8310 UEM Problems
 

I have removed a working UEM IC (for prcatice) from a 8310, reballed the IC and put the same working UEM back on the board. I now find that the phone will not power up.

I have replaced many IC's on 3310's and 8210's etc ie Hagars, Cobbas etc and I am experienced with reballing/BGA work but this is my first UEM IC.

I understand UEM's need programming but surely not the same IC that has been taken off the board and put back on the same board.

Any clues were I may be going wrong, amy suggestion what to check?

Replies would be appreciated.

:confused:

To revive your phone you will need empty UEM IC, put it in phone and then program phone with DCT-4 IMEI changer.

IMEI in DCT-4 is stored not like in DCT-3. You can't reprogram existing UEM chip, so you need empty one. DCT-4 calculator costs about 900$.

Thanks FractalizeR ,

Actually I understand about the re-programming. However I think I have found the solution as I have now put a new UEM IC on and it works fine.

I believe my problem was that I removed the old UEM, re-balled it and then put it back on the board, this was probably too much heat and the IC couldnt take it.

The UEM is thinner than say a Haga or Cobba it cannot take too much heat. As you have removed the UEM you heated, then reballed it, ie more heat, then replaced it, ie more heat.

Try removing with a jig, I know you dont need a jig to remove as you can easily handle with tweezers but there is a jig that will automatically remove most IC's "exactly" when the solder balls have melted thus helping prevent over heating. I say "helping" as you could still have your heat setting "too" hot so keep the heat down. In other words the JIG will automatically lift the UEM off the board for you as soon as the last ball has melted, you just apply the heat it really is easy to use but fiddly to set up for the first time.

The jig is available from www.excelldirect.co.uk To be honest I use it more for removing Hagars or when the IC is really surrounded with loads of components (Hagar on a 3310) as it is safer with a jig.

Hope this helps
Paul

Fuse,,

try to make your hot air at 260~280 C,
and before you install UEM, you can "pre-heat" that PCB on UEM area , and put flux at UEM side , then install UEM without any nozzle !

Willy

Thanks Willy

Thats sounds like a decent tip, many thanks.

Maybe I can pass a tip back to you. There are many UEM on the market that are not good. I am waiting for a new adaptor for my Universal Programming Box that should allow me to read the IC and check it for errors before I put it on the board. Keep an eye open for bad UEM's........

By the way I did get the phone working again and I have been successful with a couple of other UEM's.

Fuse

Fuse

Good job .

for those UEM, you can test on pin P8,N9, N11, N14
and M6 N5 and P5 for "resistance", but, it not help so much !
because, even it is good , and when you install to phone can make phone power up, but ,,,,,,,maybe it is USED, already wrote IMEI there,, then it is still useless , and it will got off after 35 sec.

Willy

Thanks for the notes Willy,

By the way the UEM's that have problems are fresh from the factory and still sealed in the packets (reel packaging) My guess is that a bad batch has been produced which should have been dumped yet found its way onto the market were it is traded as new.

I'll let you know how I get on testing the UEM's on a Universal Programmer once I get the UEM adaptor.

Fuse

Fuse,,

i am interested,, that you said adapter and Universal programmer ,, can it work read/write/earse UEM ??

Willy

Willy

The Universal Programmer that I use is used to program IC's its used widely in industry by software developers. It has a nice "test" facillity that checks the software on the IC and also all the pins for good contact. The UEM IC is a "write once" only IC, I would guess the Universal programmer is capable of writing to the UEM IC but this would not be good as the UEM needs to "shake hands" with the CPU and the Flash IC whilst on the motherboard. Therefore as its only a write once IC I dont expect the UEM would work if programmed by the Universal Programmer off the MB, then re-calculated whilst on the MB along with the CPU and Flash......But I will tell you more once I test this theory for myself.

Fuse

Fuse,

ok,, but can you tell me, which mode Universal programmer can read/write to UEM with adapter ? or it is special custom made ?

Willy

Hello Willy

I think this is what you mean if it isnt let me know.......

I need to order a adaptor that fits the UEM IC this is "custom made", this adaptor fits into the main programming box (large metal box) linked to the PC by an LPT connection. My computer software will first of all check all the pins (legs/balls) on the UEM IC and make sure every one is correct and working. Next it checks the software inside the IC. I wouldnt say that the check is able to spot any small software errors more like major software faults. As an example only: if I have the correct adaptor I can usually place an IC into the adaptor and copy and save "all" the info/software stored in the IC to my harddrive on my PC (If I wanted to do this). I could also reverse this an write from the PC to an IC or erase the software on the IC in fact almost anything

Hope this is what you was asking for........

Fuse