Im working with this unit. here is what im getting
35v at each of the 4 speaker out connectors, I measure
all the out put mosfet, and no short.
thanks in advance
35v at each of the 4 speaker out connectors, I measure
all the out put mosfet, and no short.
thanks in advance
Could be...
loss of the opposite supply rail. You should have both + and - 35 out of your power supply rails.
Or, you could have a shorted component upstream of the outputs.
Since it appears to be on both speaker outputs, I'd guess that you lost a power supply rail.
Do not connect any load (speaker or otherwise) to your outputs until you resolve the DC problem.
loss of the opposite supply rail. You should have both + and - 35 out of your power supply rails.
Or, you could have a shorted component upstream of the outputs.
Since it appears to be on both speaker outputs, I'd guess that you lost a power supply rail.
Do not connect any load (speaker or otherwise) to your outputs until you resolve the DC problem.
Do you have both positive and negative rail voltage?
Do you have both positive and negative regulated voltage on the op-amps?
Can you post a photo of the inside of the amp. The partial model number could be several amps.
Do you have both positive and negative regulated voltage on the op-amps?
Can you post a photo of the inside of the amp. The partial model number could be several amps.
back to this amp, I have + - 36 volts out
of the rectifiers, no output mosfet is getting
hot. there are 2 set of 4 contacts for the
speakers, the 2 inner contacs are ground, and
the 2 outer contats are speaker +. all the outer
contact have + 35. there are 11 8pins chips
part # tlo72c. any sugestion?
of the rectifiers, no output mosfet is getting
hot. there are 2 set of 4 contacts for the
speakers, the 2 inner contacs are ground, and
the 2 outer contats are speaker +. all the outer
contact have + 35. there are 11 8pins chips
part # tlo72c. any sugestion?
Could be a defective TL072 op amp. Do you have any DC on the outputs of the op amps (pins 1 & 7 on each chip). If the input op amp was delivered a hot signal, it could short resulting in the op amp output going to the supply rail ( either + or - 15V).
here is the reading for all the op amp ic's
pin
1= .8v
2= .8v
3= .8v
4= -10v
5= .8v
6= .8v
7= .8v
8= 31v
pin
1= .8v
2= .8v
3= .8v
4= -10v
5= .8v
6= .8v
7= .8v
8= 31v
some one put the wromg reg,
instead of a lm317 they use
a lm337. know after I replaced
the reg for the right one, Im
getting 12v at pin 8 of the op amps,
but Im still getting 35v at the speakers
output.
instead of a lm317 they use
a lm337. know after I replaced
the reg for the right one, Im
getting 12v at pin 8 of the op amps,
but Im still getting 35v at the speakers
output.
Check the drivers for each channel. They are Qx19, Qx20, Qx21 and Qx22. You may need to lift two legs to check for leakage and to confirm that both junctions are intact for each driver.
With all transistor back in the circuit (or at least the ones you need to measure the voltage on), what is the DC voltage on the collector of the drivers Q120 and Q121?
Do any of the op-amps have significant DC voltage on their output pins? Connect the shield ground to the amp's ground before measuring the DC voltage.
The shield ground is the ground for the RCA jacks. Connect the RCA shields on the RCA jacks to the amp's ground.
all the op amps have the same reading
pin 4 = -11.5v
pin 8 = 11v
all the others pins have 0 volts
pin 4 = -11.5v
pin 8 = 11v
all the others pins have 0 volts
What's the DC voltage across R119?
Did you check all of the output transistor with all lead configurations (1-2, 1-3 and 2-3)?
Did you check all of the output transistor with all lead configurations (1-2, 1-3 and 2-3)?
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