Hello.
Integrated amplifier HARMAN KARDON PM 635.
Strange problem.
Power on.The amplifier sounds clear, no problem. But after 1-2 minutes, the sound slowly disappears on both channels. After turning off for 10 minutes, the sound reappears for a few seconds and then slowly disappears again.
No bad soldering.
SM
HARMAN KARDON PM635 OWNER'S MANUAL Pdf Download | ManualsLib
Thank you.
Integrated amplifier HARMAN KARDON PM 635.
Strange problem.
Power on.The amplifier sounds clear, no problem. But after 1-2 minutes, the sound slowly disappears on both channels. After turning off for 10 minutes, the sound reappears for a few seconds and then slowly disappears again.
No bad soldering.
SM
HARMAN KARDON PM635 OWNER'S MANUAL Pdf Download | ManualsLib
Thank you.
Certainly sounds like the typical result of a HR soldered connection.
But you have eliminated that so------- next on my list would be a faulty resistor .
But you have eliminated that so------- next on my list would be a faulty resistor .
Check all the resistors for value.
Some might read oddly if in parallel with other devices.
My first stop is always a careful visual inspection. Look for bad soldered joints.
Check all connectors are tight.
Then start looking at voltages starting at power supply end.
Some might read oddly if in parallel with other devices.
My first stop is always a careful visual inspection. Look for bad soldered joints.
Check all connectors are tight.
Then start looking at voltages starting at power supply end.
Thats a good point by Nigel , if you are now saying ---"no sound at all " is the amplifier still powered up ?
Voltages are ( approx ) 38 volts+/- DC .
If no voltages then check fuses for HR connections.
Schematic available on HiFi engine.
Voltages are ( approx ) 38 volts+/- DC .
If no voltages then check fuses for HR connections.
Schematic available on HiFi engine.
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Amplifier power on.
The fuse is ok.
Service manual on Poste #1
Now the sound is very good,but after 1-2 minutes nothing
The fuse is ok.
Service manual on Poste #1
Now the sound is very good,but after 1-2 minutes nothing
Perhaps its time for the cold-spray or insulated poking stick? Somethings heat sensitive in there, could be a cracked pcb trace, dry solder joint, damaged component, the first step is track down the sensitive part...
What Mark was trying to point out was the logical engineering way to locate a fault like yours ,even TV engineers use spray or a heat gun to aim heat at different parts of a circuit to bring on the fault quicker.
Coolant spray can sometimes restore a faulty circuit long enough to locate the area of a fault but you seem pretty adamant that nowhere on your amplifier is faulty --yet you complain it cuts out and that I take it is with the power supply in good working order --yes ?
Clip on your meter to the plus and negative supply lines AT the OUTPUT --run your amplifier and watch your meter .
Try and remember we are working virtually not sitting at a workbench with a host of test equipment connected to your amplifier .
Coolant spray can sometimes restore a faulty circuit long enough to locate the area of a fault but you seem pretty adamant that nowhere on your amplifier is faulty --yet you complain it cuts out and that I take it is with the power supply in good working order --yes ?
Clip on your meter to the plus and negative supply lines AT the OUTPUT --run your amplifier and watch your meter .
Try and remember we are working virtually not sitting at a workbench with a host of test equipment connected to your amplifier .
So you really did resolder every joint? You did not? Than this is an assumption only
And did you do as I asked in post #12 ----- clip on your multi-meter to prove its not a power supply failure at the output supply to the output transistors ?
Cool the parts with a freezer spray.
Cool the parts with a freezer spray.
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