COBRA 142GTL SQUEALING
 

Can anyone help. I am stuck with this problem
In receive, when I turn the volume, it starts to squeal at around 70% ???

I tested a dozen of lytics around the AF power amp. Found C118 had hi ESR.
Replaced it , it still squeals the same. Tried it with a 8 ohms dummy load
and scoped it., same it squeals.
???
Thanks

"Réjean Mathieu" wrote in message
...
Can anyone help. I am stuck with this problem
In receive, when I turn the volume, it starts to squeal at around 70% ???

I tested a dozen of lytics around the AF power amp. Found C118 had hi ESR.
Replaced it , it still squeals the same. Tried it with a 8 ohms dummy load
and scoped it., same it squeals.
???
Thanks

Look for poor grounds, also scope the power supply around the audio chip,
could be an open supply bypass cap. Since the audio chip starts to pull some
power when you crank it up, it CAN get back into the 12 volt supply if a
bypass electrolytic is open.

rewire the mic dillhole
"Réjean Mathieu" wrote in message
...
Can anyone help. I am stuck with this problem
In receive, when I turn the volume, it starts to squeal at around 70% ???

I tested a dozen of lytics around the AF power amp. Found C118 had hi ESR.
Replaced it , it still squeals the same. Tried it with a 8 ohms dummy load
and scoped it., same it squeals.
???
Thanks

"K. Rogers" wrote:
rewire the mic dillhole

Which mic has a dillhole?

audio power supply not enough?
had the same thing with a audio section in a scanner. was a pass resister in
the dc power source. reisitor broke down under load, not supplying enough
current, started squeeling at high volume.



"Réjean Mathieu" wrote in message
...
Can anyone help. I am stuck with this problem
In receive, when I turn the volume, it starts to squeal at around 70% ???

I tested a dozen of lytics around the AF power amp. Found C118 had hi ESR.
Replaced it , it still squeals the same. Tried it with a 8 ohms dummy load
and scoped it., same it squeals.
???
Thanks