How to: Fix F90 Error without Vender USB board

This is how I fixed all 3 of my MPPT MAX-8000 inverters. This might be different for other models and hardware reversions. Follow at your own risk.
I bought 3 8kw inverters from Foshan Ouyad Electronic a few months ago and one by one they have all stopped working with various errors and hardware faults. The one fault they all have in common is the Serial number registration failure error - F90

I got impatient waiting for Foshan Ouyad Electronics to respond so I decided to explore other ways to communicate with the main processor without this ridiculously priced board they say we need. I used a 3.3v USB to TTL UART adapter and Axpert Setting Serial Number Tool V1.00. You will be connecting Gnd, TX, RX to the 6 pin plug coming from the inverter. You don't need to do anything else with the other wires.

This is how I connected mine.


Inverter Pin 1 TX to TTL RX
Inverter Pin 2 RX to TTL TX
Inverter Pin 3 GND to TTL GND

Please make sure you only use a 3.3v TTL adapter as the MCU is only 3.3v tolerant. A wrong connection could damage the MCU.
This is the one I used.


Remove AC input power from the inverter, disconnect all 3 connectors from the front panel. Make your TTL connections into the 6 pin plug as above, plug the USB TTL adapter into the computer and load up the software.
Return AC input power to the inverter and wait a moment for it to go red, in the software select RS232 and click Search - it should display a product ID, click apply and you should get settings successful! msg.



That's it, Error F90 fixed. Remove AC, reconnect everything and power back up.
Will report back if it returns again after the 60 day timeout.

Axpert SN Tool - https://www.mediafire.com/file/dc9cq674ult69xj/AxpertSetSN.rar/file

Hope that helps and saves people money.
Enjoy your day and stay safe.

Well done, where can we find the Axpert Setting Serial Number Tool V1.00, also on the inverter side how do i know which is ground and which is tx and rx . On the ttl its marked . But the inverter side is not . Thanks and again great work

Hey

I've updated the picture above to show the Inverter pinout. Connect Inverter pins to TTL device pins as follows.

TheBattMan said:

Inverter Pin 1 TX to TTL RX
Inverter Pin 2 RX to TTL TX
Inverter Pin 3 GND to TTL GND

Click to expand...

The software is here.

TheBattMan said:

Axpert SN Tool - https://www.mediafire.com/file/dc9cq674ult69xj/AxpertSetSN.rar/file

Click to expand...

TheBattMan said:

Hey

I've updated the picture above to show the Inverter pinout. Connect Inverter pins to TTL device pins as follows.


The software is here.

Click to expand...

I picked up on that thanks, i tried it like 20 lins ago . But the laptop wouldn't recognize the inverter , the usb to ttl when pluging in made a sound but nothing showing in devices, and when i pressed search, no product number came up . Im not sure what is wrong .

Did you manage to work it out?

If nothing is showing up in the device manager, not even listed under unknown device. Then I would try a different USB cable/port or even see what happens if you plug into another computer. Could be the TTL device itself.

TheBattMan said:

This is how I fixed all 3 of my MPPT MAX-8000 inverters. This might be different for other models and hardware reversions. Follow at your own risk.
I bought 3 8kw inverters from Foshan Ouyad Electronic a few months ago and one by one they have all stopped working with various errors and hardware faults. The one fault they all have in common is the Serial number registration failure error - F90

I got impatient waiting for Foshan Ouyad Electronics to respond so I decided to explore other ways to communicate with the main processor without this ridiculously priced board they say we need. I used a 3.3v USB to TTL UART adapter and Axpert Setting Serial Number Tool V1.00. You will be connecting Gnd, TX, RX to the 6 pin plug coming from the inverter. You don't need to do anything else with the other wires.

This is how I connected mine.
View attachment 117519

Inverter Pin 1 TX to TTL RX
Inverter Pin 2 RX to TTL TX
Inverter Pin 3 GND to TTL GND

Please make sure you only use a 3.3v TTL adapter as the MCU is only 3.3v tolerant. A wrong connection could damage the MCU.
This is the one I used.
View attachment 115109

Remove AC input power from the inverter, disconnect all 3 connectors from the front panel. Make your TTL connections into the 6 pin plug as above, plug the USB TTL adapter into the computer and load up the software.
Return AC input power to the inverter and wait a moment for it to go red, in the software select RS232 and click Search - it should display a product ID, click apply and you should get settings successful! msg.

