Dreamer Heater Bed Won't Stop heating...

[batroost]

I have a Flashforge Dreamerthat’s developed a fault – I think I may have caused a short whilst the printerbed was heating (accidentally touched the +/-24 volt terminals with a scraper whilst live, and yes, I now realise that trying to clean the bed whilst it is heating is a BAD idea).


The printer starts and runs fine, but if I turn on bed heating, it keepsheating and won’t stop at any set temperature. The temperature indication seemsto working fine – all the way to nearly 130 degrees! It just won’t stop heatingwhen it reaches the setpoint, so I can’t use it. I've checked all the connections, reformatted the internal TF card and can't see anything damaged/burn-out on the boards.

I’m guessing I probably need to buy a replacement part, but I don’t knowwhether that’ll need to be a replacement bed heater, coreboard (connected for the bed temperature sensor) or driverboard (connected to the bed power supply)?

Is there anyone who can advise me on which bit I've broken?

Many thanks

[Axl_Myk]

It could be a problem with the power supply. Such as the temp control circuit gone south. Or even a mainboard problem. Tough call.

[Gambo]

Hi I don't know you machine but from what you say since the bed is warming up and the machine is displaying the bed temp the fault is most likely to be the semiconductor switch whic switches off and on the power to the heated bed. That would be consistent to a short circuit across the dc power to the heated bed.
I dont know where this is located on your machine but probably on the main board.

[batroost]

Hi I don't know you machine but from what you say since the bed is warming up and the machine is displaying the bed temp the fault is most likely to be the semiconductor switch whic switches off and on the power to the heated bed. That would be consistent to a short circuit across the dc power to the heated bed.
I dont know where this is located on your machine but probably on the main board.

Thanks I've tried replacing the heated bed circuit board but that hasn't fixed it. I now have a replacement driver board on order - that's where the power to teh bed comes from. If that doesn't fix it I'll order a new motherboard. I'll let uou know how I get on. Cheers.

[Gambo]

Please let me know i am always curious.

[batroost]

I replaced the printerbed heating board but that had no effect. Today I replaced the driverboard and everything is back to normal. To be fair, that was the advice I received by email from flashforge (but that was after I'd ordered the printerbed). £49 for the bed, £80 for the driverboard. I'll be more careful in future...

[curious aardvark]

plastic scrapers are a good idea :-)

Printing your own from polycarbonate is a fun project :-)

[MsIkari]

It happens sometimes to those metallic heaters. Sometimes it is really good to heat everything around you, but sometimes you simply don't want this to happen but cannot do a single thing about it. You either freeze or die warming. I can offer you a solution that I have find for myself a long time ago. Simply start to use ceramic heaters. Especially the ones that I use, ceramic heater, are good because you can find a variety of ways for using them, from home to markets, to heat all of the room or just a spot. This material, ceramic I mean, is amazing because of its chemical characteristics. I really hope that I have helped you with this.