Found the bad solder joint.Its powering up again.
I installed the rectifier.I still have 38 vdc across speaker terminals with no outputs installed.
Probe on - and probe on + just so you know.
I double cleaned and checked for bridges at output locations.
I installed the rectifier.I still have 38 vdc across speaker terminals with no outputs installed.
Probe on - and probe on + just so you know.
I double cleaned and checked for bridges at output locations.
This doesn't make sense to me.There's no solder bridges.
If I jump drain to source on the low side its taking significant voltage to ground and the amp won't start.There's 50 vdc on drain pad of one output and 20vdc on the other.Of coarse outputs are removed.
If I jump drain to source on the low side its taking significant voltage to ground and the amp won't start.There's 50 vdc on drain pad of one output and 20vdc on the other.Of coarse outputs are removed.
Sorry,just noticed on the jl 500 page about speaker terminal voltage with outputs removed.
Now that's settled.
Does this mean that the amp will not properly power up without outputs or jumpers installed because of DC offset?
Now that's settled.
Does this mean that the amp will not properly power up without outputs or jumpers installed because of DC offset?
I haven't worked on many of these but the 500 will power up with no output transistors. This amp is virtually identical.
Are you sure that you're jumping the low side FETs?
With the low side jumped D-S, there should be no voltage on the drain or source of the L-S FETs.
Are you sure that you're jumping the low side FETs?
With the low side jumped D-S, there should be no voltage on the drain or source of the L-S FETs.
Perry there is 50 vdc on one drain location and 19 vdc on the other(low side).With no outputs installed.
I'm not sure at what point the 15 volt supply should start but it isn't.
With the outputs and rectifier(d300) removed.The amp takes at least 15 seconds to power up if that's what you want to call it.
Green light does not illuminate and the amp goes to full duty cycle.No current limiting in B+ line .13.4Vdc input.
And my 10 pin connector isn't getting -15.
I don't know exactly what should happen with outputs and or rectifier removed.
But I don't believe the power supply should goto full duty cycle.It must be drawing current from somewhere.
I'm thinking there are still problems in the preamp board and or preamp board area.
I honestly don't know a whole lit about these and it seems I have several issues and don't wanna kill you with 2000 messages.
I have no clue what to do next.
I'm not sure at what point the 15 volt supply should start but it isn't.
With the outputs and rectifier(d300) removed.The amp takes at least 15 seconds to power up if that's what you want to call it.
Green light does not illuminate and the amp goes to full duty cycle.No current limiting in B+ line .13.4Vdc input.
And my 10 pin connector isn't getting -15.
I don't know exactly what should happen with outputs and or rectifier removed.
But I don't believe the power supply should goto full duty cycle.It must be drawing current from somewhere.
I'm thinking there are still problems in the preamp board and or preamp board area.
I honestly don't know a whole lit about these and it seems I have several issues and don't wanna kill you with 2000 messages.
I have no clue what to do next.
With the rectifier out of the circuit, you can't have rail voltage on the drain of the high-side output so it's not clear whether you have the rectifier in the circuit or not. Is it in the circuit?
Is the 5v regulator producing 5v?
Is the 5v regulator producing 5v?
I'm sorry.The voltage on the drains of outputs is obviously with rectifier installed.
Yes, 5 volt regulator is working.
For what its worth.I bridged opamp u408.Installed low side jumpers.
Amp starts to draw current then backs off.Even touched remote them removed.
Terrible low side drive and zero high side drive.
I think I still have a problem with whatever components are needed for for the amp to properly start and get the main power supply going.
I may be wrong,wish I had another one here to see how they act with various parts removed.
Yes, 5 volt regulator is working.
For what its worth.I bridged opamp u408.Installed low side jumpers.
Amp starts to draw current then backs off.Even touched remote them removed.
Terrible low side drive and zero high side drive.
I think I still have a problem with whatever components are needed for for the amp to properly start and get the main power supply going.
I may be wrong,wish I had another one here to see how they act with various parts removed.
What do you mean by 'main supply'?