View attachment 115107

That's it, Error F90 fixed. Remove AC, reconnect everything and power back up.
Will report back if it returns again after the 60 day timeout.

Axpert SN Tool - https://www.mediafire.com/file/dc9cq674ult69xj/AxpertSetSN.rar/file

Hope that helps and saves people money.
Enjoy your day and stay safe.

Click to expand...

Hi there! I have the same issue with error 90. MPPSOLAR sent me the software to write the serial number. I have used a

USB to RS232 Male Adapter with PL2303 Chipset connected to the cable that comes with the inverter. I located the correct win 10 driver and no errors in device manager. I select rs232 and hit searech. nothing shows up. I also followed your steps and created a connection using​

USB to TTL 5PIN Serial Converter Adapter Module Downloader for UART STC 3.3V and 5V with Jumper Wires. the same issue hit search and nothing. I even see the activity light flash red and blue when I hit search. U mentioned something about 5v being an issue?? This is what I bought: https://www.amazon.com/gp/product/B07D6LLX19 Any ideas?​

I had error 90 about 6 months ago but it resolved itself after non-use for a month. I am thinking lights out on day 60 again so I want to fix this to avoid any trouble.

its gotta be the voltage..I wonder if I can set it to just use3.3v..

NO LUCK..do u have an amazon link for the adapter.... all I see is 3.3V/5v versions.
the driver works and do see flashing red and the blue light for a second. what is the procedure with powering down and up again of the inverter... I dont see a red light

NO_SafeSpace_4U said:

Hi there! I have the same issue with error 90. MPPSOLAR sent me the software to write the serial number. I have used a

USB to RS232 Male Adapter with PL2303 Chipset connected to the cable that comes with the inverter. I located the correct win 10 driver and no errors in device manager. I select rs232 and hit searech. nothing shows up. I also followed your steps and created a connection using​

USB to TTL 5PIN Serial Converter Adapter Module Downloader for UART STC 3.3V and 5V with Jumper Wires. the same issue hit search and nothing. I even see the activity light flash red and blue when I hit search. U mentioned something about 5v being an issue?? This is what I bought: https://www.amazon.com/gp/product/B07D6LLX19 Any ideas?​

I had error 90 about 6 months ago but it resolved itself after non-use for a month. I am thinking lights out on day 60 again so I want to fix this to avoid any trouble.

its gotta be the voltage..I wonder if I can set it to just use3.3v..

NO LUCK..do u have an amazon link for the adapter.... all I see is 3.3V/5v versions.
the driver works and do see flashing red and the blue light for a second. what is the procedure with powering down and up again of the inverter... I dont see a red light

Click to expand...

Were you able to resolve this?

TheBattMan said:

This is how I fixed all 3 of my MPPT MAX-8000 inverters. This might be different for other models and hardware reversions. Follow at your own risk.
I bought 3 8kw inverters from Foshan Ouyad Electronic a few months ago and one by one they have all stopped working with various errors and hardware faults. The one fault they all have in common is the Serial number registration failure error - F90

I got impatient waiting for Foshan Ouyad Electronics to respond so I decided to explore other ways to communicate with the main processor without this ridiculously priced board they say we need. I used a 3.3v USB to TTL UART adapter and Axpert Setting Serial Number Tool V1.00. You will be connecting Gnd, TX, RX to the 6 pin plug coming from the inverter. You don't need to do anything else with the other wires.

This is how I connected mine.
View attachment 117519

Inverter Pin 1 TX to TTL RX
Inverter Pin 2 RX to TTL TX
Inverter Pin 3 GND to TTL GND

Please make sure you only use a 3.3v TTL adapter as the MCU is only 3.3v tolerant. A wrong connection could damage the MCU.
This is the one I used.
View attachment 115109

Remove AC input power from the inverter, disconnect all 3 connectors from the front panel. Make your TTL connections into the 6 pin plug as above, plug the USB TTL adapter into the computer and load up the software.
Return AC input power to the inverter and wait a moment for it to go red, in the software select RS232 and click Search - it should display a product ID, click apply and you should get settings successful! msg.

