Dimension 3D Printer Repair

This is for troubleshooting and repairing a no heat problem on Stratasys Dimension BST 1200 3D Printer

If it is already broken... there is no harm in digging into if further...

Step 1: Background

Should I get it????

I was allowed to power it on but that was the extent of the testing.

It failed start up with a code 14.133. Heater failure(I checked later and went back)

Visually it looked good.

Included was 18 partially used ABS and Support cartridges

10 factory sealed NEW cartridges

about 50 print plates.

And the original software and manuals.

The print head cover was missing.

Step 2: Testing

Working blind as I was unable to find any documentation...

I used a multimeter to check the heaters and found that both have 2 internal elements and all 4 were within the same reading. about 225 to 255 ohms in this case. The thermocouples in the head were good as well.

Time to inspect the electronics cabinet...

There is a service manual available for the 768 elite online from hackaday... I suspected that the electronics should be similar.

Found the code and the checks all look like I have a bad PDB or Power distribution board.

Opened the case and sure enough the F1 fuse is blown. Board bottom left-ish beside the 9 pin connector.

From the service manual I have a GEN2 board

From the back of the machine I had to remove the left panel to remove the connectors for the PDB from the back of the board.

Step 3: Find the Problem

So play safe...

A little reading of the service manual and the section of the PDB that has the blown fuse is the 120VDC section. this is a little weird since the status LEDs on the board clearly show that the 120VDC is working normally...

No Schematic to work from... and replace board as a solution...

That said the board is broken, it is more than likely that I cant possibly break it any further.

I Started with a visual... I noticed the signs of a hot component between the 2 heat sinks on the bottom right.next to the 2 red film capacitors.

It is not so burned to be able to read that it is a US1M diode (Got lucky on this one), it seems to read funny; it passes diode test on my Fluke in both directions...

Replaced the diode and fuse (3.15A 250V) and reinstalled the board... Power on and POP!!! Fuse blown again.

More board probing and I found that the diode is input protection from the MOSFET on the lower right of the board.

Resistance measuring of the MOSFET shows 3.5 ohms from the gate to Drain as well as the Gate and Source...

MOSFET visually looks fine, got me there...

I replaced it with the current replacement part and had to insulate the back of the the MOSFET from the heat sink using Kapton tape.

MOSFET - 20N60C3

Step 4: Test Print

Upon reinstallation of the board the machine now operates normally...

The part shown is a test print from the machine library.

I calibration is probably needed but for now I happy to have a functional high quality printer with a massive amount of material to work with.

I hope that this helps...

In my case This went from an expensive mistake...to an incredible bargain!

Step 5:

Comments

[benbrotz]

Anyone have the issue of lost communication with the model cartridge after about 45 min or so into a print job? model drops to 0% and machine aborts.. reboot and sometimes it reads the cartridge and sometimes it doesn't?? Error 14 - 110.. any solutions? SST 768

[fefilippi]

Hello! It seems I am not the only one with this error (133) on BST!, Fuse1 keeps blowing, Y did some mesaures and inspection, based in your great report, and everything seems ok. Can you tell me what value should the MOSFET give? I measured 5 omhs. No diode seems broken or any other component looks bad. I am lost here... please help! best,F

[Random_Canadian]

Datasheet here: https://www.infineon.com/dgdl/Infineon-SPP_I_A20N6...

It is best to remove the MOSFETfrom the circuit for testing. The testing needs to be as follows.
With the MOSFET is removed from the circuit and your DMM is diode test mode.
Short all of the pins (you can use your finger) of the MOSFET together to turn off the MOSFET
Connect the black lead to the Source pin (for all steps) and the red lead to the Drain pin, the reading should be OL (infinite)
Next Remove the red lead from the D pin and connect it to the Gate pin for about 5 to 10 seconds.
Remove the red lead from the G pin and connect it to the D pin, the reading should be effectively 0 or really close to.

remove the red lead and short all the pins together. Connect the red lead to the D pin and the reading should be OL again.

I hope that this helps.

Good luck.

[fefilippi]

Thanks a lot for your help. I will come back when I have news. Best!
F

[fefilippi]

Thanks a lot for your ansewer and concern, I will try to remove Mofset. It looks brand new, and I did not find any component with details.
I read somewhere that Thermocouple can give a good mesure, and be the problem anyway. I mean, when it has been replaced, the problem dissapears. Right now, my problem is that Fuse1 blows always, plugged or not different parts (umbilical, head, heater, thermocouple, etc) I am taking off the PDB to inspect it better. Best Regards! I will come back with news.. F

[Random_Canadian]

If it blows on initial start up then there is likely a larger portion of the circuit you will need to check. If it blows when the machine goes into the heating phase of the startup then it is indeed in the heat part of the circuit.

[christopherToFu]

Hey, as an owner of one and possibly a second, I LOVE these machines, once you get past how expensive they are and their other quirks they really are quit pleasant, and fyi ive been arguing with GrabCad to make more advanced features available, so keep an eye out.

[KaavainSE]

Hi! Great to found your report. Got the same problem - but with uPrint SE device. My PDB looks the same and also the same F1 blown. But I fount that model 120V line shorted to ground. Did you found some circuit diagram of that PDB?

[Random_Canadian]

Sorry I have never found a schematic.