Marshall stanmore II Identify value of resistors in power supply

I have the Marshall Stanmore II bluetooth speaker with power supply part number DSO602-240250-17417. The diode bridge is damaged and shorted, and has damaged other parts of the circuit. After cleaning and sanitizing, I cannot clearly identify the value of resistors R8, R9 and R10, especially R9.
R8 and R10 appear to be 10 ohms (marked 100) but R9?

Can somebody help me ?

Hello!

Please, post a clear picture of primary side of the power supply from both sides of the board.

Is it ok?

These three resistors are shunts to sense the current flowing through the transistor Q1.
What is the marking of chip U1?

matic написав:¿Cuál es la marca del chip U1?

GR8874

Replace all three resistors R8, R9, R10 with a value 1Ω/1%, package 1206.

Also check the resistor R11 (470Ω) and measure the resistance between pin 4 and pin 6 of chip U1 (it should be high - in kΩ range or greater).

matic написав:Reemplace las tres resistencias R8, R9, R10 con un valor de 1Ω/1%, paquete 1206

Could I place the 3 1.2Ω resistors? The supplier has them of that value, but not 1Ω
Will it influence?

No, you couldn't.
The value of these resistors is critical and should be within a few % tolerance. At 1.2Ω resistors, the tolerance is 20%, which is not acceptable.

The option is to use three pieces of 1.2Ω resistors and an additional one piece of 2Ω (or 2.2Ω) resistor, which you solder on the top of resistor R9.

Note that the tolerance of used resistors must be 1% (the classic resistors with a tolerance of 5% are not acceptable here).

matic написав:También verifique la resistencia R11 (470Ω) y mida la resistencia entre los pines 4 y 6 del chip U1 (debe ser alta, en el rango de kΩ). o mayor).

The value of R11 is correct.

The resistance between pins 4 and 6 of U1 (with the chip soldered on the board) is 2k, can this be considered valid?

Q1 (svf10n60f) was also damaged and is shorted

Zemog написав:The resistance between pins 4 and 6 of U1 (with the chip soldered on the board) is 2k, can this be considered valid?

That's probably fine, so the chip U1 probably survived.

Zemog написав:Q1 (svf10n60f) was also damaged and is shorted

That's expected and is also a reason for the damage on resistors R8, R9, R10.
The fuse F1 is probably also damaged.

The 3 resistors go in parallel, right?
According to the first photo, although the track is damaged, it seems to me that they are in parallel, and I have repaired the track on both sides of the resistors.

Zemog написав:The 3 resistors go in parallel, right?

Yes, exactly.

Hello, sorry for the delay but I have not been able to continue with this repair before.
After replacing the resistors and other damaged components, there is still no current at the output.

In the Drain of the 10N60 I now have 330V but in Gate and Source 0V.
Would it be logical to change U1 (GR8874)?

- Measure the resistances to ground on pins 3, 5, 6, 8 of chip U1.
- Measure the voltage to ground on pin 8 of chip U1.

matic написав:Medir las resistencias a tierra en los pines 3, 5, 6, 8 del chip U1

Pin 3 ... 7 Ohm4
Pin 5 ... 10k
Pin 6 ... 1,7k
Pin 8 ... More than 2 Mega ohms

matic написав:Mida la tensión a tierra en el pin 8 del chip U1

Pin 8 ... 311V

PD. Pin 6 (VCC) ... 0V

Zemog написав:Pin 3 ... 7 Ohm4

What does it mean? Is it 7.4Ω or what?

No, sorry! I missed the 4 without realizing it. It's 7 Ω

Not fine. It should be 470Ω.

There are only two options:
You have replaced the resistor R11 with a wrong value, otherwise the chip U1 is damaged.

matic написав:el chip U1 está dañado

U1 chip (GR8874) changed, and now the equipment is working. Thank you very much