Heat Bed Temperature too hot warning

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Posts: 2
Joined: Sat Jun 13, 2015 6:00 am

Heat Bed Temperature too hot warning

Post by yungamos » Sun Jun 14, 2015 4:09 pm

I own my UP! Plus since 2012, it is a great little machine and is quite advance at that time.

In the past half year, my UP! Plus start to report heat bed over-heat warning. That is troublesome as the warning will halt the print and render the printed object useless.

After a lot of trouble shooting, I can conclude there are three problems:

1. Broken wire from the motherboard to the connector on the horizontal Y'axis arm.

This broken wire is difficult to detect, but after a lot of up/down motion of the platform and observe the temperature signal on the software, i conclude there a broken wire on the ribbon cable. When I open up the steel casing of the machine, I found out that on a part of the ribbon cable, there are tiny burnt marks on the cable surface. Clearly that the power to the heater carries thru a number of wires in the ribbon cable, when some wire got broken after extensive up/down movement during print, the electric current the cable can deliver will be greatly reduced and the loading will goes to the wire left - which in turn create higher burden on those wires left.

The temperature sensor signal runs thru 2 wires in the ribbon cable only, therefore when one is broken, the temperature sensor will return overheat signal..... but most of the situation we can found is that the overheat is in a very short time, when the cable move to other position, the connection restored and the temperature measurement is right again.

2. Broken wire from the connector on the horizontal Y-axis arm to the heat bed block heater and temp sensor.

On my 1st gen machine, it is a long silvery 4-wire cable inside the Y-axis arm. The wire carrying heater power did burn to broken, Using a 10X magnifier can see the wire is broken. The quality of the wire is not the issue, but the shrinkage tube on the outside did create a pulling effect on the wire. While the wire will heat up during power delivery, the cable break easily. PP3DP did sent me another cable many years ago, and both cables are now broken. I turns copper wire into little spring before I soldering it on the broken wire and connect it - or the soldering joint will be apart very soon after massive movement of the platform.

3. The connector plug on the Y-axis arm which connector the ribbon cable from the PCB to the 4-wire cable of the heater and temp sensor.

This is the most difficult area to discover the problem. After I abandon the internal ribbon cable by substituting it with another set of thicker ribbon cable, and soldered the silvery cable, I still found out that the over-heat problem happening. I can only imagine that the connector causing the problem and so I opened up the connector and check it under my 10x magnifier. Clearly the contact pins showing signs of oxidation. My machine is stationed in a air-conditioned room and oxidation did surprise me. Anyway, I replaced the connector with a new and bigger 4-pin connector.

And after I done all these three things, the over-heating problem is gone.

I wish my findings can help others to repair their little machine and have this little great machine works for life. :D

P.S. while opening up the steel case, I recommend to add some Vaseline grease to the tracks to protect it from rust and reduce the noise.
My new external heater/temp sensor cable.
20150612_184422_HDR.jpg (230 KiB) Viewed 7462 times

Posts: 3
Joined: Fri May 27, 2016 12:22 am

Re: Heat Bed Temperature too hot warning

Post by Rach » Fri May 27, 2016 1:40 am

I've got the exact same issue! :(

I purchased my Up about 3-4 yrs ago and so far I've only had to do minimal maintenance (I've replaced one extruder head and one platform heater assembly)

In the last week or so, I've began getting these irritating platform overheat errors, the printer keeps giving readings of precisely 387.1 degrees (meanwhile, it's probably sitting around 20/30 degrees when I power it up).

If I try to print or preheat the bed, the heater is physically working but unfortunately due to crazy temp readouts the printer stops itself due to "overheating".

I checked all connections and there doesn't appear to be an issue on the assembly, from reading all the discussions the majority suggested to replace the platform heater assembly.
After days of failure, I finally purchased a new assembly and installed it into the printer last night.
(I use the V3)

I put the printer back together, powered it up and for a few seconds I was getting an accurate reading of about 29 degrees but within seconds it was straight back to displaying 387.1 degrees again.. $89 down and no closer to solving my issue.

I tried wiggling each of the wires to test for an intermittent fault but could not see any change in the temperature.

The only thing left I can think of that could be at fault is that white paper ribbon cable. I cannot find it available to buy as a spare part anywhere, I see you've made a custom plug, is it possible to get a bit of info on how you did that? I know a few technicians and I'm hoping they may be able to help me here if I could get some idea of pin wiring.

It's been 2 weeks of down time now and I'm really behind in orders for my online store and freaaaaaking out!
Any help will be greatly appreciated.

Posts: 166
Joined: Wed Dec 30, 2015 6:07 pm

Re: Heat Bed Temperature too hot warning

Post by ricks01 » Fri May 27, 2016 4:59 pm

rachaelnadine wrote: The only thing left I can think of that could be at fault is that white paper ribbon cable. I cannot find it available to buy as a spare part anywhere
Contact support@pp3dp.com, they should be able to send you a replacement ribbon cable or tell you where you can get one.

You can also try http://www.octave.com as they sell Afinia printers which are the same as the UP! Plus. They have a live online chat you can use.

Posts: 327
Joined: Tue Feb 14, 2012 11:47 am

Re: Heat Bed Temperature too hot warning

Post by mr6k » Tue May 31, 2016 9:56 pm

It may be similar to the -problem related to in the thread "[BUG REPORT] Heating platform stopped heating"

I initially had the wire supplying the bed heater fail, then some months later the thermistor detector cable failed.

Images on this thread show where the failure tends to occur, on a UP Plus. It is almost always on the tight radius of the 4 wires between the heater element and the front of the cable guide. The wire fracture can be difficult to see through the semi transparent cable insulation . the heater wire fracture is normally easier to see as it has probably arced and burnt a bit. The thermistor fracture will not have arced or burnt at all.

I replaced all the cables around the outside of the platform as shown in the photo within the named thread.


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