My Alpine mrp f240 amp, has no audio when the car engine shuts off and turns back on. The power light is on, 12.8-14.5 volts is at the remote and battery terminals. When this happens I have to disconnect the B+ from the amp for a few seconds and then reconnect, and the audio comes back. Has to be done with the radio on. Please help as this is sometimes frustrating to do, Everytime the car has to be started
Is this a new install or has the amp been working perfectly and this just started?
If you simply turn the head unit off (to kill remote voltage) and turn it back on, does the amp cycle perfectly every time?
Is B+ connected directly to a constant power source?
If you simply turn the head unit off (to kill remote voltage) and turn it back on, does the amp cycle perfectly every time?
Is B+ connected directly to a constant power source?
A new installation for me but its was said to be in good working order by previous owner, if the head unit is turned off the remote voltage goes and comes back the the head unit comes back on. But this process needs atleast a minute or 2, before the audio starts coming from the amp.
So, you're saying that the symptom when starting the car is different than switching the head unit on and off?
Are you going to try to repair the amp yourself if it's found that the amp is defective?
Are you going to try to repair the amp yourself if it's found that the amp is defective?
Both situations give the same result, and i already have a repair manual for the amp and want to try repairing it myself
I realise that it audio does not play through the amp until the b+ has being removed after the car is started, even though the blue led is showing that the amp has power, just no audio. Removing the b+ is like carry out a reset, which seems to drain the capacitors each time its done.
If you want help, you will have to be more consistent. For cycling the remote, you state that it needs 2 minutes to have audio. For starting the car, you state that you have to remove the B+. These are very different things. Which is right?
You will have to be able to replicate this problem on the bench. Can you do that?
You will have to be able to replicate this problem on the bench. Can you do that?
Ok, here is the thing, ill try to as simple as possible. With all wires connected to the amp which includes B-, remote and B+.
When turning on the head unit there is no audio from the amp ( there is 12volt plus remote 12volt at amp with led lit)
However if i disconnect the B+ with the head unit still on for a couple of seconds and tge reconnect it (B+) the amp lights up and audio now comes through the amp
When turning on the head unit there is no audio from the amp ( there is 12volt plus remote 12volt at amp with led lit)
However if i disconnect the B+ with the head unit still on for a couple of seconds and tge reconnect it (B+) the amp lights up and audio now comes through the amp
How does the DC voltage on the collector of Q802 differ from when the LED is lit but no audio and the LED is lit and there IS audio?
Not finding the Q802 but in seeing Q602 is it the same? I'm not a professional here so please understand
I found it on the topside of the board. The test with audio shows 13.5volts at emitter and 0volts when there is no audio
I attached q802 and labeled the point where I got voltage.
Point 1 -2.6.v inconsistent (voltage goes to 13.5v when there is no audio)
Point 2 13.5v inconsistent (voltage is 27mv when there is no audio)
Point 3 13.5v consistent
I'm not sure which point is the emmiter, collector and base. But these are the findings
Attachments
Do the same for 801, 803 and 804. The part numbers are given. Go online and look up the datasheets for each and they will tell you the pin configuration.
I notice that if I added a 13.5v at pin 2 on Q802 with the amp on the audio comes through until disconnected from the power, would the transistor be at fault?
Working voltage on the left and silent on the right
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What is the B+ voltage measured across the power and ground terminals of the amp?
Are you sure that the batteries in your meter are good?
Are you sure that the batteries in your meter are good?