If the amp is producing rail voltage or has a square wave on the drains of the power supply FETs, the main supply is operating.
If the amp is producing rail voltage or has a square wave on the drains of the power supply FETs, the main supply is operating.
Why does the power supply goto full duty cycle with no load at 13 volts?
Should the green light come on with or without rectifier?
What keeps the aux supply from powering on?
Why is there excessive DC voltage on low side drains with FETs removed?
I figured it would be easier and save many messages if I just asked those questions in that fashion.
Maybe your answers will perhaps get me looking in a particular direction.
Should the green light come on with or without rectifier?
What keeps the aux supply from powering on?
Why is there excessive DC voltage on low side drains with FETs removed?
I figured it would be easier and save many messages if I just asked those questions in that fashion.
Maybe your answers will perhaps get me looking in a particular direction.
The green LED should come on when you have 12v on pin 13 of the PS driver board.
Again, full duty cycle with rectifier in or out?
If you have excessive voltage on the L-S drains with the jumper in place, you have a broken ground. The source leg of the L-S FETs is directly connected to ground.
Again, full duty cycle with rectifier in or out?
If you have excessive voltage on the L-S drains with the jumper in place, you have a broken ground. The source leg of the L-S FETs is directly connected to ground.
I do have 12 volts on pin 13 of pwm driver board.
Amp goes to full duty cycle with rectifier removed.
Rectifier and outputs are removed and u 408(pins1,2) is bridged.Low side drains to source also bridged.
Q404,407 high side
Q405,406 low side.
These voltages I don't know about and might tell you something.Reference to ground.
I can resintall the rectifier if this doesn't tell you anything.
High side gate pads. .3 vdc
q405 gate pad. 10vdc
Q406 gate pad. 1 vdc
Sorry if this info is worthless.Just seems odd to me because I'm unsure.
Amp goes to full duty cycle with rectifier removed.
Rectifier and outputs are removed and u 408(pins1,2) is bridged.Low side drains to source also bridged.
Q404,407 high side
Q405,406 low side.
These voltages I don't know about and might tell you something.Reference to ground.
I can resintall the rectifier if this doesn't tell you anything.
High side gate pads. .3 vdc
q405 gate pad. 10vdc
Q406 gate pad. 1 vdc
Sorry if this info is worthless.Just seems odd to me because I'm unsure.
It's going to full duty cycle because it sees no rail voltage. There can be no rail voltage without the rectifier in the circuit.
Did you check to see if you had continuity from the L-S source to the main ground?
Did you check to see if you had continuity from the L-S source to the main ground?
I have no voltage on the l-s drains now because there driven to ground because of the jumper.
Maybe I didn't specify completely.
The voltages I just gave you for the gates are with the jumpers installed and rectifier removed.
With the jumpers removed.
I have roughly 50 vdc on one l-s drain and roughly 20 on the other.There connected to the speaker terminals so of coarse I have 30 vdc offset which I'm guessing is keeping the amp from fully powering up.
With the rectifier installed,l-s jumpers installed,u408 pins 1and2 bridged.
There's no high side drive whatsoever.
The low side has extreme ringing.
I don't know where we got lost in the 50 messages but I apologize.
Maybe I didn't specify completely.
The voltages I just gave you for the gates are with the jumpers installed and rectifier removed.
With the jumpers removed.
I have roughly 50 vdc on one l-s drain and roughly 20 on the other.There connected to the speaker terminals so of coarse I have 30 vdc offset which I'm guessing is keeping the amp from fully powering up.
With the rectifier installed,l-s jumpers installed,u408 pins 1and2 bridged.
There's no high side drive whatsoever.
The low side has extreme ringing.
I don't know where we got lost in the 50 messages but I apologize.
Did I understand correctly that you confirmed that pin 1 and NOT pin 7 of U408 had a 1k resistor directly connected to it?
DC voltage on all pins of U408 and the LM319 nearest the 555 timer?
Also confirm that there is a triangle waveform on pin 5 of that LM319.
Also confirm that there is a triangle waveform on pin 5 of that LM319.
- Status
- Not open for further replies.