ISL88739 on battery, the lcd flickers

[clrscr]

Re: Lenovo Yoga 500-14ISK - No battery charge

find the resistor on image and change it with 10 ohm resistor

With the ISL88739 ic, the VCC pin corresponds to the CMSRC pin?
can you tell me , thanks!

[mcplslg123]

No. The architecture is totally different for both type of charging IC.

[clrscr]

No. The architecture is totally different for both type of charging IC.

My laptop uses the ic ISL88739 in motherboard and has a problem: when plugged in to the charger, it runs normally, but if I unplug it and run it on battery, the lcd flickers. Can you give me a solution?

[mon2]

Review the 4R7 ohms resistor on pin 20 (VDD) of the charger chip. Remove all power. Meter in resistance mode. Test across the resistor contacts. What is the measurement in ohms?

[clrscr]

Review the 4R7 ohms resistor on pin 20 (VDD) of the charger chip. Remove all power. Meter in resistance mode. Test across the resistor contacts. What is the measurement in ohms?

I checked the 4R7 resistor on pin 20 R ~~ 5 Ohm

[mon2]

Test the resistor on pin # 18 (DCIN) - sharing a similar schematic.

[clrscr]

Test the resistor on pin # 18 (DCIN) - sharing a similar schematic.

Thank you for your reply, I have checked resistor on pin # 18 (DCIN) R = 20 Ohm All parameters remain unchanged. I still don't understand why the device doesn't work properly on battery

[clrscr]

resistor on pin # 18 (DCIN) R = 20 Ohm

[mon2]

This value should be 10 ohms. What voltage is present on pin #18 with the battery? Test also the dual diode that feeds into pin #18.

[mcplslg123]

I bet this unit is charging the battery fine. Right?
If so,then there is unlikely to be a problem in charging section.
Measure volatge on EDP pins
01.On adapter only
02. On battery only.

However, first try with another compatible screen.

[clrscr]

This value should be 10 ohms. What voltage is present on pin #18 with the battery? Test also the dual diode that feeds into pin #18.

I have checked everything is fine (I also replaced the dual diode PD102 ),if replace R = 10ohm, the charging ic does not work. I'm thinking the charging circuit might be good, Do you have any other solution to help me check?

[clrscr]

I bet this unit is charging the battery fine. Right?
If so,then there is unlikely to be a problem in charging section.
Measure volatge on EDP pins
01.On adapter only
02. On battery only.

However, first try with another compatible screen.

That's right, the charging circuit works fine, the problem is it runs on battery - lcd flickers

, i also replaced another screen, problem still not solved

[mon2]

Which model of laptop do you actually have? What are the markings of your logic board? Do you have a link to the schematics?

What is the voltage of your battery? (it is fully charged?)

[mcplslg123]

EDP pins measurement not shared. So cant suggest anything further.

[Stevedb]

Hi how much voltage do you have on backlight pins on lcd connector on battery . For the fuse and after.

[clrscr]

Which model of laptop do you actually have? What are the markings of your logic board? Do you have a link to the schematics?

What is the voltage of your battery? (it is fully charged?)

I don't have the mainboard diagram.
main code: DAG3MMB4AC0 REV: C
battery is fully charged: OUT ~~ 17.5V

[clrscr]

EDP pins measurement not shared. So cant suggest anything further.

I don't have the main diagram, can only check it on EDP in mainboard.

[clrscr]

Hi how much voltage do you have on backlight pins on lcd connector on battery . For the fuse and after.

I have checked it. Everything seems to be fine, do you have a circuit diagram of it?
main code: DAG3MMB4AC0 REV: C

[mon2]

Attach the power adapter. What is the voltage on the same EDP pins? What is the voltage with the adapter where you have measured 17v5?

To confirm again, the lcd flickers only if operating from battery? No LCD flicker if both the adapter & battery are plugged into the board?

[mcplslg123]

Have you tested with a new screen?