Instead of the usual 4G reception bars at the top of my phone I am now getting a circle with a line across it. The sim card manager shows sim unknown and unknown number. I am unable to send or receive calls or text. When connected to a wireless network I am able to send and receive calls but not send text, only receive, The sim card works fine in another phone.
Go to p.12/48 to view the troubleshooting flowchart for the SIM section.
There are also board layout diagrams in the manual that will help to show the location of the component mentioned in the flowchart. Use the search function of your browser (Ctrl + f) and search for the component ID in the document. You may have to zoom in a lot to find them on the layout diagrams.
Unfortunately there's no parts list in the manual so if a component is faulty you may have to search online to find out what it's specifications are.
Thanks for the service manual. The phone has been dropped a few times over the years but not from great heights and with no visible damage as it was in a case. There is no water damage but it has been in a steamy bathroom a few times. Recently I replaced the USB charging port card as the connector was loose and I was thinking maybe I over did it with the hot air gun (hair dryer) on the back. This was my first ever internal phone repair.
Ouch, this isn't going to be much help, I'm afraid, but it sounds like an issue with the SIM card socket. Unfortunately, it's soldered onto the motherboard and would require somewhat sophisticated board level repairs to fix or replace. That sort of repair wouldn't be cheap; from my brief look online it appears motherboards for your phone are running anywhere from about $40 to $150 USD, depending where you get it from, so that might be an option.
Before you go quite that far, it might be worth your time to have a shop take a look at it and see if they can find any issue inside the SIM card slot. They will probably charge you some for the diagnosis, but at least then you'll know what you're working with.
By the way, your phone has a dual SIM card tray; have you by any chance tried the other position for the SIM card?