Hi everyone:
First let me state that this is not a project to be taken lightly, If you have not worked with line level voltages DO NOT take this warning for lightly. Working on this level of voltage is dangerous and should not be undertaken by anyone who is not skilled in electronics. It involves the complete disassembly of the heat bed and the original cable to get the small control wires free of the original cable. I am not responsible for any damage to your printer or injury. This is for information purposes ONLY!
I’m not going to post photos of the tear down or reconstruction, I’m doing this for your own protection and mine.
First one of the biggest problems of the attempt at rebuilding is the molded grommet on the cable. There is no easy way to salvage that. So I was able to make a new version of it using CAD, I actually made 2 versions one that is split so that you can use it without cutting or disassembling the control wires. The second would require the removal of the connectors at one end to slip it through, I opted for the split version.
After doing forensics on my damaged cable I did see heat damage, BUT mine was inside the original grommet, and like most others had the black wire (AC Hot) slightly melted to the white and ground. A heat scan would have never seen this because it was deep inside the printer base.
The control wires are a bit tricky because it actually has a bare ground wire that wraps around the entire length control wire harness, then it connects at both ends to the power wire ground wire. I reconfigured that to fix the issue so they are 2 separate connections now. This also isolates the wires from each other so the harness is more flexible.
I needed to look up the power specs for the A1so I know how much power I was dealing with, The A1 comes it at 95 Watts average, that works out to about 1 amp total current draw. If I boosted the numbers to 220 watts the average is still 2 amps.
So with those numbers in hand I started looking for wire, Silicone test lead wire is what I already use on all my printers. It’s super flexible and had more strands than the wire currently in use. I opted for wire rated at 800 volts and 13 amps. The new wires inside diameter is twice the diameter of the original. Test lead wire is meant for extreme environments that require high numbers of bending cycles, and the silicone jacket will stay flexible for many many years. I then used a flame retardant braided wire snakeskin to create 2 wire harnesses that separated the control wires from the bed power. I bought the proper crimp tool to recreate the crimps of the bed cables but I opted for gold plated terminals instead of tinned.
With all that said, I re-trammed the bed. Did a full re-calibration let the bed run at temp for an hour. All looked good. Did a test print and no problems. Tested the wires for heat and nice and cool. So here is some photos of the final result:
It all looks very good and clean. Is it possible to modify the housing so that the heating cable comes out on the right side? so that you can put the printer closer to a wall? Another question: you haven’t gotten a new heated bed yet?! but modified the old one?
Correct, this is the original heat bed. Since the replacements heat beds aren’t coming online for another month I needed to get this unit back in production.
As for your other question, anything is possible if you have the room to do so. The issue here is that there are 2 circuit boards inside the unit that eat up much of your space. Also having the cable exit the right side would put an extreme bend on the heat bed connection.(not advisable) since the bed movement would cause the cable to have to twist and in some cases might actually interfere with it’s ability to fully move the bed. Perhaps a much longer cable would fix that issue, I’m not sure but if it had the extra room to bend up and then had a way to support the extra cable so that it had a relaxed bend coming back down you could use less space. (That is only a thought not proven or tested)
I don’t think they would, they can not sell it as a new part if they rebuilt it and what do you do with hundreds if not thousands sitting in a warehouse somewhere? The real key to doing this is carefully document all wires and their paths. I’m considering putting the .stl file up on thingiverse and printables. As I stated I used the split version, it has holes to add 2mm pins to help hold it together.
If your interested in those files let me know.
Happy Printing
M
I could but I’m hesitant to do so because of the liability involved. I’ve been a Audio/Video Engineer for over 30 years, working around these type of voltages and circuits are very common for me. And I still treat them with respect. But for those who have not done so there is a potential for damage to your printer, injury or worse.
This involves the total disassembly of the heat bed, and the complete disassembly of the heat bed cable. To do so means you will have to carefully dissect cable and the total destruction of grommet, hence the need to print a new one.
The original reason for the post was simply a proof of concept that this could be done. Since I’ve Built, rebuilt and modded almost every 3D I own over the years, it’s a pretty straight forward process for me.
There is a great video on Youtube from a user by the name of Vector3D he totally disassembles a A1 and you can see what’s involved in taking the bed apart.
Here is the link to that video. A1 Teardown
Even his analysis of the bed cable is incorrect. But you’ll get the idea of how to take a bed apart from this.
Oh my God…
Are you just now thinking about it?
Should you have done that before you posted here or are you really that naive and believe that no one else will want to do the same?
So I wouldn’t risk my BBL guarantee or my life and limb to imitate it.
But anyone who does this, with or without instructions, should take note of the nickname so that they can possibly make claims if it goes wrong.
I don’t see anything @user_219516602 has done wrong here. He isn’t saying “hey everyone you need to do this!”… He’s simply shown us something he did based on his experience and he made that clear. I appreciate what he posted. I have the experience, but won’t do it myself even though I know I could, and that’s my choice. If I did, that’s also my choice and I know I would be taking that risk. It’s mine to own. Why would you think anyone should be able to blame him if they decide to do it and it goes wrong? He didn’t state that it’s a certified solution. I get there are some dense people out there that just go with what they read, but that’s their problem and a choice they have made.
Claims? If someone doesn’t know their own level of competence that isn’t this guys problem. Its replacing a wire, not rocket science. Anyone that is capable of this, already knows their ability level.
Don’t show anyone what you can do unless you’re sure they can do the same.
He shows you, but is reluctant to show you what he did because he is afraid that he will be prosecuted for it.
But how many people here do it even though they don’t know how to do it and from that point on it shouldn’t even be shown here.
Because you can use it to sign for others.
That’s why I have no understanding for posts like this.
No one can prosecute anyone from posting information on here, get real. If anyone is incapable of replacing a wire but does it anyways THEY are responsible for what happens. Get real, you can’t read something on a forum, do it, then sue whoever because you are an incompetent moron.
Seriously?
With a mentality like that, there would be absolutely no education ANYWHERE, at any time, and NO ONE would be able to learn how to do anything at all.
There would also be no progress, no inventions, and no developments in any industry. The entire world would come to an abrupt screeching halt.
If you don’t feel comfortable doing something, then don’t do it.
There really isn’t a need for you to chastise someone for simply sharing information.
If you cannot form your own opinion as to why information such as this gets posted, then perhaps you should re-evaluate your own usage of 3D printers as a whole.
Even if someone does try this and fails, it is inherently human that we learn way more from our failures than we ever do from our successes. Failure is NOT a bad thing. You learn what not to do next time, and if used properly will give you the motivation to do it better the next time.
No reward comes without risk, no matter what the process is.
As someone stated before, this is not rocket science, brain surgery, or tight rope walking over the grand canyon. It’s replacing a few wires and doing it properly.
Anyone qualified to carry out such a repair safely does not need further instructions.
Anyone who needs instructions should stay away for safety reasons.
