Bad read value from dc42 IR sensor

Charpy

Hi everyone,

For my core XY I' work on a duet 2 wifi rev 1.02+ with the 2.05 firmware and the wifi version is 1.23.

Here is my problem : My sensor never give me a read value of 465 or 535 but directly 986 and it stay's like that...
In result i have very bad accurency when probing...

The sensor flaches 4 times at start up and the led light's up correctly when probing.
I've tried different surfaces like hand, black tape, white paper and different ambiant light but the result is the same...

i've define like this in my config.g file :

M558 P1 X0 Y0 Z1 F100 T2400 H3 A3
M557 X10:440 Y10:530 S30:30
G31 P500 X3 Y108 Z2.160

Thank's in advence !
Charpy

Phaedrux

Try increasing your dive height from H3 to H10 and see if it improves.

Charpy

Thank's for your answer !
I have the same result : the value of the probe is the same : 986...

Phaedrux

Is this a new probe?

Charpy

I hope ! i've buy it last 2 month on RepRapworld.com
On the back of the pcb it's writed ver1.3.

Phaedrux

Can you try cleaning the sensor gently with a cotton bud and some isopropyl?

Charpy

I did it,
Now the result is 984

Charpy

Finally I found it!
based on the diagram here: https://raw.githubusercontent.com/dc42/OrmerodSensorBoard/master/SchematicAndPCB/Mini-differential-IR/V1.2/schematic.png

I saw that the value of the R5 resistor was +10M ohms.
In fact the resistor was poorly soldered and is not possible to see it with naked eye!

Now the probe read correctly 465 and 535.
Luckly i'm not bad with electronics. someone else would just have tossed it in the trash! ...

Phaedrux

Well done!

Charpy

I still have a mistake...
I've leveled my bed as best as i can by hand but the height map look like this : 2020-05-07 15_59_03-CoreXY.png

And is impossible I have 1.4 mm higher on the back
The probe seems to "drift" by the time. (as you can see on the X moves)
I tried other cables and different microstepping setup but the result is the same
This is possible ?
Any idears ?

thank's in advence

Charpy

It is possible that the sensor is damaged by the bad solder of the resistance ?

I think i have tried all i can do... I need some help ! ...

Phaedrux

I'm affraid it may be time to replace the probe.