It depends what you mean by static !
For eg, it might mean that the driver is damaged in some way, but still works.
If you're SURE it's ok, then it could be a faulty capacitor, or more than one in the Amp. You would need to check each one in turn !
Also check ALL the connections INSIDE the plugs/sockets & ensure they are soldered ok to the cable.
For eg, it might mean that the driver is damaged in some way, but still works.
If you're SURE it's ok, then it could be a faulty capacitor, or more than one in the Amp. You would need to check each one in turn !
Also check ALL the connections INSIDE the plugs/sockets & ensure they are soldered ok to the cable.
zero d
thank you, I did find a cap that would not read. I had a small electronics course but could not finish it for money reasons. I know how to check most components. anyway thank you for your help. the circuit I found the cap in had two 220uf 25v caps and 3 zener diodes next to 2 6800uf 63v caps. would you know what the circuit was called? I am disabled now and trying to learn more of the electronics.oh the caps were c34 and c35 220uf 25v.
thank you kenny
thank you, I did find a cap that would not read. I had a small electronics course but could not finish it for money reasons. I know how to check most components. anyway thank you for your help. the circuit I found the cap in had two 220uf 25v caps and 3 zener diodes next to 2 6800uf 63v caps. would you know what the circuit was called? I am disabled now and trying to learn more of the electronics.oh the caps were c34 and c35 220uf 25v.
thank you kenny
You might consider checking the relay contacts for not connecting both rails to the amp power section.
This relay is constantly switching on and off for power reduction during "no signal" conditions.
I had a JBL sub brought to me with this issue once...took out two drivers before I realized what was the root cause.
It can sound "scratchy" when both rails are not connecting well.
This relay is constantly switching on and off for power reduction during "no signal" conditions.
I had a JBL sub brought to me with this issue once...took out two drivers before I realized what was the root cause.
It can sound "scratchy" when both rails are not connecting well.
Hi harleyman58,
Just a few questions and thoughts:
1. Do you get hum when the signal cable is not connected to the subwoofer, or only w/ the signal cable connected?
2. Do you get hum with the signal input terminals shorted?
3. Have you tried turning the input AC plug around (if that is possible)?
4. Have you measured the voltages Zero D asked for in Post #8 after replacing C34/C35?
5. Right next to the zener regulators for the input control circuits (R74/ZD6/C34 and R73/ZD5/C35) are the zener regulators for the opamps (U6) at the input of the power amplifier section: R57/ZD3/C29 for the negative side, and R56/ZD4/C28 for the positive side, Have you measured the voltages there, e.g.: across C28/C29?
6. What solder are you using? Most modern electronics use lead-free solder. IMO the old leaded solder (SN63/Pb37) is a much better solder But, if you mix solders, make sure you remove all of the old solder. Particularly on big capacitores like C37 and C38 it is easy to end up with cold solder joints. By the way, how are you testing the capacitors?
7. DUG suggested in Post #9 checking the relay contacts. You can do this by clipping jumper wires across the relay contacts shorting them out. Make sure you know what you are doing, and make connections only with the power cable unplugged.
8. Some board discoloration around the zener regulators may be normal. Hard to tell from here.
Regards,
Just a few questions and thoughts:
1. Do you get hum when the signal cable is not connected to the subwoofer, or only w/ the signal cable connected?
2. Do you get hum with the signal input terminals shorted?
3. Have you tried turning the input AC plug around (if that is possible)?
4. Have you measured the voltages Zero D asked for in Post #8 after replacing C34/C35?
5. Right next to the zener regulators for the input control circuits (R74/ZD6/C34 and R73/ZD5/C35) are the zener regulators for the opamps (U6) at the input of the power amplifier section: R57/ZD3/C29 for the negative side, and R56/ZD4/C28 for the positive side, Have you measured the voltages there, e.g.: across C28/C29?
6. What solder are you using? Most modern electronics use lead-free solder. IMO the old leaded solder (SN63/Pb37) is a much better solder But, if you mix solders, make sure you remove all of the old solder. Particularly on big capacitores like C37 and C38 it is easy to end up with cold solder joints. By the way, how are you testing the capacitors?
7. DUG suggested in Post #9 checking the relay contacts. You can do this by clipping jumper wires across the relay contacts shorting them out. Make sure you know what you are doing, and make connections only with the power cable unplugged.
8. Some board discoloration around the zener regulators may be normal. Hard to tell from here.
Regards,
questions
number one.. no hum without the cable hooked up. it only buzzes while I am pluging the cable in and stops after it is fully seated.
like I said before I am only just learning some of the stuff I don't know how to check the zeners I checked the caps with my meter made to read the caps. I don't know how to check anything with the power on.
number one.. no hum without the cable hooked up. it only buzzes while I am pluging the cable in and stops after it is fully seated.
like I said before I am only just learning some of the stuff I don't know how to check the zeners I checked the caps with my meter made to read the caps. I don't know how to check anything with the power on.
Hi harleyman58,
Post #13: "...no hum without the cable hooked up. it only buzzes while I am pluging the cable in and stops after it is fully seated..."
So, after the signal input cable is fully seated the hum stops, and everything is working correctly? That sounds almost normal, except that the no signal interrupt circuit should have the relay K1 de-energized during turn-on. How about if you turn the sub off, make all connections, and then turn the sub on?
To check a zener regulator you first turn off the power, then you connect a voltmeter (any cheap multimeter will do) accross the zener (or the filter capacitor parallel to the zener). When you are sure that everything is connected securely, and that your hands are not anywhere near the circuit board, you turn the power back on; the voltage you read on the meter should be the nominal voltage for the zener (in this case they are all 15V). If you read anything that's more than 1V of the rated zener voltage something is wrong. Probably best to find a buddy with some electronics experience.
Regards,
Post #13: "...no hum without the cable hooked up. it only buzzes while I am pluging the cable in and stops after it is fully seated..."
So, after the signal input cable is fully seated the hum stops, and everything is working correctly? That sounds almost normal, except that the no signal interrupt circuit should have the relay K1 de-energized during turn-on. How about if you turn the sub off, make all connections, and then turn the sub on?
To check a zener regulator you first turn off the power, then you connect a voltmeter (any cheap multimeter will do) accross the zener (or the filter capacitor parallel to the zener). When you are sure that everything is connected securely, and that your hands are not anywhere near the circuit board, you turn the power back on; the voltage you read on the meter should be the nominal voltage for the zener (in this case they are all 15V). If you read anything that's more than 1V of the rated zener voltage something is wrong. Probably best to find a buddy with some electronics experience.
Regards,
zeners
ok I checked everything going by the schematic everything looked ok. so I checked the coil on the driver it read 3.3 ohm which is correct. went over everything again still nothing. so I hooked up another speaker it worked great. then I checked the other speaker, when I moved the speaker manually it made a noise like it was rubbing.
ok I checked everything going by the schematic everything looked ok. so I checked the coil on the driver it read 3.3 ohm which is correct. went over everything again still nothing. so I hooked up another speaker it worked great. then I checked the other speaker, when I moved the speaker manually it made a noise like it was rubbing.
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