Re: Need Help with this Circuit Please
Well for some reason it is working fine now. Might have been a loose connection somewhere. I will have to do some more looking.
tfs2015
Senior Member
Last Activity: 06-23-2018, 07:21 PM
Joined: 02-14-2015
Location: Wells, MN
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Re: Need Help with this Circuit Please
ok will do. We need to get part of this thread moved to a new one. Especially the troubleshooting and theory part. I have learned a lot from working on this system. Fortunately according to Fender the new PA systems are designed better then the old ones.
Many thanks for the help and the knowledge passed on.
I guess I will have to check D201 next.
Thanks,
Tom S. Wells, MNLeave a comment:
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Re: Need Help with this Circuit Please
Turned around Z201 and guess what less pop on Left and Right channels However it is not as bad as before. Reading 6.62 vdc across Z201. I Guess with this circuit you cannot mute out all of transient pop noises during power off or is there something else that I need to check?Leave a comment:
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Re: Need Help with this Circuit Please
So does that mean that it is installed wrong on the board?Leave a comment:
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Re: Need Help with this Circuit Please
ok I really cannot figure this out. Z201 tested fine out of circuit with 6.5 voltage drop. In circuit it only shows a voltage drop of 670 mV something here just does not seem correct to me.Leave a comment:
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Re: Need Help with this Circuit Please
If I connect the left and right inputs to the power amp and then ground that to the audio signal GROUND, I am still getting a little bit of audio going through the speakers but a lower level. Looking at page 24 in the manual, CN5 pin 3 is fed by -15vdv signal that connects to the anode of Z2. The cathode of Z2 connects to R143 (mixer circuit board) and that connects to CN5 pin 3, I am assuming that is control line that you have been talking about. Z201 only has .690 vdc across it. According to the parts list for the amp board, Z201 is rated...Leave a comment:
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Re: Need Help with this Circuit Please
ok will check voltages and report back tomorrow. Thank you for the advice.Leave a comment:
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Re: Need Help with this Circuit Please
You are right it is not in the schematic just in the parts list. One end connects to R206 the other end connects to q209...Leave a comment:
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Re: Need Help with this Circuit Please
the 112Jfet's are working because they are brand new I just put them in a couple weeks ago.Leave a comment:
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Re: Need Help with this Circuit Please
Z201 was installed when I first got this unit over a year ago, and I have already replaced R206. Should I disconnect one end of Z201 to see if that helps? I am reading about to 3vdc through the speaker outputs (speakers disconnected of course).
Thanks
TomLeave a comment:
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Re: Need Help with this Circuit Please
How do I check out this muting circuit? Thank you for your help and I apologize if you were confused by that previous post. I am still kind of new at posting my exact problem(s) on this forum.
Thanks
Tom S....Leave a comment:
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Re: Need Help with this Circuit Please
One power switch....the main one. The Mixer section is a board that contains all of the controls for the PA System its self. The power amp is another board that is part of the system as well. It is physically mounted to the heat sink as well as the power supply. Now back to the power switch. It has line voltage 115 VAC going thought it. When you turn that switch on the SMPS turns on and sends 15 VDC to the mixer to power the op amps and reverb board. 51vdc is sent to the Amplifier section to power it....Leave a comment:
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Re: Need Help with this Circuit Please
Look at the manual it shows the block diagram, and a schematic for each section of the PA System...Leave a comment:
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Re: Need Help with this Circuit Please
the SMPS on this unit supplies power to the mixer circuit board, amp circuit board and the reverb circuit board. The SMPS turns on when you turn the power switch on. If you unplug CN6 from the amp board which is the input from the mixer board there would be no input from the mixer to the power amp board. The mixer also sends line level signals to the SEND outputs of the PA system. Please see this manual from a better explanation....Leave a comment:
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Re: Need Help with this Circuit Please
Ok, there are no protection relays connected to the speaker outputs on this unit. I disconnected CN6 which is the input from the mixer board to the power amp section and guess what, no squeal or pop coming from the speakers so what does that mean?Leave a comment:
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Re: Need Help with this Circuit Please
If I just turn on the Passport with no input going to it and then turn it back off, it is still making that sound through the speakers. If I unplug the Reverb board power and then shut down I don't hear that sound through the speakers. I notice that with my car amps when you shut them off, they turn off nice and quiet with no noise from the speakers.Leave a comment:
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Re: Need Help with this Circuit Please
Ok when I turn the power switch on both the mixer and the power amp receive power at the same time, so all I can do is ground the input of power amp to see if it makes that same noise. If I remember correctly if I unplug the reverb board power that sound that is heard when turning the power switch to the unit off is not heard anymore but I need to confirm that and I will let you know.Leave a comment:
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Re: Need Help with this Circuit Please
Everything is working good except for a popping sound is heard when the unit is powered down and I cannot figure out why any help would be greatly appreciatedLeave a comment:
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Re: HIFONICS ZXi 1008 car amp has output on one channel only
The op amps tested OK, and I have found the reason for the offset and fixed it. The problem that I am having now has to do with the audio signal going from the op amps outputs into the current voltage gain stage. I don't understand where the signal is entering that stage. If anyone could help me with that it would be greatly appreciated.
Thanks
TomLeave a comment:
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Re: HIFONICS ZXi 1008 car amp has output on one channel only
Found a DC offset on one of the speaker terminals how can I fix that? Goes from 1vdc to 3vdc before the protect circuit kicks in.
Thanks
TomLeave a comment:
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