BL Touch not doing self test

Have 3 month old Ender 5 Plus w pre-installed BL Touch. Been working with moderate success until yesterday. The bed doesn’t move up when pushing the home button, only down. The BLT is constantly blinking red. With several power off/on the BLT is still blinking red and the probe doesn’t drop. With power off I can easily pull the probe down then up and down again w/o any force. When power on the probe moves up and stays in the up position and blinks red.
Set up is nothing fancy, using SDcard until i learn more. Assume latest v of BLT since 3 months old.

The version of BLT (hmmmm Bacon,Lettuce,Tomato sandwich :slight_smile: ) is silkscreened in tiny print at the bottom of the circuit board, underneath the cable connector.

Biggest problem with BL Touch is the cables on the mainboard. Check to make sure none of them are loose maybe even pull them loose and re-install them. Some people even go as far as hot gluing them in. I cut the dupont connectors off and put a 5 pin female JST connector on it ( the ender 3 V2 has a 5 pin JST male connector for the BLTouch)

For sure check those connections. My BLTouch didn’t power up until after the 3rd reseating of the connections.

This is why I don´t like these flimsy sensors.

They just don´t save time and they create additional sources for errors (wires, mechanical problems). Especially the mechanical touch sensors are under constant stress, as they are mounted next to the hotend with 200°C or more. Also the heat from the build plate 60-110°C constantly blows around it. This screams for an over time error of the sensitive and small mechanical hardware in these picking sensors. Induction sensors are not as “on point”, but better, if you want a sensor at all.

Better get a flat surface in the first place and make your Z-Endstop adjustable by a hardware turn wheel. So you have the adjustments under the bed and once the bed is leveled, you tune the adjustment on the Z-Endstop to get the z distance. Done. Works forever.

I find that my bed changes level after several prints and I have to do the level again. Also, my bed is glass so a capacitance sensor isn’t likely to work very well. And, so far, the BLT seems to be working well. I could see that working if I got rid of the springs & bolted the bed directly to the undercarriage, with some standoffs so as not to pinch the bed heater wiring. If seems unlikely it could change at that point.

Agreed love my PEI power coated spring steel sheet as it makes it a breeze to remove prints, but one draw back with it is it’s not perfectly flat. And i had the same problem you did where the bed level was not the same each time.

Thank you all very much.
I did open the control panel and pushed.seated all the wire connectors to their matching pairs. Didn’t feel any give on any so I don’t know if I made the necessary wire touch. In the end, the BLT (not the sandwich) came back to life and I’m printing again. Self check succeeded.

Question for you all experienced folks. I see many people including yourself modding, changing boards, hot gluing connectors, etc. In my first foray into looking at the gut of this thing I was surprised how awkwardly designed the device was for the customer based that seems to be encouraged to mod their printers. The E5+ literally required access from the bottom requiring tipping the printer on a side where the motors could be a resting point.

Maybe Creality is better or worse for this than other 3D printers, but it would seem to be in their interest to make access for switching boards and adding other components more mod friendly. It took 2 people with one holding up the printer on 2 corners and the other unscrewing the bottom plate and pushing connectors.

I also noticed a couple open connectors inside the control case as if waiting for some other device(s) to plug in. I realize you may not have an E5+ but does anyone think or know what the future intention of Creality is for these? (I should have taken a picture.)

Thank you again,