Hi!
I'm working on a RF P1000X1D. It got two yellow LED's and two red LED's.
Both yellow LED's are lit when remote is connected. According to the manual RED is power OK and yellow is protect 😱.
Now, this amp came in with missing +15V on all TL072's (pin 8). Only 4.4VDC were to be found. This was due to a loose winding on the power transformer (T1) providing power to D5 and D7.
After repairing this and assembling the amp, being certain that this was the only and major culprit, exactly the same behaviour shows up: no sound, yellow LED's.. 🙁
Rail Voltage 69.5VDC and no shorted or bad output FET's.
This amp has only 4 pcs output FET's and 2 pcs switching-FET's for the transformer. It also only have ONE rectifier diode (63CTQ100) for the rail Voltage. There isn't any diodes creating negative rail Voltage. Seems car negative ground is used all over.
I'm a bit lost in this design and was wondering if anyone has got a service manual or circuit diagram for this amp (or equivalent)?
I'm working on a RF P1000X1D. It got two yellow LED's and two red LED's.
Both yellow LED's are lit when remote is connected. According to the manual RED is power OK and yellow is protect 😱.
Now, this amp came in with missing +15V on all TL072's (pin 8). Only 4.4VDC were to be found. This was due to a loose winding on the power transformer (T1) providing power to D5 and D7.
After repairing this and assembling the amp, being certain that this was the only and major culprit, exactly the same behaviour shows up: no sound, yellow LED's.. 🙁
Rail Voltage 69.5VDC and no shorted or bad output FET's.
This amp has only 4 pcs output FET's and 2 pcs switching-FET's for the transformer. It also only have ONE rectifier diode (63CTQ100) for the rail Voltage. There isn't any diodes creating negative rail Voltage. Seems car negative ground is used all over.
I'm a bit lost in this design and was wondering if anyone has got a service manual or circuit diagram for this amp (or equivalent)?
Some Rockford amps have flyback power supplies instead of push-pull power supplies. This may be one.
If it has only one rail, it's likely a full-bridge design. These typically use two driver ICs and when it's operating, the DC on both speaker terminals will be 1/2 rail voltage.
I nave no definitive information on this amp. I haven't seen one and don't have the diagram for it.
If it has only one rail, it's likely a full-bridge design. These typically use two driver ICs and when it's operating, the DC on both speaker terminals will be 1/2 rail voltage.
I nave no definitive information on this amp. I haven't seen one and don't have the diagram for it.
You're right as for the flyback-theory, Perry.
Still need som diagram pointing out Voltages though.. :-(
Anyone else got access to such?
Still need som diagram pointing out Voltages though.. :-(
Anyone else got access to such?
Hi, again!
I now got my hands on the schematics for this amp! 🙂
I've done some measuring and all supply voltages seems OK (although what should be a 15V output from Q9 (BCP53) only reads 12.33V).
I'm now feeding RCA inputs with a 400Hz sine wave signal and traced that all the way to IC10 (TL072) pin 3 and 5 in the output stage.
Signal passes even the EQ-board, so adjusting gain control for instance will now affect the amplitude on pins 3 and 5 at IC10.
IC10 has 36VDC between its supply input pins 4 and 8.
NO signal are output from pin 1 and 7 though!
So I did replace IC10 with a new identical TL072C - no difference.. :-(
Does anyone want to have a look at the schematics I've got?
My brain still won't cope with this design.. S-)
If anyone could help me proceed with what to check next, I'll be grateful!
I now got my hands on the schematics for this amp! 🙂
I've done some measuring and all supply voltages seems OK (although what should be a 15V output from Q9 (BCP53) only reads 12.33V).
I'm now feeding RCA inputs with a 400Hz sine wave signal and traced that all the way to IC10 (TL072) pin 3 and 5 in the output stage.
Signal passes even the EQ-board, so adjusting gain control for instance will now affect the amplitude on pins 3 and 5 at IC10.
IC10 has 36VDC between its supply input pins 4 and 8.
NO signal are output from pin 1 and 7 though!
So I did replace IC10 with a new identical TL072C - no difference.. :-(
Does anyone want to have a look at the schematics I've got?
My brain still won't cope with this design.. S-)
If anyone could help me proceed with what to check next, I'll be grateful!
This can be in protect mode for several reasons, most likely a DC offset on the output stage or excess current drawn.
Check for a square wave of rail to rail on L101 ans L201. It should be symmetrical, if not check the output fets and Lo/Hi side drivers. The driver chips should be oscillating and working with pins 14 and 10 driving. Remove one of the amplifier supplies to isolate eachamplifier. If excess current is drawn, removing the FETs will show the issue. Be careful as capacitive scope leads may effect the wave formation and lead you up the wrong path. Don't look too deeply into the issue, skirt around the problem applying a methodic system of looking at the fault. It is only a few transistors and will not be too complicated in the end.
Check for a square wave of rail to rail on L101 ans L201. It should be symmetrical, if not check the output fets and Lo/Hi side drivers. The driver chips should be oscillating and working with pins 14 and 10 driving. Remove one of the amplifier supplies to isolate eachamplifier. If excess current is drawn, removing the FETs will show the issue. Be careful as capacitive scope leads may effect the wave formation and lead you up the wrong path. Don't look too deeply into the issue, skirt around the problem applying a methodic system of looking at the fault. It is only a few transistors and will not be too complicated in the end.
