Hifonics GEN X Zeus

[mike49504]

Im in the process of rebuilding 1 of theese amps again since this one came in with no outputs or power supply fets in the board and alot of other stuff missing.

My question is the outputs that are being used in this amp are 2SA1302 and 2SC3281 how do i figure out what outputs go in what locations?

[Perry Babin]

What rectifiers are they using?

Are the emitters of all of the outputs in each channel directly connected (less than 1 ohm)?

[mike49504]

The rectifiers they are using is FES16JT

All of the emitter resistors are connected together for each channel . I measured from 1 emitter to the last 1 in circuit and get 0.3 ohms

[Perry Babin]

Find the rectifiers that have their right leg that read 0 ohms to the non-bridging speaker terminals. The left leg of those rectifiers will connect to the center leg of the NPN output transistors.

If you power the amp up before reinstalling the outputs, you can check the voltage on the center solder pads for the outputs. The NPN transistors will have positive rail voltage on the center pads. The PNP outputs will have negative rail voltage on the center pads.

[mike49504]

Ok back to this amp. I replaced all power supply fets, and outputs and a few transistors.

AMp doesnt produce rail voltages or regulated voltages. Heres what i have on the TL494 and the LM324

TL494
1:3.30
2:9.24
3:9.70
4:3.01
5:7.91
6:8.94
7:3.76
8:13.92
9:2.78
10:2.78
11:13.92
12:13.13
13:10.29
14:10.28
15:10.28
16:2.91

LM324
1:0
2:11.72
3:0
4:13.20
5:0
6:6.59
7:0
8:0
9:12.10
10:8.78
11:0
12:12.04
13:6.60
14:11.89

Any ideas on what to check for next?

[Perry Babin]

You need to determine why pin 7 doesn't read 0.0v DC. It should be directly connected to ground.

[mike49504]

Replaced a couple transistors and heres what i have now. AMP still isnt producing rail voltage.

TL494
1:2.16
2:2.14
3:3.08
4:0.22
5:1.45
6:3.44
7:0
8:13.88
9:0.93
10:0
11.93
12:13.02
13:4.92
14:4.92
15:4.93
16:10.98

LM324
1:11.68 then 0
2:11.68
3:12.01 then 0
4:13.68
5:11.33
6:6.52
7:11.28
8:0
9:11.92
10:8.68
11:0
12:11.99
13:6.54
14:11.85

[Perry Babin]

You need to follow the circuit back from pin 16 to see what's driving it high.

[mike49504]

Could it be possible i have a bad 494 If i tap it lightly the amp will come on and produce audio and the voltages on the 494 are correct. Then after 1 min it goes dead again and if i tap it it will work again I reflowed the solder to all pins but i have the same issue

[Perry Babin]

It's possible but unlikely if the voltage on pin 16 is changing. Do any of the voltages on the 324 change when pin 16 goes low?

Did you determine what was driving pin 16?