discharge any static electricity that might otherwise damage electronics.

The NE2 panel board has a resistor pair (R50, R51) for selecting between Rack and Normal modes. If you can find the corresponding components on your panel circuit board you ought to be able to trace the wiring and look for any anomaly. If you have a multimeter (Ohm meter mode) I recommend verifying the resistor values - sometimes resistors crack causing an open circuit. I expect that the motherboard "reads" these resistor settings at boot to determine its behaviour mode. If some issue exists, it selects the wrong mode. Disconnecting the panel causes the motherboard to select its default mode.

The distorted audio might indicate an issue with the power supply. Please compare the the NE2 power supply circuit schematic to the NL1 and if you have a multimeter (volt meter mode) measure the supply voltages to verify all operate correctly.

If you need help, please post pictures of the circuit boards and I can try to provide guidance.

thanks man, I probably will start working on it tommorow, will be posting updates on this.

[filkry88]

I measured the voltage with the multimeter on the PSU board, everything seems to be in order, every transistor shows the correct value. Two capacitors on the main board shows almost no voltage at all (C1 and C15, near the audio outputs). I really don't know what is wrong with this thing...

[pterm]

I measured the voltage with the multimeter on the PSU board, everything seems to be in order, every transistor shows the correct value. Two capacitors on the main board shows almost no voltage at all (C1 and C15, near the audio outputs). I really don't know what is wrong with this thing...

The capacitors near the audio section might be AC-coupling capacitors in the audio signal path so they normally don't have a DC voltage across them.

The next easy thing to try is to carefully disconnect and reconnect the connectors between boards:
- disconnect the AC mains power
- take pictures so you can correctly orient the connectors when reconnecting them
- remember to discharge yourself by touching the metal chassis first before touching any circuit boards.
- the connectors have latches that must be unlocked before the disconnecting the cables. These must be locked after reconnecting.
- disconnect/reconnect only one connector at a time so you do not mix up connections and do not change the orientation.

If you are not 100% certain how to do this, please post pictures and I can reply with guidance and further explanations.

[filkry88]

hi, sorry for such a big delay in responses (work and stuff)
i took the mainboard to a repairman who desoldered and soldered back new IC's (the DSP processor and the MC6833 microcontroller)
after the repair the instrument does not do anything. the display is showing nothing
i suspected the microcontroller to go bad because when I turned on the instrument with the control panel unplugged, connecting the Nord via MIDI cable to another instrument the instrument itself was changing parameters of the selected sounds randomly.
now it is dead (lmao)
i will try desoldering the DSP processor and putting the original one back, maybe it will help
will be posting updates soon