I posted on here a few weeks back asking for help fixing my Orion HCCA 225 Digital Reference amp. With Perry & Tim's help I was able to fix the problem it had.
apparently it needs a little more TLC. Recently I noticed when you first power it up it takes 3or 4 minutes before it starts amplifying the music...it does play music through it when it first powers up but it takes 3 or 4 minutes before it starts amplifying the music. As if it's warming up. If I shut it down for little bit and turn it back on it works fine still. Only after it has sat for a while does it do it. Op-amps maybe??? I greatly appreciate any help I can get.
apparently it needs a little more TLC. Recently I noticed when you first power it up it takes 3or 4 minutes before it starts amplifying the music...it does play music through it when it first powers up but it takes 3 or 4 minutes before it starts amplifying the music. As if it's warming up. If I shut it down for little bit and turn it back on it works fine still. Only after it has sat for a while does it do it. Op-amps maybe??? I greatly appreciate any help I can get.
So I was testing the transistor that is toward the top of the pic. It was taking a long time to drop voltage. About 3 minutes in it had only reached -10v. At this point I moved the test lead over to the third leg of other transistor and the amp immediately dropped volume, the reading on that leg -3.3v. I moved back to the first transistor and it was now at -6.5v. So I moved back to the 2nd transistor again and the volume cut completely out this time.
I pulled that transistor and checked it. It is definitely bad. Going to replace them both tomorrow. Do you think it could just be those resistors causing the whole problem?
I pulled that transistor and checked it. It is definitely bad. Going to replace them both tomorrow. Do you think it could just be those resistors causing the whole problem?
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Hey Perry, I found and fixed the no sound problem. It was a resistor right behind one of the 2n5639 transistors you first mentioned (see attached photo).
So as to the original problem...I replaced both of those transistors as well as the one you pointed out in your pic, along with the capacitor(the big resistor ohmed out good). After replacing those the problem seems to have gotten worse as it doesn't reach full volume output at all now. The third leg on the two 2n5639 transistors is only dropping to a max of -6.12v(that was after 7 or 8 minutes of play). Also that voltage intermittently(very briefly - half a second) jumps up and then drops again...of course the sound drops and rises with it.
So as to the original problem...I replaced both of those transistors as well as the one you pointed out in your pic, along with the capacitor(the big resistor ohmed out good). After replacing those the problem seems to have gotten worse as it doesn't reach full volume output at all now. The third leg on the two 2n5639 transistors is only dropping to a max of -6.12v(that was after 7 or 8 minutes of play). Also that voltage intermittently(very briefly - half a second) jumps up and then drops again...of course the sound drops and rises with it.
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No, with the muting transistors out it does not reach the expected output level. Although it is closer to the expected level with them out -12v.
The 2n5639 transistors are obsolete so I had to replace them with NTE467. The info I found on the NTE467 is that it specs are identical to the 2n5639 as well as the leg orientation being the same. I did install them the same as they came out.
The 2n5639 transistors are obsolete so I had to replace them with NTE467. The info I found on the NTE467 is that it specs are identical to the 2n5639 as well as the leg orientation being the same. I did install them the same as they came out.
Okay Perry, I'm doing my best to get up to speed with you(doing my homework).
As to the positive and negative rail voltage - Are these the dual rectifiers in this amp?(see pic). I know how measure positive voltage on them but how do I measure negative voltage?
As to the Positive and negative regulated voltage on the op-amps - I was able to locate one of the caps that supplies power to one of the op-amps. The others I'm unable to follow the traces to figure it out. Will you please point them out for me in the pic? In testing the positive and negative voltage of those caps, I know the square pad is positive and the round negative. To test the negative voltage, I'm I correct in doing so by moving my positive test lead to the negative side?
Also, before I preform the above tests - should I reconnect the components you had me remove in the previous tests(muting transistors and cap) or leave them out?
As to the positive and negative rail voltage - Are these the dual rectifiers in this amp?(see pic). I know how measure positive voltage on them but how do I measure negative voltage?
As to the Positive and negative regulated voltage on the op-amps - I was able to locate one of the caps that supplies power to one of the op-amps. The others I'm unable to follow the traces to figure it out. Will you please point them out for me in the pic? In testing the positive and negative voltage of those caps, I know the square pad is positive and the round negative. To test the negative voltage, I'm I correct in doing so by moving my positive test lead to the negative side?
Also, before I preform the above tests - should I reconnect the components you had me remove in the previous tests(muting transistors and cap) or leave them out?
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