Can I check hexfet out of circuit Xtant Amp

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#102
These are in series between the regulators. What components on the board are those regulators?

Perry that op amp has a leakage between Pin4 and 5 on that op amp between the those caps as I pulled it and also that center winding on the yellow transformer for the power supply that is suppose to go to to ground does but there is 219 ohms between the trace and ground with transformer removed. Should it be 0 ohms to ground? I want to have everything ready for the new op amps I ordered. Does the op amps have to be in circuit as a load on the 15 volt supplies for them to read the 15 volts on the 15 volt negative and positive supplies?
 
#103
I'm not sure it's regulated. I should have said 'low voltage supply'. The same supply that feeds the other op-amps feeds this op-amp. The other op-amps have 10 ohm resistors between the low voltage supply and their power supply pins. This op-amp has 47.5 ohm resistors.

Why did you remove the transformer again?

What are you referring to when you say there is leakage between pins 4 and 5?

I don't think you should change op-amps without a good reason. They're relatively easy to check.
 
#104
Removed the op amp to see why those resistors change value usually because because they are heating up because of increased current draw. By leakage I mean there is a lower resistance on these pins than that of a good one has and would cause those 47.5 ohm resistors draw more current thus heating them up resulting in the value change in those resistors.
I pulled the transformer again as I cannot find a reason for why I am not getting the 0 ohms to ground and didn't want to put that fused jumper to ground permanently if I could trace the circuit and find the reason i am not getting a 0 ohm reading to ground from that point on the transformer.
The reason for the op amp change as I have signal going in and nothing coming out before this other problem arose with the protection circuit and had operating voltages on pins 4 and 8 for a 95 cent part and being the 3rd shop in the circuits with test lead and soldering irons possibly shorting pins with possibly voltage on or caps charged.
I know perry I am being paranoid but I like working on a fresh fault but not the case with this one. Don't laugh at me Perry...LOL🙂
 
#106
Perry do they exist? I never seen one or knew about this. How can one tell if you do? You have peeked my interest this is something knew in technology for me. Have you seen one before Perry? What are they used in all?

I can't wait for dvd's from you. Are they shipped? I go to mail box everyday like a little kid looking for them...lol
 
#107
If you don't get the discs by friday, I'll send you another set.

3 layer boards definitely exist. Orion, Memphis? and Zapco used them.

You can tell if it's more than 2 layers by shining a bright light from the back of the board. If the light is blocked by anything where there is no trace on the top or bottom of the board, it's likely a 3 layer board.
 
#108
Thanks Perry I must look for that from now on. Thank you as I did not they existed and now I know how to tell. In a case like that put jumper from tansformer to ground without the fuse to solve that ground problem I have been having with that yellow transformer winding and ground?
 
#113
Perry what op amps can I remove on the signal in side up to the one between the caps op amp that you found why my voltages was off on that with those resistors off value and I found leaking IC from pin 4 to pin 5 heating those resistors up causing them to change value and still keep the protection circuit off and the its led lit to run my circuits and to make sure that I have my – & + 15 volts DC to their power pins 4 and 8 op amps because as I was getting –&+ 18 volts before on all my op amps in that section with yellow power supply transformer winding center tap grounded . As 18 volts is to high for those op amps isn’t it? My power supply is putting out 13.6 volts dc to power the amp connected to work on it. Also make sure my protection circuit is not on when power up and ready to install those new op amps as they should be here tomorrow or Monday. I want everything ready and no further damage in that section to the op amps so I get my input signal up to my opto- couplers and if that is all working and have my signal all the way up to there and voltages I can put my output fets left and right banks back in and and not have plus 149 DC volts coming out my speaker output terminals with no signal in and my protection circuit led lit without going off and on . Wishful thinking right Perry as it has been a fight every step of the way so far.
 
#115
Does all the op amps need to be in the input signal side of the board for the protection circuit to work as I pulled the leaking op amps out ne5532's and the new ones I was getting on Friday haven't showed up yet and I at least have the protection section working.As the J fet is working in circuit and it is still not lighting my protection led. what else should to check to see why it is staying off in Mute mode?
 
#116
I don't think they need to be in the circuit.

What is the circuit board designation for the op-amp between the caps?

Do you have the outputs in the amp?

Post all of the voltages on the LM339.


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:
 
#117
What is the circuit board designation for the op-amp between the caps? is ic=U210

Do you have the outputs in the amp? NO

Post all of the voltages on the LM339.


Pin 1: 4.68
Pin 2: 4.68
Pin 3: 13.09
Pin 4: 5.02
Pin 5: 7.8
Pin 6: 4.09
Pin 7: 5.02
Pin 8: 4.63
Pin 9: 3.4
Pin 10: 7.68
Pin 11: 3.41
Pin 12: 0
Pin 13: 0.04
Pin 14: 0

Voltages taken in reference to ground
 
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