Hi, i have a problem with my love...Rockford 1501bd
Does anyone have service manual and schemes?
🙁
Many thanks!
Does anyone have service manual and schemes?
🙁
Many thanks!
...i have a problem... this is the situation.
I have switch on the amplifier...the sound output but...
1- Q1 - Q3 - Q13 - Q14 (LM317 and LM 337) is very very hot, i can't touch!
2- When i turn the potentiometer of Gain up and down...the audio output increases and decreased but the subwoofer connected moves up and down....i have DC on output..
3- If i switch on the subsonic filter the subwoofer no up and down.
4 - When touch the knob of frequency crossover i can hear a buzz-humm......the knob is plastic!
..can you help me?
Sorry for my english..i'm from italy!
I have switch on the amplifier...the sound output but...
1- Q1 - Q3 - Q13 - Q14 (LM317 and LM 337) is very very hot, i can't touch!
2- When i turn the potentiometer of Gain up and down...the audio output increases and decreased but the subwoofer connected moves up and down....i have DC on output..
3- If i switch on the subsonic filter the subwoofer no up and down.
4 - When touch the knob of frequency crossover i can hear a buzz-humm......the knob is plastic!
..can you help me?
Sorry for my english..i'm from italy!
It's normal for the regulators to run hot.
Which of the op-amps in the preamp section have more than a fraction of a volt of DC on their output pins.
Which of the op-amps in the preamp section have more than a fraction of a volt of DC on their output pins.
.... another problem is when I move the phase and subsonic switches the amp emits a BUMP with a cone that goes wildly up and goes into protection.
the subwoffer conected is a Rockford...RFD 3218...4+4ohm..18"
I try to upload a video of the DC
many thanks 🙂
the subwoffer conected is a Rockford...RFD 3218...4+4ohm..18"
I try to upload a video of the DC
many thanks 🙂
>>> when I move the phase and subsonic switches the amp emits a BUMP with a cone that goes wildly up and goes into protection >>> THIS DOES NOT HAPPEN ALWAYS .. 5 TIMES ON 10
..sorry for writing in uppercase
..sorry for writing in uppercase
no, I do not know how to do it but if you explain it I'll know how to do it.
Which ones?
....do you need an oscilloscope? I do not have an oscilloscope.
thanks
Which ones?
....do you need an oscilloscope? I do not have an oscilloscope.
thanks
All you need is a multimeter.
Before you measure the DC, make sure that the RCA shields are not broken.
Before you measure the DC, make sure that the RCA shields are not broken.
I checked the rca connectors and they are perfect both visually and with multimeter.
can you help me check the direct current on the op-amp?
can you help me check the direct current on the op-amp?
Black probe on the RCA shield. Red probe on the output terminals of each of the op-amps. They should all read very near 0.00v DC.
do I measure this on all the TL072s that are inside the amplifier? ... or do I measure the LM6171 too?
thx
thx
Hi, i'm here! 🙂
I measured, this the situation with amplifier without speaker and connector rca.
Only power on.
Switch Subsonic: ON
Switch Phase: 180°
TL072 - U1 output A = 0.4mV
TL072 - U1 output B = 3.3mV
TL072 - U2 output A = 5.7mV (Gain turned Left) / 0,23V (Gain turned Right )
TL072 - U2 output B = 10,4mV (Gain turned Left) / 0,24V (Gain turned Right )
TL072 - U3 output A = 12,0mV (Gain turned Left) / 0,24V (Gain turned Right )
TL072 - U3 output B = 13,0mV (Gain turned Left) / 0,24V (Gain turned Right )
TL072 - U4 output A = 0,64V
TL072 - U4 output B = 5,8mV
I have change the original potentiometer (5k)...with new potentiometer (10k)...but
but the situation is the same.
I made the measurements with the 10k potentiometer.
and now? 🙁
I measured, this the situation with amplifier without speaker and connector rca.
Only power on.
Switch Subsonic: ON
Switch Phase: 180°
TL072 - U1 output A = 0.4mV
TL072 - U1 output B = 3.3mV
TL072 - U2 output A = 5.7mV (Gain turned Left) / 0,23V (Gain turned Right )
TL072 - U2 output B = 10,4mV (Gain turned Left) / 0,24V (Gain turned Right )
TL072 - U3 output A = 12,0mV (Gain turned Left) / 0,24V (Gain turned Right )
TL072 - U3 output B = 13,0mV (Gain turned Left) / 0,24V (Gain turned Right )
TL072 - U4 output A = 0,64V
TL072 - U4 output B = 5,8mV
I have change the original potentiometer (5k)...with new potentiometer (10k)...but
but the situation is the same.
I made the measurements with the 10k potentiometer.
and now? 🙁
U2 is likely the most significant problem.
Sometimes, the TL072s age badly and all have to be replaced.
As a side note, it won't do any harm to leave the subsonic filter engaged.
What is the DC voltage across the speaker terminals with the amp at idle?
Does it change with the position of the gain (after it has had a few seconds to settle after changing its position)?
Sometimes, the TL072s age badly and all have to be replaced.
As a side note, it won't do any harm to leave the subsonic filter engaged.
What is the DC voltage across the speaker terminals with the amp at idle?
Does it change with the position of the gain (after it has had a few seconds to settle after changing its position)?
Across the speaker terminal (without connected speaker and without signal in imput) i have 89,1mV with gain at minimum ad 89,0mV with gain at maximum.
I can't see voltage peak because i have a digital tester but..when mouve the gain knob from minimum to maximum a can see on multimiter an increase in tension which then returns to 89.1mV.
What can I do? I proceed to replace all 4 TL072? or just U2? What should I buy in TL072? Which brand? Do they have to be all the same?
Many thanks 🙂
I can't see voltage peak because i have a digital tester but..when mouve the gain knob from minimum to maximum a can see on multimiter an increase in tension which then returns to 89.1mV.
What can I do? I proceed to replace all 4 TL072? or just U2? What should I buy in TL072? Which brand? Do they have to be all the same?
Many thanks 🙂
This model and brand is ok? 🙂
N.5 pz TL072C SMD SOIC-8 JFET Dual Operational Amplifier ( TL072 ) | eBay
N.5 pz TL072C SMD SOIC-8 JFET Dual Operational Amplifier ( TL072 ) | eBay
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