sansui 8080db

[georgedannyg]

hi i bought a broken sansui 8080db off ebay got it in work on the driver found two 150 ohm resisitor out bad and every thing else on the driver board was good hooked it up and brought it up easy on the varyac and the protection light still on but if i remove the board the light turns green

 

[Stene]

Protector

if i remove the board the light turns green

The Protector is saying: George, check the Driver Board. Something isn't as it should be.

 

[Morden2004]

hi i bought a broken sansui 8080db off ebay got it in work on the driver found two 150 ohm resisitor out bad and every thing else on the driver board was good hooked it up and brought it up easy on the varyac and the protection light still on but if i remove the board the light turns green

Stene's right - something else on the driver board is bad or the BIAS pots are set for high current or one or more power output transistors are shorted. I'm guessing that last one since you have checked the driver board.

If you have the service manual, read the section on setting BAIS - it will usually tell you to set the BAIS pots fullly counter-clockwise (or opposite) before adjusting the BAIS. Do that and leave them there when doing further tests until you fix the problem, then do the DC-offset and then the BAIS adjustment.

Paul

 

[georgedannyg]

hi i dont hae a service manual do you all know what the bias current should be set at and the dc offset and the pots on the outer part of the board are they for the dc off set or the bias current

 

[Morden2004]

hi i dont hae a service manual do you all know what the bias current should be set at and the dc offset and the pots on the outer part of the board are they for the dc off set or the bias current

What is the board part number (it's on one of the edge tabs)?

Paul