Speed Queen inverter board failure

[EKelectronics.gr]

What do the timers do? Switch stuff.

This board does an f ton more that just switch this switch that.

Comparing apples and oranges sure does work, right?!?

Hi, I am new to the forum but noticed other people have had the same issues with speed queen boards.

https://www.automaticwasher.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?77855

Looks like there was a bad batch of boards. How do I tell if mine was part of the bad batch?

ATEE9AGP173TW
Serial is 1511010527

Error code is ed44. Alliance/SQ says that is the 803949P which was replaced with 807175P. This part is clearly made of unobtanium since the quotes for a new board are about 850 to 1200 dollars. My unit is a few months past the 5 year warranty mark.

Board repair seems like the only viable option, though getting anyone to work on a speed queen is hard.

Has anyone figured out how to tell if these are from the bad batch and push the repair back onto speed queen for selling a lemon?

https://www.automaticwasher.org/cgi-bin/TD/TD-VIEWTHREAD.cgi?77855

Hello everyone,

I'm an electronics technician from Greece working on repairing a Speed Queen control board, part number **807175P**, which seems to trigger error code **ED44** (Drive Brake Fault).

Unfortunately, I only have the board and not the full machine, but I’ve managed to do several tests:

- The 220 V AC input is correctly routed, and I’ve verified that the board outputs:
- **+12 V**
- **+5 V**
- **+3.3 V**
- All these voltages seem stable.
- I’ve also traced the inputs that signal the relays to activate the door lock, and they respond correctly.
- However, the board’s power LED does **not** light up, even though all the voltages are present and clean.
- When powered on the bench, the board does **not** fully boot, and I suspect that ED44 may appear due to either:
- lack of communication with other modules (motor or interface board), or
- an actual internal fault (possibly firmware-related or a damaged driver IC?).

I’ve inspected both 803949P and 807175P boards and they seem **identical in components**. Does anyone know if the only difference is software/firmware?

**My questions:**
- Can ED44 appear simply because the board is not connected to the rest of the system (motor, inverter, etc.)?
- Is there any known failure point (e.g. a blown gate driver or feedback issue) that commonly causes this?
- Does anyone have a partial schematic or pinout of the motor/inverter communication lines?

Any help or insight would be greatly appreciated. I’m trying to fix this for educational purposes and to help others locally with these boards.

Thanks in advance!

 

[henene4]

I don't think you'll find board level schematics for such a device - that's way to close to "trade secret" for any manufacturer not to go after.

However, SQ is pretty upfront about what the fault is.
I'm not an electrical engineer, just an engineer, but given the fault appears to be with the current sensing circuit, I highly doubt it's down to being connected to a machine or not.


But regardless: There is a boot up communications sequence. If the boards do not communicate, there will be a fault detected.
Thus, troubleshooting a board without a machine present is kind of a thing of impossibility.
Even if you managed to somehow convince the board that the other board is present, I will not power up any of the motor drive components unless certain safety criteria are met.
And if it doesn't power the inverter, it probably won't do current sensing either.

 

[henene4]

Forgot to add:

- Even if components look the same, suppliers or specs of certain components as well as PCB manufacturing specs or even stuff as invisible as solder profiles might be enough to warrant a technical revision and part number change. Currently working on some areospace data and stuff as simple as different underfill for certain chips warrants new part numbers there...
- Given the fault is in a sensing circuit, it could be as simple as the shunt being out of spec or the solder points in that circuit being somewhat bad. But it could be IC internal as well.