LA-B843P Rev 1 2beeps

[Techtiger]

Friends need help
MB LA-B843P Rev 1 with 2beeps code error all Coils Voltages are ok SOC CPU PCH ect , in Ram slot
pin 30 DRAMRST 0.27V this is the fault
pin 203/204 VTT0.68V
pin 75 VDD 1.37V
pin 200/203 3.3V DATA CLK
i tract it back but could find R410 C1301 but i trace it back up to PCH line same voltage 0.27V

[Techtiger]

Re: LA-B843P Rev 1 2beeps

Schematic https://www.badcaps.net/forum/showthread.php?t=66749
.

[piernov]

Re: LA-B843P Rev 1 2beeps

It has to detect memory through SMBUS first. Make sur eyou're using known good compatible RAM stick DDR3L. Also make sure you tried with touchpad disconnected.
Then measure diode mode to ground on the SMBUS SDA/SCL lines

[mcplslg123]

Re: LA-B843P Rev 1 2beeps

Q1201/1202 probed?? Bios flashed??

[Techtiger]

Re: LA-B843P Rev 1 2beeps

It has to detect memory through SMBUS first. Make sur eyou're using known good compatible RAM stick DDR3L. Also make sure you tried with touchpad disconnected.
Then measure diode mode to ground on the SMBUS SDA/SCL lines

i have 2beeps with or with out RAM change stick same issue SDA diode mode 498 SCL in Diode mode 575

Q1201/1202 probed?? Bios flashed??

Q1201 S 1.36V D 4.08V G 1.36V
Q1202 S 1.36V D 1.29V G 4.08V
i havent flash BIOS yet do you think this is BIOS issue ?

[piernov]

Re: LA-B843P Rev 1 2beeps

Usually SCL and SDA should measure within 1% of each other in diode mode to ground.

Could be BIOS too.

[mcplslg123]

Re: LA-B843P Rev 1 2beeps

yes, have seen DRAMRST missing due to bios on many platforms. Eg dell cedar 13269-1 intel motherboard. So will strongly suggest to flash bios first.

[Techtiger]

Re: LA-B843P Rev 1 2beeps

yes, have seen DRAMRST missing due to bios on many platforms. Eg dell cedar 13269-1 intel motherboard. So will strongly suggest to flash bios first.

Usually SCL and SDA should measure within 1% of each other in diode mode to ground.

Could be BIOS too.

i will flach BIOS and update

[j4rzyn]

Re: LA-B843P Rev 1 2beeps

Did you solve your problem. I have same issue with same board. 0.12V on DRAMRST - pin 30 of DDR slot. Ive try 3 different BIOS dump.

[Techtiger]

Re: LA-B843P Rev 1 2beeps

Trace it down to SOC and put a jump Voilà

[limpidity]

Re: LA-B843P Rev 1 2beeps

Trace it down to SOC and put a jump Voilà

How did you jump?

[Techtiger]

Re: LA-B843P Rev 1 2beeps

How did you jump?

What is the issue with the board DRAMRST missing ? if so check R410 for voltage on both side ?

[limpidity]

Re: LA-B843P Rev 1 2beeps

What is the issue with the board DRAMRST missing ? if so check R410 for voltage on both side ?

There was a problem with the resistance, so I replaced it, but the symptoms remain the same

The DRAMRST# voltage is 0.125v, approximately 0.67kOhm when measured by the tester as shown in the ground

working donor board 4kOhm. Is it a cpu problem?

[Techtiger]

Re: LA-B843P Rev 1 2beeps

There was a problem with the resistance, so I replaced it, but the symptoms remain the same

The DRAMRST# voltage is 0.125v, approximately 0.67kOhm when measured by the tester as shown in the ground

working donor board 4kOhm. Is it a cpu problem?

What voltage do you have top side of the R410 is it 1D35V_S3 or 0.125v ? If you don't have 1D35V track it back page 49 VDDQ_VTT for thé moment cannot rule out CPU

[limpidity]

Re: LA-B843P Rev 1 2beeps

What voltage do you have top side of the R410 is it 1D35V_S3 or 0.125v ? If you don't have 1D35V track it back page 49 VDDQ_VTT for thé moment cannot rule out CPU

The r410 resistance is measured, and you get 1 mega ohm

I replaced it with 470, but the symptoms remain the same

DDR3_DRAMRST# r404 0.125v....

Other voltages are normal output

Is it cpu memory controller problem?