DELL INSPIRON 24-5477 - brak zasilania procesora

Witam,

Płyta główna: IPCFL-GL
GPU: N17P-G0-A1 (GTX 1050)
EC/KBC: SMSC SCH5553-NU
CPU: i5-8400

Mam problem ze sprzętem All-in-one marki Dell a mianowicie:
Po uruchomieniu komputera dioda na włączniku miga 2x szybko, krótka przerwa, 1 wolnej, sekwencja kodu błędu się powtarza.

W trakcie uruchomienia wszystkie napięcia są poprawne oprócz napięć procesora, są kompletnie nieobecne i nawet na sekundę się nie załączają.
Przetwornica faz procesor - NCP81220

Podmieniałem:
- Procesor
- Pamięć RAM
- BIOS (z tego forum)

żadnych zmian w działaniu płyty.
Jakich sygnałów potrzebuje ta przetwornica, żeby była poprawnie skonfigurowana?

Hello!

Measure the voltages to ground on pins 2, 3, 4, 5, 6, 7, 10, 30 of the CPU power supply controller chip NCP81220.

Jaki tam masz CPU?
Czy podmieniłeś na taki sam w tym sensie, że jeśli siedział i3 to też włożyłeś i3?

Hello Matic,

matic написав:Measure the voltages to ground on pins 2, 3, 4, 5, 6, 7, 10, 30 of the CPU power supply controller chip NCP81220

When the board is running:

n.2 = 2,5V
n.3 = 1.05V
n.4 = 1.05V
n.5 = 1.05V
n.6 = 0.07V
n.7 = 3.79V
n.10 = 1.05V
n.30 = 0V

carrneiro написав:Jaki tam masz CPU?
Czy podmieniłeś na taki sam w tym sensie, że jeśli siedział i3 to też włożyłeś i3?

Jak w temacie "CPU: i5-8400"
wcześniej był i7 - 8th

Mostek: SR405 - FH82H370

Stary procesor który miał takie samo zachowanie, został zamontowany w komputerze przez klienta, a pamięć RAM dołożył do laptopa i wszystko działa poprawnie.
Ja użyłem wyżej wymienionego (sprawnego i testowanego).

Please, post a clear picture of the chip NCP81220 area of the board with a nearby surroundings.

Please,

Please, post a picture of the same area from the other side of the board.

I have marked an area of ​​the layout and it seems that there is an element missing in one place? there are traces that something was there (marked next to the capacitor).

The missing component is a resistor 2.2Ω/5%, package 0603.

After installing the resistor, the voltages on the processor have returned, and all are correct, but during startup:

- The motherboard performs the correct 3 restarts after resetting the BIOS.
- After the third restart, the fan runs at full speed and then slows down to a normal speed after about a minute, with the power LED glowing white.
- After the third restart, the screen polarizes for a second, showing five white lines in the middle, and then they disappear after a second.




I tried connecting an external monitor via HDMI, but no image is displayed. I checked the continuity of connections from the motherboard to the screen connector cable, and all connections are fine.

IC TSUMU88CDT9-1 also working (thermal imaging measurement)

dernis написав:Podmieniałem:
- BIOS (z tego forum)

Reflash the BIOS chip again with the old (original) dump.

If it does not change anything, thoroughly inspect the entire board under the microscope for even more missing/physically damaged components.

I found another missing element:





Do you know what should be here?

Use an ohmmeter and check, if one pad of the missing component is connected to the ground.

n.1 - 60 ohm
n.2 - GND

Remove the marked capacitor from the board, measure its value and use the same value for the missing component.

The capacitor has a capacity of 1200nF, I used 1uF (I don't have more capacity) to see if there would be any difference...
The effect is still the same, there are no more damaged elements on both sides of the board.
Bios also reprogrammed.

dernis написав:there are no more damaged elements on both sides of the board.

Double check, just in case...

I checked six times for damaged components and traces on the PCB, but I didn’t find anything else—not even a scratch.

Measure the power consumption (in mA) of the board, when the machine is turned on with and without RAM memory connected.

The board behaves as follows:
- Every time it's powered on, there is a current spike up to 1.44A, followed by a restart.
- After the restart, the current reaches 1.10A and then fluctuates in a cycle for about 20 seconds, alternating between 1.10A, 1.13A, and 1.16A in sequence.
- When I connect a keyboard to the USB port and press "Enter," the board resets. Additionally, the "Num Lock" and "Caps Lock" keys respond when pressed.

So it seems that the board has completed the POST procedure and is likely waiting for interaction, as I don't have a disk or any bootable media connected.

Without RAM, the board signals an error by holding the power LED on (blinking orange, similar to a missing CPU power error) with a current draw of 1.37A.

I checked the TCON board of the display panel, and the 3.3 V, 5 V, and 19 V voltages are present, so I ordered a new panel. I’ll let you know the result after installation.