targa 200 amp led turns on and off under a load

[eroc1313]

this is an old targa hexfet 2ch 200 watts amp.when rca.s installed and speaker wires hooked up it is fine. when it is turned up , the power led turns off and on. the output transistors and power supply transistors do not get hot

 

[eroc1313]

more pics of amp

pics

 

[Perry Babin]

Are you 100% sure that the DC voltage across the power/ground terminals is remaining well above 12v?

 

[eroc1313]

the power supply goes from 13.69 at idle. When i turn up the radio im using for a signal, it doesnt drop below 13.49 vdc. im using a fluke 117 meter with leads on power terminals of amp.its a little intermittant. sometimes it will work for a minute. and after testing, i touched the power supply and output transistors and they are barely warm

 

[Perry Babin]

Post the DC voltage on all pins of the power supply IC when it refuses to power up. Copy and paste this into your post.

IC#
Pin 1:
Pin 2:
Pin 3:
Pin 4:
Pin 5:
Pin 6:
Pin 7:
Pin 8:
Pin 9:
Pin 10:
Pin 11:
Pin 12:
Pin 13:
Pin 14:
Pin 15:
Pin 16:

 

[eroc1313]

C#
Pin 1: 2.7
Pin 2: .1
Pin 3: 4.9
Pin 4: 0
Pin 5: 1.5
Pin 6: 3.7
Pin 7: 0
Pin 8: 12.4
Pin 16: 2.1
Pin 15: 4.9
Pin 14: 5.0
Pin 13: 13.5
Pin 12: 13.5
Pin 11: 13.12
Pin 10: 0
Pin 9 0
the light and the sound only cuts off for a little less than 2 seconds

 

[eroc1313]

normal voltages with light and sound not cutting off are as follows for the ic>
Pin 1: 2.7
Pin 2: 2.9
Pin 3: 1.79
Pin 4: 0
Pin 5: 1.56
Pin 6: 3.7
Pin 7: 0
Pin 8: 12.44
Pin 16: 3.7
Pin 15: 3.7
Pin 14: 5.0
Pin 13: 5.0
Pin 12: 13.56
Pin 11: 12.49
Pin 10: 3.7
Pin 9 3.81

 

[Perry Babin]

You have the pins numbered incorrectly. Look up the datasheet for the IC to see how they're numbered.

Pin 16 appears to be the input that's causing the shutdown. You'll have to find what's driving that pin.

 

[eroc1313]

i edited my last two posts , i numbered the ics wrong
im going to look at the data sheet for the ic

 

[eroc1313]

got specsheet its like a tl494, its a Kia494p

it has the same pinouts as a tl494. the problem is pin 9 since i renumbered it. Pin 9 is the E1. Ill try to trace it down on the board to find the problem .

 

[eroc1313]

got specsheet its like a tl494, its a Kia494p

it has the same pinouts as a tl494. the problem is pin 9 since i renumbered it. Pin 9 is the E1. Ill try to trace it down on the board to find the problem .

 

[Perry Babin]

Pin 16 is likely the problem. It's the one with 3.7v on it.