The Amp is working at the start, 13,5V 2,5A, then after some time the drive dies, consumption drops to 1,5A.
The 12V Regulator only put out 11,88V, the new one does 12,11V. That didn´t solve it. +/-5V is there and doesn´t go down as the drive dies.
I desoldered the Driver-Board and put new IC´s and transistors in. LM211, TL072C and LM293.
Still the same, it takes longer than at the beginning, where it shutdown after a few seconds.
What could cause this behaviour? The Inductor beads have around 1Ohm.
Did someone have this kind of failure in the past?
Thank you for your answers.
The 12V Regulator only put out 11,88V, the new one does 12,11V. That didn´t solve it. +/-5V is there and doesn´t go down as the drive dies.
I desoldered the Driver-Board and put new IC´s and transistors in. LM211, TL072C and LM293.
Still the same, it takes longer than at the beginning, where it shutdown after a few seconds.
What could cause this behaviour? The Inductor beads have around 1Ohm.
Did someone have this kind of failure in the past?
Thank you for your answers.
I don't have anything on that specific amp but since there are a lot of clone-type amps, I may have something close. Post a good quality photo (no flare from the flash, in focus...) of the component side of the main board and the component side of any driver boards in the amp and I'll see if it looks familiar.
Are These okay? I will Add photos of the Power Supply Board tomorrow.
Attachments
I have a clean sine-signal of 100Hz at the output. Still shutdowns after some time. The protect Pins of the PS Board and the Outputboard stay both at around 0V. So it doesn't seem live they are pulling it down.
Adjusting the Level of the Amplifier results in a not so clean output that stabilizes, the consumption rises with the level and output.
Something I haven't seen so far without a load, when it clips the current goes up slightly but below that it stayed Constant in my previous amps.
I will clean the Potis and measure the input into the driver board.
Adjusting the Level of the Amplifier results in a not so clean output that stabilizes, the consumption rises with the level and output.
Something I haven't seen so far without a load, when it clips the current goes up slightly but below that it stayed Constant in my previous amps.
I will clean the Potis and measure the input into the driver board.
I've got no diagram, but the Inputs and outputs of the driver boards got markings, high low side signal etc.
OK. You won't see input to the driver board when the amp is producing normal output. You need to find the last op-amp before the driver board and measure audio on its output when the amp is operating normally.
The diagram below is from a similar amp. It may help if you can't find that op-amp.
The diagram below is from a similar amp. It may help if you can't find that op-amp.
Are you saying that the signal on the input pin of the audio driver board remains precisely the same when the amp is operating normally and when the output stops?
I measured at the input of the Op amp, to clarify the high low side drive shutdowns. I'm sorry if i was missleading. The 100Hz sine wave stayed the same.
Monitor the audio on the input pin of the driver board from the time remote is applied until the audio stops. How does the signal there change?
Does the relay cut out?
Does the relay cut out?
I don' hear the relay Falling off, when the drive goes off the input sine wave is visible at the input Pin of the driver board.
When I switch it off and on again the relay clicks off and on again, but it needs to "cool" down to again drive the output.
When the audio is lost, what signal do you see on on the output terminals of the TL072 and the LM211?
Do you have 12v across all of the 12v Zener diodes on the driver board when the audio is lost?
What signal do you see on pin 1 of the 21844 driver ICs when audio is lost?
What's the DC voltage on pin 2 of the 21844 when audio is lost? You need to place the black meter probe on the negative rail when measuring this voltage.
Do you have 12v across all of the 12v Zener diodes on the driver board when the audio is lost?
What signal do you see on pin 1 of the 21844 driver ICs when audio is lost?
What's the DC voltage on pin 2 of the 21844 when audio is lost? You need to place the black meter probe on the negative rail when measuring this voltage.
I think it is more of a heat problem at the 21844 Drivers.
What could cause the Driver to Overheat? I ordered a new batch of FQA38N30. They measure fine but still maybe it is a load problem.
I will measure your suggestions tomorrow, thank you very much for your help so far.
What could cause the Driver to Overheat? I ordered a new batch of FQA38N30. They measure fine but still maybe it is a load problem.
I will measure your suggestions tomorrow, thank you very much for your help so far.