5 yeas ago, I got a 2040B first time, and it displays OMEM ERROR after power on. From that time, I started in looking for service manual or even user manual, but I got nothing except datasheet
.
In Jan 2016, I got the sencond 2040B
, but..............................it got the same problem: OMEM ERROR
It's really a sad story!
Last week, I took it from corner and try to fix it.
I took out the mcu board, applied 5V power source to it directly and found the DMA chip MC68440R8 showed much higher temperature than other chips when its power consumption is about 1.1W.
And then, I removed it from the mcu board, restored the board into 2040B, after power on, 2040B showed the same error message.
So after a roughly diagnosis, I think maybe the MC68440 or some ROM chips around it are bad, so the first step is got a reliable MC68440 but it is really a old chip and hard to buy for now.
I decide to replace it by MC68440FN8 and a 68pin PLCC to PGA socket and now waiting for these components...