power supply blown components

[DjKrish]

Hi guys, i have a thonet & vander model Grub speaker system. The problem is there was 3 components burned and blown.

1 transistor which is - WFF7N60
1 IC which is - CR6848T
2 resistors thats 1 is through hole resistor 0.68Ohms and 1 SMD resistor.

I managed to replaced all the components except for the smd resistor. The top is blown so ive no idea to find out the value. Ive managed to check the datasheet for the IC CR6848T and the one goes from the gate connects to a resistor with the value 47 Ohms. Is it safe to assume 47 ohms can be used as a replacement?

[petehall347]

Re: power supply blown components

one circled is 4720 ....472 ohms 1 percent +-

[DjKrish]

Re: power supply blown components

one circled is 4720 ....472 ohms 1 percent +-

Ive already fitted 47 ohms there. The one u see in the circle is a new resistor (47R0 marking which is 47 ohms). I dont dare to fire it up yet Just to reconfirm i posted the photo.

[DjKrish]

Re: power supply blown components

Datasheet for the IC

[DjKrish]

Re: power supply blown components

Anyone? Any suggestion?

[petehall347]

Re: power supply blown components

data sheet says 100 ohms . the sense one shows 4.7 ohms

[DjKrish]

Re: power supply blown components

data sheet says 100 ohms . the sense one shows 4.7 ohms

Im sorry but i uploaded the wrong one. This is the correct one

[DjKrish]

Re: power supply blown components

Why diff datasheets has diff specs on typical application circuit? Although its the same IC. Perhaps the different DIP package? Certain datasheet shows 47 ohms for CR6848T, certain datasheet shows 100 ohms for CR6848.

[budm]

Re: power supply blown components

Gate driver resistor requirement:
https://cdn.badcaps-static.com/pdfs/...c4f1beb5e3.pdf

Just search for 'gate driver resistor selection'.

[DjKrish]

Re: power supply blown components

Gate driver resistor requirement:
https://cdn.badcaps-static.com/pdfs/...c4f1beb5e3.pdf

Just search for 'gate driver resistor selection'.

Thanks budm. Still in dilemma within 47 and 100. Checked your resources, many pointing towards 47 and some to 100 ohms.

[budm]

Re: power supply blown components

Based on your pictures in post 1, the marking is 47 Ohms.

[DjKrish]

Re: power supply blown components

Based on your pictures in post 1, the marking is 47 Ohms.

Sorry, ive already replaced it with 47ohms. Thats why it shows 47 ohms as i replaced it according to the datasheet it says 47 ohms and a few other datasheet says 100 ohms. The original resistor the tops has blown off. The unit works, ive tried 100 ohms and 47 ohms, both works. But just wondering which will be the right value in between gates of WFF7N60 and CR6848T. Whats your take on this budm?

[DjKrish]

Re: power supply blown components

So far, just to be safe im using 100 ohms as a bridge from IC gate to transistor gate. Been testing, theres no distortions or any drop in sound quality. No overheating either. So far so good.

[petehall347]

Re: power supply blown components

it looks like if the gate resistor is a different value so is the one that goes to ground ..