Different lot number part numbers reference the same part: CQ891-67019
I've had service calls on several T120 with similar error codes. The last one was BA7E70E6. The 'B' codes harkens back to the day when I routinely saw this type of error on the old 1050c\ 1055cm models. I used to tell customers you have the 'error code of death'. In more technical terms, the Main PCA Board has a defective chip or routine call somewhere on it and needs to be replaced. Replacing the (CQ891-67019) has resolved the error for me.
THIS ITEM IS FOR THE REPAIR OF YOUR DEFECTIVE PART.*
I will send you a pre-paid shipping label for the shipment of your defective part. When the package arrives, your part will be repaired and shipped back to you. * The item listing on the website is for repairing the customer's board. Regretfully, I cannot repair the network port. If you need a new Main PCA Boards, an invoice for the additional cost of $70 will be sent to you after checkout.