Seems a double problem may be here. I didn't see your loss of 15v due to a bad connection on the transformer, apologies. I will take a fresh look at the schematic for more clues.
Was wondering if someone could e-mail me the schematic, I do not have this one.
seankane89@hotmail.com
seankane89@hotmail.com
Is the yellow LED still lit?
What is the DC voltage measured directly across ZD1?
What is the rail voltage?
What is the voltage on the cathode of ZD12?
DC voltage on all legs of IC10 and IC17? Black probe on amp ground.
What is the DC voltage measured directly across ZD1?
What is the rail voltage?
What is the voltage on the cathode of ZD12?
DC voltage on all legs of IC10 and IC17? Black probe on amp ground.
Yellow LED still lit.
DC voltage across ZD1=7.35
Rail voltage (cathode D12)=69.5
Voltage cathode ZD12=32.7
DC voltage IC10:
Pin1=13.32
Pin2=26.57
Pin3=26.01
Pin4=12.05
Pin5=26.02
Pin6=26.59
Pin7=13.34
Pin8=48.5
DC voltage IC17:
Pin1=6.44
Pin2=6.44
Pin3=8.3
Pin4=4.14
Pin5=6.62
Pin6=11.89
Pin7=2.591
Pin8=2.591
Pin9=3.35
Pin10=1.89
Pin11=1.441
Pin12=0.00
Pin13=1.262
Pin14=6.44
DC voltage across ZD1=7.35
Rail voltage (cathode D12)=69.5
Voltage cathode ZD12=32.7
DC voltage IC10:
Pin1=13.32
Pin2=26.57
Pin3=26.01
Pin4=12.05
Pin5=26.02
Pin6=26.59
Pin7=13.34
Pin8=48.5
DC voltage IC17:
Pin1=6.44
Pin2=6.44
Pin3=8.3
Pin4=4.14
Pin5=6.62
Pin6=11.89
Pin7=2.591
Pin8=2.591
Pin9=3.35
Pin10=1.89
Pin11=1.441
Pin12=0.00
Pin13=1.262
Pin14=6.44
For both output driver ICs...
Measure the resistance between pins 9, 10 and 11. Do you have any readings between any of those pins with any probe/pin combination that is less than 1000 ohms?
Do the same for pins 13, 14 and 15.
Measure the resistance between pins 9, 10 and 11. Do you have any readings between any of those pins with any probe/pin combination that is less than 1000 ohms?
Do the same for pins 13, 14 and 15.
I do not.
IC14:
Between 9 and 10 I got approx 3MOhm
Between 9 and 11 I got approx 14kOhm
Between 10 and 11 I got approx 300kOhm
Between 13 and 14 I got approx 19kOhm
Between 13 and 15 I got approx 11MOhm
Between 14 and 15 I got approx 11MOhm
IC15:
Between 9 and 10 I got approx 3MOhm
Between 9 and 11 I got approx 14kOhm
Between 10 and 11 I got approx 300kOhm
Between 13 and 14 I got approx 19kOhm
Between 13 and 15 I got approx 9MOhm
Between 14 and 15 I got approx 9MOhm
IC14:
Between 9 and 10 I got approx 3MOhm
Between 9 and 11 I got approx 14kOhm
Between 10 and 11 I got approx 300kOhm
Between 13 and 14 I got approx 19kOhm
Between 13 and 15 I got approx 11MOhm
Between 14 and 15 I got approx 11MOhm
IC15:
Between 9 and 10 I got approx 3MOhm
Between 9 and 11 I got approx 14kOhm
Between 10 and 11 I got approx 300kOhm
Between 13 and 14 I got approx 19kOhm
Between 13 and 15 I got approx 9MOhm
Between 14 and 15 I got approx 9MOhm
I've seen this type of IC fail and cause an amp go into protect but that doesn't appear to be the case here.
What is the DC voltage measured directly across the B+ and ground terminals?
It appears that the LM339 pin 11 should be higher. This appears to monitor the DC input voltage.
If it's 11v or higher, post the DC voltage on both ends of D23 (black probe on ground).
What is the DC voltage measured directly across the B+ and ground terminals?
It appears that the LM339 pin 11 should be higher. This appears to monitor the DC input voltage.
If it's 11v or higher, post the DC voltage on both ends of D23 (black probe on ground).
I've got 12.62V directly across B+ and ground terminals.
D23 anode got 1.441V and the cathode reads 1.025V.
D23 anode got 1.441V and the cathode reads 1.025V.
It appears that the voltage on pin 11 is being held down by D23. This can be due to several things. I need the DC voltage on all terminals of Q13, 14, 15, 16 and 19.
Q14 B=0.959
Q14 C=-22.97
Q14 E=1.025
Q15 B=-23.01
Q15 C=0
Q15 E=-23.06
Q19 B=0.679
Q19 C=0
Q19 E=0
Q13 and Q16 are both "hidden" on a sub pcb which calls for some challenging measurement. I'll try accessing them though..
Q14 C=-22.97
Q14 E=1.025
Q15 B=-23.01
Q15 C=0
Q15 E=-23.06
Q19 B=0.679
Q19 C=0
Q19 E=0
Q13 and Q16 are both "hidden" on a sub pcb which calls for some challenging measurement. I'll try accessing them though..
I'm going to have to study the diagram a bit more. The CSD line seems like it should be high in some places but low in others.
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