Argon Small Mige Setup 16A fuse blows on first startup

i bought a used OSW Setup with a ripped of usb port of the disco board.
when i switch power on of osw the 16 A fuse of my socket blows. i activate the 16a fuse and try to power on the osw again.
the second time the servo is phasing and ffb is working.

the fuse of the argon is 6.3 A .

the previous owner changed Inrush current limiter resistor R7 . i measured instead of 33Ohm only 3 Ohm. i changed R7 with a 100R and when i measure the resoldered R it only shows 1 Ohm !!!?

where is the problem and how can i solve this ?


Are you saying the fuse/ breaker that controls the outlet on your wall fails?

If yes what other things in your house no longer work when this happens.

If the breaker trips as soon as you turn on you Argon control I would suspect you have a short circuit somewhere in your control or cabling.

Please post pictures of the inside of your control.

i checked the wiring several times. i have another working argon osw too. worng wiring is not the problem.

i think the Amps of loading the capacitors is to high when i power on the osw for first time.

i think the white 5 V relais could be stuck on open and so the loading resistor is always bypassed and for very short time a lot of amps are drawn.

i removed the heatsink and the relais is working. but i think think the transistor is fried. unfortunatly the printing of the tranistor is gone. what kind of transistor is this ?

I found some pieces of the transistir

We have this troubleshooting page in our wiki

I think we will get @Esa to comment this week or next week about this.

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Yes this is an Esa project.
Thanks for responding so quickly Mika. :wink:

@Mika the troubleshooting page points to the brake tranistor

i did some research this weekend:
STGF10NC60SD(IGBT 600V 10A 25W TP220FP), this could be the broken chip, but its obsolete.
is STGF10NC60KD(GBT 600V 9A 25W TO220FP) or STGF14NC60KD (IGBT 600V 11A 28W TO220FP) a usuable substitute ?

If the braking resistor failed I would suspect the MOSFET circuit probably failed also. At least that is what usually happened with the Simucube boards.

Hopefully Esa can help you soon.
Out of all of the Argon controls I built I never had any failures.

i dont know what happend to the argon before. perhaps the cable to the braking resistor was not isolated correctily so there was a contact to ground … and that would kill the braking transistor

I just went back and looked at your pics.
I suspect the transistor with 3 legs is the MOSFET. I am not positive, so don’t quote me on that. :wink:

Hi Jens

The fault description sounds like the RL2 is not working properly, it’s likely to be stuck to closed position which short circuits the R7. This can be verified by listening to relay clicks when the Argon STO is turned off.

Argon requires STO signal to turn on the safety relay RL1 that connects HV voltage to the capacitors. After the HV voltage has stabilized the RL2 is turned on to short the inrush current limit resistor R7.

Should this be the case, you can try to open the RL2 by SHORTLY connecting 5 to 9 volts shortly to the relay coil pins few times. The coil pins are the closer ones to each other, picture below, A1 and A2 pins.


If that doesn’t help, it’s possible to open the relay packet and mechanically open the connection. Or replace the relay altogether.

That broken transistor is indeed IGBT and STGF14NC60KD would be better replacement for the original part. It is the driver for the braking resistor. I find it weird that it has broken, might have been a voltage spike in the HV bus because the bypass relay hasn’t worked ok. Cannot say with 100% certainty though.

Let us know how the repairs go.

Kind regards, Esa

Hi Esa,

you were right. When I measured R7 it was about 1R. After testing RL2 the Relais is working again and R7 is now 33R. Now I have to wait for the new

Best regards ,Jens

Today after too many days of waiting the STGF14NC60KD arrived.

after changing the burnt chip , now it works again. both relais are clicking and no fuse is blown :slight_smile:

later i will check with granity software, if there are any faults.


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Jens I wish you success!
We all learned a little from this problem.

Granity shows no faults. I think the repair is successfull.