Directed 650 5 channel amp

[mike49504]

C3200 Meter set to diode check

1-2:OL
1-3:OL
2-3:0.574

Probes reversed

1-2:OL
1-3:OL
2-3:OL

The other C3200

1-2:0.587
1-3:0.631
2-3:0.624

probes reversed
1-2:OL
1-3:OL
2-3:OL

 

[Perry Babin]

I think both of those are defective (I'm assuming that these are out of the circuit).

 

[mike49504]

Yes both were out of circuit.

 

[Perry Babin]

Pull one more and check it.

I checked one I have here and it read precisely as expected.

 

[mike49504]

Pulled another one and it measures

1-2:0.578
1-3:0.626
2-3:0.620

Probes reversed
1-2:OL
1-3:OL
2-3:OL

 

[Perry Babin]

There's almost no chance that you'd have two that failed in the same way. I don't know why you have leakage from 1-2. The attached image shows what the c3200 I have reads.

 

[mike49504]

Just put new batteries in my meter heres the reading i get on all 4 C3200's

1-2:0.950
1-3:0.635
2-3:0.628

Probes reversed
1-2:OL
1-3:OL
2-3:OL

1-2:OL
1-3:OL
2-3:0.576

Probes reversed
1-2:Ol
1-3:OL
2-3:OL

1-2:OL
1-3:0.623
2-3:0.617

Probes reversed
1-2:Ol
1-3:OL
2-3:OL


1-2:0.596
1-3:0.631
2-3:0.624

Probes reversed
1-2:OL
1-3:OL
2-3:OL

do theese appear to be defective?

 

[Perry Babin]

I don't see any that appear to be normal. Look at the image I posted. The only times you should read anything other than OL is with the red probe on leg 3 and the black probe on legs 1 or 2. Biasing transistors RARELY fail. To have multiple defective biasing transistors in one amp is VERY strange.

 

[mike49504]

Ill just order new ones to be safe and rule out that problem.

Do you know of a good place to get them?

 

[Perry Babin]

They appear to be in short supply. What TO-92 NPN transistors do you have on hand?

 

[mike49504]

Just naming a few that i have i have more if theese wont work.

2n4401
C3198
MPSA06
MPS6521
Mpsa12

 

[Perry Babin]

use the C3198.

 

[mike49504]

Put the C3198's in now the amp comes on for a sec then goes off and 3 mins later comes back on for a sec then shuts back off

 

[Perry Babin]

If you switch it off (via remote voltage), will it come right back on?

Do you see a pulse of DC on any of the emitters of any of the output transistors when it initially switches on?

 

[mike49504]

If remoe is applied the light will come on for 1 sec then shut off and if i remove remote and apply it agin amp will not come back on .


With only Power and remote hooked up NO remote applied The emitters of all output transistors have pulsing DC voltages on them regradless if the light is on or off

 

[Perry Babin]

Post a photo of the power supply section of the amp showing the 494 and protection components.

 

[mike49504]

Heres the pic as requested If you need more let me know

 

[Perry Babin]

Post the DC voltage on the 494 when it's in protect. Copy and past the following into your post to save some time.


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:

 

[mike49504]

Pin 1: 0
Pin 2: 4.84
Pin 3: 0.05
Pin 4: 4.84
Pin 5: 1.41
Pin 6: 3.51
Pin 7: 0
Pin 8: 13,82
Pin 9: 0
Pin 10: 0
Pin 11: 13.82
Pin 12: 13.82
Pin 13: 4.84
Pin 14: 4.84
Pin 15: 4.84
Pin 16:0

 

[Perry Babin]

It's being driven into protection on pin 4. Follow that back to see what connects to it.