That’s cheaper than what I already spent on an Arduino and serial adapter to use in fiddling with this problem. I’m surprised there is only one relay on that board.

great tip! That’s something I would need to buy but I often see battery backups for PCs at my local street market which I could probably get cheaply.

I’m trying to get a handle on what VCC and AVCC is. This thread gives some chatter on it but I’m still not correlating this to the TTL port.

https://overflow.manganiello.tech/exchange/electronics/questions/86207/atmega8-why-do-vcc-and-avcc-have-to-be-connected

They are talking about digital analog conversions with port C (and I think the eeprom serial port i am trying to talk to is port D).

A Bus Pirate would probably be ideal. But I don’t do cloud shopping. Guess I need to see if I can find that sold in a physical shop.

Since the error code possibly implies a drain pump issue, the pressure fill switch would be related. There is continuity across the two pins that are not taking voltage input. When I blow into the hose, the resistence make no change. But I guess it’s not a proper test. I think I need to buy a multimeter that has a frequency (Hz) function to see if the frequency changes as the water level fills.

I tested the USB to TTL adapter itself by jumping the TX and RX pins. When I type something into Minicom the character echoes back. I could perhaps try to talk to an Arduino clone (which I have on hand).

When I connect the ground pin of the adapter to the ground pin of the w/m, the TX and RX LEDs light up (either solid or rapid fire). That must be wrong, no? The tx and rx LEDs should flash when data traverses the circuit. If we could imagine that the w/m is transmitting data nonstop, certainly Minicom is not, so at least the TX LED should have stayed unlit. I could have something dodgy going on with my ground line.

i don’t have one. I’ll keep my eye out for a 2nd-hand handheld one in the local street markets.

There are repair cafés in my area but they reject large appliances. I might be able to remove all the components from the cabinet and wiring harness and effectively stuff all the innards in a backpack which I could then layout on a repair table. Seems like a long shot because whoever helps work on it will be equally blind about Bekos secret diagnostic steps.

Thanks for the suggestion. I’ve seen them in Indian YT videos. I’m half tempted but online shopping is mostly a non-starter for me and I don’t suppose I would find that locally. I bought an Arduino clone and some relays, which might be my nuclear option.

I spent a lot of time on YT even to the point of watching Arabic videos of my model just to see what actions were taken. I tried the door latch-unlatch trick and unplugging for a long time… holding the cancel button. Holding the 1st auxillary button. Not sure what else there is to try apart from serial comms.