Happy to post the first time, in this forum.

I have a VMIII 24v and the screen say "F09".(soft start failed)

When I put the 230v AC IN, the screen is OK, the AC (~) is light, the panel (FV) is blinking, and also show fv=111v (without panel). 

When check the C176 capacitor (with AC IN power) the capacitor have 300v DC.

The BUS capacitor is 0v. But when I put 60v DC it keep the 60v any time (no short on BUS)

Two questions:

1/ I have seen then with fv, the soft start don't work. Is it right?

May be, that if the control board see 111v FV, it don't start the soft start.

I have check all the motherboard whith the service manual, and don't see anythink bad.

May be that the control board is defective?

 

2/ I have another VMIII but 5k and 48v.(working).

Can I check the VMIII 24v with the control board of the VMIII 48v?

I have seen in the mppsolar shop, that they sale the same control board (for VMIII 3k and/or 5k).

Please excuse me for my bad english.

 

 

 

 

If I connect the battery (24v), the screen light  and show(F09), battery light, PV panel blink, And show 111v PV (without PV panel connected.

The fans are working at full speed, and I can't stop the VMIII with the On/off keyboard.

I have update the firmware 47.00 to 41.17 with USB. Flashing, OK, but no change

Edited April 12, 20242 yr by Bki
Post was in French.

I dont think the control boards are interchangable, when you get an F09 Error (soft start failed), it usualy means that the IGBT bridge that converts the High Voltage DC into AC have faulty component or short, but in your case where you get 111V on the PV without PV panels connected, the problem will most probably be on the MPPT board (the PV input board). I should also mention that you wont always see faulty components, the inverter will go into protection, such as and IGBT short unless in severe cases you will see blown components.

19 hours ago, Danny Coghill said:

Thanks for the answer, Danny, but I think that this control board VMIII 3k is the same for VMIII5k. (no for VMIII 3,6k and VMIII 6k)

And also think, that if the control board receive a informacion of 111v PV voltage, the Soft Start is not activated. May be a bad Aop  (like TL072C) on the principal board or on the control board.

 

Edited April 13, 20242 yr by Bki