Ok guys I had been without my phone for about 2 weeks due to it not detecting the sim card. After replacing the sim card, as well as the slot and many other parts, I thought the only remedy to fix my phone was by replacing the main board. Through research and having the additional sim slot by my side, I came up with a great idea that finally worked! This is what I did. First, open the sim slot door and locate a tiny black switch, this is the one that is controlled by the switch on the outside. Push it up all the way and power up the phone. Hold press firmly on the sim card against the phone, with the outside door open. Wait for the phone to boot up and the green light to flash, which means it is getting a signal, then you can release your grip and close the door by locking it. Everytime you reset the phone you will have to follow this procedure, but at least the phone will work. I am thankful that I came up with this idea because it saved me from having to buy a new phone. I believe the problem is that the outside switch is not fully catching the inside one, which is why the sim isn't being detected. Hopefully this resolves everyone's problems, because it sure worked for me! Let me know if you have any more problems.
Wow no responses? After all the problems people were having with sim detection? Please post feedback because I was curious if this worked for others as well. Thanks.
id help u out but i had 2 tilts and just fixed this problem of mine today, i just changed the part of the phone with the sim card holder on it and it works perfect.
Awesome!!!!!!!!!!!!
I have had an AT&T Tilt for about 6 months with this problem, i just read your post today and that totally fixed my problem, thank you so much!!!!!! Although in the down time of the one Tilt I purchased another one from a friend, oh well now i have two working Tilts, thanks again!!!
worked for me
i just have a small square of cardboard stuck to my sim, then the door pushes the sim against the contacts, but same idea as yours really. but this problem started for me when i replaced a smashed screen so i had assumed i shifted everything a little in the process of putting it back together.
works
i tried your method and that better than holding that door, thanks for the suggestion!!!
Glad to hear it has worked for you guys.
Lifesaver
Flashed a buddy's phone tonight. Spent three hours trying to get his phone to read his SIM. Found this thread and your advice worked like a charm. Thanks
No problem. Glad to help. I just wanted to help all the people who were having this problem so they didn't have to deal with what I had to deal with and be without their phone for 2 weeks!
Fantastic this Worked!!!!
This worked straight away. You ought to be congratulated. Ingenious. All these other threads I checked couldn’t find the solution. They talked of dry magnetic head spray cleaner, deoxidizing boards, flashing the phone etc. With some saying success after a few goes. Its kind of funny that what might have been happening for them, is that constant opening & closing the simm card cover in their processes probably inadvertently fixed prob by pushing switch in enough. Whereas your solution goes straight to the problem & solves it. Hilarious. Thanks Heaps Tilt Fanatic. Nice to have my TYTN II back up.
bravacudda said:
This worked straight away. You ought to be congratulated. Ingenious. All these other threads I checked couldn’t find the solution. They talked of dry magnetic head spray cleaner, deoxidizing boards, flashing the phone etc. With some saying success after a few goes. Its kind of funny that what might have been happening for them, is that constant opening & closing the simm card cover in their processes probably inadvertently fixed prob by pushing switch in enough. Whereas your solution goes straight to the problem & solves it. Hilarious. Thanks Heaps Tilt Fanatic. Nice to have my TYTN II back up.
Click to expand...
Click to collapse
Thanks. Oh and no problem. Glad it worked for you. Just thought I'd give back to the community so people didn't have to deal with the pain I went through.
hi guys..i'.m having the same problem...i wonder how u guys do it bcoz when i turned on the phone (while the simdoor is open) the error msg appear "simdoor is unlocked.please locked it. the device will automatically turned off in 10 sec". anyway after I locked the simdoor, the error msg still appear so now my htc got 2 prob. 1 is not detecting sim, another is the simdoor unlocked error msg (even if i already locked it).. hope u guys can help me on this...thank in advance..
hi guys,
i got HTC tytnII/kaisser over a year ago,
and now i got this problem "sim card is missing",
i tried to put some paper and it didnt work,
try anything in this forum and it didnt work...
almost frustrated and thinking of put it on a cupboard.
anyone have another solution?
thank you
Related
I have had my Tilt for quite some time and a few months back it started telling me there was no SIM card and it can't dial out. At first it was an easy fix, just disconnect and reconnect from network, but over time that stopped working. I found someone in the forums here had put a folded piece of paper in the SIM door to press the SIM against the contacts, so I tried that. Again, it worked for a while but the problem came back. I replaced the paper with a small piece of cardboard, and now it will connect again but the SIM is getting warped and I fear it's only a matter of time before this starts becoming an issue again. It still does it from time to time, and I jiggle the cardboard into a new position and it works again. I was wondering if anyone else has had this problem and perhaps found a better, more permanent fix? The SIM contacts are clean as is the SIM card, btw, I already tried that. Any help is much appreciated.