View attachment 115107

That's it, Error F90 fixed. Remove AC, reconnect everything and power back up.
Will report back if it returns again after the 60 day timeout.

Axpert SN Tool - https://www.mediafire.com/file/dc9cq674ult69xj/AxpertSetSN.rar/file

Hope that helps and saves people money.
Enjoy your day and stay safe.

Click to expand...

Are available to answer some quick questions? I need some assistance

Did you ever find a solution?
I am now having the same issue on my EG4 6500 from Signature Solar

howiegrapek said:

Did you ever find a solution?
I am now having the same issue on my EG4 6500 from Signature Solar

Click to expand...

Hi Howie, please reach out to our tech department for assistance. We are here to help! 903-441-2090

SignatureSolar2015 said:

Hi Howie, please reach out to our tech department for assistance. We are here to help! 903-441-2090

Click to expand...

Hi Thanks! Yes, I have been patiently working with Signature Solar for over 3 weeks now as I have in the past (and when I do get them on the phone, they have been very helpful). However, I'm a bit frustrated now, and still looking to try to repair it going down other avenues. This seems like a good resource to gain more information.

The reason is that SS and I have gone through all the diagnostic steps together. I have received the Axpert Error Code F90 repair software, and tried that - did not work; I have received new control panel, when plugged in, the same error occurs, and the supplied software does not work either; I now have two different emails from two different SS resolution team members this week indicating that it was agreed that I will receive an RMA 6500 Inverter (agreed upon this past Monday), but as of this morning, still have not seen an order online for shipment of new or refurbished equipment, nor have I received an email that it is being processed and shipped.

While waiting for the replacement inverter to be shipped (assuming that it will, and there is inventory to send me), I'm trying to revive the seemingly dead hardware. I find it hard to believe that the we cannot push the appropriate serial number to the main unit. After all, it is just a software push to update an EEProm. I didn't think I have a hardware issue, but who knows, maybe the current hardware/eeprom/memory is now faulty. I just don't know. SS believes the hardware is defective, which is fine. Just send me a replacement under warranty already so I can get back off grid..

Some background info regarding cables I am using: I was, in fact, able to flash the firmware in the past using the cable set I have. I used the originally supplied cable which came with the the 6500 (rj45 to db9) and connected a purchased DB9 to USB2 cable - from Amazon:- Product number: B084RJWXMK.

Some background info about me: As seasoned software engineer (30 years in the tech industry), I totally understand how all of this communication is supposed to work, and understand the rationale and behind why the 6500 to become bricked after 60 days. I've flashed many kinds of hardware over the years (switches, routers, computer bios, mechanical equipment, etc) and never had this kind of issue. Why does the inverter think it is a clone? Is it just that the serial number is now gone? is it a bad EEProm? Is it software? Is it hardware?

Anyway, I am fairly confident that this pinout with the two cables described above was working for communications between my old dell laptop running Windows 10 with a USB2 port to the eg6500, as the flashing previously worked.

Historically speaking, After over a year of running the pair of 6500's with 6 eg4 batteries and 15kw of PV on 4 strings with minimal issues, I decided to flash the firmware due to the LEDs blinking in my office lights (I was told that the firmware repairs that problem). When I did it, I was able to flash the master, but when I tried to flash the secondary inverter, it bricked the display panel. Completely blank. So, SS replaced the Panel, and it repaired the problem. Exactly 60 days after replacing the display panel and previously flashing firmware, I am getting the FC90 error on 2P2 as described herein.

Going on 3 weeks now... After the initial error, I contacted SS and they supplied me with the Axpert software kit, with the actual serial number I provided to them. But when I try to run the software, it doesn't work - I got "settings failed" error. (see image below)

The instructions provided by SS to perform the F90 patch install were as follows:

1. Locate the zipped folder you just downloaded and extract it
1. Right-click on the folder downloaded in step 1
2. Left-click on "Extract All..."
i. A new window will pop-up
3. Left-click on the "Extract" button in the bottom right
i. A new window will pop-up
5. In this new window, Left-click on the "Tools.exe"
6. Select "RS232"
7. Left-click "Search"
8. Left-click "Apply"
9. A window should pop up saying "Setting successful!"
10. Left-click on the button inside the popup window.
11. Perform a full system restart using the steps below

Please follow the steps below for proper shutdown and startup procedures:

1. Power Off

i. Turn off Inverter
ii. Turn off AC INPUT
iii. Turn off solar panels
iv. Turn off batteries
v. Turn the inverter back on for about 30 seconds to drain the capacitors.
vi. Then turn it back off.

