hi
Turning the trim pot has no effect on clarity of signal.
This scope goes no higher than 10V/div.
That was the setting in last photos.
I adjusted the trace as instructed.
The hot side breifly shows a wave, but it disappears in half a second..😕
Let me know what next step is, if I need to get a better scope I will.
It will take some time though..
paul
Turning the trim pot has no effect on clarity of signal.
This scope goes no higher than 10V/div.
That was the setting in last photos.
I adjusted the trace as instructed.
The hot side breifly shows a wave, but it disappears in half a second..😕
Let me know what next step is, if I need to get a better scope I will.
It will take some time though..
paul
Did you find both the astigmatism and the focus controls?
The scope is probably good enough.
Does the outer v/div control go to both extremes and does it line up with the last markings on both extremes?
The scope is probably good enough.
Does the outer v/div control go to both extremes and does it line up with the last markings on both extremes?
Burn-in procedure in-car?
Success!
Because of setting up the scope correctly (well more correctly), I was able to find a bad 9640.
It was opening up and fading out and doing weird stuff that the others were not.
That was not easy to find, and this was probably not a good 'first amp' with no real experience using a scope.
I replaced the fet, amp is idling cool now.
I am wondering what burn-in procedure to use, or if that's only for a repair for somebody else's amp..
I have less than 25 amp power supply on bench, so it will need to be done in the car.
Thanks again Perry,
paul
Success!
Because of setting up the scope correctly (well more correctly), I was able to find a bad 9640.
It was opening up and fading out and doing weird stuff that the others were not.
That was not easy to find, and this was probably not a good 'first amp' with no real experience using a scope.
I replaced the fet, amp is idling cool now.
I am wondering what burn-in procedure to use, or if that's only for a repair for somebody else's amp..
I have less than 25 amp power supply on bench, so it will need to be done in the car.
Thanks again Perry,
paul
If it's yours, reinstall it and use it. I'd suggest using three 25 amp fuses (three 20s may be enough). It doesn't need three 40 amp fuses. The 25 amp fuses will help reduce the damage if something fails. If you blow the fuses, reinstall ONE 15 amp fuse and power it up. If the single 15 amp fuse blows (no audio), the amp has failed again.
If the defective transistor was recently replaced, it may have been damaged by static discharge. It's not a problem for areas where the humidity is relatively high but where it's cold or where the humidity is low, static electricity can damage the insulating layer between the gate and the rest of the FET. It's recommended that techs handling FETs wear anti-static wrist/ankle straps to prevent static buildup.
If the defective transistor was recently replaced, it may have been damaged by static discharge. It's not a problem for areas where the humidity is relatively high but where it's cold or where the humidity is low, static electricity can damage the insulating layer between the gate and the rest of the FET. It's recommended that techs handling FETs wear anti-static wrist/ankle straps to prevent static buildup.
okie dokie.
ESD is what fried the amp fixing it this last time.
Thanks for tip on those 40's, they do seem ridiculous. 3 20 fuses I will try first.
I am driving this into a 4ohm load/ported enclosure, so I won't be hammering this amp much at all.. at least at first.
I will report...
paul
ESD is what fried the amp fixing it this last time.
Thanks for tip on those 40's, they do seem ridiculous. 3 20 fuses I will try first.
I am driving this into a 4ohm load/ported enclosure, so I won't be hammering this amp much at all.. at least at first.
I will report...
paul
I,m sorry, I consider to post because is the similar problem I have this exact amp and the psu driver transistors are blown a1266, what do you think about replace this with a1023?..... I have in hand, if this is not a good idea i could get a1266, I asked about this because i have repairef another class d amps use in their psu a1023 as transistor drivers.
Thank you
Thank you
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Please don't post in a repair thread that was started by someone else unless you are trying to help them.
Start a new thread if you need help with a repair of your own.
Start a new thread if you need help with a repair of your own.