Check Perforated Board Conumdrum!

Hi, I'm new to this board.  I have an interesting problem though.  I'm hoping to figure out the cause of it.

I started getting the message "Check Perforated Board contacts and restart printer" recently.

I'm only had my printer for a week.  The printer is a demo model, but the heated bed, perforated board, and cable are all new.

I also want to say that the printer had been factory refurbished prior to me getting it.

The problem started when I removed the perforated board to remove a printed object.  When I replaced it was when I started getting the message.

What I found to be confusing is that if I put the board on the heated bed and I only put a few of the screws in, I don't get the message.

If I screw it down with all the screws, I get the message.  If the board is just sitting on the heated bed, no message.

It appears that the tighter the contact that the board has with the heated bed is causing the problem.

I checked and re-soldered the connector and found that it didn't do anything to help or hurt.  I read another post, on this forum, suggesting that the connector could be a problem.  It doesn't seem to be, in this case.

I looked carefully at the bottom of the perforated board and I found one scratch that revealed bare metal.  It was a very small scratch.

I thought that maybe it was causing some kind of short, so I tried covering the scratch with tape.  I got a mixed result.  At first, it helped, but then, I started getting the message again.  Once again, if I used all the screws in the board, I got the message.  If I only used a few, I didn't get the message.

I tried downgrading the printer firmware to .8, but that didn't help.

I finally decided that the board must be defective and I ordered a new one.

I haven't gotten my new one in, yet, so I can't test to see if that makes a difference or not.

But, in the meantime, I decided to try something else.  I covered the bottom of the perforated plate with Kapton tape.

I placed it back on the heated bed and it worked.  But, I didn't replace all the screws.  I only used a few.

So, I'm still not sure what could be causing the problem.

If anyone has any ideas, I would appreciate the help. 

There could be some kind of short indeed. Get back with result after replacing heatbed because it is kinda interesting.

Okay, here's the latest!  I put all the screws in place on the perforated board and I tightened them.

Everything is working.  No problems occurring.

There has to be some sort of electrical arc or short happening between the perforated plate and the heatbed.

That's the only thing that explains this.

For now, I'm happy that I can get back to printing.  I won't be able to test a new board until April because I have to go out of town for a spell.

If anyone else has this happening, they might want to try this same trick to solve it.

I'll update this post if anything new takes place!

I've mentioned before that the counter sunk screw holes in the perf board could be scratched such that the contact layer is exposed thus allowing a grounding path from the perf board through the screw into the mounting plate, this would seem to be why some screws can be used and those that cause the short have to stay out, try repainting the c-sunk holes in the perf board to regain the insulating layer.

If you´re problem still exists, you can read this thread. The root cause might be the same (and the conclusion at the end)

My fix for the problem is to cover the aluminium bed with Kapton tape. This insulates the perfboard, which if you run a multimeter over the bottom will almost definitely find is conductive in areas.