Orion HCCA 10002

[Perry Babin]

Did you see a trace making that connection to the other terminal?

 

[imraneesa]

Yes from back it is connected.

 

[Perry Babin]

I can't understand what you have because you have a ± rail but you have both the positive and negative rectifiers connected to the same capacitor.

 

[imraneesa]

I am really confused with this amp. I saw positive voltage on drain of one set mosfets and negative on source of another set of output mosfets. So thought it has positive and negative rail. Actually it is just positive rail. The actual problem with this amp is output sine wave clips very funny way. While probing waveforms I saw those ringing all over so first wanted to figure it out why I am getting those ringing.

 

[Perry Babin]

These amps (at least some of the various models) have a strange limiting circuit that makes the amp clip in a strange way.

 

[imraneesa]

But I know the problem it is the digital volume control board have the problem. The negative 5v dipping to 1.6v when the board is inserted. And ibam not seeing any shorts on the board I guess some ic is malfunctioning. But besides that where is the good ground that I can use to probe the waveforms?

 

[Perry Babin]

There are 10 ohm resistors on the output of all of the various voltage regulators. Check ALL of them.

 

[imraneesa]

Yes the same negative 5v line that I was talking about had 10ohm resistor burnt I replaced it and the voltage still dips.

 

[Perry Babin]

Did you check ALL of the rest of the 10 ohm regulator resistors?

Did you check the voltage on the input and reference legs of the regulator feeding that circuit?

 

[imraneesa]

Yes all the 10ohms are fine. Input to the regulator is good and stable -25v middle pin. Pin 1 is having -3.6v and pin3 is having -4.4v.
One side 10ohm resistor has -4.4v and other side that going to the board dips to -2.2v.

 

[Perry Babin]

On this regulator what is the DC voltage measured directly across the output and reference terminals with the board in and out of the circuit?

 

[imraneesa]

Voltage when board in is 1.23v and voltage when board is removed is also 1.23v

 

[Perry Babin]

Voltage between the output leg of the regulator and the positive terminal of the output filter cap for that regulator (that terminal should be ground).

 

[imraneesa]

It is -4.5v with board in and -6v when the board is out.
Positive regulator in the other hand has 6v when the board is in and out.

 

[Perry Babin]

Do you have a FLIR imager or canned air?

 

[imraneesa]

Yes I have flir image.

 

[Perry Babin]

Do you see any components on that board that are heating up?

 

[imraneesa]

Yes this part is getting very hot. Attaching picture. After removing it voltage back to -6v. What I can replace it with?

 

[Perry Babin]

It looks like a 4.7uF 25v tantalum capacitor.

 

[imraneesa]

Can I use electrolytic?