HP Pavilion 17F - No internal display, but external works.

[mattpd]

Board DAY11AMB6E0 REV E - https://www.badcaps.net/forum/attach...1&d=1474124578

Known good LVDS cable and LCD screen.

Laptop works fine with HDMI connected.

LCD is controlled by Realtek RTD2136R (page 23)

Pin 5, 18, and 22 should have 3.3v input but actual voltage is around 2v.

The schematics call these 3.3v rails "+3.3V_2136_A" and "+3.3V_2136_D"

The bottom of page 23 says these rails originate from a rail called "+3v" which isn't very helpful.

Trying to figure out where these rails originate from, and why they are low.

My best guess was PU6 (page 43) but this IC does not exist on this particular board.

Now I am kind of lost. Any idea? Maybe bad RTD2136R pulling it down?

[Techtiger]

Re: HP Pavilion 17F - No internal display, but external works.

LVDS Conn pins you have check are not correct test voltage on pin 1 4 40

[mattpd]

Re: HP Pavilion 17F - No internal display, but external works.

LVDS Conn pins you have check are not correct test voltage on pin 1 4 40

0v on pin 1 and 2.

That voltage comes from RTD2136R which has low input voltage.

Backlight pins have voltage. Around 20v I think. Board isn't in front of me now

[Techtiger]

Re: HP Pavilion 17F - No internal display, but external works.

0v on pin 1 and 2.

That voltage comes from RTD2136R which has low input voltage.

Backlight pins have voltage. Around 20v I think. Board isn't in front of me now

as for the Schematic pin 1 & 2 should be +19V pin4 3.3V PIN40 3.3V for the moment leave RTD2136R

[mattpd]

Re: HP Pavilion 17F - No internal display, but external works.

as for the Schematic pin 1 & 2 should be +19V pin4 3.3V PIN40 3.3V for the moment leave RTD2136R

My mistake, I stated the pin number incorrectly in the other post.

I should have said 0v on 39 and 40.

19v are on pin 1 and 2.

Pin 39 and 40 come from RTD2136R which has low input and no 3.3v output.

[Techtiger]

Re: HP Pavilion 17F - No internal display, but external works.

Ok that’s good now trace back U2 IC in the MB this IC converts +3V to +3VLCD_CON Via PCH Signel on pin 4/5 you should get +3V pin1 if everything is working fine Voltage should be 3.3V it will cross through a coil L8 feedback

[mattpd]

Re: HP Pavilion 17F - No internal display, but external works.

Ok that's good now trace back U2 IC in the MB this IC converts +3V to +3VLCD_CON Via PCH Signel on pin 4/5 you should get +3V pin1 if everything is working fine Voltage should be 3.3V it will cross through a coil L8 feedback

This board is missing L8 and U2. I guess it's LVDS only.

[Techtiger]

Re: HP Pavilion 17F - No internal display, but external works.

ok then find a +3V line & put a jumper to the pin 39 40 LVDS for a test uplode pic near the LDVS conn before

[mattpd]

Re: HP Pavilion 17F - No internal display, but external works.

ok then find a +3V line & put a jumper to the pin 39 40 LVDS for a test uplode pic near the LDVS conn before

Everything starts working correctly with 3v injected into those pins.

How appropriate would it be to grab a 3v_s0 power line and jumper it permanently to these pins? Conformal coat over the wires of course.

[mcplslg123]

Re: HP Pavilion 17F - No internal display, but external works.

Its safe provided you cut the track of pin39/40 on mb and then jumper 3v directly on these pins.