Dead duet?

[MrBlom]

Hello i have just installed a 2 hotend
and now all hotends 1,2 and the heatbed is 2000 degrees
even with no cable in bord it still says 2000
it also like this on usb
only thing i did was to change the hotend

is it dead or what can i do?
im runing the lates beta

i dont have a PT-100 sensor or a daughter board
just a normal duet wifi

[MrBlom]

hmmm after some searching i think it may be a short that did it
others have killed there VSSA fuse when installing a hotend
i found a thread how to replace it
https://www.duet3d.com/forum/thread.php?id=247

but one question how do i test if my VSSA fuse i broken
also dose a short in the heater affect allt thermistors ?
the all show 2000c

sorry for the bad english

[dc42]

If the VSSA fusa blows then usually all the thermistors normally show -273C.

You can test the VSSA fuse by using a multimeter to measure the resistance between the VSSA pin of one of the thermistor connectors, and the ground pin of one of the endstop connectors - with power off, of course.

Which version Duet WiFi is it? The version number (1.0, 1.01 or 1.02) is printed on the top side of the board.

[MrBlom]

its a 1.01

sorry but can you show exat where to measure and what the correct value is?
i thinks its a short in the heater that did it

[MrBlom]

i found the vssa pin
what is a good value on the multimeter?

[dc42]

The resistance should be no more than about 5 ohms.

[MrBlom]

seting the multimeter to 200
and doing the mesaur i have a value of 0.03
good or bad ?
soory dont know mush about this

[MrBlom]

just tried a new thermistor it get a
"Temperature reading fault on heater 1: sensor open circuit"
2000c
but the rest works , motors ,web ui , fans

[dc42]

0.03 ohms sound suspiciously low. Are you measuring between a VSSA pin and a ground pin? Did you disconnect all the thermistors from the Duet first?

The "Thermistor open circuit" message is typical of a VSSA fuse failure.

The picture at https://duet3d.com/wiki/Connector_and_spare_part_numbers#VSSA_fuse shows a GND pin and a VSSA pin. You can measure the resistance between them, with the thermistors disconnected.

[MrBlom]

this good new i think
i did measure from the top of the board where the thermistor gose in and the vssa on the back
igusses that was wrong
measuring again from the 2 pins in the picture i have "OL" = broken fuse ?

im thinking of doing the
"Bypass the original fuse with an external cartridge fuse, fitted between one of the VSSA connections and one of the ground connections."

just to dubble check can i use any ground on the board?

Thanks dc42 for a fast and grate support

[dc42]

Yes you can use any ground, but for the lowest thermistor noise level I suggest you use one of the endstop connector grounds.

[MrBlom]

it was the fuse !
1000 thansk again for greate support DC42!!!!!

[MrBlom]

grrr still broken
gose from normal values to 2000 to -2
random spikes

https://www.dropbox.com/s/1fbatrcs0sx5us9/Screenshot%202017-07-30%2017.14.28.png?dl=0

Hmmm may be the fuse holder …..

[dc42]

The 2000C spikes suggest a bad connection somewhere.

[MrBlom]

yes it was a faluty fuse holder
solder it on the holder and now its been stable the last 5 min
thanks again!

[MrBlom]

well its just not my week this week
run 2 print with out problem
one on each extruder
after that i tried to start a dual print
left the room and came back after 5 min and the duet is dead all light is black
and no i cant turn it on by the psu
it works by usb but not by normal power
i also did see a smal spark by the heater led light in the left corner
so my guess this time is that its somthing wrong with the heater

can i fix this also ?
sorry for being a pain but is just not my lycky week

[dc42]

I'm not sure what you mean by the "left corner" - do you mean the bed heater LED or the E1 heater LED?

See the note at https://duet3d.com/wiki/Mounting_and_cooling_the_board about not using metal washers.

[MrBlom]

its E0 heat lead i think
and im not using metal washer

what can i do now to fix this

[dc42]

If all the LEDs on the Duet are off, then no power is reaching the board. Either your PSU has stopped working, or the VIN terminal block screws are no longer tight, or something is shorting the PSU out.

[MrBlom]

you have right again
the psu dont provide 24v any more
thank for the fast support !