Live & Learn..... I Guess

It’s been an interesting couple of days. 1st, after dialing in my new BLTouch, I decided to redo things a bit. Someone posted that it helps to dial the bed springs up tight, then loosen them a couple of turns. Sounded like a good idea.

1st problem: after powering up & trying to AutoHome, the printer tried to drive the nozzle to China. Fortunately, I hit the power switch before any damage was done – the glass didn’t even break. I tried cycling the power a couple of times, with my finger hovering over the power switch. Good thing: I had to quickly power off both times.

Then, I realized that the BLTouch wasn’t powering up, nor the LCD. Opened up the power chassis, reseated the breakout board 3 times (until I finally got a normal display instead of a blank screen).

While I had the power chassis open, I decided to replace the ribbon cable that links the control board to the display, because the original 1 was being stretched just a little after I moved the LCD Display unit up to make room for the storage drawers underneath. I wanted to give extra length because I’m thinking of redoing the drawer unit to make the drawers a little taller & probably add 1 or 2 more drawers. These ribbon cable connectors are a real PITA to dissassemble, but I’ve done it a number of times in the past, so I knew what I was in for. On the positive side, the new ribbon cable worked 1st time :slight_smile:

Next was to dial in the Z Offset again. I reviewed a couple of YT videos to see if they had any tips or tricks I wasn’t aware of.

I ran into a problem. I used Pronterface to talk to the printer. I issued a G28 to AutoHome the printer. The X axis moved all the way to the right, as expected, then started to move back on the Y. However, something weird happened: the hotend moved about halfway back then moved forward & left as if it was moving to the center to home the Z axis using the BLTouch. Unfortunately, it didn’t stop at the center. It kept moving left & forward until it started to bang into the front cross rail. Power button time again. Tried it again a couple of times. Then, I stood up from the chair I was sitting on & noticed something. The cable that links the hotend to the control board had flopped over to the rear of the printer and, guess what, it was being pushed into the Y axis limit switch. So, a note to the wise… Also, it seems like a good argument for a cable chain.

I flipped the cable back up where it belongs and AutoHoming started working properly again. I did the paper trick to find the Z Offset value, then printed a few of the 20mm X 20mm 1-layer squares, adjusting the Z Offset before each print. Got it dialed up pretty well, but the squares were coming out a little thick, so I reduced the flow rate from 98 to 95.

That’s about it for now. So, watch out for little things like cables flopping over, and axes moving where they don’t belong.

Good advice. Been there bought the t-shirt and threw it away. More then once actually. ?

You can usually babystep Z in Marlin 2.x.x (if enabled), by pressing the wheel quickly twice. This allows you to lower the nozzle on the fly to see the result

When the position is ok you can use that value to configure your z offset.

I know, I mentioned it before, but I have all my z-endstops with an adjustment knob, so I can turn a wheel just like the once under the bed to get the perfect position. This is very handy and never failed me.

Speaking of dangling things within the print area: I fixed the Raspberry Pi mount I broke and screwed it onto my AnetA8 printer again. I later on had a minor issue and wanted to fix that, before starting a 12 hour print, when I noticed that the Raspberry Pi, would have fought with the z-gantry as it was straight mounted in its way at a z level of 100mm. That would have given a big bang.

Sometime you need to be lucky. :smiley:

Yeah, like being able to hit the power button just in time.