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Now playing: Radiohead - Knives Out
via FoxyTunes
i have had no problems before, i flashed a couple roms in it before, but in the end, i kept very lightly modded rom very close to OEM rom for the tilt that i got from here. all was well for months and months.. until now.
i noticed that the phone will lose signal. and not detect a sim card anymore. at first i thought it was sim. so i tried it on my other tilt (i have 2) and i determined that its the phone.
if i restart it, it works for about 1 min or less if im lucky.. then i have to to go comm. manager, turn off phone signal, and turn it back on, usually, that does the trick. but now, that wont even work anymore.
the only way to get the sim recognized again is if i slide the phone out, go to comm. manager, turn off phone and turn back on, and LEAVE the phone slided out. once i slide the phone back in, it will not detect the sim. ive tried diff. spl, different roms, and searched before i came back here.
ive had it for over a year, have broken the screen and messed up keyboard by closing hood of my car on it,
but ive fixed it. and that was long ago. maybe this new problem is because of this. if someone had similar problems, let me know what you did. or if anyone can point me into the next direction. i guess ill have to crack it open again.
I had a similiar issue where my phone would turn on ok, then lose signal and then get the no sim card error (dialer screen). What I ended up doing was taking a piece of tape and put it on the back of the sim card then slid it into the holder and locked it. (It was a thick metal tape, if you use scotch tape I recommend using a few pieces). Once I did that I havent had another problem with it. Its a pain to get the sim out of the phone because it ruins the tape but I would rather deal with that than not have my phone work correctly.
Let me know if that works for ya.
Jim
i see. so it seems that your problem was that the sim shifted out of place sometimes... i will try that. hope it works. its so odd that my sim card dissapears when i close my tilt
I just recently had a similar problem and I finally figured out it was a bad contact with the SIM card. you can either use the tape trick, or if you have a steady hand, take a thin object (such as a paper clip or glasses screwdriver) and very gently lift the contacts up underneath of where the sim card goes. they may have been pushed down due to abnormal pressure exerted on the back of your phone, I think that's what happened to mine.
thanks for your help. the sim contact issue was the first thing i suspected, AND tried. i used a needle. i raised the level of each of the 8 contacts making sure the sim will make contact with each pin. but the problem remains.
i will try this again. to double check. i will respond with the results
i tried pushing the pins up a little bit again, i still have the same problem
*but now i have an update, it seems that the sim card stops being detected right before i actually fully slide the phone back in. for examplle, before the slide-in tone is played, and before the screen tilts back.
i already took it apart for a look inside, everything seems fine. and i dnt really know wht to look for.
Hi,
was reading about ur issue, just tought on jumping into the wagon, I suspect it might be the flex cable that connects the sim to the motherboard, if there is such cable, i haven't opened my kaiser yet but my Pioneer car radio has this flex cable issue when the drive is closed the screen turns on and the whole radio but as soon as you press eject (the face will scroll and unveil the cd slot) the radio actually turns off and i have to move the face back to its original position in order to work. At the end I took the flex cable out and 1/4 of it was teared, in the end I had to order a new part
thanks so much for your help. i guess there is nothing left to do but to take it all apart. somewhat blindly. at least i know what to look for. bad cables, contacts... im clueless as to whether it can be a bad grounding issue? or a short. i dnt know. i guess i may be the first one to experience a problem like this on a tilt.
so i will do my best to get this problem resolved. and maybe include some pictures if it is intereting enough
my tilt totally stopped recognizing the sim.. it first happened when i dropped it and had to keep it open to keep contact.. then i was sitting with it open and tilted up, it fell and closed somehow and now the sim isnt there at all... i guess something is disconnected or whatever, im afraid to take it apart, but its either that or a paper weight.
New Sim
I had a similar problem. My sim card would disappear on occasion then one day I woke up and no phone. Just an annoying sim card not installed message. Checked the phone by putting in a known working sim card and it was fine. Called ATT for a new sim card and now my phone is working. Try a new SIM CARD.
