Help with rewiring PFC Throttle Quadrant

[Norman]

I have finally come round to rewiring the internal of my PFC Throttle Quadrant new potentiometers and the Leo Bodnar board. The buttons I can solder and connect to the board easily enough, but the slide potentiometers are a pain to connect reliably. Some potentiometers I am able to solder and form a solid connection, but some would jump or act erratically if I were to jiggle the wires. This could be my soldering skills (or lack thereof) and I can't seem to troubleshoot the exact cause. I have attached a few pictures of my soldered terminal and I hope someone with experience can help me.

 

The weird thing is sometimes I will connect a certain potentiometer to the board and it looks fine with a full range of stable response, but will be non responsive if i were to reconnect the USB cable. Right now I have 4 out of 6 levers wired satisfactorily and I can't seem to get the last 2 to work reliably no matter how many times I resolder. These are Bourns 20k ohm potentiometers. The USB cable is connected directly to the motherboard and not to a USB hub. Is it the power draw that is the issue? Or poor soldering?

 

Any insight is much appreciated, thanks

 

 

 

 

I am now toying with the idea of using hall sensors instead for the sake of longevity. Would running a long bar magnet up and down close to a hall sensor work? I have mostly seen magnets rotated around the sensor with gears for a throttle system though.

Edited October 10, 2020 by Norman
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[Sokol1]

Solders looks OK, bright.

 

But those potentiometer looks very old. You have clean then inside, using isopropyl alcohol?

 

Problem with HALL sensor using sliding magnet is that you will achieve a short useful course, ~1 cm at much.

[Norman]

Thanks Sokol, tried to clean them but I haven't been able to get them to reliably work. I have ordered new potentiometers to see if that's the problem. 

 

The travel for the throttle and potentiometers are about 30mm. If I were to convert to HALL sensors, what is the best way to mechanically implement this? I just got a Virtual Fly TQ6+ and they use gears to rotate the magnets around the HALL sensor. Rotation is better than sliding travel? Since as you say the useful course is only 1cm.

 

[Sokol1]

This Quadrant use levers or "Vernier" like slider rods?

 

If are "Vernier" difficult will find appropriated contactless sensor for this 30mm course.

 

 

 

 

 

 

 

 

 

[Norman]

They are levers that translate the rotational action into linear sliding rods as in the photo. Basically these rods push and pull slider potentiometers. The new potentiometers came and they seem to work better. These are 100k ohms as opposed to the 20k ohms of the older ones. Could it be because the 20k ohm potentiometer requires more power from the USB? With 6 sliders requiring power, perhaps it is unreliable for that reason. 

[Sokol1]

Yes, lower K values requires more current from USB, but they are more "noise" proof than high K values pot.

 

Since the Quadrant use levers, can use Bi-Tech 612x Hall sensor, assembled like a conventional pot.

 

https://br.mouser.com/ProductDetail/BI-Technologies-TT-Electronics/6127V1A60L5?qs=sGAEpiMZZMs0JOhy9PM0UT2KuCf1H3wX0A4NJp8zcxs%3D

 

The linked model have 60º of "effective electric angle" (check datasheet) what probable are close to the levers angle movement. A 35 degrees model is available:  6127V1A35

 

[Norman]

Yes it seems like the higher power draw for the 20k potentiometers is the issue. I replaced 4 of the 6 20k pots with 100k pots and everything seems stable now. I managed to get quite a bit extra 100k pots so hopefully this set up will last for a long time. If they pots get faulty it will be an easy swap out. 

 

Unfortunately the way the quadrant is set up, I have to use the linear push rods to translate mechanical action into the pots. The levers are interchangeable, so I can swap out a 6 lever set up to a 3 lever setup and vice versa. It's a pretty good design actually. I will shelf the hall effect sensor idea for now.

 

Thanks Sokol for your feedback and help!

[matt511]

Hi Norman

 

Sorry to butt in but you don’t happen to have a potentiometer part number do you?

 

Would be really helpful if you could help.  

 

Many many thanks

 

Matt.