Soundstream XTA 880.2

[mike49504]

Does anyone know the value of the resistor that goes in the power supply?

1 end connects to the middle leg of the power supply fets the other end connects to a cap then to one of the windings on the transformer..

I believe its a 1 watt resistor but dont know the value since it burnt pretty bad

Its circled in this pic but cant make out the color bands

[1moreamp]

Looks like there are two power supplies and so I am taking a stab at the possibility that you will find a similar device on the second power supply opposite of the one that is circled that is burnt.
It also looks like a simple Zobel filter <RC network > and these typically have values between 4.7 and 10 ohms. And yes it appears to be a 1watt ceramic metal film resistor...Hope this helps some I don't have any info on this series of offshore amps

[mike49504]

Thanks i found the other one but thats burnt also .. I can make out a few of the color bands

first color band either dark purple or black

Second color band white

3rd color band is either white or silver

4th band is gold

Any ideas what the value may be?

[mike49504]

Closer i look at it it may be a 9 ohm resistor..


So im gonna try a 10 ohm resistor in the amp to see if it works

[1moreamp]

Here is a color scale to help some...

[mike49504]

Ok i replaced the 2 resistors.

I removed the rectifiers from the amp..

I only have 1 fet per power supply right now..


Drivers check good..

As soon as i power it up the fets get red hot within 2 secs..


Do i need more them 1 fet per power supply to see if there is any other problems ?


Or should 1 work per supply for now ?

[Perry Babin]

At the very least, you need 1/bank (2/supply).

[mike49504]

I put 2 fets per supply..

I put 10 ohm resistors in place of the burnt resistors that i could not make out the color bands..


I checked all power supply drivers and they all test good..


Within 3 secs all 4 of the fets get hot in both supply's ..


if thoose resistors arent the correct value would that cause the fets to heat up ?

Or what would i check next?

[mike49504]

OK i found another amp here its a Kole audio and its very very close to this amp ..

The resistors are 22 ohms..

I guess ill recheck the drivers since both supplys have problems with the fets heating up within 2 secs..

[mike49504]

Hers what i got on the gate pads for the power supply fets ..

First pic is 1 supply 2nd pic is the other supply..


Scope set to 5us 1 volts div..


Do theese look ok?