For the original poster -- that fact that it works when the keyboard is in one position but not the other indicates that it is likely a bad flex cable.
Agreed
Its most likely the cable. I used a new SIM, the extra pressure trick, cleaned contact, etc on mine yesterday, but the problem remained.
I got a used Tilt from Craigsliist , reusing the SIM and case, and it works great.
i wonder if anyone has bought this item before and if it works? upon research, i think our problem comes from the sim card flex and ribbon:
http://cgi.ebay.com/HTC-TyTN-II-P45...AU_MobilePhoneAccessories?hash=item2a05bd88c4
It definitely comes form that ...but the repair cost is more than the replacement cost..so why bother with repairing it?
Hey, I'm having the same problem, my phone just out of the blue after a year of use says no sim card. My card is fine in other phones, and no cards work in my phone. I tried the pressure thing and cleaning the pins, but no good. My next option will be a hard reset/ wipe the phone and see if that clears the problem. I'm not optimistic after reading the thread. Did any one have luck with one of those Kaiser Flex Sim Card Slot Repair Parts that loller90278 mentioned? If so, I would rather spend $16 to fix a phone that has worked well up till now, rather than spend $100 on an unknown used phone. Still I don't want to bother if it's not going to work.
Thanks
well well...i'm going to have to join this "club" of affected kaiser users
my kaiser just started misbehaving last night. i bought it brand new exactly 1 year and 11 months ago
i took good care of it, barely ever tilted the screen during my almost 2 years of use. the current behavior is that when the keyboard is closed, the sim is hardly ever detected (1 out of 10 times perhaps). when the keyboard is opened, the sim is fairly regularly detected (9 out of 10 times perhaps).
i am not going to bother with investigating the possibility of a software problem because of my observations. given all the threads i've read about this issue, i am convinced my sim flex cable is either loose and/or broken.
anyway, it seems the kaiser's flex cable is just not built to last much longer than 2 years. if i can have it repaired for up to around $50, i'll go for it...if not, HD2 here i come!
ASCIIker said:
well well...i'm going to have to join this "club" of affected kaiser users
my kaiser just started misbehaving last night. i bought it brand new exactly 1 year and 11 months ago
i took good care of it, barely ever tilted the screen during my almost 2 years of use. the current behavior is that when the keyboard is closed, the sim is hardly ever detected (1 out of 10 times perhaps). when the keyboard is opened, the sim is fairly regularly detected (9 out of 10 times perhaps).
i am not going to bother with investigating the possibility of a software problem because of my observations. given all the threads i've read about this issue, i am convinced my sim flex cable is either loose and/or broken.
anyway, it seems the kaiser's flex cable is just not built to last much longer than 2 years. if i can have it repaired for up to around $50, i'll go for it...if not, HD2 here i come!
Click to expand...
Click to collapse
just wanted to follow up on my own post above.
i just got my kaiser back. its been repaired
the dude cannibalized the main flex cable and sim assembly from a tilt and transplanted it into my tytn2. BUT! there has been an interesting side effect...because the tilt does not have a front cam, my guess is that its flex cable is unable to carry the signal of the front cam in the tytn2. so now my front cam is no longer detected. the camera app shows no icon to switch to another camera. the icon is blank!
i figured i could either have a kaiser with sim problems or a working kaiser with no front cam. i chose to keep the flex cable from the tilt because there is no 3G in my region and i hardly ever used the front camera otherwise.
long story short, my kaiser is back in business!
Similar problem !!!
Hello mate, .,. the problem in you case is the connecting ribbon between the keyboard that holds the sim card beneath it and the screen. I recommend u to replace the ribbon that connects. Its around 40 USD and that should do the trick.
Cheers !!!!!
Hey guys i have had a HTC TILT for a while. I stopped using it a while ago, but i tried recently and i did the HARD SPL installed a 6.5 rom did the radio as well, but i'm getting a "sim is missing" error, with any sim that i try. Are there any fixes to this? I'm confused, thank you
No offence, but, are you sure you're inserting the SIM correctly? I spent half an hour trying to figure that one out on a late night... .
If not that, then check the contacts are in the correct position and free from any dirt/grime.
Dave
DaveShaw said:
No offence, but, are you sure you're inserting the SIM correctly? I spent half an hour trying to figure that one out on a late night... .
If not that, then check the contacts are in the correct position and free from any dirt/grime.
Dave
Click to expand...
