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Mk1 bed connector issue  

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PJR
 PJR
(@pjr)
Antient Member Moderator
Mk1 bed connector issue

Hi Guys

About 4 months ago, I had the heated bed cable fracture because of continuous Y movement, so I replaced the cable and all was good.

Yesterday while in the middle of a print, the heater stopped working - I was out at the time, but monitoring the print via OctoPrint.

Fortunately, I was printing with PLA, so the print stuck well to the bed until it was complete.

This morning, I disassembled the printer expecting to have to change the cable again, but this time, it was the connector itself which had failed - burnt out with melted plastic. When I removed the connector, I checked first that it was fully inserted into the socket.

The pins on both the socket and plug of the connector are black, so this is exactly what we have seen before, and I had put down to the plug not being fully inserted into the socket (yes, it seems I was wrong again).

I will now solder the heater leads to the bottom of the RAMBo, as the connector is to burnt to be re-used. However, I now have the thought that if there is an issue here it could also affect the Mk2. Time will tell...

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 10/07/2016 10:46 am
AustinTruelove
(@austintruelove)
New Member
Re: Mk1 bed connector issue

I had one burn up on my with my MK1. Today, the same with my MK2. When I first upgraded, the connector burned a little, but stopped. Today We have a full on melt down. Luckily though I have a spare connector. Hopefully I can get it to work. I don't want to solder on the board itself if I don't have to.,

Posted : 10/07/2016 7:33 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Topic starter answered:
Re: Mk1 bed connector issue

Yeah, the problem is the socket is also likely to be damaged and the worst thing to do is to attempt to de-solder the socket from the board. Most likely outcome of that will be broken tracks & RAMBo replacement.

The soldering onto the board is very straightforward; just ensure you reflow the board connectors with a lead-based solder.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 10/07/2016 9:07 pm
henrik.w
(@henrik-w)
Estimable Member
Re: Mk1 bed connector issue

I have seen this happened on more expensive machines for CNC milling. The vibrations will find their way into every screw and bolt on whatever thing that is connected to the machine. The time that it may take before a screw come loose is perhaps less that 300 hours(this on a semi-professional machine). The stepper motors themselves generate quite a lot of vibrations and I would recommend to dismantle the Rambo-cage to be able to tighten the screws on every plug connected. Why not tighten the screws after every filament roll that has been exhausted as a precaution?

/Henrik

Posted : 19/07/2016 9:13 pm
PJR
 PJR
(@pjr)
Antient Member Moderator
Topic starter answered:
Re: Mk1 bed connector issue

Henrik

Tightening screws where there is vibration is fine, but this is not a screw coming loose; the main problem here is a significant current (10+ Amps) being passed by an interference fit plug and socket. Even when the plug is latched fully home any slight movement can cause intermittent connection, arcing, high resistance joint and melted plastic.

Peter

Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage…

Posted : 19/07/2016 11:13 pm
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