MA Audio HK602SX

[mike49504]

I replaced the outputs in this amp and its still stuck in protection mode.

Heres what i have on the 494

1:10.36
2:3.11
3:4.76
4:0.05
5:1.48
6:3.43
7:0
8:13.91
9:0
10:0
11:13.91
12:12.54
13:4.98
14:4.98
15:4.77
16:0

[Perry Babin]

Post the DC voltage on the op-amp near the 494.

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

[mike49504]

NJM2904L

1:0
2:8.54
3:2.55
4:0
5:9.02
6:4.98
7:11.06
8:12.53

[Perry Babin]

If there is a PNP transistor with it's collector connected to pin 5 of the op-amp, pull it. Does the amp power up?

Be careful, the amp may draw excessive current.

[mike49504]

Ok theres 3 transistor in the power supply section 2 C102's and B631K pulled 1 at a time amp still is in protection

[Perry Babin]

Did any of those have their collector connected directly to pin 5?

[mike49504]

ON the C102 transistors do you know which leg is the collector I cant seem to find a datasheet on theese

[Perry Babin]

I think the pin configuration is ECB.

[mike49504]

none of them had the collector directly connected to pin 5 . The 3rd leg of the C102's connected through resistors then to pin 5

[Perry Babin]

I'm using the 802 as a reference so it may be a bit different. Is there a diode with its anode directly connected to pin 1?

If so, reinstall any parts from this area that are out of the circuit and desolder one leg of that diode. That should defeat the protection circuit so you can determine if the fault is in the audio circuit or in the protection circuit.