Click to collapse
I inserted the right way. This issue was happning even before i did the hard spl. But the phone didn't have this issue until like a year of not using it. I tried googling stuff i see many people had this issue too but i cant find the answer.
I had the same problem and had to replace the main flex cable which ran me about $30 on ebay. Everytime you slide open your phone the flex cable gets worn down and this can cause other problems such as it not reading your memory card and white screen of death.
But before you do anything see if applying more pressure on the sim card by putting a thin piece of paepr between the sim card and locking dor. I heard that this can fix it if it's a minor problem. Good luck man.
Being the phone unused for one year, maybe the sim bay's contacts gets oxidated?
Buy a dry contact cleaner in an electronics-store (sometimes you can get it at hardware too) but be sure it's the DRY type
Turn off the phone, pull off the battery and spray contact cleaner in the sim bay
Leave it evaporate (the greasy one doesn't evaporate... :-( )
Restart phone and check if solved....
So here's my situation
While crawling across a rapids I slipped, dipped my phone in the river, and thought all was lost.
I pulled the case and back shell off immediately and it seemed all was well once I dried the G2 with rice for 12 hours. BUT, the sim card no longer would read. After getting back home from my trip I pulled the entire phone apart and discovered the reader looked a bit rough and the slot was probably shot from the water hitting it. SIM card works fine in my S3 mind you.
So where I am at is I have a new SIM reader on its way here to install in a day or so which I THINK should solve the issue. Im curious if anyone else has installed this component before?. Appears to be 6 solder points that hold it in and thats about it. Hell of a thing that the entire phone works flawlessly but the SIM reader shat itself. Never seen anything like it.
Any and all input or ideas are welcome.
Cheers
Mrdobin said:
So here's my situation
While crawling across a rapids I slipped, dipped my phone in the river, and thought all was lost.
I pulled the case and back shell off immediately and it seemed all was well once I dried the G2 with rice for 12 hours. BUT, the sim card no longer would read. After getting back home from my trip I pulled the entire phone apart and discovered the reader looked a bit rough and the slot was probably shot from the water hitting it. SIM card works fine in my S3 mind you.
So where I am at is I have a new SIM reader on its way here to install in a day or so which I THINK should solve the issue. Im curious if anyone else has installed this component before?. Appears to be 6 solder points that hold it in and thats about it. Hell of a thing that the entire phone works flawlessly but the SIM reader shat itself. Never seen anything like it.
Any and all input or ideas are welcome.
Cheers
Click to expand...
Click to collapse
Did you end up installing it?
My sim reader always gave out and I'm thinking of ordering the part but haven't been able to find a tutorial for the replacement.
I too would like to know the result...
Conclusion
rustypie said:
I too would like to know the result...
Click to expand...
Click to collapse
I did end up installing the tray. However, as I removed the contacts that were placed on the board itself and so when I soldered in the new tray there was two points which would not adhere. I ended up replacing the whole board in order to remedy things.
But, most importantly I confirm the board install isnt too hard and will work if you just make sure to properly remove the old tray and dont just pry it off. The prying will rip the contacts from the board and then the solder wont hold.
Mostly just browse these forums, and as you can see, don't post often.
Since about 2 weeks after I got my Nexus 6 directly from Motorola, I've been having intermittent issues with my sim card. It varies wildly in time frame. Longest I've gone without the message popping up, and losing connectivity is about a week and a half. I shut the device down, restart, and it's back. Sometimes it happens as frequently as within the same 5 minutes. As you can guess, I'm highly irritated.
First, I called Verizon and they were nice enough to send out a new nano sim. Popped it in an adapter, activated in Galaxy S3, and into the Nexus. Didn't solve anything, but at least I can rule out a faulty sim card.
Second, called Motorola to ask for a replacement. 5 business days later I call to ask where my phone is and I'm told that they don't have any "like-new" stock and that they don't know when they will. I ask for a refund to buy another phone and they say it will be 4-6 weeks.
Can someone smarter than I tell me if this is for sure a hardware issue? I'm guessing it is, and that it's specific to my device since I literally can't find anything on the web/forums about others having this issue with the N6.
Help is much appreciated, thanks.
Check your apn settings
provide more info, are you stock, custom rom, unlocked, etc.
You may need to try a nuke and repave to start fresh. After a week, something happened to my SIM on a custom rom and the fix is to nuke and repave and that includes userdata.
so back stuff up but only restore what you seriously cant redo, thats working so far for me.
