Are you still driving a signal into the amp?
Is the input level as high as it was?
Do you have signal reaching the driver board?
Did you do anything to the amp between the last time you had output on pins 7 and 12 and now?
Is the input level as high as it was?
Do you have signal reaching the driver board?
Did you do anything to the amp between the last time you had output on pins 7 and 12 and now?
Yes still driving a strong signal, the output on pin 7 is still present
yes i see the signal on the driver board
i might have installed the outputs after checking those pins, cant recall now...
yes i see the signal on the driver board
i might have installed the outputs after checking those pins, cant recall now...
below are input pins for output pin 12
pin 4
pin 5
pin 4
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pin 5
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Is there significant DC across the speaker terminals?
If yes, does the amp draw excessive current if you connect a dummy load to the speaker terminals?
Are the outputs in the circuit?
If yes, does the amp draw excessive current if you connect a dummy load to the speaker terminals?
Are the outputs in the circuit?
I see -1v on the positive speaker terminal
I don't have a meter to check the current draw
installed a pair fets per side
I don't have a meter to check the current draw
installed a pair fets per side
remove the outputs and if there is still more than a tiny fraction of a volt across the speaker terminals, connect a load to pull the voltage as close to 0v as possible.
Do the drive signals return?
To have drive out of the LM319, the voltage on pin 4 must fall between the top and bottom of the triangle waveform on pin 5. Having DC across the speaker terminals is likely what caused the offset on pin 4 of the 319.
Do the drive signals return?
To have drive out of the LM319, the voltage on pin 4 must fall between the top and bottom of the triangle waveform on pin 5. Having DC across the speaker terminals is likely what caused the offset on pin 4 of the 319.
While probing the board i shorted the below:
R919 - 15k resistor
zener diode - please help with value of this
R919 - 15k resistor
zener diode - please help with value of this
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The zener diodes have a DZ or ZD designation. This could be a standard 1N4148 type diode. See if you can find its corresponding diode on the following diagram:
http://rollmeover.com/bronco_fab/amps/autotek/mx1500/Dlogixs/dlogix_4500_sch.pdf
http://rollmeover.com/bronco_fab/amps/autotek/mx1500/Dlogixs/dlogix_4500_sch.pdf
I have the square waves on the emitters of Q902,903.
But still see them at gate pads on the outputs
But still see them at gate pads on the outputs
I removed the IRF7319
get the below on G1 and G2
is it possible the irf7319 has failed?
G1
scope setting
G1
G2
get the below on G1 and G2
is it possible the irf7319 has failed?
G1
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scope setting
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G1
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G2
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I think those are generally ±9v but since they're of equal value, they're likely OK.
Did you check the FET?
Did you check the FET?
Low side gate
high side gate
drains of the irf7319 (not seen on the drains of the fet pads - outputs are not installed)
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high side gate
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drains of the irf7319 (not seen on the drains of the fet pads - outputs are not installed)
An externally hosted image should be here but it was not working when we last tested it.
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