820-3115 chime but no display

[dukefawks]

These have no GPU and I doubt the PCH is bad. Check SMC_LID again and the 100K pull-up resistor on this line. Inspect the LCD connector closely for corrosion and replace to be sure. You have done a PRAM reset?!

 

[Repairable]

SMC_LID 3.46volt
R5071 99.2k
R6961 100.6

pram reset done twice now still no change
also stil 0 volt on LCD_IG_PWR_EN


checked connector looked good, made sure to replace it stil same

 

[dukefawks]

Check with Oscope if there is any pulses on pin 6 and 7.

 

[Repairable]

i am probably gone say something stupid today....

I took out my rigol and normaly I can get the lines big inuf so I can see it going up and down somehow today.......pffffff

pin 6 and 7 both vmax jump between 3,2v and 3,6v
pin 6 and 7 both vavg jump between 3.02v and 3.06v
pin 6 and 7 both vmin jumpo between 2.v and 2.4v

line is like picture, voltage set on 1 volt

 

[dukefawks]

Yeah I suggest you first find some Oscope tutorials. You need to set the time base to match the expected signal, also select DC coupled. There will only be a short burst of data on this bus after power on, this will be hard to catch so you cannot mess with the scope to find the correct time base.
I dunno with this board now, willing to send it my way so I can have a look?

 

[Repairable]

There will only be a short burst of data on this bus after power on, this will be hard to catch so you cannot mess with the scope to find the correct time base.
QUOTE]

aa did not know that i was measuring when the system was on already.
yes indeed some tutorial would be nice MJLORTON seems to explain it good.

ill send you a pm about sending the board.

 

[Repairable]

hi Duke, did you get the message?

 

[Repairable]

Hi duke.

did you get my message?

how mutch for the checkup?

 

[dukefawks]

Yeah, it'll have to wait till next week or so. Or is this a customer repair with time limits?

 

[Repairable]

good. ty. next week would be great, its a customer board but he understands the issue is bigger (or I am less in the right direction, just don't tell him)

week after that I am going to Ijsland for a week (he would like it if its back just before I go....)

 

[Repairable]

No Title

pin 7

 

[Repairable]

No Title

pin 6 ,,
hope its what you need to know .
if not kick me

 

[Repairable]

is this good duke or not ?

 

[dukefawks]

It says nothing, it is just a voltage. There is no data by the looks of it. The burst of data on this bus will be very short and you will need to "catch" it. No idea if your scope can store data like that,

 

[Repairable]

still willing to look at it ?

 

[dukefawks]

Sure, but just send it in and let me have a look. To busy to work out other options. Send it to com-europe.nl and TAV Duco.

 

[Repairable]

grrrr this pisses me off, putting work in a shit pile when lied to....
also pisses me off because i missed a spot.
it had s solder spot,

LCD_BKLT_EN is not there!!

they connected PP3V3_S0 so that it looked like there was voltage.

anyhow usefull to even look further? or is that a sign of a bad PCH

after the meltdown,
LVDS_IG_PANEL_PWR also missing.


pm_slp_s4_l 3.346 v
smc_lid 3.3463v

 

[dukefawks]

Of course all those signals are missing when the LCD is not recognized. You know where to send it.