GL
Can you advise what to check in APN's? (Sorry for the dumb question)
I was rooted running stock rom for a week, but unrooted and factory reset when I thought I was returning it to Motorola. Has had issues both ways.
Try hitting the contacts on the sim card with a pencil eraser.
mrbrooks .. i have a nexus 5 and i have this exact same problem .. leads me to believe maybe its software related .. started after lolipop .. havent been able to find a solution yet !
jeetash said:
mrbrooks .. i have a nexus 5 and i have this exact same problem .. leads me to believe maybe its software related .. started after lolipop .. havent been able to find a solution yet !
Click to expand...
Click to collapse
nexus 5 doesnt work on verizon(not fully at least). the op said that he ordered a replacement, which sounds like you should do, as the nexus 5 did have an issue with coming with a bad sim card holder on occasion.
simms22 said:
nexus 5 doesnt work on verizon(not fully at least). the op said that he ordered a replacement, which sounds like you should do, as the nexus 5 did have an issue with coming with a bad sim card holder on occasion.
Click to expand...
Click to collapse
worst part is that it is happening on an Replacement device after i RMAd my first nexus for a power button problem !!
i hope its software related and can be fixed .. because google is now refusing to rma this as im now out of my warranty period !
just to be clear im not on verizon .. im on a gsm carrier and have tried 4-5 different working sims
it latches on to network and works fine for a few hours and then just drops and refuses to catch networ k...
any other ideas ??
can the bad sim card holder be fixed or repaired ??
Did this ever get figured out for any of you? I have the same issue on a Nexus 6. It won't read my AT&T SIM card at all anymore, but knows it's in there. When I put in a Verizon SIM card, it see the card and updates information in the status section, but still says No Sim Card at top of screen. I am currently in the middle of getting a replacement from Motorola, but now I am worried this will happen on my next one too.
Ryououki said:
Did this ever get figured out for any of you? I have the same issue on a Nexus 6. It won't read my AT&T SIM card at all anymore, but knows it's in there. When I put in a Verizon SIM card, it see the card and updates information in the status section, but still says No Sim Card at top of screen. I am currently in the middle of getting a replacement from Motorola, but now I am worried this will happen on my next one too.
Click to expand...
Click to collapse
This just happen to me as well, google knows nothing about it, neither does motorola , they are sending me a replacement hopefully that fixes the issue.
I just got out of the shower and suddenly had the "no sim card" message. Restarted the phone, still nothing.
Removed the sim card. Put it back in... Now I have data again. Wtf?
I just noticed this running chroma. It always happened on boot and always went away. Never seen it stock unlocked rooted and tweaked with things like the Motorola command center, tethering, and such.
I have just got a N6 today and mine seems to be doing this. Have you guys had yours replaced?
Eager to know if i need to send it back or if its software. The sim card works fine in my s5.
EDIT: it looks like I can make it do it. If i type really quick , the vibrations/haptic feedback must make it have a poor contact and it disconnects.
f1ux said:
I have just got a N6 today and mine seems to be doing this. Have you guys had yours replaced?
Eager to know if i need to send it back or if its software. The sim card works fine in my s5.
EDIT: it looks like I can make it do it. If i type really quick , the vibrations/haptic feedback must make it have a poor contact and it disconnects.
Click to expand...
Click to collapse
I am curious, have you guys figured out this issue? I just got a new Nexus 6 that does this intermittently. The phone can read the card, but then every once ina while (about three times a day) it says 'no sim card - emergency calls only'.
I've noticed that banging mine against a hard surface (I do have a case on) seems to fix it for me, as horrible as it sounds... Mine does not fix itself after a reboot.
That said, it hasn't happened to me since I've had marshmallow on here.
In short. I have no idea what's going on.
Sent from my Nexus 6 using Tapatalk
I have had my replacement Nexus 6 for about 9 months and have not had this issue occur on the replacement unit. I'd highly suggest sending it in for replacement if you are still under warranty.
Sent from my Nexus 6 using Tapatalk
Push the SIM tray in really hard!
Push the SIM tray in as hard as you can!!!
I tried every other solution and this worked for me with Nexus 6.
I have same issue No SIM CARD with droid turbo, restart always solve issue, its common problem with Motorola phones, lot pf people are facing this but no solution yet
yeah my shamu after a new sim card did this, took it in, no fix, mytrendyphone service in england claimed they could fix it,, I paid they didnt fix it, kept it two months, sent it back unrepaired.
yes fairly ticked off. wifi only paperweight now.