2. Power On

i. Turn on ALL inline breakers
ii. Turn on the batteries
iii. Turn on the solar panels
iv. Turn on AC INPUT
v. Turn on inverter
vi. Adjust settings for your needs

With USB checked, it replies with no hardware/not connected (or something to that effect)
With RS232 checked, When I click search and wait, it doesn't find the correct serial number (or any serial number) - it filled in "D>>",
When I click apply, I get "Settings failed!" See image:



I tried many times different ways, used different USB port on the laptop, removed, reinstalled the drivers. Tried both panels, no avail.

My question to @Samsonite801 and the community here :
In your efforts to get the serial number applied with the Axpert software, exactly what was the process which worked?
When you click "Search", what is supposed to happen?
Were both inverters powered ON? only the secondary?
Did you have the PV panels turned on, or only run on the DC from the Battery?
What cables were used to connect the computer to the inverter?

Any help would be appreciated.

Thanks.

howiegrapek said:

My question to @Samsonite801 and the community here :
In your efforts to get the serial number applied with the Axpert software, exactly what was the process which worked?

Click to expand...

Did you see my post here?

I could only get it to work using a Win7 computer which had a real DB9 serial port on it, COM1.. (not sure though how many of those details made an actual difference).

howiegrapek said:

When you click "Search", what is supposed to happen?

Click to expand...

Search should pull up a value for whatever serial number is on the device EEPROM already.

howiegrapek said:

Were both inverters powered ON? only the secondary?

Click to expand...

I believe I had the other inverter turned on, but configured as SiG inverter since it was providing power, I only had the one inverter (the adjacent one) have the F90 error, not both on mine.

howiegrapek said:

Did you have the PV panels turned on, or only run on the DC from the Battery?

Click to expand...

I fixed ours at night time, and since whenever the power switch is off, the inverter needs to get power either by PV power or by generator (or other AC input source), then we had to run our generator to keep the display on while inverter was in standby.

howiegrapek said:

What cables were used to connect the computer to the inverter?

Click to expand...

We had tried the micro-USB, and the serial cable with built-in USB, neither worked, wound up having success using the version 1 EG4 cable (direct DB9 to RJ45)...

howiegrapek said:

Any help would be appreciated.

Thanks.

Click to expand...

Hope you can figure it out. I was getting a lot of failures ('Setting failed!') same like you with all the previous attempts using other cables, it wasn't until I brought over the other legacy PC and used the real DB9 serial connection, which happened to have Win7 on it (instead of Win10), and that worked.

Read my other post from link above in case I forgot any details here.

Samsonite801 said:

Did you see my post here?

EG4 6500 48 volt error 90

I have two EG4 6500 EX inverters that have been working very well in parallel for the past 6 months. When I woke up this morning I saw that the power in my house was out. I went to my battery/ inverter room and saw that the 2p2 inverter was alarming and the LED band was red and an F90...

diysolarforum.com

I could only get it to work using a Win7 computer which had a real DB9 serial port on it, COM1.. (not sure though how many of those details made an actual difference).




Search should pull up a value for whatever serial number is on the device EEPROM already.



I believe I had the other inverter turned on, but configured as SiG inverter since it was providing power, I only had the one inverter (the adjacent one) have the F90 error, not both on mine.



I fixed ours at night time, and since whenever the power switch is off, the inverter needs to get power either by PV power or by generator (or other AC input source), then we had to run our generator to keep the display on while inverter was in standby.



We had tried the micro-USB, and the serial cable with built-in USB, neither worked, wound up having success using the version 1 EG4 cable (direct DB9 to RJ45)...




Hope you can figure it out. I was getting a lot of failures ('Setting failed!') same like you with all the previous attempts using other cables, it wasn't until I brought over the other legacy PC and used the real DB9 serial connection, which happened to have Win7 on it (instead of Win10), and that worked.

Read my other post from link above in case I forgot any details here.

Click to expand...

