Punch 45

[pking75]

When I put my test light to the negative side of this diode I get power and the amp works correctly. What is this issue? I checked the diode and it is good. Even replaced it so I assume it is another component.

 

[Perry Babin]

Post the DC voltage on all terminals of the 8-pin IC adjacent to the TL494. Copy and paste the following list and fill in the blanks.


Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:

 

[pking75]

Pin 1: 11.99
Pin 2: 0.13
Pin 3: 4.45
Pin 4: 1.68
Pin 5: 0.21
Pin 6: 1.68
Pin 7: 4.06
Pin 8: 0.00

 

[Perry Babin]

I think you have the pin configuration wrong. Look up the datasheet for the IC.

 

[pking75]

Pin 8: 11.99
Pin 7: 0.13
Pin 6: 4.45
Pin 5: 1.68
Pin 1: 0.21
Pin 2: 1.68
Pin 3: 4.06
Pin 14 0.00

 

[Perry Babin]

Check the diode and capacitor indicated by the arrows.

Are the diode and resistor connected as indicated by the green lines?

 

[pking75]

yes they are on the bottom of the board

 

[Perry Babin]

Are the capacitor and resistor (didn't mean diode) OK?

 

[pking75]

Resistor is bad. Have yet to find one in my circuit boards used for parts though

 

[Perry Babin]

For testing, install any high-value resistor. If you have something near 100k ohms, that's OK for now.

 

[pking75]

Will look. should have