MrBroox said:
Mostly just browse these forums, and as you can see, don't post often.
Since about 2 weeks after I got my Nexus 6 directly from Motorola, I've been having intermittent issues with my sim card. It varies wildly in time frame. Longest I've gone without the message popping up, and losing connectivity is about a week and a half. I shut the device down, restart, and it's back. Sometimes it happens as frequently as within the same 5 minutes. As you can guess, I'm highly irritated.
First, I called Verizon and they were nice enough to send out a new nano sim. Popped it in an adapter, activated in Galaxy S3, and into the Nexus. Didn't solve anything, but at least I can rule out a faulty sim card.
Second, called Motorola to ask for a replacement. 5 business days later I call to ask where my phone is and I'm told that they don't have any "like-new" stock and that they don't know when they will. I ask for a refund to buy another phone and they say it will be 4-6 weeks.
Can someone smarter than I tell me if this is for sure a hardware issue? I'm guessing it is, and that it's specific to my device since I literally can't find anything on the web/forums about others having this issue with the N6.
Help is much appreciated, thanks.
Click to expand...
Click to collapse
OK first off I had the same issue. intermittent no sim detected. go worse and worse, until did not detect at all...
First I placed a piece of this card stock behind sim and jammed it into the slot. that worked for a bit and the again it started with the same issue.
and became a pain again...
(FYI, I am an electrician by trade)
What I has appeared to fixed it permanently (so far anyway).
All electrical contacts get a corrosion (a patina layer) some more than others from humidity, sweat, dissimilar metal touching, or just cheap metal..
On a hunch I gooped up the sim contact surface with a de-ox compound (De-oxidation) and worked the sim in and out a few time to "clean the contacts (you could use a small long skinny piece of paper board to to it also (I didn't think of it until after) and insert the Sim. So far it has done the trick.
the is many de-ox compound available (home depot or electrical supply)so are blacking and gritty. what I used was ilsco Non- grit De-ox Compound".
I hope this helps as this seem to be a pretty common issue.
As always, Your actual mileage may vary.
---------- Post added at 06:28 PM ---------- Previous post was at 06:01 PM ----------
MrBroox said:
Mostly just browse these forums, and as you can see, don't post often.
Since about 2 weeks after I got my Nexus 6 directly from Motorola, I've been having intermittent issues with my sim card. It varies wildly in time frame. Longest I've gone without the message popping up, and losing connectivity is about a week and a half. I shut the device down, restart, and it's back. Sometimes it happens as frequently as within the same 5 minutes. As you can guess, I'm highly irritated.
First, I called Verizon and they were nice enough to send out a new nano sim. Popped it in an adapter, activated in Galaxy S3, and into the Nexus. Didn't solve anything, but at least I can rule out a faulty sim card.
Second, called Motorola to ask for a replacement. 5 business days later I call to ask where my phone is and I'm told that they don't have any "like-new" stock and that they don't know when they will. I ask for a refund to buy another phone and they say it will be 4-6 weeks.
Can someone smarter than I tell me if this is for sure a hardware issue? I'm guessing it is, and that it's specific to my device since I literally can't find anything on the web/forums about others having this issue with the N6.
Help is much appreciated, thanks.
Click to expand...
Click to collapse
I know this is an old post,.. but I'm answering in hope of helping others that my need the solution
OK first off I had the same issue. intermittent no sim detected. got worse and worse, until did not detect at all...
First I placed a piece of this card stock behind sim and jammed it into the slot. that worked for a bit and the again it started with the same issue.
and became a pain again...
(FYI, I am an electrician by trade)
What I did next had appeared to fixed it permanently (so far anyway).
Many electrical contacts get a corrosion (a patina layer) some more than others from humidity, sweat, dissimilar metals, or just cheap metal..
On a hunch I gooped up the sim card's contact surface with a de-ox compound (De-oxidation) and worked the sim in and out a few time to "clean the contacts" inside the sim slot (you could also use a small long skinny piece of paper board to to it also (I didn't think of it until after) and insert the Sim. So far it has done the trick.
the is many de-ox compound available (home depot or electrical supply)so are blacking and gritty. what I used was ilsco Non- grit De-ox Compound".
The compound will not (should not) damage and the phone, its is for electrical and electronic equipment.
I hope this helps as this seem to be a pretty common issue.
As always, Your actual mileage may vary.
Veronica