The 21844 ICs run warm to hot but shouldn't overheat within seconds.
Is one heating more than the other?
Check the outputs of the TL072 and the LM211 with the output FETs out of the circuit.
Is one heating more than the other?
Check the outputs of the TL072 and the LM211 with the output FETs out of the circuit.
Sorry for the late answer, didn´t see that we reached the second site.
It takes a lot of time till they get hot, but they keep rising in heat till they break down. Then I can wait till they cool down anf start anew.
It takes a lot of time till they get hot, but they keep rising in heat till they break down. Then I can wait till they cool down anf start anew.
How long to lose audio from a cold start?
How long does it take for the 21844s to get too hot to touch continuously?
A reminder:
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.
How long does it take for the 21844s to get too hot to touch continuously?
A reminder:
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.
6:55 2,55A
7:00 2,44A to hot to touch for a prolonged time
7:05 2,40A
7:11 2,38A
7:16 2,36A
7:21 2,04A soon after 1,44A, output drive down
SD Pin is at 5V to -VCC
Pin1 of 21844 9,60V 120kHz to -VCC
Pin1 of TL072 Triangel 860mV
After drive is lost
SD pin is at 1V
U1 pin 1 no signal, U2 Pin1 9,44V with a Bad Form the Falling and rising of the signal is swinging initially
Pin 1 of TL072 is only a little wobble
On the Board are no Z-Diodes
7:00 2,44A to hot to touch for a prolonged time
7:05 2,40A
7:11 2,38A
7:16 2,36A
7:21 2,04A soon after 1,44A, output drive down
SD Pin is at 5V to -VCC
Pin1 of 21844 9,60V 120kHz to -VCC
Pin1 of TL072 Triangel 860mV
After drive is lost
SD pin is at 1V
U1 pin 1 no signal, U2 Pin1 9,44V with a Bad Form the Falling and rising of the signal is swinging initially
Pin 1 of TL072 is only a little wobble
On the Board are no Z-Diodes
Pin1 of 21844 9,60V 120kHz to -VCC <<< Do you mean 9,6v of amplitude above the negative rail?
Why is Q4 missing from the driver board?
Do you start to have excessive DC offset at the speaker terminals when audio is lost?
Are the output in or out of the circuit right now?
Sorry about the Zener question.
Why is Q4 missing from the driver board?
Do you start to have excessive DC offset at the speaker terminals when audio is lost?
Are the output in or out of the circuit right now?
Sorry about the Zener question.
Yes above negative rail
Just a photo when I desoldered Q4 to know what's underneath
Output of U2 is completely there 6 Fets, U1 only 1 per bank
Will measure if I have DC on the outputs
Just a photo when I desoldered Q4 to know what's underneath
Output of U2 is completely there 6 Fets, U1 only 1 per bank
Will measure if I have DC on the outputs
No DC at the output, with Drive 0,020V DC at the output, when drive is lost 0,000V at the output.
Solder a bridge between pins 2 and 3 of each of the 21844s. Make sure that the rail voltage is drained off before doing this.
Does either IC heat up?
Does either IC heat up?
After soldering in the bridge, not directly on the IC a capacitor on Pin 2 and the -VCC rail.
They are warm and stay at that temperature, could be my fingerbias expecting heat.
Pin 1 has a square wave of about 10V above the -VCC
They are warm and stay at that temperature, could be my fingerbias expecting heat.
Pin 1 has a square wave of about 10V above the -VCC
I wouldn't expect the ICs to heat up.
Confirm that the supply voltage on pin 7 is still about 12.11v.
Let it idle for the length of time when it would normally shut off, does everything remain exactly as it is now?
Do you have any DC voltage across the gate and source of any of the output FETs? Measured with a multimeter.
For the circuit board designations on the main board, how close are they to the diagram I posted?
Confirm that the supply voltage on pin 7 is still about 12.11v.
Let it idle for the length of time when it would normally shut off, does everything remain exactly as it is now?
Do you have any DC voltage across the gate and source of any of the output FETs? Measured with a multimeter.
For the circuit board designations on the main board, how close are they to the diagram I posted?
12,15V at both Drivers at Pin7, 0,001V DC from Gate to Source.
No Chance over time as far as I can tell.
The Output Board or the PS board?
No Chance over time as far as I can tell.
The Output Board or the PS board?
Find the equivalent of D51 on the diagram. Connect your meter across it. What is the DC voltage as the amp initially powers up and then for the next 10 seconds?
About 0V then it slows down at about 0,378V and it keeps rising slowly 0,4 as the input current slowly falls. 0,418 to 2,50A at 13,53V.