Samsung Galaxy S4 — SGH-I337 Galaxy S4 with Android 4.4.4 on AT&T getting the "no SIM detected message"

My wife has her SGH-I337 with Android 4.4.4 on AT&T getting the "no SIM detected message" with a known new working SIM and a newly replaced SIM + microSD card reader installed.
This may or may not be related to some small amount (less than 3 ml) of water getting into the phone next to sink a week before. Phone was sealed in can of baked out silica gel for 2 days to draw out any remaining moisture.
Phone was working OK for a week after the water incident and a new SIM from the local AT&T Store. .

I used the SIM from her S4 in my S4 and it's working OK. Also, the touch sounds and the boot screen sounds are distorted and garbled on her S4, but the music and media sounds are fine. Did hard reset and also booted this S4 into safe mode, and still no SIM is detected message is appearing.
Can read microSD well. Display is working well, WiFi is good, GPS, BT, all good, all buttons, contacts look good inside, just trouble reading SIM and distorted touch sounds.
All that I can find online is to take motherboard out and clean any suspicious gold contacts with 91% isopropyl or even to replace the motherboard, sanding down oxidized contacts...etc.... I am looking to find what other gold contacts or circuits are involved in the SIM card reader that might prevent it from connecting to the logic or the processor.
Please let me know if you have any ideas or suggestions to get this SGH-I337 back on the AT&T network.

Thanks in advance!

George P

OK, Thanks, - Yeah, It's 1.5 years old now unfortunately. I soaked the motherboard only in 91% last night and scrubbed it with a new soft toothbrush, then the touch sounds were great when it powered back up, but still no SIM could still be recognized. Everything looks good under 50X magnification. Not sure what else to try, other than replacing more parts.

Raj arya

you should contact to mobile technician.

OK, Thanks. Which One? A Samsung Technician I am assuming?