Perry I removed LM361 and I noticed that pin 9 does not connect to anything , I removed LM361 carefully .. On the JBL 1200 diagram U108 is LM361 , I can not make out pin out ?
I noticed that a memphis amp I have need repairs too , its LM361 as well pin 9 went nowhere . So I installed another LM361 and it is doing the same thing ? Could it be the F16 MC14060?
If you zoom in, you can see all pin connections clearly. The Datasheet (either download or in the semiconductor datasheets folder under LM161) shows the internal schematic for the IC.
The 14060 takes the crystal frequency and divides it, If the 14060 has a clean square wave on pin 5, it's working. The various waveforms for a similar amp are on the Generic Class D - Type 1 page. Where there are waveforms, you can right-click to zoom in to see them. Have you read through that page?
The 14060 takes the crystal frequency and divides it, If the 14060 has a clean square wave on pin 5, it's working. The various waveforms for a similar amp are on the Generic Class D - Type 1 page. Where there are waveforms, you can right-click to zoom in to see them. Have you read through that page?
Yes I see the diagram on the dvd , but on the borad the traces do not match up to anything. I see pin 9 on the diagram through 2.2 resistor and drives 3 transistors. The closest pin I jumped from LM361 pin 9 to a cap 104 C191 , and now the voltage regulators are burning up and a transistor Q182 on the board with LM361 gets super hot in seconds ( it is not shorted). Undid the jumper and still regulators and close transistor to LM361 get super hot. For the life of me I can not find the trace for LM361 pin 9 , but now to deal with the short I have now.
Last edited:
2 shorted caps the one I put a jumper on C191 and C192 4.7uf 16V . For C191 it has a making of 104 what could I use ?
Ok are they bipolar and it is ceramic ?
Because on the memphis amp it has a jumper as well LM361 pin 9 to a cap right next to it, or it looks like it does ?
Is there anything you can think of for the LM361 9 pin and why it does not have any traces on it or next to it ?
Because on the memphis amp it has a jumper as well LM361 pin 9 to a cap right next to it, or it looks like it does ?
Is there anything you can think of for the LM361 9 pin and why it does not have any traces on it or next to it ?
The one marked 104 is likely polyester/mylar. I don't know about the other ones. I have no information on this amp other than what you've posted.
Pin 9 may not be used. Some of the amps that use this drive system use only 9 OR 11, not both.
Pin 9 may not be used. Some of the amps that use this drive system use only 9 OR 11, not both.
Ok I will check the radio shack because I dont have any of those thank you.
LOL I was up 5:30-8:00am trying to find a trace for pin 9 on the LM361. Haha I feel dumb . Thank you Perry once again. LM361 pin 11 does have a solder pad.
LOL I was up 5:30-8:00am trying to find a trace for pin 9 on the LM361. Haha I feel dumb . Thank you Perry once again. LM361 pin 11 does have a solder pad.
Ok changed out the bad caps, and ever things good no more heating up. Powered up amp and no square wave on the F16 MC14060 Pin 5 changed out MC14060 and still nothing ? Could it be the crystal ? It does not look damaged , looks good . ICs don't do anything no waveforms at all MC14060 , LM361 , TL072. I still have +12V and -12V on IC's though.
The jumper between pins 1 and 2 is there to prevent the output of the TL072 from swinging toward the power supply rail (which would make the signals on the input of the LM361) have too much DC. You can remove it.
The crystal could be defective but the only tine I've seen one defective was when it had a broken leg. The crystal relies on 2 small capacitors connected to it. Is either one damaged or missing?
The crystal could be defective but the only tine I've seen one defective was when it had a broken leg. The crystal relies on 2 small capacitors connected to it. Is either one damaged or missing?
As I stated before, the only information I have on this amp is what you provide. Look at the JBL manual to see if you can find a corresponding part.
Ok all good now everything has there waveforms , but the output of the LM361 pin 11 has nothing no square waveform. Have you seen this before ? The Kicker KX1200.1 amp diagram is more helpful on this amp , with out your dvd . I don't think I would be able to do anything...
If you have a triangle waveform on pin 4, no signal or an audio signal on pin 3, no significant DC on either of those pins, negative and positive supply voltage on the appropriate pins, pin 11 should have output.
Ok I remove one of the output driver boards that I installed a quick disconnect on and still no square waveform on LM361 pin 11. Undid the trace going to the other output driver board that is still soldered in place, from the LM361 pin 11 still no square waveform . LM361 pin 9 has square waveform , pin 11 is just sitting at -.655 whats going on ?
Last edited:
If nothing is connected to the pin, the LM361 would appear to be defective.
I double-checked an amp I have here and with nothing connected to the pin, it will still produce a square wave.
I double-checked an amp I have here and with nothing connected to the pin, it will still produce a square wave.
- Status
- Not open for further replies.