Good morning,
I have this CXA1800.1 Kicker amp. First it was going in and out of protect and I replaced the caps in the Voltage Ladder Circuit, since I didn't have the 24v across ZD4. Now the amp powers up but I have no audio.
By reading the other post I see that I am suppose to have a sawtooth signal on pins 3 and 5 of IC11, I have a square wave. However; I do have a sawtooth on IC9 pin 1.
I have 91.3 volts rail. Measuring from power ground to drains of Q103 and Q203.
Any and all help will be appreciated!
I have this CXA1800.1 Kicker amp. First it was going in and out of protect and I replaced the caps in the Voltage Ladder Circuit, since I didn't have the 24v across ZD4. Now the amp powers up but I have no audio.
By reading the other post I see that I am suppose to have a sawtooth signal on pins 3 and 5 of IC11, I have a square wave. However; I do have a sawtooth on IC9 pin 1.
I have 91.3 volts rail. Measuring from power ground to drains of Q103 and Q203.
Any and all help will be appreciated!
Attachments
Up date, I now have the sawtooth and square wave, Pins 1 and 7 and pins 3 and 5 respectively. Still no audio though. Still working on it.
Check in box. but otherwise the link below will be a source for Q100 and Q200-J108
MMBFJ108 ON Semiconductor / Fairchild | Mouser
MMBFJ108 ON Semiconductor / Fairchild | Mouser
For the benefit of others who may have similar issues, cajones found Q100,200. They are the muting transistors and may be the reason no audio is passing to the opamps. I suggested he remove JFET's temporally to see if this allows audio to pass through and replace them to finalize the repair. There may be other reasons other than failed JFET's and possibly the muting circuit that supplies the voltage to the JFET's.
Once we have cajones results when pulling the JFET's, we can go from there.
Once we have cajones results when pulling the JFET's, we can go from there.
Last edited:
The news is bad Bill, pulling the JFET's didn't result in any audio. Have to look a little more.
On a side note don't buy a Hantek DSO5072P oscope, way to much interference in the signals. My signals just look like they are sparkling. Just a rant, forgive me.
On a side note don't buy a Hantek DSO5072P oscope, way to much interference in the signals. My signals just look like they are sparkling. Just a rant, forgive me.
Shouldn't the connection between IC1's pins 4 and 11 be more than 203k ohms? IC2 is the same way. All of the op amps have that reading from ground to V+, is that correct, I would expect mega ohms?
https://datasheet.octopart.com/ZXTC2045E6TA-Diodes-Inc.-datasheet-11587830.pdf
Is this the correct driver for the outputs?
Is this the correct driver for the outputs?
Do you have 17Vdc at IC1 & IC2 pins 4(+17Vdc) & 11(-17Vdc)?
Shouldn't the connection between IC1's pins 4 and 11 be more than 203k ohms? IC2 is the same way. All of the op amps have that reading from ground to V+, is that correct, I would expect mega ohms?
https://datasheet.octopart.com/ZXTC2045E6TA-Diodes-Inc.-datasheet-11587830.pdf
Is this the correct driver for the outputs?
Yes this is correct. Why do you think they need to be replaced? If you have a squarewave with the amplitude of rail voltage at the output coils,your drivers are good.
Where are you losing the audio? What are you using for input? I would recommend a test tone at 40hz or 50hz.
Measure from Power ground (Black probe) to Pins 4 and 11.
Across the pins I have 30vdc.
1st question, don't need them, was just in case ever did. So I keep a file of part numbers with the different amps. So it is just for my info. Thanks.
2nd question, I am losing signal at ic1 when I power up the amp. As long as no power is applied I get a signal. I know that sound weird. I am using a BK Precision Function Generator and I am using a 50hz signal.
Ref from power grd to:
Pin 4.... 15.3vdc
pin 11.... -15.3vdc
2nd question, I am losing signal at ic1 when I power up the amp. As long as no power is applied I get a signal. I know that sound weird. I am using a BK Precision Function Generator and I am using a 50hz signal.
Ref from power grd to:
Pin 4.... 15.3vdc
pin 11.... -15.3vdc
Check the 3.5mm remote gain port. If the contacts are bad it will not allow audio to pass through IC3.
Also look for bad solder on through hole caps around IC1 IC2 and IC3.
Also look for bad solder on through hole caps around IC1 IC2 and IC3.
I got sound when I plugged into the 3.5mm port, but when I turned up volume not gain, it blew my test speaker.
With the JFET's in and out. Using the same, because the JFET's weren't shorted.
Gate 0v
Drain 0v
Source -15
Gate 0v
Drain 0v
Source -15
With the JFET's in and out. Using the same, because the JFET's weren't shorted.
Gate 0v
Drain 0v
Source -15
This is correct.
When there is no remote gain control plugged in the 3.5mm socket connects R98-20.5K ohm across Pins 6 & 7 of IC3, which sets the gain of the opamp. I'm not sure what has failed but an open socket will open up the signal ground tied to R98 and affect the gain of the opamp. When plugging in the gain control and you may have overloaded the signal to the main board.Check socket, connections to R98, to Pins 6 & 7 of IC3 and around IC3. It's also possible there is a bad solder joint on R98,capacitors around IC or socket itself. I'm sure that the problem is in this circuit and close inspection and ohmmeter checks should weed out the lack of output[comment][/comment]
I got sound when I plugged into the 3.5mm port, but when I turned up volume not gain, it blew my test speaker.
- Home
- General Interest
- Car Audio
- Kicker CXA1800.1 No Audio