Nord Lead Pitch Bend Error and PCMCIA card

[catosim]

Hi
Recently purchased a second hand (or, third, fourth...) Nord Lead (1). I've given it a caring treatment, and cleaned every part.
Tried to bleach the keys (the've been quite yellow), but the result was not superb (didn't try with dental bleacher )
Anyway, upon startup the display reads Pitch Bend Error, and the pitch bend doesn't work.
I did run the test program (Shift+System+Slot C), and the display reads 5.6. If I turn the bender to the left, the value decreases to .2, and to the right the value increases to C7.
Can't find much info, or any Service manual for the original lead - so I'm not familiar with what the values should read.
Any insights will be highly appreciated.

Also I've installed the Voice expansion V1.2 to add more polyphony. I've read some older threads about the possibility to use newer PCMCIA cards, instead of the originals (that are expensive and hard to find).
Any advices about this?

[catosim]

Bumping this thread

[catosim]

Let me rephrase the question.
If I replace the pitch-stick, will it be sufficient just to solder and attach the new one, or does it need any calibration afterwards in order to operate as it should?

[23skidoo]

My gut says you might want to try re-calibrating the current one, if that's an option. It may just no longer be giving a reliable centre point. IIRC it uses two flex sensors in opposing directions. I'm not familiar with the calibration process, though, or if it's even field-possible. Usually those are resistive potentiometers of some sort, so you might want to probe those connections and read the voltages at the centre, and then sweep it left and right, and compare those with another model - you have an A1, I wonder how different the pitch stick values are? Might be a good starting point to see if your stick is the problem or if it's just gone out of calibration (resistive values do change over time, it might be outside some pre-set drift range or something?). If you're handy with a DMM, do it with the board powered up so you can see the supply voltage to the stick and the resistor-provided signal back.

.. Thinking about it, it might also mean one channel's gone bad but not the other. Look for discontinuities in the signal - full supply voltage or shorted to ground, etc. I'm guessing the pinout has V+, Gnd, and P1/P2 for the two pots, but I don't know in what order. You'll have to just poke around and see.

[catosim]

Let me rephrase the question.
If I replace the pitch-stick, will it be sufficient just to solder and attach the new one, or does it need any calibration afterwards in order to operate as it should?

No calibration is needed (I replaced one on my older NS2), the principle by which the Nord Pitch Stick works (differential/resistors bridge) does not require a fixed/hw calibration, it is calibrated at every power-on by reading its zero (balance) point (which is why you should not move it during boot and you know if it is broken you get a "Calibration error" at boot, in fact, at least on NS)

[catosim]

Let me rephrase the question.
If I replace the pitch-stick, will it be sufficient just to solder and attach the new one, or does it need any calibration afterwards in order to operate as it should?

No calibration is needed (I replaced one on my older NS2), the principle by which the Nord Pitch Stick works (differential/resistors bridge) does not require a fixed/hw calibration, it is calibrated at every power-on by reading its zero (balance) point (which is why you should not move it during boot and you know if it is broken you get a "Calibration error" at boot, in fact, at least on NS)

Yea, I'm aware of that the pitch bend shouldn't me moved during start-up. The "logic" conclusion is to assume that that it is faulty due to heavily bending in the earlier life og the synth.
Anyway I'll give the suggestion from Skidoo a try as well, when I get time for it:

so you might want to probe those connections and read the voltages at the centre, and then sweep it left and right, and compare those with another model - you have an A1, I wonder how different the pitch stick values are? Might be a good starting point to see if your stick is the problem or if it's just gone out of calibration (resistive values do change over time, it might be outside some pre-set drift range or something?). If you're handy with a DMM, do it with the board powered up so you can see the supply voltage to the stick and the resistor-provided signal back.

.. Thinking about it, it might also mean one channel's gone bad but not the other. Look for discontinuities in the signal - full supply voltage or shorted to ground, etc. I'm guessing the pinout has V+, Gnd, and P1/P2 for the two pots, but I don't know in what order. You'll have to just poke around and see.

Thank you, guys

[23skidoo]

I guess it is either one of the cables disconnected or one (or both) of the sensors damaged. Have a look at the patent diagrams https://patents.google.com/patent/US5696345
It would be good to find out who makes the sensors or a suitable replacement (can't be that expensive) so it can be repaired without having to pay for the whole pitch stick assembly.

[catosim]

I guess it is either one of the cables disconnected or one (or both) of the sensors damaged. Have a look at the patent diagrams https://patents.google.com/patent/US5696345
It would be good to find out who makes the sensors or a suitable replacement (can't be that expensive) so it can be repaired without having to pay for the whole pitch stick assembly.

The cables didn't have any visible damage, so I suspect the problem is somewhere on the stick.
The sensors are referred as Strain gauges, nr. 21 on fig.1 and fig.2. Not sure if this one is replaceable, or maybe the entire leaf spring (nr.3).
Need to do some investigation if these parts are possible to obtain from any dealers. Your help is very much appreciated Mr_G

[23skidoo]

If you can get me the dimensions of the strain gauges and maybe a high-res photo, I can perhaps suggest a suitable replacement part. They're quite simple and 350 ohm is a standard size. The circuit is trivial.

You won't need to replace the leaf spring at all, it's not the problem for sure, unless it's snapped in half or something! I'd be more concerned that the entire pitch stick is actually fine and the opamp or adc are where the problem is. Until you measure the resistance of the strain gauge though, it's hard to say.

[catosim]

So, finally made the effort to measure the resistance of the strain gauge.
This is what came out of the measurements:

Skjermbilde 2022-11-20 kl. 18.17.55.png (20.19 KiB) Viewed 3253 times

Skjermbilde 2022-11-20 kl. 18.17.49.png (19.77 KiB) Viewed 3253 times

Skjermbilde 2022-11-20 kl. 18.17.41.png (22.52 KiB) Viewed 3253 times

Skjermbilde 2022-11-20 kl. 18.17.35.png (25.21 KiB) Viewed 3253 times

Here are some photos from the wiring inside:

315965648_3379013409092176_3132604670381913585_n.jpg (296.9 KiB) Viewed 3253 times

315915765_629402612306558_8594074311005386898_n.jpg (207.38 KiB) Viewed 3253 times

315530033_3381780642101649_6929028886121209690_n.jpg (208.84 KiB) Viewed 3253 times

I did the measuring using the red measure-pin on the left, and the black on the right side.
When a switched opposite, the measurements was reading:

Left Center Right
277 249 221