No power to heat bed! please help

K8200 3D Printer K8200 - Wiring and electronics
1

Hi,

I have been printing for some months now with few issues, however today I turned on my printer and the heat bed would not heat up. I turned it on in repetier and un-pluged the heat bed cable but the voltage measured 0 across the pins. a similar test across the heated nozzle pins produces 15.4v. any ideas of what to do next would be greatly received.

2

Does the indicator led on the board light when you turn on the bed?
Can you measure if the gate of the MOSFET is driven?
(left pin of MOSFET).

3

the red led doesn’t come on.
how do I check if it is driven, I measure between the gate (left pin) and where?

4

Hi scottnikita,

the reference should be ground, e.g. the (-) side of the power input screw terminal.

Cheers,
kuraasu

5

Thank you Kuraasu.

there is no red LED and no voltage measurement between the lefthand pin and ground of the MOSFET directly above the heater 2 plug. measurement was taken with the power on, bed turned on and all cables plugged in.

similar measurement for heater 1 MOSFET gives a voltage of 0.2v

Ideas???

thank you inadvance

Scott

6

Please respond:) I’m at a loss what to do next.

Thanks

Scott

7

Hi Scott,

doesn’t look good for the heater 2.
What experience do you have in soldering?

Just to be sure, was your voltage measurement on heater 1 (0.2 V) done with the hotend switched on or off? Was the LED for heater 1 on, blinking, or off?

Cheers,
kuraasu

8

Hi Kuraasu,

yes the hotend was switched on and the LED is constantly on. Heater 1 is working fine.
my soldering is far from prefect but I am improving and willing to give things a go.
do you think it is repairable? or is it a new board?

Cheers

Scott

9

Hi Scott,

that’s strange. The gate must have been at more than 0.2 V to switch the MOSFET on. Please check for possible errors. If you are unsure whether you really measured the gate pin, have a look at the datasheet (page 2 has a schematic).

[quote=“scottnikita”]my soldering is far from prefect but I am improving and willing to give things a go.
do you think it is repairable? or is it a new board?[/quote]
Difficult to answer. There may be a chance, as indicated in another thread. However, there may be just as well some other error on the board. Anyways, contact the VEL guys before attempting this and get their clearance, so you can get the board replaced in case soldering doesn’t help.

The other thread with a similar issue is here. Another word of caution: HansBaer also measured voltages on the ATmegas pins. It is feasible to do this, obviously, but anyone attempting this should be aware of the risk of creating a short-circuit on the (powered!) ATmega with the measurement tip, e.g. by slipping of a pin and connecting two pins at once.

Cheers
kuraasu

10

Thank you your a star! I will re check measurements and let you know how I get on

Scott

11

you were right Kuraasu, I was measuring across the wrong pin, the correct voltage for the hotend MOSFET is 4.94v when it is powered. re-checking the heat bed MOSFET still shows 0.0v with no LED when powered.

I suspect a fault on the board, please can Support respond as next course of action as the printer is quite new and has done less than 50 hours run time.

Thanks once again Kuraasu,

Scott

12

You’re welcome.

I hope there’s fast solution for this, having a “headless” printer is annoying. Are you located in Europe or the US?

13

yes a fast resolution would be great.

I’m in England, how about yourself?

Scott

14

Hi Scott,

Northern Germany, Baltic Sea region.

Since you’re in Europe, you will most likely deal directly with Velleman in Belgium then. But let’s see what the VEL guys have to say about this case.

Cheers,
kuraasu

15

If you are positive that the board is at the cause of troubles, then you can return it for inspection/repair/exchange, either to your distributor or to:

Velleman Projects Tech. Dept.
Legen Heirweg 33
9890 Gavere
Belgium

16

Thank you, I will get it into the post