Random flashing led smart effector

[Quadcells]

Hi,
I have had my Smart Effector since Febuary 2018, The Z-Probe led started Random flashing and cannot auto cal.
What can I do?

[dc42]

First check whether there is a bad crimp connection in the +3.3V or the ground wire in the 8-pin connector.

[Quadcells]

The 3.3v looks stable at the connector on the effector, but I am going to re-do the crimps and see what happens.

[Quadcells]

I have the same results:
Turn on printer, green LED flashes twice, then a few seconds later the green LED just randomly flashes. A weeks ago I had posted that I was not receiving any measurements after sending command G30 S-1 but that suddenly worked after a reboot. Not sure if the two are related.

[dc42]

Has there been any damage to the strain gauge traces on the PCB?

[Quadcells]

is the strain gauge traces the ones that go from r11 and r13, if so I measure 46.4 ohms.

[dc42]

That's one of them. The other goes between the same point on R11 and one end of R14. Schematic at https://github.com/T3P3/SmartEffector/blob/master/SmartEffector/SmartEffector_v1.3/SmartEffector_Schematic_v1.3.pdf. Both strain gauge traces should have approximately the same resistance.

[Quadcells]

R11 to R14 is 16k ohms , R11 to R13 is 47 ohms, problem:(

[dc42]

R14 to R11 is the strain gauge trace on the top side of the PCB. Can you see any damage to it?

[Quadcells]

@dc42 sadly I do. I must of scraped when I re-assembled the hotend after a jam. I have to be more careful in the future.
I can order a PCB from Filastruder, better than buying the whole setup.

[dc42]

@quadcells, if you can see the damage and it is localised, and you have a fine-tipped soldering iron, it might be possible to repair it by soldering a single strand from some stranded wire over the break. The traces are only 0.15mm wide, OTOH I've hand-soldered 0201 SMD components (0.25 mm × 0.125 mm) before now.

It would probably be OK to paint some polyurethane varnish or similar on to the PCB to help protect the traces in future.