Thank you so much, I appreciate your quick answers.
I have read all of your posts, and will continue to try alternative cables, and see if I can locate an older computer with an actual serial port
If I make any progress I'll post here accordingly.

howiegrapek said:

Thank you so much, I appreciate your quick answers.
I have read all of your posts, and will continue to try alternative cables, and see if I can locate an older computer with an actual serial port
If I make any progress I'll post here accordingly.

Click to expand...

Sure no prob..

I didn't have any laptops with DB9 port anymore, so I had to bring an old home server (small, with Mini ATX board PC), over there, with my tiny 7" Lilliput marine monitor (had VGA port), and used my Lenovo USB keyboard (with built-in trackpoint/touchpad on it), and set it all up on my neighbor's workbench, just to make it all possible hehe. Total Macgyver but it worked..

I also don't know if it had anything to do with it, but I was using COM1, and not COM2 or any other port, because the Axpert tool doesn't give any option to select COM port in it, not sure if it has any trouble with detecting which COM port to natively try and use or if it is supposed to have enough logic in the code to detect proper COM port, but took precaution to just use the physical COM1 port on the motherboard of the PC.

Let me know if you have any other questions, good luck...

howiegrapek said:

Thank you so much, I appreciate your quick answers.
I have read all of your posts, and will continue to try alternative cables, and see if I can locate an older computer with an actual serial port
If I make any progress I'll post here accordingly.

Click to expand...

Well, I tried new cables, and a completely different computer (with usb 2) - and latest drivers. The COM port is seen when connected to inverter, but I still cannot update it. I have not located a laptop (or older desktop) with a db9 serial port on it... I've asked around.

Signature Solar has agreed that this is a damaged 6500, and has agreed to replace it with a refirb'd unit. I expect to get that this week.

I assume that will repair my issue. Fingers crossed.

Tried the Axpert SN Tool using win 7 home premium. Received the ID # but the program will not reset the SN. says failed. Guess I will have to wait on sg power to answer their email... unfortunately it is slower than snail mail'. The have a wonderful web site but tech support is...............
I hate to change vendors but I need robust inverters that work. Probably need to go to a 120/240 all in one to keep ahead of the game. I live in hurricane area and NEED the power.

traffman2370 said:

Tried the Axpert SN Tool using win 7 home premium. Received the ID # but the program will not reset the SN. says failed. Guess I will have to wait on sg power to answer their email... unfortunately it is slower than snail mail'. The have a wonderful web site but tech support is...............
I hate to change vendors but I need robust inverters that work. Probably need to go to a 120/240 all in one to keep ahead of the game. I live in hurricane area and NEED the power.

Click to expand...

Which cable option are you using? When I tried via the micro-USB port, I could read data but error on write, when I used the other USB-to-serial cable which came with the inverter, I had same issue, could read but not write. It wasn't until I used the legacy serial (DB9 pin) serial (to RJ45) cable with a computer that had a native DB9 serial port on it (on Com 1), that it was able to read and also write the S/N data.

Samsonite801 said:

Which cable option are you using? When I tried via the micro-USB port, I could read data but error on write, when I used the other USB-to-serial cable which came with the inverter, I had same issue, could read but not write. It wasn't until I used the legacy serial (DB9 pin) serial (to RJ45) cable with a computer that had a native DB9 serial port on it (on Com 1), that it was able to read and also write the S/N data.

Click to expand...

I have a serial card in the PC using a 9 pin to the rj45 jack on the inverter.
9600,8,none,1,none

traffman2370 said:

I have a serial card in the PC using a 9 pin to the rj45 jack on the inverter.
9600,8,none,1,none

Click to expand...

Probably or maybe didn't matter, but just for ultra paranoid measure, I made sure the port I used was set to Com1 (on the computer, it was a native motherboard comm port), and I ran the Axpert tool as (right-click) 'Run as Administrator' just for extra paranoia measure..

Again, not sure if it matters.

There are also a few different versions floating around out there of the Axpert SN Tool, I remember a couple of them had different names. It is kind of a sub-par tool though, seemed really finicky at best...

I am having trouble now, remembering if the inverter had to be on or off, or in firmware upgrade mode or normal mode or what, since it was several months ago I did it.

I tried everything you said and then more. But doesn't seem to be working. Hopefully I will get an email from Sungold support tomorrow. Thank you for all your help and support.