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ednevell is offline ednevell
2008-01-24 , 19:47
Posts: 14 | Thanked: 0 times | Joined on Jan 2008
#11
A good challenge never hurt anybody, LOL

Just trying to not only help myself but also help you guys too.

I personally like the 770 more that the newer 800 and 810 cause of the slimness. So why not find a way to end the wsod nokia vacations that we send our slim hotties on?

I for one will get this fixed and working. I just have to find the part number of that 8 prong chip on the pcb.

Thanks for the reply, it was needed as I didn't know they were posted.

Rick
 
ednevell is offline ednevell
2008-01-24 , 19:50
Posts: 14 | Thanked: 0 times | Joined on Jan 2008
#12
Originally Posted by luciditydigital View Post
I am posting from my 770 at work, so this will be fast, (more to come later) I see on the ribbon cable/pcb, that there is a 8pin sdip chip. Can you get the number from that for me? Looking at this I would say that that is probably NOT the controller. But I would like to check it out, I expected a chip with alot more pins than that.
Has anyone tried to swap a WSOD screen sub assembly with a good one?

Because just a guess, but the chip may be under the metal housing behind the illumination panel. See how there is a separate ribbon going into the housing on the left? That would be for the CFL inverter assy, so if they have the inverter inside, it would stand to reason that the controller could be inside as well.
any chance of further dis-assembly?
-ezra
Good point I will grab my dead screen for that I dont want to damage a WSOD screen.

I will let you know what I find when I get it apart, bad part is I think the tac joined the two tin halves of the screen tin together.
But I will try.

thanks ezra

Rick
Last edited by ednevell; 2008-01-24 at 19:57. Reason: missspelled
 
ednevell is offline ednevell
2008-01-24 , 20:20
Posts: 14 | Thanked: 0 times | Joined on Jan 2008
#13
OK I disassembled the screen down to individual layers and components.

I have to say that the controller has to be that 8 prong IC.

There is nothing in the screen or next to the screen under that tin cover.

So that said we should start looking for the parts on that PCB board and go from there.

Numbers I have gotten of the few parts with them.

The 8 prong IC is 3C66
RG

There are the 4 smaller IC's with 6 prongs from left to right from the 8 prong

74 AVA (the last A is rotated sideways)
AVA (same as the last A) 74

I am willing to bet we need to source that 8 prong.

Thanks ezra for the pointer and for you previous posts.

Rick
 
luciditydigital is offline luciditydigital
2008-01-24 , 20:55
Posts: 64 | Thanked: 2 times | Joined on Oct 2007
#14
again, will have to wait untill i get home, but did you try alldatasheets.com? you might be able to find it and check the datasheet to check its function.

i may pull appart my 770 just to get a look tonight. i have been itching to see its guts anyway.
 
ednevell is offline ednevell
2008-01-24 , 23:49
Posts: 14 | Thanked: 0 times | Joined on Jan 2008
#15
Originally Posted by luciditydigital View Post
again, will have to wait untill i get home, but did you try alldatasheets.com? you might be able to find it and check the datasheet to check its function.

i may pull appart my 770 just to get a look tonight. i have been itching to see its guts anyway.
That would be great, lets get every one who has a WSOD to take a peak and see what the IC chip says.

The more info we have the farther along I think we can get.

My research so far says it is a voltage controler to the screen, the 2 parts I have sourced are 1.8V and the other is 2.7v.

http://pdf1.alldatasheet.com/datashe...-10TU-1.8.html

http://pdf1.alldatasheet.com/datashe...-10TU-2.7.html


We figure out what voltage it is and I would be willing to start the trials.

keep the posts coming guys, the more the merrier.

Rick
Last edited by ednevell; 2008-01-24 at 23:57. Reason: forgot link
 
ednevell is offline ednevell
2008-01-25 , 01:08
Posts: 14 | Thanked: 0 times | Joined on Jan 2008
#16
Ok so I have ordered a new 770 and am going to test a working IC and see if there are any faults in the chips voltage.

Does anyone know what the RACE condition is and where it happens in the circuitry.

have a good night guys,

Rick
 
ednevell is offline ednevell
2008-01-25 , 17:34
Posts: 14 | Thanked: 0 times | Joined on Jan 2008
#17
Ok so after jumping pins 3 and 4 on the 3c66 IC I get a white screen with no gray lines. If I remove the jumper I get the gray lines back. LOL just goofing off with it as the ic is toast.

I couldnt get a solid voltage reading of any combination of prong tests. The curent on the 6 7 and 8 prong are dead, no current.

So that has to be the part we need.

I found these on many online retailers for in between 12 and 34 cents a piece, but they reqiure a order of at least $50.

So I may just order them and if I am wrong about the part I will just sell them on ebay to recoupe a loss.

I am 95% sure its that part, the other 5% is just adoubt cause I am not an electrical engineer, LOL.

Ok so i am off if anybody else has anything to add feel free to drop it in here and we will chat it up.

Rick
 
bac522 is offline bac522
2008-01-25 , 18:01
Posts: 449 | Thanked: 29 times | Joined on Jun 2006
#18
Is that the LCD driver chip? I seem to recall the the WSoD had to do with a voltage overload sent into the LCD driver chip during a power cycle, probably missing a a cap that controls a voltage driven into one of the LCD driver chip inputs, so chance are that the same thing might happen again. Then again maybe the part itself had a flaw that has since be corrected. You might have a nice little side business here if you figure it out, there were quite a few WSoD in the 770 that Nokia failed to own up too.
 
luciditydigital is offline luciditydigital
2008-01-25 , 18:34
Posts: 64 | Thanked: 2 times | Joined on Oct 2007
#19
I would have to chime in that the chip we are talking about here, doesn't appear to actually be the LCD driver chip, (to me) but a power regulator/supply controller.
It is possible that this was the cause of the WSOD, but replacing that chip may not fix it as 'BAC522' pointed out above that the power surge popped an internal cap in the controller.

That is why I asked if anyone had replaced a good LCD sub-assy with one that was WSOD to see if the problem was on the sub-assy and not the main pcb.

Another thing I should point out is that most suppliers will send out chip samples, and if you only need one or two will many times only charge shipping. Also, I order ICs & other compnents from time to time, and if you were willing to wait a week or so for my next order, I could tack on a pack or so, that way you won't have to risk $50 worth of chips that may not solve your problem.
-ezra
 
luciditydigital is offline luciditydigital
2008-01-25 , 18:36
Posts: 64 | Thanked: 2 times | Joined on Oct 2007
#20
Originally Posted by ednevell View Post
Ok so I have ordered a new 770 and am going to test a working IC and see if there are any faults in the chips voltage.

Does anyone know what the RACE condition is and where it happens in the circuitry.

have a good night guys,

Rick
be sure that when you test on a working unit, that you are using an isolated meter, and you don't accidentally let the probes touch. It only takes once and you will have two 770s to repair.
(not trying to discourage you, but just a friendly warning)
-ezra
 
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