HP Board La-C701P-Work only with external Monitor

[vabea]

Hello, i have this Hp board (LA-C701P), it work but no image (only with external monitor) when i power on the lcd stay a more black but no image, i have change the lcd without results.
Any idea?

regards

[ktmmotocross]

Re: HP Board La-C701P-Work only with external Monitor

du u have discrete GPU?

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

No, only the cpu graphics card...

[ktmmotocross]

Re: HP Board La-C701P-Work only with external Monitor

did u have all needed voltage on LVDS? did u try to change LVDS cable?

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

Pin 15 and 16(+LCDVDD) in board connector is 0v, i dont have a 2º cable to test but the pin 1 and 2 dont have continuity between the connectors and according the Schematics i have pin 1 and 2 are (LVDS_TXP0, LVDS_TXN0).
maybe a cable problem?

[Techtiger]

Re: HP Board La-C701P-Work only with external Monitor

Pin 15 and 16(+LCDVDD) in board connector is 0v, i dont have a 2º cable to test but the pin 1 and 2 dont have continuity between the connectors and according the Schematics i have pin 1 and 2 are (LVDS_TXP0, LVDS_TXN0).
maybe a cable problem?

Upload the Schematic to help

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

I have download this Schematic:
https://www.badcaps.net/forum/attach...2&d=1562740525

[Techtiger]

Re: HP Board La-C701P-Work only with external Monitor

Check UG1 pin 1 3 4 5 voltage & check INVPWR_B + 19V on the LVDS 28/29

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

28 and 29 , 19v
4,5 - 3,3v
1,2,3 - 0v

[Techtiger]

Re: HP Board La-C701P-Work only with external Monitor

Back trace R172 should be near the IC what voltage other side ? Short pin 5 & 1 just to check voltage is crossing +3V

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

Short 5 and 1 nothing happens, voltage in R172 is 0v

[Techtiger]

Re: HP Board La-C701P-Work only with external Monitor

You have to keep holding from a tweezer or put a jumper that voltage must cross over , check voltage LVDS pin 37 38 27 28 15 16 screen must be connected

[Dumah Brazorf]

Re: HP Board La-C701P-Work only with external Monitor

How's started? Have you disconnected the panel with the battery connected?

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

When i short (1,5) i lost de 3,3v in pin 5 (stay o volt) only 3,3 v in pin 4, with the short 37,38 - 0 v; 27,28-19v; 15,16-0v
Without short same voltage in LVDS

[Techtiger]

Re: HP Board La-C701P-Work only with external Monitor

remove UG1 & test all pins again for voltage after test Ohms in pin 1 you have 2 caps in this line CG2 CG3 test one of the are fault or not their is another prob DATA & CLK is missing on pin 37 38 LVDS was the screen connected when you check voltage ?

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

I dont see the capacitores, do you see them in the image i attached? yes when i test the pins 37,38 the screen was connected...

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

i remove the UG1, and only in pin 4 i have voltage (3,3v)

[vabea]

Re: HP Board La-C701P-Work only with external Monitor

Hello i have correct the issue, thanks for the help techtiger, like you say when i remove the UG1 and short pin 1-5, i have have all the voltages in the lvds pins, but still not working, so o chage the cable, and now are working...
Thanks